A preliminary study on fishery of tuna purse seine in China

Based on the investigation from June,2002 to May,2003 in the Central-Western Pacific,the catch operations by A and B tuna purse seine vessels are reported.The results indicated that 70% of sets was free-swimming school sets,and the rate of empty net was 52.5%;30% of sets was floating-object sets,and the rate of empty net was 9.5%;Katsuwonus pelamis was 90% and Thunnas albacares 10% in catch weight,dominant body lengths were 40~60 cm and 100~150 cm respectively.Fishing areas were mostly lying between 5oN～5oS,150oE～ 178oE.The rate of empty net fluctuated between 9%～64% per month,and the catch varied from 185t to 940t one month per vessel.Mean catch per set was more than 20t and the max catch per set was 260 t.