Sharks: Bycatch in the tuna longline fishery in the Indian Ocean by Thai tuna longliners in 2012

This report was based on the data extracted from fishing logsheets by two Thai tuna longliners namely, “Mook Andaman 018” and “Mook Andaman 028”, which declared to Department of Fisheries, Thailand. Data from their logsheets displayed important information of their fishing operation and effort.
In 2012, fishing grounds were mainly in the Western coast of Indian Ocean. The total catches were 470.40 tons with 387 days of fishing effort. The average catch rate of total catch was 10.83 individual fish/1,000 hooks. The major catch species were bigeye tuna (Thunnus obesus), yellowfin tuna (T. albacares), swordfish and shark.
Sharks are present as an important role in the ocean ecosystem. The fishing operation was reduced their population. Among the bycatch of tuna longline fishery, The percentage of sharks to the total catch is 4.64% by weight and 3.94% by number. Numbers of shark were 544 individual fishes with 18,528 kg. The catch rate was 0.5 individual fish/1,000 hooks, 17.10 kg/1,000 hooks. Catch data of sharks are classed into a single group of “sharks”, due to species unidentification.