绿鳍马面鲀资源评析与合理利用

本文依据1984年1—4月对1255尾绿鳍马面鲀的年龄观察资料，得到各年龄的平均体长和相应的平均体重，求得生长参数，并根据最高年龄求得其自然死亡系数，还根据该种群的生长参数和自然死亡系数，用Ricker模式进行评析，估算出绿鳍马面鲀渔业的最佳捕捞水平和最佳开捕年龄。同时，根据1977—1985年的渔业统计资料，以机轮拖网投网次数为标准捕捞努力量单位，运用Schaefer模式，对绿鳍马面鲀渔业进行评析，求得其最大持续产量MSY和其相应的捕捞努力量水平ASY。据此估测，作者认为目前绿鳍马面鲀的利用已达较充分的程度，近两年有捕捞过度的趋势。为此，作者提出应降低目前的捕捞水平和推迟开捕年龄等具体建议。

AN ASSESSMENT OF THE FILEFISH POPULATION AND RATIONAL EXPLOITATION OF THE RESOURCE

An analysis of the present abundance of the filofish population(Navodon septentrionalis) and the retional exploitation of the resource are discussedin this paper. The analysis is based on the age date of 1253 filefish examined betweenJan. and Apr. in 1984 as well as the fishing statistical data from 1977 to 1985. Rickerand Schaefer models are edopted, with reference to filefish natural mortality M=0.257,M =0.183. All technical calculation is computer processed. The results show: 1) The present exploitation of the filefish abundance has already reached the fullextent. In 1984 and especially in 1985 there appeared a tendency near over fishing. 2) The maximum sustainable yield in weight of the fish is MSY=205 M_T and thecorresponding fishing efforts is f(may)=47227 haul, according to the present age atfirst capture to=1.5.But the fishing effort on the filefish in 1985 is f_(?)=53869 haul. 3) If the age at first capture increases from tc=1.5to tc=2.5, the filefish fish-ing will be in the better condition, with the fishing level F=0.6-0.8(the fishinglevel in 1985 F_(95)=0.8-1.0).