Population structure of a whale shark Rhincodon typus aggregation in the Red Sea

Abstract
The presence of whale sharks Rhincodon typus were recorded around Shib Habil, a small, coastal reef off the Red Sea coast of Saudi Arabia, from 2010 to 2015. A total of 267 suitable photographs resulting in the identification of 136 individuals, were documented from 305 encounters. Sharks were divided evenly between the sexes with no evidence of temporal or spatial segregation. All individuals were immature based on size estimates and, for males, juvenile clasper morphology. Scars were reported for 57% of R. typus with 15% showing evidence of propeller trauma. Estimates of population size and patterns of residency were calculated by modelling the lagged identification rate. Multiple models were run simultaneously and compared using the Akaike information criterion. An open population model was found to best represent the data and estimates a daily abundance between 15 and 34 R. typus during the aggregation season, with local residence times ranging from 4 to 44 days. Residence times away from Shib Habil range from 15 to 156 days with a permanent emigration–death rate between 0·07 and 0·58 individuals year−1. These results are broadly similar to those from other aggregations of R. typus, although the observed sexual parity and integration found at this site is unique for the species and needs further study. © 2016 The Fisheries Society of the British Isles

Citation
Cochran JEM, Hardenstine RS, Braun CD, Skomal GB, Thorrold SR, et al. (2016) Population structure of a whale shark Rhincodon typus aggregation in the Red Sea . Journal of Fish Biology 89: 1570–1582. Available: http://dx.doi.org/10.1111/jfb.13054.

Acknowledgements
Financial support was provided in part by KAUST Baseline Research Funds (M.L.B. and M.G.G.), KAUST award numbers USA00002 and KSA 00011 (S.R.T.) and the U.S. National Science Foundation (OCE 0825148; S.R.T. and G.B.S.). The authors thank all current and former members of KAUST's Reef Ecology Lab for field assistance. They would also like to specifically thank E. F. Cagua for help with figures, C. Nelson and A. Manjua for administrative support and the staff of Dream Divers operations in Al Lith for on-site, logistical assistance. In addition, the authors acknowledge the contributions of the larger KAUST community who participated in various R. typus watching trips, supplied us with their photographs and facilitated additional field research. Finally, this manuscript was improved by the revisions and suggestions of S. Blaber, S. Pierce and an anonymous reviewer.

Publisher
Wiley

Journal
Journal of Fish Biology

DOI
10.1111/jfb.13054

PubMed ID
27401632

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