- الرئيسية
- وقائع المؤتمر
- QScience Proceedings
- وقائع المؤتمر
The 4th International Whale Shark Conference
- تاريخ المؤتمر: 16-18 May 2016
- الموقع: Doha, Qatar
- رقم المجلد: 2016
- المنشور: ١٥ مايو ٢٠١٦
67 نتائج
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Butanding Network's whale shark awareness conservation efforts and challenges in the Philippines
المؤلفون: Elson Q. AcaBackground The Philippines is an archipelagic country consisting of 7,107 islands with 36,289 kilometers of discontinous coastline. 14 out of 15 administrative regions (or 93%) are coastal regions, 62 out of 80 provinces (or 78%) are coastal provinces, while 832 out of 1,496 municipalities (or 56%) are coastal municipalities. It was estimated that the total coastal population will reach 73.3 million by 2011. Approach Initial awareness efforts through dialogue and lectures targeted staff of the regional offices of the Bureau of Fisheries and Aquatic Resources (BFAR), who has the mandate for the protection of whale sharks in the country through the Fisheries Administrative Order 193 (series of 1998). However, in 2010, through Administrative Order 282, several agencies were included in intensifying the protection of whale sharks, including the Department of Environment and Natural Resources (DENR), local government units (LGUs) and the academe, which become additional agents of the awareness campaign. Posters were distributed in areas visited to make the information more visible in the government offices and coastal areas. A website called Butanding Network (www.butandingnetwork.net) was created, and later converted to a page in the social media, to target people that are active in cyberspace. For the kids, awareness were done through storytelling sessions in schools and some public establishments. Collaborations were established with other non-governmental organizations (NGOs) and television shows to act as a resource speaker for whale shark information. Results 13 of the 14 coastal administrative regions were visited, of which either or both the BFAR and DENR regional offices were informed and encouraged to disseminate whale shark knowledge to their coastal jurisdictions. 15 State Universities and colleges (SUCs) around the country with biology, marine biology, environmental science and/or fisheries courses were encouraged to delve into whale shark research in their coastal waters. Children, ages ranging 6–12, were able to attend story telling sessions on 10 different occasions in 6 different locations. Whale shark related issues were relayed to the public through social media, television shows and documentaries. Conclusions The archipelagic nature of the Philippines makes it difficult to spread awareness in the country. The government agencies mandated to protect and conserve the whale sharks don't have a structured program for spreading awareness, and do not see conservation as a priority. Whale sharks and other large marine animals were not included or only discussed briefly in biology/marine biology/fisheries courses topics. Social media, television shows and documentaries are great ways to reach a larger audience, however, there is a need to standardize the contents and how it is presented to prevent misinformation of the public.
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On their way to pupping grounds?: Unprecedented parade of large female whale sharks at Darwin Island, Galapagos Marine Reserve
Background The Galapagos Whale Shark Project is a multi-institutional effort initiated in 2011 with the aim to characterize the presence, population structure and movement patterns of whale sharks within and around the Galapagos Marine Reserve. This specific study aimed to understand their occurrence, residency and habitat use around Darwin Island, located at the northern tip of the Galapagos Archipelago, where large individuals had been reported to be seasonally abundant. Approach This study followed a diversified methodology approach that included: analysis of a local underwater visual census database of pelagic species (2007–2013) to establish seasonality in their occurrence; specific whale shark surveys (2011–2013) to collect information about shark's size (laser photogrammetry), sex, behavior and signs of potential pregnancy; photo-ID records (2011–2013) obtained during these surveys to determine residency and abundance; and the deployment of acoustic tags for continuous tracking around Darwin Island to assess habitat use at the study site. Results Whale shark presence at Darwin Island follows a seasonal pattern. During the cool season (July–December), a strongly female-biased whale shark population, composed mostly (91.8%) by large individuals (11.35 m ± 0.12 m (TL ± SE)), pass through the study site. The great majority of these individuals show clear distended bellies, which could be a sign of a potential pregnancy. Population dynamics models for these apparently pregnant sharks estimated the presence of 3.76 ± 0.90 (mean±SE) sharks in the study area per day with an individual residence time of 2.09 ± 0.51 (mean±SE) days. Assuming constancy in these rates for the entire cool season, we can estimate a net abundance of 695 ± 166 (SE; 95%CI 442–1110) apparently pregnant whale sharks per season. Movement patterns analysis of four apparently pregnant individuals revealed an intense use of Darwin's Arch, where no feeding or specific behavior has been recorded or could be inferred from their dive profiles, together with periodic excursions around the island's vicinity. Sharks showed a preference for intermediate depths (20–30 m) with occasional dives mostly to mid-water, remaining the majority of their time at water temperatures between 24–25°C. Conclusions The lack of evidence of specific behavior observed at Darwin Island, together with the short residence time and strong intra-seasonal abundance and high turnover rate, indicate that this location is not an aggregation site but an important stopover in a migration. In the case of adult R. typus individuals observed, this migration might involve reproductive purposes, as all but one were apparently gravid.
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Establishing the ecological connectivity of whale shark aggregations across the Indian Ocean – a photo-identification approach
Background The seasonal aggregations of whale sharks that occur at coastal sites throughout the tropics are the focus of growing ecotourism industries. Genetic and modelling studies suggest that these aggregations may be linked by migration, although the temporal and spatial scales at which this occurs is unknown. Here, we utilized a continuously expanding photoidentification database collected by citizen scientists and researchers to assess connectivity and residency patterns of five whale shark aggregation sites across the entire Indian Ocean at timescales of up to a decade. We also investigated the effectiveness of such an approach in detecting different levels of migration given the population size at each aggregation site. Approach We used the semi-automated program I3S (Individual Interactive Identification System) to compare 6,519 photographs of the unique natural marking patterns of individual whale sharks collected from aggregations at Mozambique, the Seychelles, the Maldives, Christmas Island (Australia) and Ningaloo Reef (Australia). We searched the database for matches between aggregations (migration) and matches between years within aggregations (residency). A Monte Carlo simulation approach utilizing population sizes of aggregations reported by previous studies was used to examine the sample sizes that would be required to reliably detect varying levels of migration rates among four of these aggregations. Results We found no evidence of connectivity of whale shark aggregations at ocean-basin scales within the time frame of the study, and evidence for only limited connectivity at regional (100s–1000s km) scales. A male whale shark sampled in January 2010 at Mozambique was resighted eight months later in the Seychelles and was the only one of 1,724 individuals to be photographed at more than one site. On average, 35% of individuals were re-sighted at the same site in more than one year. The Monte Carlo simulation study showed that the power of this photo-identification approach was strongly dependent on both the number of individuals identified in aggregations each year and the size of resident populations. The simulation also indicated that there was a higher chance of detecting migrants (if they were present) in aggregations at Ningaloo Reef and the Maldives than the Seychelles and Mozambique given the current numbers of individuals identified each year. Conclusions The weight of evidence from both our photo-identification study and previous tagging studies suggests regional or small-scale movements (10–100s km) may be more common in whale sharks than movement at ocean-basin scales. We recommend that the management of whale sharks in the Indian Ocean occur at regional scales, and photo-identification databases are expanded to include additional sampling sites within each region.
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Temperature-depth-recorder tags reveal modified diving behaviour by whale sharks at a provisioning site in Cebu, Philippines
المؤلفون: Gonzalo Araujo, Jordan Thomson, Jessica Labaja, Sally Snow, James Montgomery and Alessandro PonzoBackground Whale shark tourism is increasingly popular at coastal predictable aggregations around the world. However, only one description accounts for provisioning of whale sharks (Rhincodon typus), which is at Oslob, Philippines, where sharks are provisioned between 6 am and 1 pm daily within a demarked tourist interaction area. Understanding the potential effects of provisioning on the behaviour of this species is important for their conservation. Approach To investigate whether whale shark diving behaviour was affected by the provisioning, four whale sharks with known extended residency at the study site were tagged with CEFAS G5 temperature-depth-recorder (TDR) tags. Three individuals were juvenile males with estimated total lengths of 4.5, 5.0 and 6.5 m (P-432, P-480 and P-403 respectively), and a fourth individual was a juvenile female measuring 5.5 m (P-385). A Hawaiian-sling spear pole was used to deliver stainless steel anchors with a tether carrying a swivel 10 cm into the subdermal layer of the whale sharks on the ventral side between the first dorsal fin and the first lateral ridge. Three TDR tags were randomly deployed amongst the individuals over a period of 18 months. Linear mixed effect models were used to test how attendance at the provisioning site affected shark depth use and variability. Results Tags were deployed for an average duration of 49.5 provisioned days (sharks present daily at the site) and 33.8 non-provisioned days (sharks were absent from the site). The deepest dive was recorded by P-403 to 1,251 m, at a minimum temperature of 12.1 °C. The tags revealed a pronounced shift in habitat use by individuals when away from the provisioning site. Specifically, during provisioned days, time spent at the surface (0 – 2 m) between 6 am and 1 pm was ca. six times longer than during non-provisioned days. During provisioned days, deep dives occurred mostly near or at the end of the provisioning activities (i.e. 10 am to 2 pm), whereas on non-provisioned days, deep dives occurred mostly between 4 am and 10 am. This shift could suggest that whale sharks have a need to thermoregulate following a prolonged period of time at the surface where temperatures regularly exceed 31 °C. Conclusions The use of TDR tags on whale sharks revealed modified diving behaviour at Oslob, a unique provisioning site. This behavioural modification should be considered when developing guidelines for sustainable tourism and conservation measures for the species.
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Daily abundance and residency patterns of whale sharks (Rhincodon typus) at a unique provisioning site in the Philippines
المؤلفون: Jordan Thomson, Gonzalo Araujo, Jessica Labaja, Emer Mccoy, Ryan Murray and Alessandro PonzoBackground Shark viewing tourism is a burgeoning global industry. Numerous operations provision sharks to increase sightings yet the effects of provisioning on shark behaviour are often poorly understood. At a unique provisioning site in Oslob, Cebu, Philippines, whale sharks (Rhincodon typus) have become the focus of a mass tourism operation since late 2011, receiving over 185,000 tourists a year. Approach To better understand and advise management bodies on the effects of provisioning on these animals, we used photographic identification (photo-ID) to assess the daily abundance and site visitation patterns of the sharks. Principal coordinate analysis (PCoA) based on co-occurrence matrices was used to investigate visitation patterns amongst individuals and define groupings. Modified maximum likelihood methods were then used to model mean residency for these different groups. Results Between March 31st 2012 and March 31st 2015, we identified 209 (165 males, 34 females and 10 of unknown sex) individuals at the site (a 0.065 km2 demarked area located 50 – 100 m from shore), with an average of 12.4 (SD = ± 4.8, range = 2 – 31) sharks sighted per day. Daily shark abundance increased over time and showed strong seasonal variation, with annual peaks occurring between May and November. We documented a spectrum of site visitation patterns ranging from single sighting (21% of sharks identified) to year-round residency (5% of sharks identified). For frequently sighted sharks, PCoA revealed two primary residency groupings: highly resident sharks (N = 9), which were seen year-round with few prolonged absences, and seasonal sharks (N = 21), which were primarily present between May and November. The daily abundance of highly resident sharks varied nonlinearly over time with no clear trend, while the daily abundance of seasonal sharks showed a clear increase during peak season in each year of the study. Mean residency for highly resident sharks was estimated at 55.5 ± 175.5 SE (95% CI 49.5 – 730.0) days, 58.3 ± 161.7 SE (95% CI 23.2 – 81.4) days for seasonal individuals, and 16.8 ± 1.8 SE (95% CI 14.8 – 22.2) days for infrequent sharks (N = 130). Conclusions The difference in residency patterns between frequently sighted and infrequent individuals was almost fourfold. This shift in residency could have long-term implications for ca. 15% of identified whale sharks at the site. We provide insight into the impacts of provisioning on shark movements and inform the debate surrounding the future of this controversial activity.
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Testing the affinity of whale sharks, Rhincodon typus, to offshore oil platforms in a newly discovered aggregation site off the cost of Qatar in the Arabian Gulf
المؤلفون: Steffen S. Bach, David P. Robinson, Ali A. Abdulrahman and Mohammad Al-JaidahBackground A large aggregation of whale sharks in the central part of the Arabian/Persian Gulf has recently been documented by the Qatar Whale Shark Research project. Observations made by offshore workers have indicated a continuous presence of whale sharks close to platforms in the Al Shaheen oil field during the summer months. It has been established that the sharks come here to feed on fish eggs of the Mackerel tuna, Euthynnus affinis. The Al Shaheen location is characterized by numerous offshore platforms that could attract the spawning Mackerel tuna and thereby influence the numbers and distribution of whale sharks in the area. Understanding the movement and residency patterns of whale sharks is critical for their management, particularly in an offshore oil field. Approach In the period from 2012–2015 a total of 104 whale sharks were fitted with acoustic V16 tags. The sharks were all tagged in the Al Shaheen oil field during the aggregation period from May to September and ranged in size from 4 to 10 meters TL. The movement pattern of sharks within the Al Shaheen field was monitored using an array of up to 15 VR2W receivers placed a minimum of 4 km apart. The receivers were placed on the seabed at different distances from selected offshore installations and recovered using remotely activated releases. Results Of the 104 tagged sharks, 102 were detected by the deployed receivers during the study period. The maximum detection distance was estimated to be between 500–1000 m from the receiver. More than 99% of the detections occurred between the months of April–September. Average annual residence time in the Al Shaheen area was 38.5 days (±27.5 SD) with some sharks showing a continued presence during the entire April–September period. Conclusions The results indicate that the whale sharks are almost only present in the Al Shaheen area during the April–September period, confirming the visual observations made by workers on the offshore installations. Aggregations, sometimes numbering more than 100 individuals, have only been observed while the whale sharks were feeding on Mackerel tuna spawn. The long residence time indicates that the Al Shaheen area is a highly important feeding ground. The sharks showed a high affinity for the same platforms throughout the study period, while their presence was only rarely recorded at other platform locations. This could indicate that the Mackerel tuna are spawning in a confined location within the study area and that the whale shark distribution within Al Shaheen is strongly associated to the spawning site and the prevailing currents. The platforms themselves may concentrate whale shark presence in the spawning area, but their full importance for the behavior of whale sharks is still to be determined. Mitigating measures have been established in order to minimize potential impacts on whale sharks related to offshore activities.
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An overview of whale shark movement ecology projects in the Red Sea Research Center
المؤلفون: Michael L. BerumenBackground The Red Sea Research Center is part of a relatively new university on the Saudi Arabian Red Sea coast, the King Abdullah University of Science and Technology (KAUST). KAUST officially opened in 2009 but began global collaborative research projects in 2007. Among the early discoveries arising from these collaborative projects was the identification of a whale shark aggregation site in the Red Sea. KAUST researchers have been studying this aggregation site since 2008. Approach KAUST researchers have employed various methods and technologies to track whale sharks, including acoustic tagging, satellite tagging technologies, genetics, and some technologies integrating the use of autonomous vehicles. Our whale shark studies include determining the population demographics of the sharks visiting our sites, the site fidelity of the sharks, and any potential connections with populations outside of the Red Sea. In 2012, KAUST began a collaborative effort with colleagues in the Marine Megafauna Foundation to study a whale shark aggregation at Mafia Island, Tanzania. Results The results from our movement studies highlight the pros and cons of various methodologies, and overall emphasize the importance of using multiple methods simultaneously to maximize the clarity of results. In Saudi Arabia, the whale sharks are very near to 50% male and 50% female, unusual compared to most aggregations. Satellite tracking suggests that the Saudi sharks migrate away from the site in the “off-season” and some are confirmed to have left the Red Sea. However, the majority of the sharks remain within the southern half of the Red Sea. Acoustic tracking of whale sharks at Mafia Island, in Tanzania, shows unexpected cryptic residency with many sharks being detected year-round despite a clear seasonal pattern in the sightings of whale sharks in boat-based surveys. These and brief summaries of our findings from other methods will be discussed. Conclusions The results from the Saudi aggregation are strikingly different from results of an aggregation we have been studying at Mafia Island, Tanzania. Future studies of plankton dynamics and fine-scale analysis of whale shark behavior may reveal fundamental differences in the sites that explain these differences in residency. Many emerging technologies hold great promise for improving our ability to learn more about the world's largest fish.
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Communities and corporates for conservation: A decade of conservation effort to save whale shark. Success story from Gujarat, India
المؤلفون: Farukhkha Bloch, P.V.R. Premjothi, Manoj Matwal, Diresh Joshi, S Goutham, Praveen Kumar, B.C. Choudhury, Rahul Kaul, Vivek Menon and Sajan JohnBackground Prior to 2001, due to the lack of legal protection, whale sharks were brutally and extensively hunted across the shores of Gujarat state in western India. Wildlife Trust of India (WTI) actively lobbied the Ministry of Environment and Forests (MoEF), Government of India, for legal protection of the species by placing it in Schedule I of the Wildlife (Protection) Act, 1972. Approach A brief survey during 2004 along the coastal town of Veraval, the hub of the whale shark slaughter, revealed a low awareness level (19%) of poaching and the protection status of whale sharks among the fishers. Following the survey, WTI launched a large-scale whale shark awareness campaign in 2004, with a special focus on Veraval, with the funding support of Tata Chemicals Ltd (TCL), which led to the training of 1500 fishers into an organised information providing network. Results The whale shark campaign spread awareness on the plight of the species and its protected status in Gujarat. The campaign not only helped convert Gujarat fishermen into protectors of the whale shark by bringing about a major change in the perception and attitude of local people, but also helped in local protection of the species. As a result of the campaign, seven coastal towns adopted the whale shark as their city mascots. The campaign led to a model relief programme that offered monetary support to fishers whose nets were damaged or had to be cut open during the rescue and release of whale sharks. To speed up the release and reduce stress on the sharks, a self-photo documentation process of whale shark rescue for fishers was started. 1200 waterproof cameras were distributed to fishers to document the rescue and release of whale sharks. The captured images of a rescue by fisher folk served as evidence to prove the damage to nets. The photos also helped fishermen claim financial relief from the government scheme to repair/replace nets. From its inception until 2015, 571 whale sharks had been rescued and voluntarily released by fishers with not a single record of whale shark slaughtering. To further strengthen the whale shark conservation activities among fishers, fourteen “Vahlino Mitro” clubs (Vahlino Mitro =Friends of whale sharks) were registered in the fishing villages of Veraval and Mangarol (seven clubs each), with an objective of motivating fishers to fish in a whale shark friendly manner, and to make coastal school children understand the importance of coastal ecosystems and involve them in action based programmes related to whale shark conservation. This project has won several conservation laurels. These include the Bombay Natural History Society (BNHS) Green Governance Award in 2005, the Gujarat Ecology Commission (GEC) Award during 2012 and the UNDP Indian Biodiversity Award to the Gujarat Forest Department for co-management in 2014. Conclusions The whale shark conservation project with the support of fishing communities and corporate house has stopped the killing of whale sharks along the Gujarat coast. The project also instilled a sense of pride among fishing communities along Gujarat coast and ongoing annual International whale shark day celebrations and Gujarat whale shark celebrations are keeping the whale shark conservation message alive among the communities and coastal school students.
