Some aspects of the distribution and biology of the IndoPacific sailfish, Istiophorus platypterus (Shaw and Nodder

The Indo-Pacific sailfish, Istiophorus platypterus, is an epipelagic oceanic species, occurring as a bycatch in tuna longline fishing. Annual production in the Indian Ocean is about 2153 t, of which 460 t (21.4%) is contributed by the longline fishery in India. Studies of the distribution and biology of the species are very limited. Tuna longline fishing by chartered vessels and the recent resources surveys in Indian seas have generated valuable data on sailfish. Results of longline fishing by chartered vessels in Indian waters indicate that sailfish form 2.64 % of total catch, with an average CPUE of 17.16 kg/1000 hooks. Season-wise, the first and second quarters of the year are observed to be more productive, and the spatial distribution pattern shows a general tendency of higher hooking rates near continental borders. Results from resources surveys around Andaman & Nicobar Islands indicate high hooking rates during the third and fourth quarters, with average annual hooking rates of 1.43 fish/1000 hooks (45.76 kg/1000 hooks). The length (lower jaw to fork) ranged from 135 to 245 cm, with two modal classes. The mean weight was observed to be 32 kg. The study indicates that the Indian seas, particularly the Andaman & Nicobar waters, are productive areas for sailfish