Exploitation Strategy Evaluation for Yollowfin Tuna in the Indian Ocean

Exploitation strategy of yellowfin tuna in the Indian Ocean was evaluated using per recruit model and Schaefer production model.Fmax、F0.1、F20%SPR、F40%SPR inferred from per recruit model was 0.76,0.44,0.56,0.32 and the corresponding referrence catch was 367,346,361,342 thousand tons.The relative catch will increase with fishing mortality in the next ten years,but vice versa with relative residual spawner biomass.The probablity of relative residual spawner biomss below 20% will be lower than 10% if the fishing mortality is controled within 0.3,but greater than 90% if the fishing mortality is greater than 0.6.The biomass will show increscent,stable,slowly descendent,and quickly descendent trend in the next ten year when total allowable catch is set at 300,350,400,and 450 thousand tons.It is suggested that the production would be stable if fishing mortality was controlled below 0.5 and total catch was limited within 350 thousand tons.