东海区带鱼伏季休渔效果及其资源的合理利用

根据2002-2003年东海区带鱼年龄鉴定资料,并引用以往的带鱼渔业生物学研究结果,作为估算带鱼死亡系数和建立动态综合模型所需的有关参数值估算的依据,从而运用Ricker动态综合模型分析了在现行渔业条件下东海区带鱼伏季休渔效果和带鱼资源利用状况以及变更渔业利用情况对带鱼渔业所产生的影响。结果表明:在现行渔业下(tc=0.5a,F=2.61/a),东海区实施3个月的伏季休渔制度能使年平均资源量增加87%,年产量增加29%,渔获平均体重增加42%;带鱼资源的利用虽处于捕捞过度状态之中,但尚能承受较大的捕捞压力,资源结构利用不合理之处是捕捞大量的幼鱼群体,渔获个体依然过小,渔获平均体重仅为75g/ind.;单位补充量渔获量(Y/R)随tc变化的影响大于随F的变化,建议在维持现有伏季休渔制度下,应逐渐降低捕捞强度,并以提高起捕规格放大网目尺寸作为今后一个时期首选的渔业管理目标,应是较为现实的资源合理利用措施。

The Effect of Summer Closed Fishing and the Reasonable Utilization on Hairtail (Trichiurus japonicus) Resources in the East China Sea Region

Based on the data analysis on age of hairtail(Trichiurus japonicus) in the East China Sea Region from 2002 to 2003 and research result cited on fishery biology in previous studies,which were basis of the coefficient of mortality and dynamic pool model,the effect of summer closed fishing on hairtail resources,the resources utilization status,and the alteration of hairtail fishery utilization status were analyzed by the Ricker population dynamic pool model.The results showed that:as present fishery condition(tc=0.5yr,F=2.61/yr)stands,the average annual resources,catch and average individual body weight could be increased by 87%,29% and 42%,respectively,as a result of the enforcement of three months summer closed fishing in the East China Sea.Although the status of hairtail resources utilization was over-fishing,it could still endure the heavy fishing stress.The main aspect of unreasonable utilization on hairtail resources was that the ratio of young fish in the catch was high.The individual in the catch was too small comparatively,with the average body weight being 75g/ind.Compareing with F,tc influenced Y/R more greatly.The constant maintenance of the summer closed fishing policy was suggested.At the same time,reducing the fishery stress and magnifying the fishery net size should be viewed as the central aim of the hairtail resources management in the future,which is also the reasonable strategy on hairtail resources utilization at present.