金枪鱼延绳钓环形钩和圆形钩钓获率比较

Comparison on catch rate between circle hooks and ring hooks of tuna longline in the tropical high seas of the Indian Ocean

根据“华远渔18号”和“华远渔19号”两艘冰鲜金枪鱼延绳钓渔船2005年9月15日~12月12日在印度洋热带公海水域（0°47′~10°16′N,61°40′~70°40′E）作业期间收集的数据,以每千钩钓获尾数和平均净重,对环型钩与圆型钩对大眼金枪鱼和黄鳍金枪鱼的选择性、钓获率差异等进行了比较研究。结果表明：不同钓具漂移速度下环型钩与圆型钩各自对大眼金枪鱼和黄鳍金枪鱼的选择性无显著差异;不同钓具漂移速度下环型钩与圆型钩之间对大眼金枪鱼和黄鳍金枪鱼的钓获率无显著差异;环型钩与圆型钩之间对大眼金枪鱼和黄鳍金枪鱼渔获物净重无显著差异。

By means of the survey data collected on board of two chill sea water tuna longlining vessels ＂Huayuanyu No.18＂ and＂Huayuanyu No.19＂ of Guangdong Guangyuan Fishery Group Co.,LTD,in the tropical high seas of the Indian Ocean（0°47′N-10°16′N,61°40′E-70°40′） since Sep.15th 2005 to Dec.12th 2005,and based on number of fish to be caught per thousand hooks or average gilled and gutted weight,in present paper there have been made a comparison on the selectivity and hooking rate of Bigeye tuna Thunnus obesus and Yellowfin tuna Thunnus albacares between ring hooks and circle hooks.The results revealed that there were no significant differences in gear selectivity of ring hooks and circle hooks between Bigeye tuna and Yellowfin tuna at the varied drafting speeds of the longlines,as well in the catch rate of Bigeye tuna and Yellowfin tuna between ring hooks and circle hooks at the varied drafting speed of fishing gear tested,and in the average gilled and gutted weight of Bigeye tuna and Yellowfin tuna caught by ring hooks and circle hooks respectively.