中国金枪鱼围网船队大眼金枪鱼渔获物的特征变化与人工集鱼装置禁渔期的关系

研究了2012-2015年中国金枪鱼围网船队大眼金枪鱼(Thunnus obesus)渔获物的特征变化与人工集鱼装置(fish aggregation devices,FAD)禁渔期的关系,文章收集了2012-2015年中国大陆金枪鱼围网船队在中西太平洋的渔捞日志数据,对随附鱼群捕捞努力量与小体大眼金枪鱼和大体大眼金枪鱼的船均产量进行分析比较。结果显示:1)从2013年开始,对随附鱼群投网的次数占总投网次数的比例有所降低,均不超过50%;2)K-S检验显示研究期内禁渔期前后的船均随附鱼群网次存在显著差异(P0.05);3)2013-2015年大眼金枪鱼渔获量的平均水平明显低于2012年;4)从2013年开始,禁渔期结束后的第一个月(即11月)的船均产量都发生猛增;5)从捕捞努力量与渔获量的相关性结果看,不论是小体大眼金枪鱼还是全部大眼金枪鱼,2013年和2014年两者都呈现出显著的强正相关关系(P0.05)。这些结果表明2012年以后中国船队对大眼金枪鱼幼鱼的兼捕水平有所下降,延长FAD禁渔期的管理措施对于保护大眼金枪鱼幼鱼在某些年份可能具有一定的效果。

Relationship between change of bigeye tuna catches by Chinese tuna purse seine fleets and FAD closure

We analyzed the relationship between the change of bigeye tuna (Thunnus obesus) catches by Chinese tuna purse seine fleets and fish aggregation devices (FADs) closure during the Conservation and Management Measures in the Western and Central Pacific Ocean from 2012 to 2015.The Chinese tuna purse seine fishery data were collected to compare the difference between fishing efforts (sets) of associated school and catches of small and large bigeye tuna.The results show that:1) The proportion of associated school sets among total sets had declined since 2013,which was under 50％.2) The result of K-S testing shows that the average associated school sets were different before and after FAD closure significantly.3) The average catch of total bigeye tuna from 2013 to 2015 was lower than that in 2012 significantly.4) The catch of bigeye tuna had increased since 2012 in the first month at the end of the FAD closure rapidly.5) The fishing effort and catches of both small bigeye tuna and all bigeye tuna had significant positive correlation in 2013 and 2014 (P ＜ 0.05).The results show that the bycatch of juvenile bigeye tuna by Chinese tuna purse seine fleets had decreased since 2012,which might result from the FAD closure measure adopted in 2013 which had extended additional onemonth FAD closure.