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Inferring feeding habits of the whale shark (Rhincodon typus) using fatty acids, in the Northern Mexican Caribbean
Background In the Mexican Northern Caribbean, whale sharks feed on abundant plankton. Assessing the trophic role of this species is key to understanding its general ecology. Non-lethal sampling combined with biochemical methods such as analysis of fatty acids (FA) are promising approaches for investigating the assimilated diet of the whale shark. Approach During 2010 and 2011, a total of 68 whale shark samples (dermal tissue) were collected from free-swimming individuals while they were feeding. Zooplankton samples were collected near feeding whale sharks at the surface. These samples were divided in two categories: mixed zooplankton - several groups of zooplankton, and fish eggs - more than 95% of sample components were fish eggs. FA profiles were assessed from biopsies and zooplankton. ANOSIM was performed to identify the level of significant difference among the different groups of FA composition. Non-metric multi-dimensional scaling (MDS) plots were used to visualize grouping among whale sharks, zooplankton and fish eggs FA profiles. Results The FA profiles of R. typus and their potential prey were dominated by saturated FA. Whale shark FA profiles were significantly different from mixed zooplankton items (ANOSIM R value= 0.87). Fish egg and whale shark FA profiles formed separate groups with overlapping values (ANOSIM R value= 0.67). Whale shark and fish egg FA profiles registered high levels of oleic acid. Arachidonic acid (ARA; mean + SE=8.3+0.8) was the polyunsaturated fatty acid present at the highest level in the whale shark FA profile. These levels did not match the levels of mixed zooplankton and fish eggs. Conclusions The FA profile of the whale shark differs from other zooplanktivore animals whose profiles are usually dominated by polyunsaturated fatty acids. Results of the FA analysis suggest that R. typus is feeding mainly on near surface zooplankton. This is supported by whale shark behavioral observations and low levels of bacterial FA in R. typus profiles. The fact that levels of ARA registered in superficial zooplankton did not explain the ARA content found in biopsies suggests that the whale shark could have other complementary feeding sources, such as demersal zooplankton, in this aggregation area.
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Distribution and feeding habitat characterization of whale sharks Rhincodon typus in the Northern Mexican Caribbean
Background The conservation of whale sharks, like other endangered species, requires, among others factors, an understanding of the effects that variability in habitat have on long-term species viability. In the Mexican Northern Caribbean, a Habitat Monitoring Program for the whale shark was established in 2005 to describe the spatio-temporal variability of environmental data and whale shark distribution. Approach From 2005–2014, when whale sharks were present in the region (May to September), monthly trips were made to record whale shark sightings and hydrological data (sea surface temperature, salinity and dissolved oxygen). Water samples were collected to determine nutrients (nitrite, nitrate, ammonium, silicates and phosphates), as well as chlorophyll-a (Chl-a) and zooplankton biomass. We compared the environmental variables at sites with and without whale sharks present. Maps of zooplankton biomass were produced for each year in order to explore their relationship with the distribution and abundance of whale sharks. Results Areas with high whale shark abundance have been identified inside the study region. At these sites the whale shark feeds, taking advantage of the abundance of zooplankton, as a result of two events: the intensity of the Yucatan upwelling and the presence of dense masses of fish eggs. The whale shark aggregation areas influenced by the upwelling were characterized by high Chl-a concentrations (mean±SE 0.9±0.4 mg/m3), high nutrients and mixed zooplankton in which several groups were present (usually copepods were the most abundant group). In the whale shark aggregation area called “Afuera”, the zooplankton samples were dominated by fish eggs. This area registered significantly higher zooplankton biomass (mean±SE 3356.1±1960.8 mg/m3) in comparison with that recorded in upwelling areas (mean±SE 103.5±57.2 mg/m3). Zooplankton biomass was the most influential environmental variable to determine whale shark abundance, supporting the close relationship between this species and their food availability. Spatio-temporal changes in distribution and abundance of whale sharks have been recorded in the region, as well as changes in their food availability. Conclusions The whale shark uses selected areas within the Mexican Caribbean. These areas have different hydrobiological characteristics. Changes in distribution and abundance of whale sharks inside the study area may make it more difficult to implement suitable management strategies. We need more data to understand the reason for these changes, for example increased knowledge about the ocean circulation patterns at this site and other factors that may influence and characterize spawning inside the aggregation area. The continuity of hydrobiological monitoring is key to ensure the integrity of this critical habitat.
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Further evidence of the importance of St. Helena as habitat for whale sharks
Background Remote oceanic islands may play important roles in the life history of whale sharks; they have been hypothesized to be the site of mating or pupping in this species. One such island is St. Helena in the South Atlantic, which was recently discovered to play host to a seasonal population of adult male and female whale sharks. Approach Two collaborative expeditions have been conducted to St. Helena since the 3rd International Whale Shark Conference. The goals of these were: to document whale shark abundance and population composition, to characterise behaviour and habitat use around the island, and to determine regional scale movement patterns using satellite telemetry. Results The whale shark population observed at St. Helena consisted of an approximately equal mix of mature males and females. The animals were 8.5–11 m in length, i.e. larger than the sub-adults seen in most coastal aggregation sites, but smaller than the large female animals seen regularly in the Galapagos. Two reliable eyewitness accounts of mating behaviour have been recorded at St. Helena, but we have not directly observed this behaviour during the expeditions. An acoustic array was deployed around the island in January 2016 to determine local habitat use patterns, but data are not expected to be available from this effort until the end of 2016. Conclusions Preliminary satellite telemetry results suggest that St. Helena whale sharks travel to the west coast of Africa, not to the east coast of South America. We propose that regional movement patterns are similar to those observed in the eastern Pacific, with animals apparently feeding in coastal upwelling zones, and travelling to remote oceanic islands to fulfill aspects of the reproductive cycle. Environmental regulations have recently come into effect that completely protect the whale shark in waters surrounding St. Helena.
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Population structure of a Red Sea whale shark aggregation
Background The Red Sea has received little study when compared to other areas. This holds true for sharks in general and for whale sharks in particular. The discovery of a seasonal aggregation off the Saudi Arabian coast has made the targeted study of Red Sea whale sharks more feasible. Assessing the size and structure of this aggregation is a first step toward understanding the basin-scale population within the Red Sea and how that population fits into the wider Indian Ocean. Approach Photo-ID records were collected from 2010 through 2015. These were analyzed and fit to several population models. The most parsimonious model was then used to describe the aggregation. Demographic data, including the size and sex of individual sharks was collected and compared to reports from other aggregations. Size was visually estimated to the nearest half-meter and sex was determined by the presence or absence of claspers between the pelvic fins. Results From 2010 to 2015, 305 encounters with whale sharks were recorded within the aggregation. From these, 267 suitable photos were used to identify 136 individuals. Sharks were divided evenly between the sexes and the distribution of sightings showed no evidence of sexual segregation. All individuals were immature based on size estimates and, in males, juvenile clasper morphology. An open population model was found to best represent the data and estimated a daily abundance between 15 and 34 whale sharks during the aggregation season, with local residence times ranging from 4 to 44 days. Residence times away from Shib Habil ranged from 15 to 156 days with a permanent emigration/mortality rate between 0.07 and 0.58 individuals per year. Conclusions These results are broadly similar to those from other aggregations of R. typus, although the observed sexual parity and integration found at this site are unique for the species and need further study.
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Tracking whale shark movements in a southern Maldivian atoll: An opportunistic feeder or reliant on the local fishing industry?
المؤلفون: Francesco G. Comezzi, Hamish Taggart, Samantha D. Reynolds and Bradley M. NormanBackground Whale sharks (Rhincodon typus) are generally sighted during daytime. In the southern atolls of Maldives they are instead sighted primarily at night inside the atoll. Tuna fishermen attract baitfish with a strong halogen lamp, creating substantial plankton concentrations. Whale sharks opportunistically feed near the surface under fishing boats anchored in a 40 m deep lagoon, often disturbing bait collection. This unique occurrence is well known locally but not internationally and it has yet to be the focus of a targeted research program, due in part to the remoteness of the area. This study aims to provide preliminary answers for the following question: Are whale sharks simply moving through Thaa Atoll or do they remain inside for an extended period? Approach Two sharks were tagged in December 2015, while feeding at night under the light of fishing boats inside Thaa Atoll. Wildlife Computers SPOT 5 satellite tags, secured via non-invasive fin clamps, were deployed on the first dorsal fin of two sharks to monitor their geographic movements. This pilot tagging project was undertaken in conjunction with a photo identification study (using Wildbook for Whale Sharks), to compare to other photo ID data collected during other sighting events before and after tagging. Results The first shark (M-109) retained the tag for a period of 25 days, and appeared to remain inside the atoll during this period. Frequent movements within the atoll were recorded, up to 20 km over a 24 h period. M-109 was regularly recorded at the northeast area within the atoll, near a consistent baitfish collection ground where this individual was originally tagged. However, on occasion, M-109 was recorded far from bait collection areas and/or during rough nights with no fishing activity, suggesting natural surface feeding behavior. Despite no data forthcoming from the second tagged shark (likely because of tag dislodgement through interaction with fishers nets), this individual was resighted (confirmed through photo-identification) feeding under fishing nets, at a similar location to the first sighting, 22 days later. Conclusions 1) Satellite data, for M-109, and photo-identification data, for the second shark, confirmed both sharks inside the atoll over a 25 and 22 day period respectively, leading to the possibility of an extended stay throughout the Maldivian dry season. 2) Tagged whale shark M-109 was confirmed via satellite uplinks inside Thaa Atoll on 24 of 25 days for which we have data, suggesting it did not leave the atoll during the 25 day monitoring period. M-109 showed extensive movement within the atoll, far from bait collection areas, suggesting that local fisheries may not be the only source of food exploited by whale sharks. While the results are preliminary, the next phase of research in this potential seasonal whale shark sanctuary will focus on: establishing the frequency of fisher/shark interactions within Thaa Atoll; productivity/plankton studies inside the atoll; an increased number of whale sharks satellite-tagged; expansion of photo-identification work. This study represents the first whale shark tagging study officially recognized and permitted by the Maldivian government and it was performed under governmental supervision. It represents a milestone for the future of whale shark tracking research in the country.
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Scarring estimation in the largest whale shark aggregation
Background Ch'ooj Ajauil AC, a non-profit organization created in 2010 involving tour operator and external research collaborations, is devoted to monitoring and preserving marine pelagic life in the Mexican Caribbean. The organization explored the question, how many whale sharks are been damaged by tourism boats? Approach Six years of methodic registration of scars, injuries and abrasion on whale sharks, using video and photographs, conducted by 3 snorkelers alternating with up to 5 surface observers on board a research boat, along 150 transects, observing 1336 whale sharks, in waters off north east Isla Mujeres, México, where the largest aggregation has been reported. Results Whale shark tourism began over 15 years ago in north Quintana Roo, México on the north east coast of the Yucatan peninsula. Tour operators have been stigmatized as the ones responsible for whale shark injuries, regardless of the multiple other boats transiting the area, including commercial fishers, private yachts and huge vessels. Scars on whale sharks come from many sources including other shark bites and smack and graze, but the most conspicuous ones are propeller cuts and mutilations, mostly on the dorsal fins and body. It is hard to determine geographically where an injury happened, or when. Previous reports on the same population at a different zone, estimated between 13 – 33% of total sharks as injured. There have been statements from the public observers suggesting that up to 50% of the sharks show some kind of scars. This shark meta-population moves into other areas across a large region, including the Gulf of Mexico, the Caribbean Sea and open Atlantic waters. Actual estimations indicate that 29.64% of the whale sharks show some kind of abrasion, including healed and old scars; while less than 5% presented fresh injuries per year. Conclusions No avoidance behavior toward boats was observed from the scarred sharks or from the freshly injured, but the latter were found to be more cautious around snorkelers. Whale sharks with fresh propeller cuts did not modify their site fidelity. Boating enforcement should be improved in order to keep damage to the species at lowest rate possible. A note on healing and recovery is given to document the rapid process of this on some animals.
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Preliminary observations on whale sharks in Nosy Be, Madagascar
Background The northern Mozambique Channel is a global hotspot for whale shark sightings, based on observer records from the tuna purse-seine fleet and published literature. Nosy Be Island (NW Madagascar) hosts a flourishing marine tourism industry based on viewing whale sharks and other species. Following reports of declining sightings in other regional hotspots, such as Tofo in Mozambique, it is important to establish if these declines represent a simple shift in aggregation site, or a broader reduction. Approach Data on population structure were also collected during a preliminary field season from August to December 2015. Results Approximately 200 sightings were recorded by a single operator during 2015. Preliminary analysis indicates that the majority of whale sharks sighted were males of lengths between 3 and 10 meters. Most whale shark sightings were from October to December. Conclusions Regular whale shark sightings occur off the Nosy Be area from August to December. Limited sex and size data suggests a juvenile male-biased aggregation where whale sharks were most commonly observed traveling and feeding on copepods. New data will help to establish whether oceanographic variability has resulted in a shift in abundance to Madagascar, or whether a broad-scale decline has taken place. No species-level legislation protects whale sharks in Madagascar, and the whale shark tourism industry is presently unregulated with regard to interactions. Further work on the population ecology, movements and social importance of whale sharks in the country is justified and will inform the development of effective conservation and tourism management initiatives.
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New insights into the South Ari atoll whale shark, Rhincodon typus, aggregation
Background Examples of aggregations of large Chondrichthyes are well known worldwide and occur mostly in response to seasonal increases in prey abundance. In the Maldives, whale sharks, Rhincodon typus, are thought to have a semi-annual residency pattern, moving west from December to April and east from May to November. However, an important aggregation of predominantly immature male whale sharks seems to be persistent all year round throughout the South Ari atoll region. Understanding residency patterns of this aggregation as well as inter-atoll movements is fundamental to determine the drivers of aggregation, and to design effective conservation management plans at a regional and national scale. Approach The present study used mark-recapture photo identification of whale sharks sightings collected from 2006 to 2015 in the Republic of Maldives. For the aggregation analysis, the Maldives Whale Shark Research Programme (MWSRP) in collaboration with 52 stakeholders and citizen scientists, members of the Big Fish Network (BFN), provided over 3000 sightings, across the South Ari Marine Protected Area (S.A.MPA). Generalised linear models were used to determine seasonality patterns and the effect of environmental variables. Maximum likelihood population models were fitted to establish the size and residency patterns of the aggregation. Results Through the close collaboration between MWSRP and the BFN, 271 individual whale sharks were successfully identified. At a regional scale, as in most whale shark aggregations worldwide, the South Ari aggregation is mainly composed of immature males (86% of the sexed individuals). However, despite a large seasonal variation in sea surface temperature, primary productivity, wind speed and direction, the lag identification rate did not show any significant seasonal pattern. Population models revealed that the aggregation could be characterised as an open population, with an average of 15 sharks present at any given time. Our findings also imply that whale sharks visit the aggregation for a mean of four years and during that time stay for around two of every six weeks. Conclusions South Ari atoll aggregation shows unprecedented levels of residency and site fidelity. Despite showing size and gender structures similar to other aggregations around the world, this aggregation is remarkable because there is no seasonal peak in sightings. It remains to be investigated if this is a due to aperiodic ocean climate phenomena (as in Tofo, Mozambique) or if sharks are aggregating in response to drivers different than feeding. For instance, exploitation of an undetected food source in adjacent deep waters, and subsequent thermoregulation might account for the observed residency patterns. In conclusion, our findings have important implications for the improvement of the conservation management of this symbolic species in the Republic of Maldives, where it is largely targeted by an unregulated tourism industry.
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Whale sharks, tunas and Azorean fisherman, BFF?
المؤلفون: Jorge Fontes, Niall McGinty, Miguel Machete and Pedro AfonsoBackground The Azores archipelago lies at the limit of whale shark (WS) distribution in the North Atlantic, where sporadic sightings of “pintado” (local name) date back to the early tuna fishing operation from the mid XX century. From 1998 and 2008, only nine adult whale shark sightings had been confirmed by the Azores Fisheries Observer Program. However, from 2008 onwards there has been a dramatic increase in the numbers of reported adult individuals around the most southern island of Santa Maria. A recent study found that this increase in sighting frequency was related to an increase in local SST (above 22.5°C), and decrease in chlorophyll-a, with local variation around the large seamounts in the area. While whale sharks and tuna have long been known to associate, the nature and motivation of these associations remains unclear. Moreover the WS-tuna associations in the region remain to be characterized as well as the potential impact of fishing these associations. Approach In this study, we analysed a 13-year observer dataset (1998–2011) from the pole-and-line tuna fisheries from the Azores EEZ to investigate the regional behaviour (distribution in catch abundance and composition) of three tuna species, skipjack, bigeye and albacore during this period. We also examined how these patterns have responded to the environmental drivers, the distribution and abundance of whale sharks and compared whale shark associated fishing events and events targeting free swimming schools. We also detailed an elaborate protocol to guide future research to investigate the impact of fishing the WS-tuna associations and test the “functional bycatch” theory by combining state of the art electronic tracking and behaviour technology with physiological proxies of stress and condition of both whale shark and tuna. Results Changes in the distribution the tuna species were evident with the centre of gravity found closest to the whale shark aggregations in the latter years (2008 in particular) and was independent of fishing effort. Between 2008 and 2011 for the areas where whale sharks have been found we find the associated whale shark fishing events have significantly more individuals of skipjack and bigeye tuna and the area surrounding the eastern islands (Santa Maria etc.) also yielded the highest catches per fishing event. The albacore did not show any significant variation in CPUE for either predictor. Overall, catch rates of tuna were higher and multi-species aggregations were more likely when associated with whale sharks. Conclusions Preliminary results suggest that the presence of WS during the tuna fishing season may have an effect on fishing yields and tuna species composition of catches. It is also apparent that the fishing fleet behaviour could be responding to WS distribution and abundance. Our results support the need to investigate the potential detrimental effects that fishing WS-tuna associations may have on both the WS and tuna.
