Kedalaman Lapisan Renang Tuna (Thunnus sp.) yang Tertangkap oleh Rawai Tuna di Samudera Hindia

Abstract

The research about swimming layer of tuna conducted in February until April on Indian Ocean. The objective of research was to obtain information about processed of tuna longline operation, analyzed the composition of catches, determined the swimming layer of tuna in Indian Ocean. This research was a case study of the activities of catching tuna on KM. Bina Sejati and KM. Bintang Utara. The total catches were 998 fish from 52 setting during experiment. The member of catches consisted of target catcth were 83 (8,23%), 161 (16,13%) bycatches, and 754 (75,55%) discarded catch. The target catches consisted of bigeyes (Thunnus obesus) which was 44 (53,01%), albacores (Thunnus alalunga) 21 (25,30%), yellowfins (Thunnus albacores) 11 (13,25%), and southern bluefins (Thunnus maccoyii) 7 (8,43%). The majority of bycathes were bullet pomfret which was (Taractichthys sp.) 19,25%, black pomfret (Taractes rubescens) 17,39%, and oil fish (Lepidocybium sp.) 17,39%. The swimming layers of tuna were : albacore (Thunnus alalunga) which was at 64-232 m, bigeye (Thunnus obesus) at 64-250 m, yellowfin (Thunnus albacares) at 64-205 m, and southern bluefin (Thunnus maccoyii) at 110-205 m