Tropical tuna fisheries in the Indian Ocean of Indonesia

Indonesia lays between two large continents i.e. Asia and Australia as well as two main oceans i.e. the Indian Ocean and Pacific Ocean with a wide coverage of marine waters within its jurisdiction. This strategic location provides various advantages for Indonesia, among those particularly in the tuna fishery is the abundances of tropical tunas surrounding its marine waters. The species of tropical tuna that are commonly found in the area are yellowfin tuna (YFT), bigeye tuna (BET) and skipjack tuna (SKJ). These species are targeted by various fishing gears such as tuna longline (LL), purse seine (PS), pole and line (PL), hand line (HL), and gill net (GN). Among those, long line and purse seine are gears type that mainly contribute a significant catch from the total catch of tuna. In the recent years, hand line also contributes significant catch following the former gears as consequences FADs use in hand line fishery. There are three types of longline operated by Indonesia fishers i.e. surface longline, middle long line and deep long line. Different depth of hooks from these three types of longline showed different catch composition and proportion. Size structure and distributions of YFT and BET caught by longline are also provided in this paper.