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First ecotoxicological investigation in whale sharks of the Gulf of California (Mexico) using skin biopsy
Background The impact that pollutants have on whale sharks (Rhincodon typus) is a question that remains largely unexplored. Whale sharks (WSs) are known to aggregate seasonally in different areas in the Gulf of California. Although this species is protected in Mexico since 2001, habitats for most of these aggregations are not protected. Out of the 7 localities were they aggregate, 3 are protected whereas the other 4 need to have some protection. Urban and touristic developments are major threats to their habitats because they lead to mangrove and estuary damage, both being important areas for their food resources. Moreover, due to poor fishery regulations, whale sharks often die as by-catch in fishing nets. The growth of tourism in the area of La Paz and Los Cabos represents an increase in maritime traffic and, thereby an increase in the number of collisions of WSs with boats. Finally, the increasing human activity in WS grounds is the cause of chemical pollution from urban waste waters, vessels, agriculture and solid waste (it is common to see WSs feeding while surrounded by marine litter). Approach In this work, we perform the first ecotoxicological investigation, using skin biopsy, of whale sharks sampled in the Gulf of California. In order to evaluate the potential impact of anthropogenic activities on this species, 13 skin biopsy samples were collected in January 2014 from 12 males and 1 female whale shark in La Paz Bay. PCBs (twenty-one ortho PCB congeners), DDTs (six o,p'- and p,p'- DDE, DDD and DDT isomers), PBDEs (fourteen congeners from tri- to deca-substituted) and HCB were analyzed on freeze-dried blubber biopsy samples by GC-qMS. Biomarker responses (cytochrome P450 1A, CYP1A1) were detected, using western-blotting (WB) techniques, in integument biopsies (skin tissue samples) of this vulnerable (IUCN) species. Semi-quantitative analysis was performed for each WB using Quantity One software (Bio-Rad, 1-D Analysis Software). Results The average abundance pattern for the target contaminants was PCBs >DDTs > PBDEs >HCB. Mean concentration values (and ranges) of 8.42 (0.720–41.40) ng/g w.w. were found for PCBs, 1.31 (0.20–6.36) ng/g w.w. for DDTs, 0.294 (0.02–1.14) ng/g w.w. for PBDEs and finally 0.192 (0.01–0.66) for HCB. The detected values are lower than in other planktivorous shark species (e.g. basking shark) in other areas (e.g. Mediterranean Sea). Cytochrome P450 1A (CYP1A1) was also detected for the first time, using western-blotting techniques, in the skin samples of this species. The potential impact of microplastic (plastic fragments smaller than 5 mm) and related contaminants (such as plastic additives) has also been explored in this large filter feeding species. Preliminary data on the average density of microplastics in the superficial zooplankton/microplastic samples collected from the Sea of Cortez (La Paz Bay) showed that the values ranged from 0.00 items/m3 to 0.14 items/m3; furthermore, concentrations of mono-(2-ethylhexyl) phthalate (MEHP), used as a tracer of plastic additives, ranged from 13.08 ng/g to 13.69 ng/g. Conclusions Further ecotoxicological investigation on whale shark skin biopsies will be carried out in order to support the idea of the usefulness of non-lethal approaches in the worldwide ecotoxicological risk assessment of this vulnerable species.
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Tourist management of the whale shark in the Mexican Caribbean
Background The whale shark population in the Mexican Caribbean is one of the largest in the world. Its touristic exploitation began in 2002, with 200 visitors and 25 licensees, and by 2012 its popularity had risen to 30,000 visitors. In 2013 a load capacity study for the visitors was launched, and it was determined that no more than 160 boats should visit the aggregation each day. However, given the social pressure to give access to more service providers, in 2015 up to 234 boats were allowed per day, but not simultaneously so that the load capacity was not exceeded. The service providers were allowed to work according to this management plan with one condition, they had to work only every other day. This condition was not submitted for public consultation because the service providers did not agree to it, but chose other alternatives to avoid exceeding the load capacity of the aggregation site. The objective of this study is to determine the compliance with this plan and the ease of its supervision. Approach Supervision of boat traffic at the aggregation was performed by the staff of the Whale Shark Biosphere Reserve from June 1 to September 17, 2015, on land from the boarding sites and on tours around the area on board official and touristic boats. The supervisors recorded all boats and tourist who did not obey the regulations. Moreover, surveys were applied to the service providers. Results Supervision was performed for 52 days from the docks and for 12 days on board touristic boats, and 19 supervisions were performed from boats inside the reserve. Conclusions The conclusion was that the management program was not met by 43% of tourist boats. The supervisors found it difficult to monitor the boats, as boats do not carry any visual flags to show if they are operating or not. It was found that the visible presence of park rangers in the area is fundamental for the service providers to abide by the rules. It was determined that the daily boat load capacity was not being exceeded, but other conditions of the permits were not being respected. All the service providers manifested their disagreement with this condition of the management plan, and proposed a rotation system that does not exceed 100 boats per day, along with one day a week in which no boats visit the aggregation, to reduce disturbance to the sharks.
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The “Big Fish Network”: Using new technology to incentivise citizen science engagement in the Maldives
Background The use of citizen scientist contributions is a cost-effective approach that can provide valuable information, usually at scales larger than those attainable by individual researchers. The challenge, however, is to motivate contributors to continuously supply data when doing so can be time consuming and monotonous and where the results of the contributions they make are part of long term studies with infrequent outputs. When studying a highly mobile animal in a geographically disparate location such as the Maldives, a widely spread network of contributors submitting encounter information on whale shark (Rhincodon typus) sightings is vital to providing information on spatial movements and residency patterns. Approach The Maldives Whale Shark Research Programme created a prototype of a mobile device friendly version of the identification software I3S and linked it to an established, custom made interactive online portal called the Big Fish Network, designed to provide a platform for data exchange. Tour operators were invited to submit standardised data logs from their excursions. In return, operators were openly provided access to a photo-identification database of whale shark individuals and 8 years of corresponding encounter data. Outputs from the portal for the operators include an interactive map, a customised trip report, social-media bulletins and a mobile app. These features were designed to aid tour guides in planning and marketing their excursions and informing and engaging tourists, during and after the excursion. Results Since the launch of the Big Fish Network in July 2013, 834 stakeholder data submissions were received from external contributors; equivalent to 59.8% of the total encounters recorded in the same period, as compared to 23.4% between April 2006 and July 2013. In addition, utilising this network produced evidence for 5 instances of inter-atoll movements using sightings submitted from locations that are outside the main survey areas. Conclusions We believe that this example of using appealing technology and open data as tools to produce carefully tailored incentives may strengthen stakeholder commitment to citizen science initiatives and increase the catchment of data from a wider range of stakeholders. Employing similar models at a regional level in whale shark hotspots around the world may improve data flow to global databases for this species.
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Spatial and temporal patterns of R. typus in the tropical fjord Golfo Dulce, Costa Rica
المؤلفون: Robin HannaBackground Many population parameters of the whale shark Rhincodon typus such as growth rate, survival probability and migratory routes are still unknown, but large advances in research have been achieved primarily in areas where predictable aggregations occur. Here, results from the first study on whale sharks in Costa Rica are presented. Research was prompted by anecdotal information on aggregations of 13–55 individuals in Golfo Dulce and was submitted for assessment as part of the author's Master thesis in 2007. Approach From 20 December 2006 to 3 March 2007, a total of 47 interviews were conducted in the vicinity of this tropical fjord, and a previously established sampling transect was followed to search for whale sharks and measure surface salinity and temperature. Equipment for sampling water properties in the event of a sighting was held on the research vessel, but no whale sharks were encountered. Results The maximum number of individuals sighted from 2001–2007 was Nmax=226. To reduce the probability of multiple sightings, a more conservative minimum value (Nmin=190) was calculated from the lowest number of sharks sighted in one observation and the total number of sharks in a month, respectively, and by comparing sizes. Several accounts include juveniles of very small size (2–3.5 m tl). Categorization of sizes and behaviour as well as an approximated position of a sighting enabled the integration of the data in a GIS environment. This system is available in the participating institutions and can be updated with further anecdotal information until more precise research is in place. An illustrated literature review was included to compare global whale shark research efforts with those of Costa Rica. Conclusions This preliminary and unpublished study served to investigate an unknown whale shark habitat and suggests new null hypotheses for further research. Based on the new information made available through this study, management decisions in the area of the Osa peninsula should include the annual presence of Rhincodon typus.
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Whale shark kinship and genetics: Analysis of two populations with different ecologies
Background A recent global study of whale shark population genetics has allowed for better understanding of genetic connections between aggregations in both the Indo-Pacific and Atlantic. This overview included an aggregation found within the Red Sea near Al Lith, Saudi Arabia, however the Mafia Island, Tanzania, aggregation was not part of the study. The ecological behavior of these aggregations differs with the Saudi Arabian individuals showing strong seasonality, while acoustic telemetry data revealed cryptic residency at Mafia Island. Approach Genetic analysis using 11 microsatellite markers was performed on whale sharks from both locations. A combination of primers sourced from previous studies and newly designed primers were used to compare both aggregations and the individuals within. The Red Sea population was compared between 5 seasons spanning 6 years from 2010–2015. The Tanzanian population was compared for 2 field seasons from 2012–2014. Temporal genetic diversity was examined using allelic richness on only the Saudi Arabian individuals due to a short sampling period in Tanzania. Kinship for both aggregations was tested using COLONY and KINALYZER. Results Over a 6 year period, genetic diversity in the Red Sea showed no significant change. Contrasting to other whale shark aggregations, allelic richness in the Red Sea shows no sign of reduction. Kinship analysis using COLONY found two potential sibling pairs in Tanzania. One pair had a high probability (.993) of being a full sibling dyad while the other had a lower probability (.357). There were no sibling pairs identified in the Red Sea. Conclusions The lack of significant change of genetic diversity in Al Lith, Saudi Arabia, differs from a trend at Ningaloo Reef, Australia that showed a decrease in genetic diversity. Although these differences could be driven by location, this should encourage further long term genetic sampling at aggregations to better understand whale shark population trends. The potential of sibling pairs being found within one aggregation warrants further investigation into kinship within and between aggregations throughout the Indo-Pacific.
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Association of adult female whale sharks with open ocean and coastal upwelling frontal systems in the Eastern Tropical Pacific
المؤلفون: Alex R Hearn, Eduardo Espinoza, Jonathan R Green, David Acuña-Marrero and John P RyanBackground Although whale sharks are a mostly solitary pelagic species, most of our knowledge of their ecology is derived from around a dozen coastal feeding sites around the world where mainly immature males aggregate. Darwin Island in the Galapagos Marine Reserve is one of a few oceanic sites around the world where mostly large female whale sharks may be observed on a predictable basis. Since 2011, the Galapagos Whale Shark Project has tracked their movements from Darwin to the Equatorial Front, which is located to the north of the Galapagos Islands, extending zonally over several thousand kilometers, and is most pronounced from July through November. Towards the end of the year, the whale sharks move to the eastern boundary upwelling zone off the shelf break of Ecuador and northern Peru. Approach We placed SPOT-5 tags on 24 whale sharks in 2011 and 16 in 2012 at Darwin Island (Galapagos Marine Reserve) and tracked their seasonal movements west along the Equatorial Front then east to the eastern boundary upwelling off Ecuador and northern Peru. Using satellite data, we extracted sea surface temperature (SST) cross sections for each shark position, meridional for equatorial positions and zonal for eastern boundary positions, to emphasize habitat occupation in terms of thermal gradients relative to the sharks. We analyzed a meridional ship hydrographic section to examine habitat occupation for one shark at the EF in relation to recorded depth preferences. Results The whale sharks occupied a geographical range of 4060 km from east to west, and 2027 km from north to south. Preliminary results show that within this range, the seasonal presence of adult female whale sharks at the Equatorial Front and the eastern boundary upwelling occurs when the frontal zones are fully developed. Whale sharks were consistently located along the warm side of the Equatorial Front, occupying a narrow thermal band on average: 25–25.5 C. The depth profile of one shark in relation to in-situ vertical profiles also supports this. Similarly, they occupied the warm side of the primary coastal upwelling front, on average 21.7 C. Conclusions Although encounters with whale sharks along the coastal waters of Ecuador and Peru suggest that a larger population comprising adults and juveniles of both genders occupies the continental shelf year-round, the seasonal movements through Darwin and the Equatorial Front are mainly carried out by large, adult females. Many of these sharks display distended bellies, suggestive of pregnancy. The Equatorial Front is an important feeding ground for both planktivorous and piscivorous seabirds, while other marine filter feeders such as manta rays and southern ocean sunfish have also been tracked along the Front. We propose that Darwin is a navigational waypoint to this offshore feeding ground, which may also function as an open water pupping area.
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Atmospheric and oceanographic impacts on whale shark (Rhincodon typus) seasonality in the Bay of La Paz, Mexico
المؤلفون: Simon T. Hilbourne, Dení Ramírez Macías and Ken CollinsBackground Whale sharks (Rhincodon typus), a highly migratory filter feeding species, aggregate in the coastal regions of the southern Bay of La Paz, Mexico every year. A growing eco-tourism industry is capitalising on the aggregations, yet very little is known about the drivers of seasonality. This investigation sought to determine the patterns of whale shark seasonality and identify the influence of oceanographic and atmospheric variables on the aggregations. Approach A 12-year (2003–2015) whale shark abundance data series, collected by the Whale Shark Mexico NGO, was analysed using generalised linear mixed effects models and generalised additive mixed models to investigate the influence of oceanographic and atmospheric variables on aggregation abundance. Sea surface temperature, wind, chlorophyll, and Oceanic Nino Index were used to investigate changes in monthly seasonality. In addition to these variables, moon illumination and tidal state were used to investigate fluctuation within seasons from 2012–2014. Results Aggregations of juvenile whale sharks are restricted to the southern-most region of the Bay of La Paz and occur in highest abundance between November and January. Sea surface temperature anomaly in the Bay of La Paz showed a positive effect on whale shark abundance. Oceanic Niño Index, conversely, showed a negative effect, potentially due to the disruption of the wind-driven upwelling corridor along the east coast of the Gulf of California. A thermal preference of ~24°C was seen to significantly increase daily whale shark sightings. Aggregations are thought to be associated with foraging on zooplankton blooms in the bay which may be detected by olfactory cues. Conclusions Effects of El Nino Southern Oscillation (ENSO) events have been associated with a number of changes in species distribution and abundance in the Gulf of California, and whale sharks appear to be no exception. Analysis of Gulf of California-wide oceanographic trends, matched with whale shark satellite tracking programmes, would help further improve the understanding of the drivers and timings of aggregations in the Bay of La Paz.
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Comparison of sex and size range of whale sharks and their sighting behaviour in relation to fishing lift nets in Borneo and Papua, Indonesia
المؤلفون: Mahardika R. Himawan, Casandra Tania, Andi M. I. Yusma, Beny A. Noor, Beginer Subhan and Hawis MadduppaBackground The composition of sex and size of a population is important for management and conservation of marine organisms, including high mobility and global species such as the whale shark, Rhincodon typus. The presence of fish in lift nets in some Indonesian waters attracts feeding whale sharks. The objective of our study was to compare the sex, size and behaviour of whale sharks associated with lift nets in Cenderawasih Bay, Papua and Talisayan, East Kalimantan. Approach Data sampling was conducted for 52 days during April'June 2013 in Teluk Cenderawasih National Park, Papua and 60 days during August–October 2015 in Talisayan, East Kalimantan. Daily monitoring was carried out at lift nets located within the study area. Individual identification was conducted with photographic identification, sex determination was done through visual observation of the presence of reproductive organs, and size measurement was done by comparing the shark length with the observer–s height. Analysis of the fish catch was obtained by interviewing fishermen, and observation from the lift net was conducted to support the data. Results A total of 134 observations and 81 observations were recorded in Cenderawasih Bay (57 lift nets) and in Talisayan (43 lift nets), respectively. A total of 37 different whale shark individuals were identified in Cenderawasih Bay, and 30 different individuals were identified in Talisayan. More than 50% of the whale sharks in Cenderawasih Bay, and 80% in Talisayan, had scars on their bodies. In Cenderawasih Bay, scars were spread across the body: 20% of the scars were found on the fins, 20% on the main body including the gills, and 15.6% near the mouth area. In Talisayan, 70.6 % of the scars were found on the fins, 2.9% in the main body including the gills, and 17.6% near the mouth area. The scars result primarily from friction with fishing nets. The whale shark aggregations in Cenderawasih Bay and Talisayan were dominated by juvenile males. From a total of 37 individuals, only one female was found in Cenderawasih Bay, and from a total of 30 individuals, only two females were found in Talisayan. The dominant size of whale sharks in Cenderawasih Bay was in the range from 3–3.9 m total length, with the largest animals in the range of 6–6.9 m. In Talisayan, the dominant size range was 4–4.9 m total length, with the largest animals in the range of 6–6.9 m. The high abundance of smaller fishes that are caught in Cenderawasih Bay and Talisayan by lift nets could attract whale sharks to the area. The largest number of whale sharks seen in Cenderawasih Bay was 14 individuals on May 14th, 2013. The fishery catch in this area fluctuates, with the highest catch being 365 kg on May 9th, 2013. Whale shark activity in Talisayan was lower than Cenderawasih Bay, even with a greater lift net catch. The largest number of whale sharks seen in Talisayan was 8 individuals on August 25th, 2015. The lift net catch in this area also fluctuates, with the highest catch being 5,325 kg on August 25th, 2015. Conclusion The appearance and activity of whale sharks in Cenderawasih Bay and Talisayan have similar characteristics. These aggregations are dominated by males with a size range of 3–6 m, which are still categorized as juveniles. They were often present at the surface, performing feeding behaviours that correlate with lift net activity.
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Habitat conditions and potential food items during the appearance of whale sharks (Rhincodon typus) in Probolinggo waters, Madura Strait, Indonesia
المؤلفون: Mohammad M. Kamal, Yusli Wardiatno and Nenden S. NoviyantiBackground In Probolinggo coastal waters, part of the Madura Strait, the appearance of whale sharks (Rhincodon typus) is a common sight especially during late December to March. The aggregation of these large vertebrates in this area have become highly attractive for local coastal tourism. Yet there has been limited scientific information regarding their population, from which better conservation management might result. The present study partly dealt with an exploration of whale shark habitat conditions at their arrival in this region. Approach Twelve days of whale shark sightings were made on board a wooden fishing boat (8 m length), coupled with weather data based on Beaufort's scale and plankton sampling at the time of shark surfacing. Observations were performed from early morning to late afternoon (7 am to 4 pm). The animals were counted and their length estimated by placing the boat and a whale shark in parallel positions. Zooplankton was sampled by filtering 100 L seawater using a 250 ìm mesh-size plankton net. Site marking was done at each sight using GPS. The combination of primary data and secondary supporting information was combined to understand why whale sharks are present in the area. Results There were 72 individual whale sharks recorded during 12 d of observation, of which 94% appeared between morning to late morning. The highest number of sharks was found on day 6 with 14 individuals. Shark size ranged between 2 – 8 m, with most animals between 3 – 6 m, indicating the population might by dominated by immature individuals. During observation, there was no preferred temperature for whale shark sightings, with temperatures ranging between 28.5 – 30.0°C. Instead, whale shark presence coincided with relatively calm weather (1 – 3 Beauforts' scale). Whale sharks were absent on days 3, 7, and 12, when weather conditions were between 4 – 5 Beauforts' scale. The sharks swim as close as 1 nm to shore, in 5 – 10 m water depths. Among potential food items, there were 5 dominating zooplankton groups, i.e. crustaceans, sagittoideans, urochordatans, hydrozoans, and scyphozoans. In addition, fish eggs and larvae were also found. Regarding crustaceans, the copepods were the dominant group, especially genera Lucifer, Mysis, Sergia, and nauplii larvae forms. Conclusion The aggregation of whale sharks in Madura Strait is likely feeding-based in this area where wind-driven oceanographic conditions cause food to be in high abundance. Research on ID-based population structure of this whale shark aggregation is required.
