oa Discovery Of One Of The Largest Whale Shark Aggregation Sites In The World Off The Coast Of Qatar

Background: The Qatar Whale Shark Research Project is a collaboration of government, industry and academia founded in 2010 to investigate anecdotal reports by Maersk Oil platform workers of large numbers of whale sharks seen in the Al Shaheen Oil field, Qatar. Methods: Photo-ID records have been collected from 2011 to present. Satellite-linked and acoustic tags have both been deployed, and biochemical 'biological tags' are being collected through tissue sampling. Plankton samples and environmental information are routinely being recorded. Fixed-station platform observations are being reported daily by gas industry workers to establish seasonality and sighting trends. Results: Aggregations of 100+ whale sharks have been regularly reported in offshore Qatari waters between May and September. Molecular barcoding of plankton samples has shown that the sharks are feeding specifically on tuna spawn from the species Euthynnus affinis. The tuna are thought to gather and spawn in the area due to both the unintentional protection offered by oil and gas platforms and the artificial habitat created by the structures. Preliminary satellite and acoustic tagging results indicates that the sharks aggregate during the summer months and disperse in the winter, in conjunction with the tuna. None of the satellite-tagged sharks have left the Arabian Gulf, although photo-ID has matched sharks between Qatar and the Strait of Hormuz and northern Gulf of Oman. During the 2012 season, 226 left-side shark identities were recorded, with 24% of sexed sharks (n = 144) identified as female and 76% being male. Mean estimated length was 6.88 ± 1.37 m (n = 156; range 4-10 m). Conclusion: The Al Shaheen Oil Field off Qatar is host to a globally significant aggregation of whale sharks, driven by the presence of high densities of E. affinis tuna spawn. Preliminary tracking data suggests that the sharks stay in the Arabian Gulf throughout the year.