东海鹰爪虾的数量分布和变动

Study on biomass distribution and variation of Trachypenaeus curvirostris in the East China Sea

本文对东海鹰爪虾的数量分布和数量变动进行了研究。调查结果显示 ,该种的年平均渔获率为0 .5 2 8kg/h ,四季中以夏季最高 (0 .814kg/h) ,秋季次之 ,冬季较低 (0 .2 19kg/h)。其资源量的分布主要在 4 0～6 5m水深海域 ,在 30°0 0′N以北 ,可分布到 10 0m水深 ,以盐度 33～ 34的海域较为密集。不同海域的渔获率不同 ,中部海域渔获率较高 ,高峰期出现时间也较长 ,北部和南部海域高峰期出现时间短。由于过度捕捞的原因 ,鹰爪虾的平均资源量和最高现存资源量与 80年代中后期比较 ,分别下降 71.3%和 6 9.4 %。为合理利用该资源 ,建议在小虾出现高峰期实行休渔措施 ,以增加补充群体的数量 ,实现可持续利用。

The biomass distribution and variation of Trachypenaeus curvirostris in the East China Sea were studied. Results showed that the annual mean fishing rate of the species was 0.528kg/h in the surveyed areas. The fishing rate hit the top in summer(0.814kg/h); slightly decreased in fall and jumped to its valley in winter(0.219kg/h). The main distributing areas were between 40m and 65m in depth; and to the north of 30°00′N the distributing areas could deepen to 100m, with the highest density at the area of 33-34‰in salinity. The fishing rate might be different in areas. The higher fishing rate and longer peak period were in the middle area, while the relatively shorter peak period occurred in the northern and southern areas . Because of overfishing, the mean biomass and highest biomass of Trachypenaeus curvirostris decreased by 71.3% and 69.4%, respectively as compared with in the mid 1980s. In order to make rational use of its resource,a closed fishing season should be implemented when small shrimp were in bloom, so that a recruitment can form. Only in this way will the shrimp trawl operation be sustainable utilization.