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A Whale Shark Virtual Reality Underwater Environment
المؤلفون: AbdelGhani Karkar, Osama Halabi and Jihad JaamBackground Virtual Reality (VR) can provide an immersive experience and enables users to live in different worlds. The technology becomes affordable with the recent development in VR technology and the release of many consumers VR Head Mounted Display (HMD). VR provides a unique and efficient way of exploration and learning. The available VR systems, so far, provides seated experience where the user uses gamepad or joystick to navigate and interact. In this work, we are proposing a walking VR immersive experience where the user will be able to walk naturally and interact in the virtual world. This achieved by using cameras to track user movements. As a result, the participant will be able to lively experience the underwater live and be able to have an enjoyable learning space. Approach Recently, we developed a bilingual animal domain knowledge base (ontology) where information are stored in a hierarchical structure based on the classifications of the animals (e.g., mammal, aquatic, etc.). The knowledge base defines the relationship between the classifications (concepts). Each concept can have different properties which describe all viable facts that can be associated with. Each property can have specific settings (e.g., multiplicity, restriction, etc.). For instance, the animal cannot have two different blood types (i.e., this can be restricted using multiplicity). In this work, we propose a VR whale shark educational system that presents whale sharks and diverse kind of aquatic animals. The system extracts informative facts from the knowledge base and attaches them to the generated 3D models. The VR simulation provides the ability to walk in the world by tracking the movements of the user using cameras. The result is fully immersive VR-based simulation. The aim of the proposed system is to improve the educational skills about whale sharks and underwater environment which includes comprehension, realization, and deduction. Results Previous mobile based educational system have been developed and showed significant improvements for learners. The features of the proposed educational system include: 1) presentation of illustrations for natural text, 2) knowledge extraction from an animal domain knowledge base, 3) getting illustrations (i.e., 2D and 3D images) from a multimedia repository; and 4) querying online search engine to get new images. Our ongoing system development includes the development of a VR system for Whale shark and underwater environment. Conclusions The study presents a virtual reality educational system for whale sharks and underwater environment. An animal domain knowledge base will be used to extract semantic information about aquatic animals. The proposed system provides immersive VR with ability to walk and navigate.
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Studying spatial distribution of the whale shark in the Gulf of Tadjora, Djibouti
المؤلفون: Savinien T. R. Leblond and David R. L. RowatBackground The Marine Conservation Society Seychelles, in partnership with Dolphin Excursions and NGOs Decan and Megaptera, have been monitoring the whale shark population off Djibouti during the peak aggregation season since 2006. The first formal scientific study found a substantial aggregation of very small juvenile whale sharks off the Arta coastline and in subsequent years a significant number of photo-identified individuals were resighted and appeared to be preferentially using certain areas. Approach This study explored the spatial utilization of the site during the annual two week monitoring trip in January 2014. Monitoring was done on two surveys each day for two six-day periods. We focused mainly on the known aggregation areas around Arta and Acacia coastlines, with a one-day survey to Ghoubet al Kharab (20 km to the West) each week. A GPS waypoint was recorded for every shark encountered which was identified by the spot pattern using the I3S Photo Identification software. Geographic Information System pattern analyses (Getis Ord Gi* tool, with a 10 m nearest neighbour band) were carried out to assess whether there was any significant clustering or over-dispersion in the spatial distribution of sharks during the morning and afternoon. The encounter data were further analysed using SOCPROG to define movements between the areas and any tendency for individual associations. Results During the two week study, 782 encounters were recorded with 127 individual whale sharks. These sharks were seen along the 3 km of Arta and 4 km of Acacia coastline in the survey area. During the morning 13% of sharks clustered in significant “hot spots' off Acacia and 32% of Arta, while 13% and 1% were found to be over-dispersed in “cold spots' in both Acacia and Arta respectively (95%C.I.). When examining the spatial distribution in the afternoon no significant cold spots areas of overdispersion were found, while 33% of sharks where found in hot spot clusters off Acacia and 28% in Arta (95%C.I.). Morning aggregations at Acacia spanned a length of 3 km along each coast of Acacia and Arta while afternoon aggregations were more compact only spanning 2 km at Acacia and 1.5 km at Arta. Clusters were located up to 500 m off the shore lines in the mornings compared to 200 m in the afternoons. Movement models indicated transitions both between Acacia and Arta and also into and out of the study area. 17 sharks associated with another specific individual 6 or more times (max 46) during the study period with a Coefficient of Variation of 1.23 between sampling periods. A hierarchical cluster analysis defined 6 clusters with a Cophenetic Correlation Coefficient of 0.79. Conclusion The juvenile whale shark aggregation in the Gulf of Tadjora occurs mainly along the coastlines of Acacia and Arta with sharks forming more significant/dense clusters in the afternoons. The hot spots occur over areas of healthy coral reef with many branching and tabulate acropora corals while the cold spots form near the 45 degree rubble slopes with little or no coral cover. The westerly winds in the gulf drive plankton into the coves of Acacia and Arta which accumulate around coral reefs intensifying whale shark feeding behavior in these areas. While associations between individuals were identified between daily sampling periods this was found for only a small number of individuals over a relatively short time period; further studies are needed to see if these associations remain stable over longer periods.
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Update on the use of an open source tri-axial accelerometer tag for monitoring whale shark (Rhincodon typus) behavioral disturbance
Background The rapidly decreasing cost of electronic components has enabled access to better tools for monitoring the behavior of whale sharks on a fine scale never before achieved. We use the new Kinematic tag (Oceans Forward) and the OpenTag (Loggerhead Instruments) as a novel approach to visualizing behavior of whale sharks. Fine scale habitat use and baseline behaviors are fundamental for understanding potential anthropogenic impacts of disturbance. Approach Each tag is an Arduino compatible open-source inertial measurement unit for recording motion sensor data to a solid state memory card. A three dimensional gyroscope, accelerometer and magnetometer allow for calculating pitch, yaw, and heading, while depth and temperature sample continuously. The rechargeable lithium battery allows for deployments up to 14 days sampling at 100 Hz. The Open Tag is placed in a hydrodynamic syntactic foam float, and banded around the dorsal fin. A galvanic release incorporated into the tag allows for a release time to be programmed and a VHF tag (Animal Telemetry Systems) aids in recovery. Trackplot (University of New Hampshire) was used to visualize behavior. Further analysis was conducted using Humu signal processing suite (Humu.io). Results Five tags were successfully deployed in the waters offshore of Cancun, Mexico between 2013 and 2015. Behaviors noted included frequent surface intervals, even during the night when previously believed whale sharks were normally in deeper waters. A maximum depth of 62.2 m was observed, with mean depth of 17.2 m. We were able to identify possible harassment at the surface and visualize possible defecation events. Conclusion Both the k-tag and Open Tags fill a unique niche in whale shark studies as a useful tool to better understanding of fine scale habitat use and behavior. By incorporating these data into Trackplot with data from potentially harassing activities such as vessel traffic, we can visualize behavior and investigate potential erratic changes in depth, heading and lateral movement amplitude indicative of harassment.
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Close genetic relatedness of whale sharks (Rhincodon typus) in the Indo-Pacific region
Background The whale shark (Rhincodon typus) is a prominent species in Cenderawasih Bay. Its recent association with moored lift-net fisheries there has led to an increase in tourism that facilitates encounters for human snorkelers and SCUBA divers with the sharks. This association has also supported opportunities for research to discover various elements of their biology, ecology, movements and genetics. An understanding of the genetic composition of the sharks in Cenderawasih Bay and their relationships with whale sharks elsewhere in the Indian Ocean and Western Pacific Ocean is important for their conservation and to help design marine protected areas. Approach Skin samples from whale sharks in Cenderawasih Bay were collected with modified hog ear notch pliers and small biopsy tips. The samples were preserved in 96% ethanol and stored at 4°C in the laboratory until DNA extraction. The DNA template was amplified for the cytochrome oxidase I (COI) gene. The nucleotide composition and genetic diversity (polymorphisms, haplotypes, and nucleotides) were analyzed. The results from whale sharks in Cenderawasih Bay were compared with those available in Genbank for nearby areas of the Indian and Western Pacific oceans with the neighbor-joining method. Evolutionary distances and haplotype networks were calculated. Results Seven haplotypes were detected among the 31 whale sharks sampled in Cenderawasih Bay, for a haplotype diversity (Hd) of 0.1871 (variance = 0.00859, s.d. = 0.093). The nucleotide diversity (Φ) was 0.00244 (±0.0013) and the values for theta were 0.75094 per shark and 0.00722 per site. The neighbour-joining tree for individual whale sharks from Cenderawasih Bay and other regions appeared to be closely related to each other. They also appeared to be closely related to whale sharks sampled elsewhere in the Indian and Western Pacific oceans (Chi-square, Chi2: 3.620, df: 5, p: 0.605). Haplotype one has highest frequency (37 individuals), one haplotype has two individuals, and six other haplotypes each have one individual. The three last haplotypes have just one individual, respectively. The whale sharks that we sampled in Cenderawasih Bay had low genetic diversity (haplotype, nucleotide and polymorphic). Conclusion 31 whale sharks in Cenderawasih Bay were very closely related, and these sharks were closely related to whale sharks elsewhere in the Indian and Western Pacific oceans. The extent of movements among reproductive sharks in this large region is unknown as is the frequency and magnitude of mating among sharks from these different areas. Further research is needed to monitor the long-term movements of sharks within and among regions, particularly reproductively mature males and females, to help design conservation plans for whale sharks and the habitats that they might depend on for feeding andreproducing.
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Unveiling a new foraging area for the threatened whale shark
المؤلفون: Rossana Maguiño, Alejandra Mendoza, Shaleyla Kelez, Ximena Vélez-Zuazo and Dení Ramírez-MacíasBackground Whale sharks usually form aggregations by gender and age in many nearshore waters, but they can be as well solitary wanderers. In the Eastern Pacific, there are regular sightings of whale sharks in the Gulf of California and the Galapagos Islands. Tracking studies indicated movement of individuals from Galapagos to the edge of the continental shelf off northern Peru. Although the presence of whale sharks off the Peruvian coast has been reported since 1955, no proper research has been conducted so far. Therefore, there is a critical information gap on their biology, ecology and population status, fundamental information to plan local and international conservation actions. In Peru, no direct fishing occurs, but incidental captures had been reported and many individuals retained. In spite of being a member of international conventions, Peru does not have any local or national protection laws for whale sharks. We started a program; the first one conducted in Peru, to generate knowledge about whale sharks in the region. Approach Our monitoring program includes two components: interviews and boat surveys. Interviews were conducted with fishermen, on-board observers, captains and diving companies in fishing ports located in northern Peru. Interviews included questions about whale shark presence, their behavior, body metrics, dates, times and areas of sightings, as well as an explanation with images for the correct identification of species. Boat surveys for whale shark sightings were planned based on the interview information. During each survey, we recorded whale shark biological data like size, gender, behavior, scars, geo-position, date, time, besides water temperature. Pictures taken were compared with the database from Mexico and submitted to the Wildbook of Whale Sharks. Results We conducted 185 interviews that provided information on 272 whale shark observations. Interviews suggest that there are two marked seasons for whale shark aggregations in Peru, one in the austral summer and one in the spring, with the highest densities observed in the summer. The whale sharks were seen mostly as solitary animals, and within 50 miles off the coast. The individual size was estimated between 10 and 49 feet. The juveniles showed a mode of 16 feet and most of them were observed while feeding. Adults (>29 feet) were usually seen in the open ocean with a size mode of 32 feet. From October 2014 to March 2015 we conducted 17 boat surveys. Four more were conducted in the summer 2015–2016. Surveys resulted in twelve whale shark encounters, ten of which were observed while feeding, half as solitary animals and the rest in groups. The size of these sharks was estimated between 13 and 17 feet, which classifies them as juvenile sharks. The twelve observations resulted in ten unique individuals without a match in any of the photoID databases. From this, we were only able to determine the gender of eight of them resulting in 100% males. Conclusions Interviews and boat surveys indicate a prevalent presence of whale sharks in Peru, which is influenced by seasons. Individuals are more common during the austral spring and summer. There seems to be spatial segregation with larger whale sharks, likely adults, seen in the open ocean, while juveniles are seen closer to the coast. The northern coast of Peru seems to be used by juvenile males during the summer for feeding purposes in shallow waters. Our study has photo-identified ten new individual whale sharks for the Eastern Pacific. This represents a unique opportunity to conduct more research in the region to elucidate connectivity with other areas and to involve stakeholders in future whale shark management and conservation.
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Body measurements and size estimation of whale sharks in Okinawa Churaumi Aquarium
المؤلفون: Rui Matsumoto and Keiichi SatoBackground Okinawa Churaumi Aquarium (formerly Okinawa Expo Aquarium) has been conducting research on the whale shark, both in captivity and in the wild since 1975. Proportional measurements, including total length, girth, and weight, are essential to examine the growth, maturity, and physical condition of the animal, as well as to estimate the required quantity of food and drug dose for medical treatment. However, measurement of the precise length of large aquatic animals is very difficult and often results in errors. We formulated an allometric equation used to estimate the total length (TL) and body weight (BW) by measuring appropriate smaller body parts. Approach We used morphometric data from 33 individuals stranded or accidentally caught by commercial fishery off Okinawa Island between 1979 and 2010. We examined 66 measured characters of each whale shark. Furthermore, we applied the conventional allometric function, and modified the function to be logarithmic to use a liner approximation. The reduced major axis (RMA) test was applied to all logarithmic morphometric data, and we chose to measure characters that were highly correlated with TL. Some of the characters showing high correlation with TL according to the RMA test were further analyzed for sex-based differences using the t-test. The most suitable morphometric characters that were measurable in free-swimming sharks were chosen from the set of characters that passed those tests. In addition, we analyzed weight data from 8 specimens (7 male and 1 female) that were considered to be in an almost normal condition. We applied the conventional allometric function to an estimation equation. Girth measurement at the posterior margin of the pectoral fins was directly performed on the free-swimming individuals. Results A high coefficient of determination (R2) was obtained for 8 morphometric characters: pre-first dorsal length (PD1), pre-second dorsal length (PD2), pre-caudal length (PRC), pre-pelvic length (PP2), pre-anal length (PAL), length of dorsal caudal margin (CDM), mouth width (MOW), and interorbital space (INO). We considered that the equation formulated using PD1 was the most suitable based on sex-based differences and the animal's swimming properties. The following equation estimates the TL in centimeters:
log TL = 0.964 log PD1 + 0.443 (R2 = 0.930, n = 33)
For BW estimation, the sex-based differences could not be tested because of the small sample size. The following equation estimates BW in kilograms:
BW = 4.510 TL3.280 (R2 = 0.958, n = 8)
The data of girth measurements was collected from captive (n = 3) and wild (n = 6) sharks. Conclusions Data on proportional measurements is useful as an index of growth condition. Our focus is to monitor the size of our females and track the physiological indicators of maturation to achieve the first captive reproduction of whale sharks.
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Will the world's biggest fish get any bigger? Limits to the size of filter-feeding fishes over the last 160 million years
المؤلفون: Mark G. MeekanBackground Many taxa of marine animals have increased in size through time, with some of the largest that have ever existed being vertebrate filter-feeders targeting plankton. Present day ecological studies show that the size and body structure of whale sharks is likely to reflect a strategy for gigantothermy that conserves heat while foraging in cool deep waters. However, the temperature of the oceans has changed through time, as has the composition of the guild of large, filterfeeding fishes. What do these changes reveal about the evolution and ecology of whale sharks? Approach I synthesise the results of new analyses of the fossils of filter-feeding fishes that were the largest representatives of their guild over the last 160 million years with ecological studies of whale sharks and filter-feeding whales. This analysis offers an opportunity to examine the evolutionary forces that have shaped the biology of whale sharks. Results Throughout time, bony fishes, sharks and whales that were obligate ram filter-feeders attained similar maximum lengths of around 16–20 m and in the case of the whale shark, body masses equal to, or even greater than, many baleen whales today. This shows that ecological niche and mode of feeding are more important drivers of limits to the body size of fishes than phylogeny. Conclusions The relatively small variation in maximum sizes of the largest ram filter-feeders over the last 165 million years suggests that animals within this guild will not continue to increase insize through evolutionary time, but have already attained sizes constrained by their environment and mode of feeding.
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Democratic tourism service directory maps to help the whale shark
المؤلفون: Frederick D. Michna, Bradley D. Santos and Bradley M. NormanBackground Through travel, people discover whale sharks. They also come to know about the problem of the animals safety. Different things may be more or less strong at hurting or helping the sharks. Tourism may move other things that hurt sharks more than tourism away. Not all tourism is the same. Some tourism hurts sharks more. Not all places with sharks are the same. Some places are safer. A tourism service directory map gathers some services that help travellers. It shows different services for different things that different people may want to do. It can gather only the best services. It can show people the best services for their money and other needs. Good tourism helps sharks most where it is least safe for them. A service directory may show those services because they help the least safe sharks. If no services are where sharks are not safe, the directory can help make new services by sending travellers or giving help. If a bad thing happens to the people who give services at a place then the directory may help by sending more people to those services or giving help. People who run the directory must choose which services are good or in need. They must choose which places are safe and not safe for whale sharks. They must choose what services to show other people. Approach We look at two approaches that explain helping the whale shark with a tourism service directory. The first approach is ‘citizen participation’. All people who use the directory are its citizens. They participate by:
- Letting it help them chose services
- Learning about the whale shark and how services hurt or help them
- Knowing about this when they decide which services to use
- Gathering information about the whale shark and the things that hurt or help them when they use services,
- Asking other people to join the service directory
- Deciding which services the directory should help create to help the whale shark
- Deciding which services the directory should help when bad things hurt the people who make the services
- Deciding which tourism services are not good and should not be in the directory.
- A larger law that all other controls must follow. This helps stop the controls going too far and hurting people who serve the whale shark. It is the constitution and design stage.
- Laws of how the service directory is controlled. Where tourists and money should be put. People who create these laws should work for the good of the worst off sharks and people and not their own reasons. This is the legislation and development stage.
- People who decide on whether each service should be in the directory, whether it should be created or helped. They should act as though they are the law and are answerable to the laws of the directory. This is the enacting stage.
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Tourist satisfaction with whale shark watching and swimming tours in the Mexican Caribbean
مزيد أقلBackground In the Mexican Caribbean, tourism around the whale shark has become one of the most important sources of income for the local communities. It was estimated that during 2014 more than 100,000 tourists went on whale shark watching and swimming tours. In addition, the proximity of the tourist corridor of the Riviera Maya could further increase whale shark tourism. The vulnerability of the specie and the increased volume of tourism could become an ecological and economic problem for sustainable management of the whale shark in this region. Approach In 2014 and 2015, from June to August, a survey formed by 20 closed, reflective questions, and a Likert scale section, was applied to obtain information about perception and satisfaction of tourists during the whale shark watching and swimming activity. Questionnaires were applied to tourists who took the whale shark tour in Holbox-Chiquilá and Isla Mujeres-Cancun, in Mexico. The application method was direct, pollsters asked participants at the arrival docks about their experience during the whale shark tour. Results A total of 486 surveys were applied, and the presence of tourists from 31 different nations was recorded. The mean age was 35 years old, with a mode 27 years old (range: 9–71). From the total of tourists surveyed, 61.5% mentioned that they visited the localities solely for swimming with whale sharks. 37.7% of respondents mentioned that they had received information about the whale shark tour by person to person or word of mouth, while 30.9% did so by media, mainly Internet. It should be mentioned that 30.7% of users said they had not received information about the rules for the development of the activity, and of those who received it, 43.9% did so after boarding the boat. In our results, 70% of people qualified the experience as excellent, however, some factors that could influence public satisfaction were identified. First, 68.5% of tourists reported having seen many whale sharks, indicating values between 20 and 50 individuals. The care provided aboard the boat was another important factor for the tourist, and 72% of respondents qualified it from good to excellent, compared with the treatment received at the point of sale, where only 57% considered it as good. On the other hand, 46.7% of the tourists said that there were many boats when they participated in the swimming and watching activity, observing between 30 and 59 boats. Finally, 45.2% of respondents felt that there were only a few people who swam at the same time with a single whale shark, while 24.6% said it was many or too many people, noting up to 30 swimmers at the same time. Conclusions This activity has an “innate” guarantee: seeing an animal of this size in the wild, however, there are several factors that could affect the user experience. The presence of a large number of vessels and/or swimmers may decrease the quality of service, resulting in some level of discomfort and dissatisfaction, and consequently cause the participant to be less likely to recommend or repeat the activity. Management strategies must be designed to promote successful experiences for the visitors without altering the natural conditions around which they are developed.
