How large is the world's largest fish? Measuring whale sharks Rhincodon typus with laser photogrammetry

Abstract

Laser photogrammetry was found to be a promising new cost-effective technique for measuring free-swimming whale sharks Rhincodon typus. Photogrammetric measurements were more precise than visual size estimates by experienced researchers, with results from the two methods differing by 9· 8 ± 1· 1% (mean ±s.e.). A new metric of total length and the length between the fifth gill and first dorsal fin (r2 = 0· 93) is proposed to facilitate easy, accurate length measurements of whale sharks in the field. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.