oa 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

Background 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.