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Distribution, abundance and mortality of whale sharks (Rhincodon typus) in coastal and offshore waters of Pakistan (Northern Arabian Sea): Review of a ten year study with information on the successful release of whale sharks entangled in fishing gear
المؤلفون: Muhammad Moazzam, Hamid B. Osmany, Rab Nawaz and Saba AyubBackground Whale sharks are frequently found in the coastal and offshore waters of Pakistan, however, no information on whale shark distribution (seasonal and spatial) was available from this area. Approach A study to investigate the interaction of whale sharks with commercial fisheries gear was initiated. Data on various parameters of dead and live animals observed during 2005 through December 2014 was collected from the coastal and offshore waters of Pakistan. Additionally fishermen were trained to release entangled whale sharks from the fishing gears. Results Whale sharks are commonly found throughout the year all along the coast of Pakistan, however, the area between Ras Malan and Churna Island and the offshore Indus Delta (between Khajar and off Ghora Bari) seem to be two main hotspots for whale sharks. Sharks were mainly abundant during May to June and October to December. Newborn pups were observed during October and November, whereas juveniles were seen during December through March. Data about morphometry and other parameters was collected from a total of 76 dead specimens which were landed mainly at the Karachi Fish Harbour since 2005. In addition, information from 24 live specimens was recorded between 2013 and 2015. It was observed that the main cause of mortality of whale sharks in Pakistan is their entanglement in gillnet fishing gear deployed in coastal and neritic waters. In addition, a few specimens died from entrapment in trawl nets, but very rarely in line gears. In order to conserve the population of whale sharks in Pakistan an awareness programme was started, and fishermen were trained to safely release entangled whale sharks. Through this initiative, a total of 17 whale sharks were safely released from gillnets between October 2013 and December 2015. Conclusion Whale sharks are found throughout the year along the Pakistan coast. They are facing serious threats from fishing operations. Among these, gillnets are the main gear responsible for shark mortality. Through an awareness programme and training, 17 entangled whale sharks were released by fishermen in a span of 27 months.
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Understanding constellations: The use of ‘citizen science’ to elucidate the global biology of a threatened marine mega-vertebrate
المؤلفون: Bradley M. Norman, Jason A. Holmberg, Zaven Arzoumanian, Samantha Reynolds, Rory P. Wilson, Adrian C. Gleiss, Dani Rob, Simon Pierce, Rafael de la Parra, Beatriz Galvan, Deni Ramirez-Macias, David Robinson, Steve Fox, Rachel Graham, David Rowat, Matthew Potenski, Marie Levine, Jennifer A. McKinney, Eric Hoffmayer, Alistair Dove, Robert Hueter, Alessandro Ponzo, Gonzalo Araujo, Elson Aca, David David, Richard Rees, Alan Duncan, Christoph A. Rohner, Alex Hearn, David Acuna, Michael L. Berumen, Abraham Vázquez, Jonathan Green, Steffen S. Bach, Jennifer V. Schmidt and David L. MorganBackground Gathering data on the life of enigmatic animals remains a challenge, despite its important role in biodiversity conservation and management. For many species, biogeographic investigations are largely the result of information that is generated from multiple sources, often over long time-scales, because measuring biogeographic and biological data over large geographic areas is simply not feasible by a single team of researchers. But in the current age of a well-educated public and accessible and mobile digital technology, scientists are now able to harness the observations of many, thus infinitely increasing their power of observation. Despite its status as the world's largest fish, there remains a paucity of information on the biology and ecology of whale sharks (Rhincodon typus). This species is however a prime target for ‘citizen science’ monitoring because of its charismatic nature, presence at many coastal aggregation sites and the growth of ecotourism around this species. Approach Information on whale shark sightings worldwide can be gathered by various stakeholders and stored in the Wildbook for Whale Sharks (www.whaleshark.org) database. Whale shark identification images are collected when a swimmer photographs the individual's unique spot pattern immediately behind the gill slits, which is distinct and long-lasting, and this image (with associated sighting data and information on shark size and sex) is then submitted to the online database. Computer-assisted scanning technology is then employed to determine whether the individual whale shark in question is a ‘new’ shark or a ‘resight’ of a previously reported whale shark within the database. Wildbook can then be queried to gain insights on various aspects of whale shark biology and ecology from data available at the various global hotspots. Results Members of the public and researchers alike contributed in this collaborative citizen science project enabling (as of 31 December 2014) almost 30000 whale shark encounter reports, comprising 6300+ individuals from 54 countries, to be identified. The number of recognized global aggregation sites (constellations) has increased from 13 to 20. The majority of these (14 out of 20) show a marked sex-ratio bias towards males (>66%). Site fidelity is relatively high, with an overall mean percentage of sharks returning to the 20 hotspots in two or more years of 35.7% (to a maximum of 21 years). Despite photo-identification revealing movements of sharks between a number of neighbouring countries/regions, there are no records confirming large, ocean basin-scale migrations. Strong seasonality in sightings is evident at many locations, suggesting that in general, that these aggregations are frequently exploiting known coastal feeding opportunities. Conclusions This study demonstrates the utility of citizen science in amassing large datasets and their utility in elucidating key aspects of whale shark life-history and demographics.
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Are we losing the battle to save the biggest fish in the sea – and can we turn it around?
المؤلفون: Bradley M. NormanBackground Prior to 1999, the conservation status of the biggest fish in the sea was listed by the World Conservation Union (IUCN) as ‘Indeterminate – Data Deficient’ in its Red List of Threatened Species publication. A Species Report was commissioned in 1999 and the Whale Shark's status was subsequently upgraded to ‘Vulnerable’ in 2000. Much attention has been afforded this species since 2000, with various protective measures implemented at the local, national and international scale. But has it had any effect? Approach Literature Review and discussions with stakeholders from across the globe was used to investigate the current state of play. A recent updated IUCN Red List Report was also consulted. Areas of concern are highlighted and suggested ways forward discussed. Results Whale Sharks are listed under many international conventions e.g. the United Nations Convention on the Law of the Sea (UNCLOS); the Bonn Convention for the Conservation of Migratory Species of Wild Animals (CMS); the Convention on International Trade in Endangered Species (CITES). There is however little evidence of actions under these Conventions. The Whale Shark is known to occur in the waters of more than 100 countries – yet it receives protection in less than 50% of these. One country that lists protection for this species is China – the location of the largest active commercial whale shark fishery. Yet enforcement of existing laws is lacking. A review of the conservation status for the Whale Shark was undertaken in 2015 resulting in no change to its ‘Vulnerable’ assessment in the IUCN's 2016 Red List. The main threats are fisheries catches, bycatch in nets, vessel strikes, whale shark tourism, marine pollution, and the inability for implementation/actions under current laws and Conventions. Conclusions Where are we failing – and what needs to be done? For a start, we need better information, starting with regional and global population assessments to establish population trends globally (at present ‘unknown’ in the latest Red List Assessment). We need improved monitoring of threats and the means to implement adjustments as required (including tourism activities) to minimise impacts. We must have an increased level of data sharing: greater collaboration between researchers, especially to maximise the use of limited available resources to achieve tangible outcomes (which can then be reviewed by relevant authorities when implementing conservation measures). And then an increased level of public education on a local, national and global scale – to help minimise threats (esp. fin trade/habitat destruction e.g. various marine industries; development etc.). Perhaps consumer-driven pressure to make it unviable for stocking/sourcing of whale shark products? And then could it be possible to have a fisheries quota – and benefit the global conservation of this species? Discussions need to be had.
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Fine-scale behaviour of whale sharks off Mafia Island, Tanzania
Background Mafia Island off the Tanzanian coast features a year-round resident whale shark population. Many of the sharks are seen regularly, making this a great natural laboratory to study their behaviour in detail. At the same time, whale sharks here also face threats locally from net entanglement and boat strike. We therefore set out to determine their fine-scale behaviour using novel telemetry methods in order to establish a profound baseline. Approach We conducted field work at Mafia Island from November–December 2015 and used 3D tags (Open Tags) and satellite tags (Desert Star SeaTagMODs) to examine whale shark behaviour. 3D tags recorded depth, temperature, acceleration as well as gyrometer and magnetometer readings at 200 data points per second. Satellite tags recorded depth, temperature, acceleration and geolocation. We attached 3D behavioural tags to the first dorsal fin using a padded clamp, and double-tagged some of the sharks with satellite tags attached with a titanium dart anchor and short tether. We manually retrieved both types of tags. A total of 117 hours of 3D tag data and 53 days of satellite tag data were recorded. Data were analysed in R. Results The attachment method using a padded clamp kept the tags in a stable position throughout their deployment period, although minor scarring of the fin was evident. We suggest some further improvements to the clamp to reduce scarring. Preliminary dive depth analysis of 3D tag data indicates that whale sharks largely stayed in shallow water, with an average swimming depth of just 4.7 m, SE: ± 0.008. The sharks also spent 10.4 hours, SD: ± 2.2 or 44.4% of the day swimming near or at the surface (depth < 2 m), indicating extensive surface feeding behaviour or surface swimming. We will clarify which behaviours were exhibited following further analysis of acceleration and gyrometer data. A simple one-way ANOVA revealed a significant difference between dive depth during the day and night (p < 0.005). During daytime, the deepest dive was to 18.8 m, with an overall mean depth of 3 m ± 0.007. The deepest recorded dive (29.8 m) occurred at night. Mean dive depth at night was two times higher, at 6.4 m ± 0.012. Time spent above 2 m was twofold higher during the day with 6.9 h ± 1.9 than at night with 3.5 h ± 1.2, indicating that a diel behavioural shift occurred. Conclusion 3D telemetry is an emerging technique that provides unprecedented insight into whale shark behaviour. Here, we show some initial results that indicate the potential applications for this technology. We will continue analysing gyrometer and acceleration data that allow us to further distinguish and quantify behaviours, such as feeding and search behaviour.
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Solving the whale shark mystery: How do we save the fish we can't find?
المؤلفون: Simon J. PierceBackground Whale sharks have received significant research attention in recent years, yet key questions on their biology and ecology remain unanswered. This continues to hamper the conservation assessment of the species. The critical mass of whale shark researchers at IWSC4 presents an opportunity to collaboratively develop strategic research initiatives to close these knowledge gaps. Approach Thispresentation is intended to promote discussion, and eventual consensus, on key research questions and approaches. Accompanying this presentation will be a discussion document. My aim is to publish a multi-author manuscript outlining a framework for achieving medium-term (the next five years, to 2020) applied research objectives for whale sharks. Results Mykey questions are: (1) How many whale sharks are there? Movement models applied at single sites consistently point to transience, with a degree of site fidelity in some individuals. Some mark-recapture models are better-suited than others to modelling this reality. A more existential challenge is that, at most aggregations, we are disproportionately sampling juvenile male sharks. We need to understand habitat use of other life stages and incorporate them into population models. (2) Are regional populations present? Two major genetic subpopulations exist, in the Atlantic and Indo-Pacific, respectively. Further genetic/genomic studies, along with the expansion of photo-ID studies and medium- to long-term electronic tag deployments, will be vital in clarifying smaller-scale divisions. Biochemical studies are also showing promise. This work is vital, as the human threat profile differs between regions. (3) Are regional populations, if they exist, increasing or decreasing? Whale sharks are highly mobile. Even studies that have attempted to control for biophysical variation, such as in Mozambique, have documented declines in sightings that are steeper than can be explained by known human pressures. On the other hand, in at least some areas where whale shark sightings are on the increase, such as in the Azores, changes in the long-term ocean climate is a likely contributor. An improvement in our ability to relate local sighting trends to broader abundance is necessary. More data on whale shark demographic parameters, such as age at maturity and reproductive periodicity, are also required to understand the potential timeframe for recovery. (4) How can human impacts be mitigated? Some clear threats to large whale shark aggregations remain, such as the active whale shark fishery in southern China, ship strikes off the Quintana Roo coast in Mexico and in the Arabian Gulf, and the inadequate management of purse-seine bycatch. These examples, and others, require specific examination. (5) What is the best overall strategy for ensuring population recovery? Broadly, large juvenile and adult females are the most important individuals to the species' rebound potential. Identifying human threats to these life stages, and mitigating them, will be the most efficient means of reversing population decline. Regionally, identifying high-priority threats (i.e. the most significant impact on the largest number of sharks) will help with the development of practical mitigation strategies. Conclusions Effectivemanagement requires good data. I hope that the discussions we start at IWSC4 will go a long way towards aligning our regional research objectives towards answering these global questions in the shortest possible timeframe.
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Inter-annual feeding ecology of resident whale sharks from Mafia Island, Tanzania
المؤلفون: Clare E.M. Prebble, Christoph A. Rohner, Simon J. Pierce and C. TruemanBackground Mostdirectobservations of whale sharks occur at coastal feeding aggregation sites. The dominant food source in a feeding aggregation can often be quickly identified. However, there is a risk that short-term studies provide an unrepresentative snapshot of the sharks' long-term diet. Stable isotope analysis enables researchers to examine time-integrated results. Whale sharks at Mafia Island show a high degree of site fidelity. This provides a rare opportunity to study consistency, and changes over time, in individual trophic level and diet over a multi-year timescale. Approach Skinbiopsies were collected from free-swimming whale sharks between October 2011 and December 2014. Each shark was individually identified, sexed, and had their length estimated visually and/or with laser photogrammetry. Surface plankton was collected to measure the baseline isotopic signal. Additional samples from other local species from varying trophic levels were taken, including other planktivorous fishes, jellyfish, and piscivorous fishes. Targeted hand tows of the dominant food source in season, the sergestid shrimp Lucifer hanseni, were collected to investigate the longer term importance of this food source. The stable isotope composition of carbon and nitrogen were determined for all samples. Results Wewill be presenting preliminary results from this study. Throughout the sampling period we collected 223 skin biopsies from 79 individual sharks, 75% of which were male. Total lengths of all sampled sharks ranged from 4.5 to 8 m. One hundred and seventy two samples of zooplankton and other local species were collected. Overall there were no highly significant effects of the year of sampling of the sharks on δC13 (ANOVA p = 0.041) or δN15 (p > 0.05). Mean whale shark δN15 value (9.3 ± 0.07%) was similar to the other local planktivorous fishes sampled (Rastrelliger.k 10.79 ± 0.33%, and Hemiramphus sp. 10.84 ± 0.42%). There was considerable overlap of points in the δC13~δN15 biplot. The δC13 values of the sharks (–17.04 ± 0.07%) were, however, more enriched than the L. hanseni dominated surface zooplankton prey (–26.9 ± 0.38%). Whale sharks exhibited a wide range in δC13 values (–19.62 to 14.68%), and δN15 values (7.29 – 11.64%). Conclusions Thenumber of individuals sampled represents 60% of the identified population at Mafia Island, and as such this provides a unique opportunity to assess diet across a broad spectrum of the sharks that are routinely present. Initial results suggest no significant differences in feeding preference of the sharks over the three year study period. The broad range of both δC13 and δN15 is wider than seasonal changes reported in other elasmobranchs, so likely represents varied individual diets. The sharks appear to be feeding at the same trophic level as the other planktivorous fishes within this ecosystem. We will support these results by calculating an estimate of the trophic position of the sharks. The proximity and overlap of the whale shark isotope results compared to local planktivores suggests a high level of residency over the study period, which is further supported by photo-ID and acoustic telemetry. To corroborate this result we will be calculating the isotopic niche width using Bayesian ellipses framework in the SIBER package in R. Though the sharks may be highly resident, the enriched δC13 values of the sharks with respect to the surface zooplankton suggests they also have a more benthic or mesopelagic food source in their diet along with the seasonally abundant L. hansenii.
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An assessment of the past and present distribution status of the whale shark (Rhincodon typus)along the west coast of India
المؤلفون: P.V.R. Premjothi, B.C. Choudury, Rahul Kaul, S. Subburaman, Manoj Matwal, Diresh Joshi, Jose Louise and Vivek MenonBackground Tounderstand the historical and present occurrence and distribution patterns of whale sharks along the west coast of India in the Arabian Sea, Traditional Ecological Knowledge (TEK) and Indigenous Technical Knowledge (ITK) questionnaire surveys were conducted during May 2012 to March 2013. The surveys were conducted in the maritime states of Maharashtra, Goa, Karnataka, Kerala and the union territory of Lakshadweep. Approach Thesurvey was targeted at active and non-active fisher-folk between the ages of 25 and 90 years to obtain information on historical and current presence of whale sharks in fishing territories across the West Coast. Results Atotal of 1703 fisher folk in 118 fishing villages were interviewed using an improvised structured questionnaire developed from the standard TEK and ITK questionnaires. Over 60% of the interviewed fishers reported having sighted whale sharks in the Arabian Sea along the west coast during their fishing activities 20–100 km from the shoreline. Sightings were most frequent in the Lakshadweep Sea followed by the coastal waters of Maharashtra, Karnataka and Goa. Four major whale shark aggregation locations in the Arabian Sea were identified: close to the coast of Malvan in the Sindhudurg district of Maharashtra, Netrani Island in Uttar Kannada of Karnataka, Minicoy and Kavaratti Island in Lakshadweep and along the Saurashtra coast of Gujarat. The whale shark aggregation locations that were identified as a result of this study were found to overlap with key marine resource productivity areas, such as paste shrimp (Acetes sp.) abundance zones. The incidental capture of whale sharks in fishery operations over the last few years were notably high along the Kerala coast followed by Maharashtra. The mean number of respondents (in each village) who had caught whale sharks using gill nets were significantly higher (Kruskal-Wallis x2 218.56, df 2, p <0.05) than the mean number of respondents (in each village) who had caught the species using either purse-seine or trawl nets. Conclusions Thesurvey results indicate a lack of awareness amongst the fishing community of the whale shark being a protected species and the ban on their capture and trade; it emphasizes the need tolaunch an intensive awareness campaign along the west coast of India. The respondents also mentioned that the most common human induced threats to the whale sharks are incidental catch in gill net, purse seine and trawl.
