禁捕初期长江上游长江鲟增殖放流效果

BREEDING AND RELEASING YANGTZE STURGEON OF IN THE UPPER REACHES OF THE YANGTZE RIVER DURING THE EARLY STAGE OF FISHING BAN

  • 摘要: 为科学评估长江上游长江鲟增殖放流效果, 研究基于2021—2023年宜宾、泸州和合江3个江段渔业监测数据, 对长江上游长江鲟野外种群恢复情况进行了分析。监测期间, 3个江段共采集长江鲟849尾, 其体长分布为14.70—93.00 cm 平均体长(45.19±14.01) cm, 优势组体长为25.10—65.00 cm, 占总体的88.98%; 体重分布为24.0—6850.0 g 平均体重(892.7±960.8) g, 优势组体重为0—1250.0 g, 占总体的83.18%。分析显示: (1) 2022年和2023年监测到的长江鲟体长、体重均值均显著高于2021 年(P<0.05), 体长均值均高于当年放流群体体长均值; (2)监测的长江鲟群体呈正异速生长, 体重增长速率大于体长增长速率, 且宜宾至合江江段的生长条件因子、异速生长参数具有明显的地点和时间差异(P<0.05); (3)长江鲟单位捕捞努力量渔获量为0.1—35.0 ind./(net·d), 不同季节间呈显著差异(P<0.05); (4)在2018—2023年各大单位加大放流力度且2021年长江十年禁捕政策出台并执行后, 2021—2023年监测期间长江鲟采集数量明显增加。研究结果表明, 禁捕后长江上游长江鲟资源正逐渐恢复, 且生长状况良好, 增殖放流效果初步显现。

     

    Abstract: In order to scientifically evaluate the breeding and releasing of Yangtze sturgeon in the upper reaches of the Yangtze River, we analyzed the recovery of Yangtze sturgeon field populations based on the fishery monitoring data of three river sections, namely, Yibin, Luzhou, and Hejiang, from 2021 to 2023. During the monitoring period, a total of 849 Yangtze sturgeon were collected from the three sections, with body lengths ranging from 14.70 to 93.00 cm (mean length 45.19±14.01 cm). The dominant group, with body lengths ranging from 25.10 to 65.00 cm, comprised 88.98% of the total. The body weights ranged from 24.0 to 6850.0 g (mean weight 892.7±960.8 g), with the dominant group's weights between 0 and 1250.0 g, accounting for 83.18% of the total. The analysis showed that (1) the average body lengths and body weights of Yangtze sturgeon monitored in 2022 and 2023 were significantly higher than those in 2021 (P<0.05), and the mean values of body lengths exceeded those of the released group in the same year; (2) the monitored Yangtze sturgeon groups showed positive anisotropic growth, with weight increasing at a faster rate than body length. Significant difference in growth condition factors and anisotropic growth parameters were observed between Yibin and Hejiang sections (P<0.05), influenced by location and time (P<0.01); (3) the catch per unit effort of Yangtze sturgeon ranged from 0.1 to 35.0 ind./(net-d), with significant seasonal variations (P<0.05); (4) following increased release efforts by major organizations from 2018 to 2023, alongside the implementation of a 10-year fishing ban on the Yangtze River starting in 2021, the number of Yangtze sturgeon collected during the monitoring period increased significantly. The results showed that the Yangtze sturgeon resources in the upper reaches of the Yangtze River are gradually recovering after the fishing ban, with good growth condition, suggesting that the breeding and releasing is initially apparent.

     

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