浙江海域鲐鲹鱼资源量评估

Stock Assessment of Jack Scomber japonicus and Decapterus maruadsi in Coastal Waters of Zhejiang Province

根据2009-2010年浙江海域灯光围网捕获的鲐鲹鱼随机取样获得的数据,使用叉长结构实际种群分析法(LV-PA)对鲐鲹鱼资源状况进行了评估。结果显示,采集鲐鱼样品的叉长分布在55～396 mm之间,极限叉长L∞=406 mm,生长参数K=0.34。捕捞死亡系数(F)为0.82,峰值出现在叉长为285 mm处,等于1.29。补充高峰出现在6-8月。蓝圆鲹样品的叉长分布在34～268 mm之间,极限叉长L∞=289 mm,生长参数K=0.43。捕捞死亡系数(F)为0.35,峰值出现在叉长为135 mm处,等于0.47。补充高峰出现在4-8月。单位补充量产量分析显示,当前开发状况距最适渔业状态较远,首次捕捞叉长不足极限叉长的20%,需要增大网目尺寸,以保护鲐鲹鱼资源。结合2009-2010年浙江海域鲐鲹鱼渔获物资料和灯光围网船组资料,估算了浙江海域鲐鲹鱼这2年的现存资源量。结果表明,2009-2010年浙江海域鲐鲹鱼现存资源量为60.4×104t左右,最适可捕量为41.0×104t。浙江海域鲐鲹鱼补充率最高月份为8月份,其值达15.52%。

According to the data of opportunity sampling of Scomber japonicus and Decapterus maruadsi catched by light seining in coastal waters of Zhejiang province 2009-2010, we use LVPA to measure the biomass of S. japonicus and D. maruadsi. The result showed, when the fork length of S. japonicus distributed to 55-396 mm, and the limit fork length was 406 mm, the growth parameter K was 0.34. The mean fishing mortality coefficient （F） was 0.82, and the peak value was 1.29 when the fork length was 285 mm. The additional peak appeared during June to August. when the fork length of D. maruadsi distributed to 34-268 mm, and the limit fork length was 289 mm, the growth parameter K was 0.43. The mean fishing mortality coefficient （F） was 0.35, and the peak value was 0.47 when the fork length was 135 mm. The additional peak appeared during April to August. Analysis of amount of yield per recruit showed that current exploitation status was far from optimal state, and the first fishing fork was less than 20% of the limit fork length. So we should extend the mesh size to pretect S. japonicus and D. marua＆i sources. Combine with data collected during 2009 to 2010, we estimate the biomass of S. japonicus and D. maruadsi these two years, and the result showed that the exsiting sources of S. japonicus and D. maruadsi was about 60.4x104 t, optimal allowable fishing amount was 41.0×104 t. Supplementary rate of S. japonicus and D. maruadsi in coastal waters of Zhejiang provinces was in August, and the value was 15.52%.