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New records of neonatal whale sharks (Rhincodon typus) from the Arabian Sea and discovery of a possible natal ground on the Gujarat coast, India
Background To overcome the issue of accidental mortality in fishing nets, the Government of Gujarat started promoting the release of entangled whale sharks by providing adequate compensation for the gear loss incurred by the fishers during the release. The attempt to save entangled whale sharks was a great success. However, constant follow up and rescue information collection from the fishers was essential to monitor the rate of entanglement and release. The current reporting of neonatal whale sharks from the Indian coast was the result of these interactions with fishers. Approach Youngwhale sharks are rarely seen, with only 14 encounters with neonatal whale sharks reported in the scientific literature. The project sociologist is in constant touch with the fishers and collects all the information about whale shark sightings and rescue. The importance of recording the size class of whale sharks was detailed to the fishers. Results Atotal of four whale shark pups (size range 60–100 cm) were recorded during 2013. Interviews with the fishers of Sutrapada fishing village in Gujarat revealed that they found a whale shark pup entangled in a fishing net on 5th March 2013, exactly 10 km offshore of the Sutrapada headland. The length of the pup was approximately 60 cm. The second report is from 15th March 2013, approximately 10 km offshore of the Sutrapada headland. Fishermen from Sutrapada fishing village found the pup whale shark entangled in a gill net and released it. The fishermen recorded the entire event using a mobile telephone. Ocular estimation of the size of whale shark pup from the provided video by comparing with a fisherman's palm was approximately 60 cm. While intervening the fishers during the monsoon fishing ban along the Saurashtra coast (June–July), we came to know that the fishers saw one dead whale shark pup beached near the Sutrapada fishing village on 6th April, 2013. According to the fishers, the sighting of dead whale shark pups is not a common incident and it might be the first incident where fishermen come across a dead whale shark pup. The size of the pup was nearly 100 cm. The pup was found near the rocky shores of the beach and fishermen observed some scars over the head and second dorsal fin. Fishers also reported a whale shark pup swimming on the water surface 20 km off Sutrapada coast. Conclusions Neonatalwhale sharks are thought to have limited swimming abilities compared to juveniles and adults. Thus the new records of pups of size range 60–100 cm indicate that this region is a pupping ground for whale sharks.
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Mapping the path of the biggest fish: The whale shark from the Mexican Pacific side
المؤلفون: Dení Ramírez-Macías, Abraham Vázquez-Haikini, Victor Luja, Ricardo Murillo and Roberto MataBackground Monitoring of animal populations is critical for proper management. To have a better understanding of the population dynamics and migratory pattern of the whale shark, data is required from locations close to key aggregation sites where hypothesized connections can be validated. Photo-ID is an effective marker for capture-mark-recapture studies. Underwater photographs of sharks, combined with photo-comparison software, are used to identify re-sighted sharks, which, in turn, contribute to estimations of population size, age structure, sex ratio, site fidelity, trends in abundance, and movement patterns Approach Since 2003 we have established and maintained a photographic identification research program in the Gulf of California, at Los Angeles Bay (LAB), La Paz Bay (LPB), Espiritu Santo Island (ESI) and Los Cabos (LC), and since 2010 at the Archipelago of Revillagigedo (AR, at the Mexican Pacific). Recently, we included Nayarit (Na, in the Mexican Pacific) to the study area, San Luis Gonzaga (SLG) and Coyote Bay (CB, Gulf of California) in order to address if connectivity exists in this region. Results The whale sharks appear to segregate by size. In coastal waters of LAB (n=501), LPB (n=380), SLG (n=51), Na (n=36), and CB (n=16) aggregations are exclusively juvenile sharks (<8 m). In the oceanic waters of ESI (n=20) and LC (32), pregnant adult females (>9 m) aggregate. At AR (n=11) both pregnant females and juveniles exist but are separated by time. From 2003 to 2014 we have identified 898 sharks over the course of the study; of these 841 were juveniles and 57 were adults, mainly pregnant females. Photo-identification showed the movements of 133 juvenile sharks between LAB, LPB, SLG, Na and CB and movement of 2 pregnant females between LC and AR. We found high levels of fidelity in the juveniles. For example in LPB up to 61% of the juveniles have been re-sighted between years. In contrast only one pregnant female has been re-sighted at the same locality after 7 years. Conclusions This study demonstrated the importance of a collaborative effort to have a better understanding of the population on a regional level. The connectivity data showed the necessity to generate a regional conservation strategy; of the eight localities where we study these gentle giants, currently three are protected, the other four require protection.
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Key elements for managing whale shark tourism in the Gulf of California
المؤلفون: Dení Ramírez-Macías and Georgina SaadBackground There's no doubt that swimming with whale sharks is a fabulous experience. It's interesting, however, how our perception of sharks has changed and now swimming with the biggest shark can connect us to our oceans. Looking into the future, no one could have expected that this activity would contribute to local economies, like in La Paz Bay. In the late 90's you could see whale sharks around La Paz Bay on route to one of the popular islands in the area. By the 2000's some people started providing trips, offering the experience of swimming with the biggest fish on Earth. Problems occurred as a result of increased boat traffic coupled with a lack of guidelines to perform the activity. La Paz city is one of the most highly populated coastal areas in the Gulf of California and has the highest growth rate (2.6%) in the state. Whale shark tourism has also increased, from 26 authorized boats in 2006 to 109 in 2013. In contrast, the mean of the yearly abundance of sharks is 56, highlighting a capacity building issue. This is evidence that the whale sharks represent an important part of the economy of the city, and presents us with a challenge to protect it. Approach InLa Paz Bay we have maintained a whale shark monitoring program since 2004. Studies include abundance, fidelity, seasonality and injury analysis. Injury analysis from 2004–2008 showed that up to 54% (18 of 33) of sharks had been hit by boats. In 2006, with the collaboration of the Mexican government, a Code of Conduct was generated for whale shark tour operators. In order to enforce the management, each year since 2009 the tour operators are trained and a dissemination program is designed with the aim of communicating the code of conduct with a focus on private boats. The success of the management is measured by fresh injury analysis. Results Betweenseasons 2004/2005–2014/2015, 380 whale sharks were identified; of these, 49 (22.3%) returned between years. During the season, sharks spend periods of between 40–70 and up to 200 days in the area before leaving the Bay. Seasonality varied in some years but the common season runs from September to February. Without considering the extreme years, the abundance per year is estimated from 20 (95% CI =16–31) to 71 (95% CI= 65–85, 95% SS) sharks, with a mean of 56. Fresh injury analysis from 250 identified sharks, 135 (54%) had fresh injuries present. Of these, 60% were abrasions, 30% both abrasions and lacerations, and 9% had only lacerations. The trained personal from the tourism companies has increased from 33 in 2009 to 88 in 2014. From 2009–2012 careful monitoring of the whale shark population revealed that the affected sharks decreased by 26% (from 61 to 35%). Although these numbers increased again over the last two years, up to 64% (70 of 109 sharks) during the 2014/2015 season, this was perhaps because the sharks remained in the Bay for a longer period of time. Conclusions Morethan 10 years of monitoring have been key to establishing La Paz Bay as a critical habitat of the species, which needs to be protected. This study has been helping to measure the success of the management, which still needs to be enforced by the government and engaged by the community. The changes in abundance and seasonality need to be considered for a carrying capacity study. When tour operators and the community are engaged in promoting the rules it can reduce harm to whale sharks, as in 2009–2011. The increase in permits and lack of enforcement will increase negative effects on whale sharks.
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The whale shark genome project
المؤلفون: Timothy D. Read, Md. Tauqeer Alam, Robert A. Pettit, Chad Haase, Ryan Weil, D. Harry Webb and Alistair D.M. DoveBackground The whale shark forms an interesting subject for a genome project because it represents a phenotypic extreme: the largest body size of any piscine vertebrate. Sharks are also important comparative genomics subjects because they were the first vertebrate lineage to evolve and adaptive immune response. To date, however, no shark has had its complete nuclear genome sequenced and assembled. Approach Sequencing and assembly of the whale shark genome has been underway for almost 6 years, based on tissue samples from animals in the collection at Georgia Aquarium. Initial efforts focused on 454 pyrosequencing, and later Illumina sequencing. The most recent assembly has incorporated longer-read sequence data acquired using Pacific BioSciences technology. For the genome assembly we used a de novo approach. Results We estimate the total whale shark genome size at 3.44 Gbp, 3.5x larger than that of the closest related species for which whole genome data exist, the holocephalan Callorhinchus milii (950 Mbp). The mitochondrial genome is of fundamentally similar structure to that of other elasmobranchs and whole mitogenome phylogeny affirms the accepted phylogenetic placement of this species among the Orectolobiformes. Conclusions The availability of the whale shark genome will facilitate detailed investigations of global population structure that are a necessary precursor to effective conservation management. Moreover, whale shark genome sequence should find use in comparative studies of evolution, immunology and metabolism. Those interested in collaborating on such studies should contact the authors.
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Sustaining whale shark tourism in a diminishing population
المؤلفون: Katie E. Reeve-Arnold, Joonas Kinni, Ross Newbigging, Simon J. Pierce and Kim RoquesBackground Tofo, Mozambique has been reported as having a year-round whale shark population (Pierce et. al., 2010). An important facet of Tofo's tourism industry, which forms a large part of the area's income, has grown up around this whale shark population. Sustainable tourist interaction was investigated and a Code of Conduct voluntarily imposed. However a decline in whale shark sightings in Tofo has brought the sustainability of this population and ecotourism approach into question. Approach Commercial whale shark snorkelling trips have been routinely accompanied/participated in from 2008 to present. Photo identification records have been collected to establish residency, seasonality and other sighting trends. Whale shark encounters, tourist and whale shark behaviour and environmental information are routinely recorded. Surveys of tourists were conducted to elucidate motivation, code of conduct compliance, local economical benefit and satisfaction amongst other factors. Results Over the 8 year study period a decline in whale sharks seen on snorkelling trips in Tofo was observed. These data demonstrate a drop from 1.35 whale shark encounters per snorkelling trip, and a 65% chance of an encounter on any given trip (analysed over a 12 mth period in 2011/12) to just 0.54 whale shark encounters per snorkel trip, and just a 35% chance of an encounter on any given trip (over a 12 month period in 2015/16). For the tourism industry this literally translates as replacement of the phrase ‘you are likely to see a whale shark’ with ‘you are not likely to see a whale shark’ on any given snorkelling trip. Both numbers of new sharks seen and re-sightings have fallen. Photo ID collaboration with the international whale shark database shows no evidence that large numbers of Mozambique sharks have migrated to other aggregation sites, suggesting the ecotourism location has not simply shifted. Whale shark specific tourism has become very important to the economy of Tofo and Mozambique as a whole. Interviews of tourists currently in process, will address the satisfaction of those who participate in snorkel trips and the durability of this industry in light of the falling population. Conclusions The whale shark encounter rate in Tofo has significantly declined. However, this need not result in the abortion of this successful ecotourism approach, which has made whale shark conservation financially important in Mozambique. Whale sharks may still be used as an important attractant but tourist satisfaction should/can be maintained, despite reduction in sightings, through diversification of snorkelling goals. These findings develop new approaches to facilitate ongoing whale shark-friendly ecotourism in all locations where whale shark sightings are in decline. This study depicts a way forward which maintains the financial value of whale sharks, so continuing to encourage their conservation and study.
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Where the whale sharks are: An innovative satellite tagging programme to track the movements of whale sharks from Ningaloo Reef, Western Australia
Background Coastal aggregations of whale sharks, typically dominated by juvenile males and occurring seasonally, are now documented in many places around the world, including Ningaloo Reef, Western Australia (WA). This aggregation occurs during the Austral autumn and winter and supports a lucrative tourism industry which operates during the whale shark “season” (generally April – July). Despite being one of the most highly studied aggregations of whale sharks in the world, their location and movements outside this period remain poorly understood, but are critical for understanding long term population dynamics and for effective management and conservation. An earlier study by ECOCEAN, combining satellite tracking and citizen science sightings of whale sharks outside the “season” at Ningaloo Reef and elsewhere along the WA coast, indicates that whale sharks may move north and south along the coast throughout the year, and/or make relatively short migrations, rather than undertaking long, trans-oceanic migrations. To test this further, a novel satellite tagging programme, supported by The Western Australian Department of Education (The Department), aims to discover where the whale sharks are when they are not at Ningaloo Reef and determine whether there are other unidentified “hotspots” for foraging and/or migration, i.e. areas of habitat critical for whale sharks. This programme also aims to provide innovative learning opportunities for school children, to make them more aware of the biology and ecology of WA's marine emblem and the marine environment, as well as to encourage engagement with STEM (Science, Technology, Engineering and Maths) learning. Approach Satellite tags (Wildlife Computers SPOT tags) were deployed on 12 whale sharks (identified using photo-identification through the Wildbook for Whale Sharks) at Ningaloo Reef in July 2015 using a custom-made clamp attachment on the first dorsal fin, designed to have minimal impact on the animals. Tags were funded by 16 schools from around WA participating in a joint ECOCEAN - Western Australian Department of Education science learning programme. Tracks of the sharks are displayed publically on the ZoaTrack website (www.zoatrack.org/projects/243/ analysis) and were used by participating schools in an eight week teaching programme. Results Data from satellite tags deployed in 2015 are still being collected and will be analysed as part of an Honours project in 2016, however, the teaching programme proved highly successful: The Department developed a comprehensive suite of resources addressing science, technology, engineering, mathematics and arts subjects to support students to engage in authentic learning experiences, and classes from pre-primary through to senior high school were involved. Preliminary results from the tags show that all have successfully reported positional data, for periods ranging from 15 to 156 days (mean 93.4 ± 13.1 SE) (as at 31/12/15). Homing migrations, to the southern part of Ningaloo Reef, have been recorded for 50% of all the sharks tagged, within periods ranging from 44 to 93 days (mean 65.7 ± 7.8 SE). These data show sharks making short forays away from Ningaloo Reef, and reveal areas important for commuting and foraging. Conclusions This innovative approach to funding allowed the satellite tracking programme to proceed and not only provided new information on the movements of whale sharks from Ningaloo Reef that can be used for conservation planning and management, but also provided novel learning experiences for school children and raised awareness for whale shark conservation and the marine environment. The data gathered support the hypothesis that whale sharks from the Ningaloo Reef aggregation do not typically undertake ocean basin scale migrations, rather they make shorter forays, perhaps to exploit food resources that vary spatially and temporally, and could be used to benchmark conservation outcomes for WA whale sharks and to provide pathways for more effective protection.
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Managing the impacts of tourism on the Ningaloo whale shark aggregation – asking the right people the right questions
المؤلفون: Dani Rob and Peter BarnesBackground The Department of Parks and Wildlife manages the whale shark tourism industry within the Ningaloo Coast World Heritage Area, Western Australia. Guided by the Wildlife Management Program no. 57, Whale shark management with particular reference to Ningaloo Marine Park, the Department licences and monitors the activity of 15 commercial tour operators. A key strategy in the Management Program is to continue to research and monitor the impacts of whale shark interaction tourism on whale sharks in Ningaloo Marine Park, providing an on-going challenge. Approach This presentation will discuss the utility of the various approaches taken by both the Department and researcher activity licensed by the Department. These include the use of electronic monitoring systems on board the commercial tour operators' vessels which document encounter duration, photo identification of whale sharks, aerial behavioural monitoring and archival, acoustic and satellite tagging. Results As a management agency, the Department has identified a number of questions as outlined in the Management Program that aim to determine the level of impact on whale sharks. Potential impacts on whale sharks can arise from a number of anthropogenic sources including tourist vessels, recreational vessels and research activity. Finding the appropriate methodology to answer these questions is the key. Encounter duration is useful for determining short-term intra-season impacts. Photo identification catalogues combined with satellite tagging have been useful for determining longer-term inter-season return rates. Acoustic tagging will reveal patterns of residency while archival tagging has the potential to allow detailed behavioural studies. Photo identification also allows the analysis of scarring and potential impact on survival of the whale sharks visiting Ningaloo Marine Park and where possible can attribute scars to anthropogenic sources. Aerial monitoring of whale shark behaviour allows us to study whale shark swimming behaviours and direction in the presence and absence of vessels and swimmers. Conclusions Understanding and managing the impacts on whale sharks is a complex, challenging task. A single method cannot determine disturbance level on whale sharks. Determining which approach is appropriate to the given question and drawing upon the expertise of others to make informed management decisions is paramount and we will continue to take a multidisciplinary approach.
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Satellite tracking of whale sharks from Al Shaheen
المؤلفون: David P. Robinson, Steffen S. Bach, Ali A. Abdulrahman and Mohammad Al-JaidahBackground The Qatar Whale Shark Research Project is a collaboration of government, industry and academia founded in 2012 to investigate anecdotal reports by Maersk Oil-platform workers of large numbers of whale sharks seen in the Al Shaheen field, Qatar. Approach The Qatar Whale Shark Research Project is a collaboration of government, industry and academia founded in 2012 to investigate anecdotal reports by Maersk Oil-platform workers of large numbers of whale sharks seen in the Al Shaheen field, Qatar. Results Satellite tracking of whale sharks tagged in Al Shaheen showed that they prefer depths in excess of 40 m and rarely made dives deeper than 100 m. Temperature preferences were between 27 °C and 33 °C but the sharks were shown to regularly feed in temperatures in excess of 35 °C. Sharks were seen to aggregate in the Al Shaheen region in the summer and disperse widely throughout the region in the winter months outside of the tuna spawning season. The majority of sharks stayed within the Arabian Gulf and Gulf of Oman. Only one shark ventured southwards and left the study area where the tag popped off between Somalia and Socotra. This exceptional and large-scale horizontal movement was made by a visibly pregnant 9 m female whale shark. A previously unknown area of interest was discovered in Saudi Arabian waters 126 km North-West of Al Shaheen and 100 km offshore off Al Jubail, which could possibly be a new aggregation site for whale sharks in the Arabian Gulf. Conclusions Whale sharks tagged in Al Shaheen distributed throughout the Arabian Gulf and Gulf of Oman outside of the Al Shaheen tuna-spawning season and only one large female left the area entirely. The size of whale sharks tagged in Al Shaheen was defined by occurrence and ranged from 4–10 m. The absence of smaller or larger sharks suggest that these animals demonstrate a different movement strategy, and that this region may be a staging post for sub-adult and recently mature individuals. When not feeding in Al Shaheen, whale sharks spend little to no time at the surface. No notable difference in habitat preference was noted between male and female or juvenile and mature animals. Individual sharks display different behaviour and movements patterns, assessment of individuals and their unique behaviour is necessary to help determine the behaviour of the species. Areas of interest identified through the satellite tagging initiative warrant further investigation, especially the site of Al Jubail in Saudi Arabia that appears to be another significant aggregation site.
