TY - JOUR
T1 - Population structure, abundance and movement of whale sharks in the arabian gulf and the gulf of Oman
AU - Robinson, David P.
AU - Jaidah, Mohammed Y.
AU - Bach, Steffen
AU - Lee, Katie
AU - Jabado, Rima W.
AU - Rohner, Christoph A.
AU - March, Abi
AU - Caprodossi, Simone
AU - Henderson, Aaron C.
AU - Mair, James M.
AU - Ormond, Rupert
AU - Pierce, Simon J.
N1 - Funding Information:
We thank everyone involved in the Qatar Whale Shark Research Project, as well as the staff at the Qatar Ministry of Environment, Maersk Oil Research and Technology Centre (MORTC), Qatar and the Qatar Coast Guard for providing the platform to carry out field research in Qatar. We thank Ali Abdulrahmen from the MORTC for his support and help throughout the fieldwork; the Maersk Oil platform workers for their continued and dedicated support with data collection, especially Soren Stig for his continued enthusiasm. We thank Jonathan Ali Khan and Warren Baverstock for their support and help with the Sharkwatch Arabia initiative and thanks also go to every contributing individual and dive center for submitting images or reporting their whale shark encounters, in particular the Emirates Diving Association. We also thank Jennifer Schmidt for helpful comments on the manuscript and the Save Our Seas Foundation for their support. Chistoph Rohner and Simon Pierce’s contribution to this project were supported by two private trusts, the Shark Foundation, Aqua-Firma, and Waterlust.
Publisher Copyright:
© 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.
PY - 2016/6
Y1 - 2016/6
N2 - 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.
AB - 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.
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U2 - 10.1371/journal.pone.0158593
DO - 10.1371/journal.pone.0158593
M3 - Article
C2 - 27362839
AN - SCOPUS:84977266651
SN - 1932-6203
VL - 11
JO - PLoS ONE
JF - PLoS ONE
IS - 6
M1 - e0158593
ER -