广西银滩南部海域海洋牧场渔业资源评估

Assessment of fishery resources in southern sea area of Yintan Marine Ranching,Guangxi Province

为掌握广西北海银滩海洋牧场海域的鱼类资源状况,分别于2022年3月、2023年1月采用分裂波束式科学探鱼仪(Simrad EK80)对该海域进行了2次声学调查。利用回波积分法并结合拖网采样(网目尺寸:4.0 cm×2.5 cm)对调查海域内生物的尾数密度、生物量密度及空间分布进行了评估分析。结果表明,无论是在人工鱼礁区还是对照区,渔获组成均主要以小型个体为主(2022和2023年的个体平均体质量分别为8.64和29.8 g)。2022年3月人工鱼礁区和对照区声学评估种类平均尾数密度分别为66 003和41 903尾·km^(-2),平均生物量密度分别为726.66和469.90 kg·km^(-2);2023年1月人工鱼礁区和对照区声学评估种类平均尾数密度分别为17 194和11 110尾·km^(-2),平均生物量密度分别为665.94和406.85 kg·km^(-2)。人工鱼礁区表现出明显的集鱼效果。调查海域渔业资源主要分布于5.0 m以深水层,且礁区渔业资源较对照区垂直分布范围更广。2次调查的人工鱼礁区平均单体目标强度(Target strength, TS)均大于对照区,且人工鱼礁区检测出的单体目标较对照区多,分布比对照区更集中,表明人工鱼礁影响了鱼类的资源分布。

In order to understand the status of fish resources in the Beihai Yintan Marine Ranching sea area of Guangxi Province,we conducted two acoustic surveys with a split-beam scientific echosounder(Simrad EK80)in March 2022 and January 2023.We evaluated the fish density,fish biomass density and spatial distribution in the survey sea area by using echo integration method combined with trawl sampling(Mesh size:4.0 cm×2.5 cm).The results show that both in the artificial reef area and con-trol area,the catches were mainly composed of small individuals(Average masses of individuals in 2022 and 2023 were 8.64 and 29.8 g,respectively).In March 2022,the average fish densities of acoustic evaluation species in the artificial reef area and control area were 66003 and 41903 inds·km^(-2),respectively.The average fish biomass densities in the artificial reef area and control area were 726.66 and 469.90 kg·km^(-2),respectively.In January 2023,the average fish densities of acoustic evaluation species in the arti-ficial reef area and control area were 17194 and 11110 inds·km^(-2),respectively.The average fish biomass densities in the artifi-cial reef area and control area were 665.94 and 406.85 kg·km^(-2),respectively.The artificial reef area showed a signifi-cant fish catching effect.The fishery resources were distributed mainly in water layers below 5 m,and those in reef areas had a wider vertical distribution range than those of the control area.The average target strength(TS)of the two survey voyages in the artificial fish reef area were greater than that in the control area,and more single targets were detected in the artificial fish reef area with a more concentrated distribution than in the control area.The results reveal the impact of artificial reefs on the redis-tribution of fish resources.