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Caught in the net: A small, resident group of whale sharks feeding among fishing boats
Background Off Mafia Island, Tanzania, whale sharks are seen in a small bay that also boasts one of the country's largest coastal fisheries. We set out to determine the population structure of whale sharks here, examine their feeding behaviour and residency, and investigate the interaction between the sharks and fishers. Approach We conducted 261 boat-based surveys at Mafia Island between Oct 2012 and Dec 2015, recording all whale shark sightings as well as counting the numbers of tourist and fishing boats in the survey area during each trip. We estimated shark size visually and with laser photogrammetry and recorded sex, scars and behaviour of each shark. To examine residency, we deployed 67 acoustic tags on whale sharks and 19 receiver stations within the bay, and analysed recapture probability (both visual- and acoustic-based) with generalised additive mixing models. To investigate feeding plankton biomass and community structure, we collected 20 plankton samples when whale sharks were feeding and 202 background samples for comparison. We interviewed fishers and they recorded their fishing locations using a GPS. Results We identified 129 different whale sharks at Mafia Island, 54% of which were resighted in two or more years. Tagged sharks were acoustically detected throughout the year even though sightings were largely limited to Oct-Mar. Sharks ranged in total length from 2.5–9.7 m, were mostly male (87%), and were usually seen feeding (75%) at or near the surface. Dense patches (25 mg m–3) of large sergestids Lucifer hanseni prompted feeding, while background plankton tows were dominated by small copepods (2.5 mg m–3). Small and medium-sized planktivorous fishes also fed on the same patches of sergestids, often together with whale sharks. These smaller species were the main target of the local fishers. Fishing boats operated in the survey area on 90% of the time, but also made catches further afield. Fishers reported a conflict between whale sharks and their fishing operations on 36% of the time, although sharks were usually released from the nets without injury. A mean of 2.6 tourist boats per day searched the same survey area for whale sharks. Conclusions This small, resident group of whale sharks is routinely exposed to tourists, boat traffic and high fishing pressure. Whale sharks are commonly encircled in fishing nets and released, but scars indicate that they do occasionally get injured during this process. Mortalities are rare, based on interviews with fishers and long-term observers. Whale sharks at Mafia Island are unusually resident and face clear local threats. No defined management measures are currently in place, but we present some potential strategies for mitigating threats to whale sharks here.
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Djibouti – a kindergarten for whale sharks?
المؤلفون: David R.L. Rowat, Savinien T. Leblond, Bruno Pardigon, Michel Vely, Daniel Jouannet and Imogen A. WebsterBackground An aggregation of juvenile whale sharks were first reported off Arta, Djibouti, in 2003 and formally investigated in 2006. Standardised monitoring started in 2009 to establish the demographics of this aggregation and how it relates to the broader Red Sea and Indian Ocean whale shark population. Approach Photo-identification images have been collected from 2003 to present. Satellite relayed archival tags have been deployed to show longer term movements and tissue samples have been collected for DNA. Plankton and environmental information are routinely recorded. For the last two years digital Photo-IDs were collected by volunteers at the local dive operation to enable a longer annual study period to help establish seasonality and sighting trends. Results During 2003–2015, a total of 503 individual sharks were identified by photo-identification from more than 6300 in-water encounters; a maximum of 181 individuals were recorded in a single year. Overall 85% of sharks identified were males and mean body total length ranged from 3.5–4.3 m among years, with no significant difference between sexes. Sharks which were sighted in more than one year had a mean period of inter-annual residency of 4 years (maximum 11 years, n=3). Using data from 2003–2015, mark and recapture models estimated a gross population of 660–777 with 53–78% of individuals being re-sighted in any one year. Satellite tag data showed tagged individuals left the immediate area and travelled into the Red Sea and Northern Indian Ocean; however, 2 of the 3 PAT tagged sharks were seen off Djibouti in subsequent years. Diving depth data showed all sharks made short duration dives to depths greater than 400 m (maximum 832 m) but that all spent at least 45% of the time within 10 m of the surface and an average of 73% of the time shallower than 40 m. Comparison with plankton and environmental data showed that sharks were associated primarily with high plankton concentrations and swimming crab (possibly Charybdis erythrodactyla) spawning events. Conclusions The Arta area off Djibouti is host to a regular and significant aggregation of whale sharks. The average size of the sharks is smaller than those found in other Indian Ocean coastal aggregations suggesting that this may be an intermediate or kindergarten group from which the sharks will leave as they grow to join other juvenile aggregations. Satellite tracking and photo ID support the movement of sharks into Red Sea aggregations.
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Increasing numbers of whale sharks along the Andhra Pradesh coast, India – the conservation and management initiatives taken by EGREE Foundation
المؤلفون: P. Sathiyaselvam, P. Prashanthi, Tarun Kathula, M. Ravi Kumar, Ramesh G. Kalghatgi and S.B.L. MishraBackground The whale shark conservation programme along the East Godavari River Estuarine Ecosystem (EGREE) region, of Andhra Pradesh, east-coast of India, was started in June 2012 under the direction of the Government of India, the United Nations Development Programme, the Global Environment Facility and the Government of Andhra Pradesh Godavari Project. It was started for the conservation and management of globally threatened species protected under the Indian Wildlife (Protection) Act of 1972, and employing cross sectoral mechanisms among various stakeholders, namely enforcement departments (state and central governments), production sectors (industries), fishermen and the public. Approach Questionnaire surveys are conducted to learn the present status of whale sharks along the Andhra Pradesh Coast, and literature surveys are done to understand the past and present whale shark distribution along the east coast of India. Major fish landing centres are monitored to record whale sharks landings, including seasonality, size and sex ratio. Massive awareness programmes and campaigns are conducted to improve the knowledge levels of various stakeholders. A whale shark conservation action plan is being prepared for the Andhra Pradesh coast by cross sectoral mechanisms. Results Fishery experts, researchers and local fishermen opined that until late 2007, the whale shark was a rare visitor to the EGREE region, but the number of sharks has increased in recent years. According to fishermen, whale sharks are seen at a depth of 20–40 m and sometimes come close to shore where they become entangled in shore seine nets. The fishermen revealed that whale sharks are seen mostly solitary or in small groups of 3 to 5 individuals, but sometimes over 200–300 individuals will aggregate in the open sea near the EGREE Region. As per the available literature, the total number of whale sharks killed as bycatch was 20 along the Andhra Pradesh coast between 1889 and 1998 (110 years). But surveys by the EGREE Foundation that between June 2013 and January 2016, 79 individual whale sharks were killed. The whale shark landings happened in all months except during the fishing ban from 16th April to 15th June. In September of 2014, 22 whale sharks were brought to the landing center. Of these 22 sharks, four were alive after being caught in a shore-seine fishing net. Both questionnaire and field surveys revealed that coastal and marine areas of the EGREE region have become a hot spot for whale sharks in recent years. The size of the whale sharks brought to the landing centers ranged between 2.1–6.68 m (mean 3.71±SD 1.04, n=44), and males (58%) outnumbered females. Based on the study, conservation and management measures are being taken by the EGREE Foundation through 1) massive awareness programmes to sensitize the fishermen and local public, 2) education and awareness applied to students and elected representatives of state and central governments, and 3) training of enforcement staff such as the Indian Coast Guard, Marine Police, Fisheries, Forest and Customs and Central Excise. A whale shark conservation action plan is being prepared for the Andhra Pradesh Coast by involving various state and central government departments, production sectors like oil & gas operators, and private port operators, local fishermen and policy makers. Conclusions This study indicated that whale shark numbers have increased and a globally significant aggregation of whale sharks is happening in the coastal and marine areas of EGREE region. Long-term research and monitoring is needed in this region.
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Long-term husbandry and physical observation of the whale sharks in Okinawa Churaumi Aquarium
المؤلفون: Keiichi Sato, Rui Matsumoto, Kiyomi Murakumo and Kiyoshi AsahinaBackground Okinawa Churaumi Aquarium has established a long-term husbandry program for whale sharks since 1980. Currently, three individuals (1 male and 2 female) are housed in the 7,500 m3 capacity main exhibit tank. The male shark was caught by a set-net on March 11, 1995, and it measured a total length (TL) of 460 cm; a subsequent measurement in December 2015 revealed the TL had increased to 865 cm. The corresponding TLs of the female sharks that have been housed in this facility for nine and eight years were 762 cm and 787 cm, respectively. The growth rate, hormonal trends, quantity of food ingested, behaviors, and other physical changes along with maturation of these sharks are presently monitored. Approach The total length of each whale shark was estimated by measuring the length between the snout tip and the first dorsal fin using an equation formulated by us. Periodic measurements of the girth at the posterior margin of the pectoral fin have been recorded since May 2014. For measuring hormonal levels, blood was collected underwater from free-swimming individuals and plasma samples were extracted. The plasma concentration of steroid hormone was measured using time-resolved fluorescent antibody analysis. This data has been collected since May 2008. The quantity of food consumed and the feeding behavior of the whale sharks are recorded each day. Results The TL of the male whale shark increased from 460 cm to 744 cm by March 2005, at an average annual growth rate of 28 cm/year. Since 2005, there has been a decrease in the growth rate, to 12.5 cm/year. The two females have been growing at an annual rate of 33 cm/year (TL = 762 cm) and 37 cm/year (TL = 787 cm). Our data shows that the rate of change of girth appears to be associated with calorie intake. The plasma concentration of steroid hormone of the male shark increased from June 2011 to June 2012 (21.49 ng/ml; TL: 850 cm). This appears to be in synchrony with the rapid elongation of the claspers. Additionally, since April 2012, we have been observing the male shark rotating its entire body laterally crossing both claspers, which is a behavioral indication that the male has reached maturity. Conclusions From our long-term study on captive whale sharks, details on direct observations on the maturity process, growth rate, required food consumption, behavioral patterns, and proportional measurement changes are available. Based on these details, we expect that future attempts for reproduction in captivity would be successful and would allow us to unravel many mysteries of whale shark reproduction.
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Whale shark genetics: Where are we now and where should we be going?
المؤلفون: Jennifer V. SchmidtBackground Classic ecological approaches can reveal only glimpses of the behavioral spectrum of a longlived migratory species. Genetic analysis has the potential to inform the migratory behavior and reproductive habits of animals that are difficult or impossible to observe in the wild. Although studied primarily as juveniles at seasonal feeding aggregations, whale sharks are believed to be capable of extensive migrations. The frequency and magnitude of these movements is unknown, as is the degree to which they mediate gene flow between populations. Recent studies have asked whether the sharks observed at different aggregation sites show evidence of genetic structure, or whether they constitute a single breeding population. We published a preliminary study in 2009, based on microsatellite analysis of animals from numerous globally distributed aggregation sites, with a finding of minimal genetic differentiation. Approach Our genetic study is ongoing, and now encompasses hundreds of whale sharks representing all major aggregations worldwide. Other groups have also performed genetic analyses of whale shark population structure, focusing on both regional and global scales. Particularly for studies using microsatellite markers, direct comparisons across laboratories and platforms are not possible. Synthesizing the overall conclusions from aggregate genetic studies, however, provides additional power to understand species behaviors. Results Initial analysis of broadly distributed whale sharks found only low levels of genetic differentiation across geographically distinct populations. While sharks from the Western Atlantic Ocean showed slightly greater differentiation from Pacific/Indian Ocean animals than these populations did from each other, this result was not statistically significant. An expanded data set has now provided stronger analytical resolution between populations, revealing subtle yet statistically significant levels of genetic differentiation of Atlantic sharks. Conclusions Our previous analysis suggested gene flow between whale shark populations at a level sufficient to normalize genetic differentiation. Combined with satellite tracking and other data, these results confirmed that whale sharks can and do migrate between oceans. An expanded study, however, along with data published by other groups, now indicates reduced mixing between Western Atlantic and Indian/Pacific sharks. A significant body of evidence therefore indicates that whale sharks do not have strong population structure, nor do they represent a single panmictic population. Rather they occupy a more biologically realistic intermediate, with varying degrees of isolation by distance and by ecological features. Future genetic characterization should focus on the addition of yet unstudied whale shark populations, on building a robust mitochondrial haplotype dataset with broad applicability, and on technical standardization that could allow comparisons between microsatellite data sets across laboratories and platforms.
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Global shark protection
المؤلفون: Ralf P. SonntagBackground Sharks have been exploited over decades with very little or no management at all. This had devastating effects on many shark populations around the world. A recent report published by the IUCN Shark Specialist Group in 2014 showed that globally close to 25% of sharks and rays are threatened with extinction. They face more threats today then ever before in history. Primary drivers for this overfishing, as well as much of the bycatch related mortality, is the demand for shark fins used in shark fin soup, the demand for cheap shark meat and other traditional products, as well as the lack of management control along the whole trade chain. Approach In this respect CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) is a good instrument to help in achieving a more sustainable use of sharks and a more species specific management. Another global convention to adress this issue is the Convention on the Conservation of Migratory Species (CMS) and the associated “Sharks MoU.” However, one of the arguments used against further listing of shark species in these conventions is the difficulty of implementation and enforcement. To address this issue, many governments were approached with the offer to do implementation workshops by different NGO's. An important aspect of these workshops is the training of the participants to identify protected species or parts, especially fins, of these animals. Results Whale sharks were among the first two species which got some international protection through their listing on App 2 in CITES in 2002. This has been followed by a rising awareness and additional protection in CMS, different regional fishery regulations or national regulations. This was supported by a whole series of workshops organized by different NGOs, governments and CITES. This has led to a better understanding of the issue and subsequently to additional listings of sharks and manta rays during the last CITES conference in 2013 in Bangkok. Conclusions Since then, aditional workshops have been held and will hopefully lead to better data collection, a more species specific management and ultimately enhanced protection of sharks. They will hopefully help officials in fishery and customs to implement and enforce these new regulations to better manage sharks. First results show positive effects especially in the Middle East and aditional species are proposed to be listed in the above mentioned conventions. This talk informs about international protection of whale sharks and about the recent new CITES and CMS listings of sharks – what they mean and the efforts and global cooperation between NGOs and governments to get there.
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Vertical movement patterns of juvenile whale sharks Rhincodon typus at a seasonal aggregation in Saudi Arabian Red Sea
Background Large marine species have been a focus of scientists and public for their unique role in the ecosystem as well as in conservation. To study the behaviors of large marine species, electrical tagging is a direct and reliable method. Researchers have been utilizing technology advances in biologging tags on multiple spatiotemporal scales. This study provides a detailed insight into the vertical movement of whale sharks in a newly described seasonal aggregation off the coast of Al Lith, Saudi Arabia. Approach In the aggregation season of 2015, two biologging tags were fitted on two juvenile whale sharks and lasted over a period of 22 hours each. Fine-scaled diving behavior was recorded with a sampling rate of 10 Hz and energy consumption was generated from acceleration sensory data. Results Tagged whale sharks exhibited intensive and consistent diving behaviors throughout the day except a prolonged surface swimming in the morning and a brief surfacing around sunset. Deep dives from the two tagged sharks reached 80 meters, which is the depth of this aggregation habitat. In multiple stages of the diel cycle, whale sharks utilized different depths in the water column. Diving speeds also varied among diel stages and between two individuals, most possibly as a strategy of optimizing energy consumption from forage efforts. Combining with previous study on horizontal movement of whale sharks in this aggregation, this study portrays movement behaviors of juvenile whale sharks comprehensively. Conclusions Whale sharks in this aggregation showed a distinct diel vertical movement pattern which also effectively utilizes energy. We hope this study will benefit the management of this hot spot of whale sharks and even larger scale ecosystems, revealing potential excessive human activities (e.g. ecotourism, aquaculture) and global climate issues.
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Photo ID-based assessment of the whale shark (Rhincodon typus) population in Kwatisore, Wondama Bay, West Papua, Indonesia
المؤلفون: Sampari Suruan, Bayu Pranata, Casandra Tania and Mohammad M. KamalBackground The presence of whale sharks (Rhincodon typus) in Wondama Bay has long been known and the species is an icon of this region. In addition to their enormous size, these sharks are not dangerous to or fearful of humans, so there has been growing interest in utilizing this animal for eco-tourism. Within Wondama Bay, whale sharks distribute in several regions, including Kwatisore waters. Since biological information on this species is lacking, the present study aimed to investigate the whale shark population using photo identification, frequency of appearance, sex, and scars on the body. The information obtained from this study is important for species conservation and management. Approach The research was performed in Kwatisore waters of Wondama Bay during 2010–2013, and continued from April to June 2014. Whale shark identification was based on photos taken by divers by plotting three reference points, i.e. the top of the fifth gill slit, the posterior-most point where the pectoral fin meets the body, and the bottom of the fifth gill slit (Brooks et al., 2010). During each encounter, the animals were length measured, sex was identified through the presence or absence of claspers, and the position of scars and wounds were determined on the body. Results The total number of whale sharks encountered in Kwatisore waters were 120 and 19 animals for the period of 2010–2013 and 2014, respectively. Based on ID pictures, the population was composed of 126 sharks consisting of 122 males and 4 females. With regard to 2014 observations, the animals were all males and were immature, as the average body length was 4 m. The greatest number of sharks was observed between 0600–1200 hours, during which time 80 individuals were seen on the surface. It was found that 58% of the population had scars and wounds, of which 34% were on the lips and 25% on the fins. Conclusions Data on IDs and body length of each individual, as well as sex composition, are important information for understanding whale shark population structure, and will benefit the conservation and management of these animals.
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Characteristics of whale sharks (Rhincodon typus) in Teluk Cenderawasih National Park, Indonesia
Background The whale shark (Rhincodon typus) is an iconic species for Teluk Cenderawasih National Park (TCNP), West Papua and Papua. They appear regularly near lift-net fisheries (bagans) year round in some areas, especially near Kwatisore in West Papua, resulting in the development of limited tourism since 2009. The objective of our study was to document the characteristics (i.e., number, size, sex) of whale sharks that occur in TCNP. Approach We used photographs to identify whale sharks from natural patterns and other body markings that periodically appeared near operational bagans in southern Cenderawasih Bay. The photo ID technique was used to identify each individual based on the white body spot pattern. We also made subjective estimates of the relative sizes of each shark and determined whether they were male or female from the presence or absence of claspers. Results We obtained 8,530 photos of sharks from February 2010 through June 2015. From that database we tentatively identified 126 sharks, 83% of them male, 14% female and 3% undetermined. The estimated length of the sharks averaged 4.4 m (± 1.25 m, range = 2 m to 8 m). Around 40% of the individuals had scars, mostly around their mouths and fins. Most (59%) of the sharks were seen in one year, while only 3% were seen over more than one year during the five year study. Some exceptions were one shark that was seen 32 times over four years, and another that was seen 29 times over five years. Conclusions Juvenile male whale sharks appear to be transient and highly mobile in Cenderawasih Bay. Whether adult males or adult females occur here is not known, as they may not be attracted to the fishing bagans or do not otherwise approach the sea surface where they can be observed. Because of the increased tourism for whale sharks and the interactions of whale sharks with the fishing bagans, we recommend continued systematic observations of whale sharks and vigilant surveillance for understanding the dynamics of interactions among tourist activities, fishing operations, and whale sharks.
