北部湾二长棘鲷生长和死亡参数估计

根据上世纪90年代及60年代的生物学资料，运用体长频率分析法估算二长棘鲷的生长和死亡参数。vonBertlanffy生长方程的主要参数L∞=27．3cm，K=0．45，t0=-O．34；体重的生长拐点为2．12龄；瞬时总死亡率(Z)、瞬时自然死亡率(M)和瞬时捕捞死亡率(F)分别为2.825，1．045和1．78。当前开发率为0．63，资源处于过度利用状态。根据等渔量曲线图分析，当前的捕捞强度过高，而开捕年龄和开捕体长过低，资源出现衰竭现象。综合考虑当前的捕捞强度和社会经济效益，建议北部湾二长棘鲷的最适开捕年龄大于1龄，开捕体长大于120mm。

Esitimation of growth and mortality parameters of Parargyrops edita Tanaka in Beibu Bay

Based on length..frequency data of crimson sea bream Parargyrops edita collected in Beibu Bay in the 1990.. s and 1960.. s growth and mortality parameters were estimated using ELEFAN ..technique in FiSAT. The estimated parameters for von Bertalanffy growth equation was L .. = 27. 3cm , K = 0. 45, t0 = - 0. 34; the turning point on body weight growth curve of the stock was situated at t= 2. 12; the instantaneous rate of total mortality ( Z) was Z = 2. 825, and the instantaneous natural( M) and fishing mortality( F ) rates were 1. 045 and 1. 78 respectively . The exploitrate in recent years was 0. 63, and is in a state of over..exploitation. According to the curve of equal catch, the fishing intensity was too high but the catch age and body..length were too low , so the stocks declined. Considering fishing effort and social..economical benef it, this paper suggests that the optimum catch age should be above one year and body length above 120mm.