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Robinson D.P.,Heriot - Watt University | Jaidah M.Y.,Qatar Ministry of Environment | Bach S.,Maersk Oil | Lee K.,University of York | And 7 more authors.
PLoS ONE | Year: 2016

Data on the occurrence of whale sharks, Rhincodon typus, in the Arabian Gulf and Gulf of Oman were collected by dedicated boat surveys and via a public-sightings scheme during the period from 2011 to 2014. A total of 422 individual whale sharks were photo-identified from the Arabian Gulf and the northern Gulf of Oman during that period. The majority of sharks (81%, n = 341) were encountered at the Al Shaheen area of Qatar, 90 km off the coast, with the Musandam region of Oman a secondary area of interest. At Al Shaheen, there were significantly more male sharks (n = 171) than females (n = 78; X2 = 17.52, P < 0.05). Mean estimated total length (TL) for sharks was 6.90 m ± 1.24 (median = 7 m; n = 296). Males (7.25 m ± 1.34; median = 8 m, n = 171) were larger than females (6.44 m ±1.09; median = 7 m, n = 78; Mann-Whitney U test, p < 0.01). Of the male sharks assessed for maturity 63% were mature (n = 81), with 50% attaining maturity by 7.29 m and 100% by 9.00 m. Two female sharks of >9 m individuals were visually assessed as pregnant. Connectivity among sharks sighted in Qatari, Omani and UAE waters was confirmed by individual spot pattern matches. A total of 13 identified sharks were re-sighted at locations other than that at which they were first sighted, including movements into and out of the Arabian Gulf through the Strait of Hormuz. Maximum likelihood techniques were used to model an estimated combined population for the Arabian Gulf and Gulf of Oman of 2837 sharks ± 1243.91 S.E. (95% C.I. 1720-6295). The Al Shaheen aggregation is thus the first site described as being dominated by mature males while the free-swimming pregnant females are the first reported from the Indian Ocean. © 2016 Robinson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Bach S.S.,SPE Ali | Ahmed A.,Maersk Oil | Lawson W.A.,Maersk Oil | Reeves C.E.,Maersk Oil | And 8 more authors.
Society of Petroleum Engineers - SPE Middle East Health, Safety, Environment and Sustainable Development Conference and Exhibition, MEHSE 2014 | Year: 2014

The Al Shaheen oil field is located approximately 80 km north-east off the coast of Qatar in the Arabian Gulf. It is the largest offshore oil field in Qatar and it is operated by Maersk Oil on behalf of its partner Qatar Petroleum. The Al Shaheen area is a highly productive marine environment due to a combination of complex nutrient rich currents and high temperatures. The diverse marine ecosystem is exemplified by one of the world's largest aggregations of whale sharks (Rhincodon typus) that return to this area every summer. The whale shark is listed as vulnerable on the IUCN Red List of Threatened Species and is the largest fish in the world. Having to operate in an area that hosts such a unique natural event poses a challenge to the parties involved but after years of dedicated research the secret behind the annual aggregation of the whale sharks in the Al Shaheen field is now better understood. The knowledge that has been gleaned is currently being used to help prevent significant disturbance to these majestic species and at the same time, maintain an efficient operation. Seismic operations have been scheduled for periods outside of the known aggregation season, and vessel traffic has been restricted in certain areas of the field. These initiatives have revealed that cost effective environmental risk management is achieved by gaining the best possible understanding of the ecosystem that is being impacted. Unless substantial published information is available for the area of concern this will most often require dedicated and continued research efforts. The reward in taking an "Ecosystem Approach", however, is an opportunity to establish collaboration between the industry, regulators and academia, resulting in effective and well-documented mitigation measures. Copyright © 2014, Society of Petroleum Engineers.

Robinson D.P.,University of Edinburgh | Jaidah M.Y.,Qatar Ministry of Environment | Jabado R.W.,United Arab Emirates University | Lee-Brooks K.,University of York | And 7 more authors.
PLoS ONE | Year: 2013

Whale sharks, Rhincodon typus, are known to aggregate to feed in a small number of locations in tropical and subtropical waters. Here we document a newly discovered major aggregation site for whale sharks within the Al Shaheen oil field, 90 km off the coast of Qatar in the Arabian Gulf. Whale sharks were observed between April and September, with peak numbers observed between May and August. Density estimates of up to 100 sharks within an area of 1 km2 were recorded. Sharks ranged between four and eight metres' estimated total length (mean 6.92±1.53 m). Most animals observed were actively feeding on surface zooplankton, consisting primarily of mackerel tuna, Euthynnus affinis, eggs. © 2013 Robinson et al.

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