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Whale shark behavior with swimmers and boats present during tourism activities in the northern Mexican Caribbean
مزيد أقلBackground Whale shark watching and swimming are two of the most popular activities for tourists in the northern Mexican Caribbean. Each year since 2002, these activities have had an exponential growth, which could represent a hazard for whale sharks. It is important to monitor the tourism effect on whale shark behavior to take sustainable management measures concerning the use of this natural resource. Approach Whale shark behavior monitoring was conducted from June to September in 2014 and 2015. In order to know the effects of tourism activities and their influence on feeding behaviors and diving paths shown by whale sharks, we conducted surveys to observe whale shark behavior with and without tourism activities (swimmers and boats). Results The monitoring effort in 2014 and 2015 for whale shark surface behavior includes 571 minutes on video, of which 414 minutes include whale shark behavior during tourism activities, and 157 minutes without tourists present. In 2014, 26 whale sharks were observed without tourism activity, and 56% of these sharks showed ram feeding behavior near the surface from the beginning to the end of the observation. 42 whale sharks were observed with tourism; at the beginning of the observation 48% of these sharks presented ram feeding behavior near the surface, but this behavior decreased to 29% to the end of the observation. In 2015, only 7 whale sharks were observed without tourism interactions; 57% had ram feeding behavior from the beginning to the end of the observations. 51 whale sharks were observed with tourism interactions, where 31% of these sharks had ram feeding behavior at the beginning of the survey, but it decreased to 27% by the end of the survey. For 2014, the main behavior was ram feeding behavior. In 2015, the main behavior showed by whale sharks during tourism interactions was diving path behavior (37%). Conclusions Tourism activity might have an effect on whale shark behavior and on surface sightings, indicating a decrease in the surface feeding time in one of the most important feeding aggregations for whale sharks in the northern Mexican Caribbean. Precautionary measures are necessary for adaptive management of tourism activities and the whale sharks in this area.
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Horizontal and vertical movements of the whale shark, Rhincodon typus, in the southern waters of Japan
Background Conservation of whale sharks is making remarkable advances through many studies ongoing in tropical and sub-tropical oceans. However, there have been few studies in the North Pacific Ocean. Some whale shark appearances, as well as by-catch by set-net and purse seining in the southern waters of Japan are reported every year. These waters are important for the conservation ecology of whale sharks because they are the northern limit of the whale shark's distribution and have high productivity influenced by the Kuroshio and Oyashio Currents. However, the habitat and movement of whale sharks around Japan in the North Pacific Ocean are poorly understood. Approach To investigate the habitat and movement of the whale shark, two whale sharks were tagged with PAT-tags (MK-10, Wildlife) and released off the coast of Kouchi, Japan in October 2013 (WS13: 4.2 m in total length) and June 2014 (WS14: 7.2 m). For biological studies and rearing trials, WS13 had been reared for 6 years and 4 months in the Osaka Aquarium of KAIYUKAN, Osaka, and WS14 had been reared for 4 months in the Osaka Aquarium Biological Research Institute of Iburi Center (OBIC) of KAIYUKAN, Kochi, Japan before tagging. The PAT-tags recorded ambient temperature, swimming depth and light level data for 30 and 90 days, respectively, until the detached from the whale shark. After the PAT-tag detachment, the tag floats to the surface and transmits the sampled data via the Argos satellite system. Geolocations of tagged sharks were estimated using light measurement data from the tag and sea surface temperature from the satellite. The horizontal and vertical movements were examined in relation to oceanographic conditions. Results The two sharks moved in the same direction to the east along the Kuroshio Current after being released, despite being released in different seasons. However, WS13 remained in the eddy in the south of the Kuroshio Current, while WS14 crossed the Kuroshio Current to north and remained in the eddy near the Kuroshio-Oyashio transitional area. The total distance WS13 traveled was 1,407 km over 30 days (48.5 km/day), and WS14 traveled 3,022 km over 90 days (29.0 km/day). The mean daily speed while moving along the Kuroshio Current was higher than while remaining in the eddy for both sharks. The primary swimming depth was surface mixed water where the temperature was above 20 °C. The two sharks spent most of their time near the surface above 10 m depth. Diving over the mesopelagic zone (>200 m depth) was rarely observed while the two sharks were traveling along the Kuroshio Current, and wasn't observed while the sharks remained in the eddy. The maximum swimming depth for WS13 was 632 m, and for WS14 was 1560 m, and lowest temperature recorded was 7.1 °C for WS13 and 2.4 °C for WS14 when the sharks were at their maximum depth. Conclusions In southern waters of Japan, horizontal movements of whale sharks are influenced by the Kuroshio Current and the eddy. Their vertical movements are regulated by the thermocline and the threshold temperature was around 20 °C
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Applications for genetic inference to characterise a cryptic life-stage in the whale shark
Background Research efforts on whale sharks have so far been limited to sub-adult males which make-up the vast majority of aggregations around the world. The movements of mature sharks, their reproductive techniques and key habitats remain poorly understood, whilst details of this demographic group are the most important to mitigate current threats. This quandary qualifies the use of indirect analyses such as genetic inference to characterise cryptic life-stages of the species. Approach Tissue samples will be collected from free-swimming whale sharks from locations around the WIO with past biopsy efforts providing additional tissue from every tropical ocean. Photographic identification, approximate visual size and gender information will be recorded for each individual. Microsatellite markers will be extracted from the samples using species-specific primers from previous studies. Additional open access sequences will be obtained via GenBank for appropriate locations. Software packages simulating modes of inheritance such as GERUD will be used to reconstruct parental genotypes. Results This is an outline of potential results of the study. Parental genotype reconstruction can provide information on: 1) Number of parents per litter – maternal genotypes will be reconstructed first as the likelihood of sampling littermates is higher than sampling offspring from different females who happened to mate with the same male. Paternal genotypes can be determined once the maternal genotypes are removed from the progeny sequences. 2) Juvenile recruitment – survival rate of individuals per litter, considering however that juvenile female whale sharks are underrepresented in the majority of sampling areas. Incomplete reconstruction of a parental genotype suggests incomplete offspring sampling. 3) Reproductive mode – i.e. monoor polyandry, demonstrated by single or multiple male genotypes per litter (respectively), which may confirm or refute the single only other demonstration of reproductive mechanism, monandry, in the species. 4) Breeding site fidelity – common and complete parental genotypes of either or both parents within an aggregation or in associated areas (assuming monandry) suggests that whale sharks return to or remain in a common area to pup whereas multiple incomplete genotypes may suggest random dispersal from any given pupping site. Conclusions The reproductive patterns of mature sharks, as inferred by these analyses, will define whale shark movements within their circumglobal range and may highlight important habitats such as breeding or pupping grounds. Resources for protecting the species will be limited and so must target these groups and areas to be most effective at mitigating threats and conserving the species.
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Improving laser-photogrammetry precision for estimates of whale shark total length and applying them to a previously unstudied aggregation of whale sharks at St. Helena Island
المؤلفون: D. Harry Webb, Elizabeth Clingham, Alex Collier, Taylor Stoll and Dr. Alistair DM DoveBackground Laser-photogrammetry is a non-invasive technique used for size estimation in applications where traditional methods to determine length are either impractical or unreliable. Laser photogrammetry provides greater precision for measuring free-swimming whale sharks when compared to previous methods that compare whale sharks to objects of known size such as boat length, diver height, and rope length. These estimates are subject to the effects of water movement and visual distortion from refraction. Laser-photogrammetry uses a known reference distance projected onto a surface using pre-calibrated lasers to standardize measurements and utilizes ratios of pixel-counts to calculate a length estimate. Approach Laser-photogrammetry has been demonstrated as a useful technique for determining body length estimates in free-swimming whale sharks, Rhincodon typus (Rohner et al. 2011), but measures of variance have been lacking because repeat measurements on the same individual animals are rarely obtained. Georgia Aquarium houses 4 juvenile whale sharks that can be unequivocally identified and photographed repeatedly, and therefore provided an opportunity to refine the techniques described by Rohner. We then applied them to an aggregation of whale sharks at St. Helena Island. Results Using a similar laser-photogrammetry apparatus and body proportion equations for determining total length prescribed by Rohner, we observed relatively high variance on repeated measurements made on the same animal, such that confidence intervals for any given individual measurement estimate were unacceptably high. Using measures of central tendency from multiple measurements, rather than relying on single images, provided measurement estimates with acceptable confidence intervals for determining total length. We applied the central tendency technique to characterize lengths in a previously unstudied whale shark aggregation in the southern Atlantic Ocean off of St. Helena Island in 2015 and 2016. We used the mean of 4–27 repeated measurements to determine total length estimates of the individuals photographed in St. Helena during these time periods, instead of relying on single-point photos to determine length estimates for the study. Conclusions At 8.4–10.6 m total length, St. Helena animals are larger than those found in juvenile-dominated coastal aggregation sites like Yucatan, Mexico, but smaller than the large solitary females found in Galapagos. The central tendency approach represents a significant improvement to the photogrammetry method, but it increases workload significantly, so there is still a need to develop non-invasive measurement methods that are accurate, precise, and quick.
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Scarring instance and healing capabilities of whale sharks and possible implications
المؤلفون: Freya C. Womersley, Savinien T. Leblond and David R.L. RowatBackground With increasing levels of tourism and other anthropogenic activities around whale shark aggregations globally there is an increased risk of physical damage to sharks from boat collisions. As such, documenting the occurrence of injuries to sharks can be a useful method of recording the impacts of tourism and other marine based activities as well as the effectiveness of management efforts. The seasonal whale shark aggregation off Djibouti has seen an increase in both physical scarring and tourism and is used here as a case study. Approach Scarring records and photos in the Djibouti whale shark database from 2009 to 2015 were reviewed to establish instance and effects of injury on the viability of whale sharks. To calculate the level of injury, in-water sighting data, which recorded scarring, were sorted into major or minor scar categories after the methods of Speed et al. (2008). Major scars were classified as being potentially life threatening and include fin amputation and lacerations penetrating the sub-dermal layer. The probable origin of the scars was also attributed where possible. To avoid overestimation of population scarring and to make results comparable across aggregations, minor scars (such as abrasions, small bites and nicks) were omitted. To quantify medium-term effects of injury, photographic evidence from returning whale sharks was reviewed to estimate healing rates. Healing rates were obtained using the maximum number of years between observing a fresh injury and a fully healed scar. A fully healed scar was defined as an injury with no non-skin/sub-dermal tissue visible. Results The incidence of major scarring recorded in the Djibouti aggregation varied during the study period from a minimum of 15.6% in 2011 to 27.3% in 2015. Of these, 57.9% were attributable to boat strikes in 2011 compared to 40% in 2015. Lacerations to fins showed the quickest healing rates. Sharks observed with fresh lacerations to the first dorsal fin indicative of propeller strikes showed scar-tissue growth on subsequent re-sighting and fully healed scars within a year. Lacerations to the main body of the sharks showed healing rates of a maximum of two years. Amputations showed a maximum healing time of one year but little capacity for tissue regeneration. However, one case of a partially amputated first dorsal fin showed full re-growth of the fin after five years, an instance that is exceptional and has not been recorded before. Conclusions When reviewing scar photos it is clear that whale sharks have the ability to tolerate major injuries through their extraordinary regenerative capabilities. This suggests that whale sharks can recover from boat strikes; however, sharks that did not survive strikes will not be re-recorded and would show as a loss from the dataset. Similarly, the long-term hindrances to normal behavior that are caused by major injuries remain largely unknown. The study reinforces the need for a series of regulations including speed limits to be implemented and enforced within the study site, Arta Marine Protected Area, Djibouti. This approach of recording scars can be applied to other shark populations to improve understanding of shark healing capabilities and the species as a whole.
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Stable isotope analysis for the whale shark in the waters off Taiwan
المؤلفون: Chi-Ju Yu, Shoou-Jeng Joung, Kwang-Ming Liu, Hua-Hsun Hsu and Chia-Yen LinBackground The whale shark, Rhincodon typus, was utilized extensively in Taiwan before 1996. A quota management measure was put in place in 2002, and the whale shark fishery was completely banned in 2008. Biological studies including age and growth, and migration/ movement have been conducted. However, the feeding ecology of whale sharks in different life history stages and sexes in Taiwan waters (Northwest Pacific Ocean) is still unknown. Approach The stable isotope technique was used to analyze the tissue of whale sharks to understanding their feeding ecology. The ´13C value can be used to indicate the foraging habitat of fish, and the ´15N value can be used to estimate the relative position of the consumer in the ecosystem. The specimens (tissue) were taken from individuals entangled in set nets during the period 2008 – 2013 in Taiwan. Results In total, 66 tissue samples from 42 males and 24 females, ranging from 2.84 to 11.90 m TL (total length) were used in stable isotope analysis. Among these specimens 50 and 16 were from the eastern and western waters off Taiwan, respectively. The value of ´13C was from –13.68 to –18.42%, and the value of ´15N was from 5.17 to 13.01%. There was a positive relationship between ´13C and ´15N, and both ´13C and ´15N increased with body size. No gender or geographic difference was found in this study, but the range of stable isotope values of whale shark tissue was wider in eastern Taiwan waters. Conclusions In this study, ontogenetic changes in the diet of whale sharks were found. More specimens are needed to examine the differences in stable isotope values among different genders, seasons, and regions. The results derived from this study can provide useful information on the husbandry of whale sharks, which can help ecotourism operators become more knowledgeable about the ecology of whale sharks. In addition, the results can also be used as an important reference for ecosystem-based management in the future. Future work should focus on discussion on the habitat partition, utilization, and adaption in various marine environments for whale sharks.
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Intraspecific variability in diet and implied foraging ranges of whale sharks at Ningaloo Reef, Western Australia
المؤلفون: Lara Marcus Zamora, Patti Virtue, Heidi R Pethybridge, Mark G Meekan, Michele Thums and Peter D NicholsBackground The whale shark (Rhincodon typus Smith 1828) is the largest of the filter-feeding sharks and inhabits tropical and sub-tropical oceans worldwide. Evidence from anecdotal observations of feeding events and stomach content analysis have identified a wide range of planktonic and nektonic organisms including copepods, krill and small fish as whale shark prey. However, recent studies based on biochemical analysis (e.g. signature fatty acids (FA)) indicated that whale sharks in the western Indian Ocean had a wider foraging range than previous studies suggested, with important contributions from meso- and bathypelagic sources. However, it remains unknown if these results characterize the diet of whale sharks over the wider Indian Ocean. Here, we investigate the feeding ecology of whale sharks in the eastern Indian Ocean at Ningaloo Reef, Western Australia, by identifying differences in whale shark diet according to time of collection, sex and size-class and by examining likely food web linkages. Approach To examine whale shark feeding ecology we used signature FA analysis of both whale shark subdermal tissue and an extensive set of potential prey collected at Ningaloo Reef (Western Australia) in 2013 and 2014. Compared to other methods such as stomach content analysis, signature FA analysis provides both longer-term (up to months) dietary information and an assessment of spatial and temporal changes in the diet of predators. This is possible because some FA in animal tissues (e.g. long-chain (≥C20) polyunsaturated FA, LC-PUFA) can be used as biomarkers as they pass relatively unchanged from the low trophic levels where they are biosynthesized up the food chain. Results Whale shark sub-dermal tissue was low in lipid content (4 mg g–1 dry mass) which was dominated by phospholipids (72% of total lipid) with an energy density of 18.66 kJ g–1 dry mass. A significant intraspecific variability in whale shark FA profiles was observed resulting in four distinct groups of sharks in 2013 and five in 2014. As this variability was not related to sex or size-class, we suggest that it may be attributed to differences in the feeding habitats and thus different prey consumed by these groups of whale sharks. Variation in dietary patterns was also observed between years likely due to changes in the primary and secondary producers. Overall, examination of food web interactions showed that fatty acid profiles of whale sharks and their presumed collected prey were significantly different, suggesting that sharks fed over a wider range of habitats, including deeper waters, than we were able to access. Conclusions A significant component of whale shark diet may originate from benthic and deeper water habitats. High intraspecific variation in diet indicates that whale sharks are likely to forage over a range of distances and depths due to the challenge of inhabiting the patchy prey habitats of tropical and open ocean waters. Future studies should seek to combine signature FA analysis with other techniques such as stable isotopes, genetic and longterm tagging data to help better elucidate the feeding ecology of this iconic species.
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Human dimensions of whale shark provisioning in Oslob, Philippines
المؤلفون: Jackie A. Ziegler, Joshua N. Silberg, Alessandro Ponzo and Philip DeardenBackground Whale shark tourism can provide an incentive to protect whale sharks and their habitats by making them worth more alive than dead. However, the sustainability of these tourism activities is critical to the long-term success of this approach. Whale shark tourism in Oslob is one of only two places in the world where tour operators feed whale sharks to facilitate tourist interactions. To date, no comprehensive studies have assessed tourists' attitudes towards whale shark provisioning. This study assesses tourists' support for whale shark provisioning, as well as their satisfaction with the tour experience in Oslob. Approach TripAdvisor comments of the Oslob whale shark watching experience (n=216) were thematically coded and analysed in NViVO 10. Tourist surveys were collected during the 2014 whale shark watching season in Oslob (n=761) in order to measure attitudes towards interactions with whale sharks. Survey results were coded and analysed in SPSS Version 21. Results TripAdvisor analysis identified four main issues with the experience in Oslob: crowding, provisioning, impacts on sharks, and pricing. Survey results suggest that foreign tourists were significantly more likely to feel crowded compared to national tourists, both in terms of number of other snorkelers (37% vs. 19%; χ2(1, N=629)=23.475, p=0.000, Cramer's V = 0.193) and number of boats (50% vs. 28%; χ2(1, N=623)=30.919, p=0.000, Cramer's V = 0.223), despite the fact that both groups reported encountering the same number of people. Both the survey and TripAdvisor analyses found no significant difference in overall satisfaction with the tour between foreign and national tourists. However, the TripAdvisor analysis did identify a foreign tourist segment termed ‘guilty pleasure’, which exhibited negative feelings towards the ethics of whale shark feeding and an unwillingness to return to Oslob, but still recommended the tour to others. These findings were reflected in the survey results. Foreign tourists were significantly less likely to be willing to participate in whale shark tourism in Oslob again (62%) compared to national tourists (90%; χ2(1, N=632)=67.686, p=0.000, Cramer's V = 0.327), but the vast majority of both foreign (93%) and national (99%) tourists would still recommend the tour (χ2(1, N=632)=18.153, p=0.000, Cramer's V = 0.169). Foreign tourists were also significantly less likely to support the feeding of whale sharks than national tourists (35% vs. 65%; χ2(2, N=635)=55.209, p=0.000, Cramer's V = 0.295), with a further 35% and 22% neutral on the topic, respectively. Although the majority of both groups felt the price of the tour was appropriate, foreign tourists were willing to pay significantly more for the whale shark experience than national tourists (US$63 vs. US$33; t=–6.020, p=0.000, rpb=0.245). Foreign tourists were willing to pay the most for an experience where sharks were not fed, but there was 100% chance of seeing a shark (US$64), followed by sharks fed with 100% chance of seeing sharks (US$43). National tourists on the other hand were willing to pay US$17 for an experience where there was 100% chance of seeing a shark regardless of whether the sharks were fed. Conclusions Few participants perceived the feeding of whale sharks as a negative activity, although foreign tourists were less supportive than national tourists. Most foreign tourists would recommend the tour to others despite their stated intention to not return and misgivings regarding the ethics of provisioning or potential impacts on whale shark health. More in-depth interpretation is necessary to inform tourists of the conservation status and threats facing whale sharks, as well as the potential impacts of tourism activities, both positive and negative. Furthermore, the number of boats and swimmers should be controlled in the whale shark viewing area to address crowding issues.
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