杨炳忠, 晏磊, 李杰, 王腾, 张鹏. 南海区单船有袖单囊拖网网囊网目对金线鱼的选择性研究[J]. 南方水产科学. DOI: 10.12131/20230227
引用本文: 杨炳忠, 晏磊, 李杰, 王腾, 张鹏. 南海区单船有袖单囊拖网网囊网目对金线鱼的选择性研究[J]. 南方水产科学. DOI: 10.12131/20230227
YANG Bingzhong, YAN Lei, LI Jie, WANG Teng, ZHANG Peng. Size selectivity of codend-mesh sizes in single boat bottom otter trawls for Nemipterus virgatus in South China Sea[J]. South China Fisheries Science. DOI: 10.12131/20230227
Citation: YANG Bingzhong, YAN Lei, LI Jie, WANG Teng, ZHANG Peng. Size selectivity of codend-mesh sizes in single boat bottom otter trawls for Nemipterus virgatus in South China Sea[J]. South China Fisheries Science. DOI: 10.12131/20230227

南海区单船有袖单囊拖网网囊网目对金线鱼的选择性研究

Size selectivity of codend-mesh sizes in single boat bottom otter trawls for Nemipterus virgatus in South China Sea

  • 摘要: 为提高拖网对金线鱼 (Nemipterus virgatus) 的选择性,在南海区使用套网法对网目尺寸分别为30、35、40和45 mm的4组网囊开展了试验。使用双重拔靴法拟合网囊对金线鱼的选择性参数和选择性曲线,比较网囊间的选择性差异,并估算网囊的捕捞方式指数。结果显示,随着网目尺寸的增大,50%选择体长 (L50) 增大,选择性曲线的置信区间变窄,网囊对金线鱼幼鱼的渔获比例减小。试验网囊的L50值均小于金线鱼的开捕规格 (15.0 cm),网囊对金线鱼的抛弃率大于67%。研究表明,增大网目尺寸能够优化网囊的选择性,但选择性仍需进一步提升,才能更好地促进金线鱼拖网渔业的可持续发展。

     

    Abstract: In order to improve the size selectivity and exploitation pattern of single boat bottom otter trawls for threadfin bream (Nemipterus virgatus), we tested four experimental codends with mesh sizes of 30, 35, 40 and 45 mm by applying the covered codend method in the South China Sea. We analyzed the catch data with double-bootstrapping technique to estimate the selectivity parameters, selectivity curves, delta selectivity curves and exploitation pattern indicators. The results demonstrate that with increasing mesh sizes in codends, 50% retention length (L50) increased, confidence intervals of the selectivity curves became sharper, and retention fraction of undersized individuals decreased. However, when considering the minimum conservation reference size of the target species (15.0 cm), the L50 values of codends tested were less than 15.0 cm, and their discarded percentages were all over 67%. Though the study shows that increasing mesh sizes will improve size selectivity, it should be further improved to achieve a sustainable trawl fishery for threadfin bream.

     

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