长江泰州段刀鲚群体生长特征的时间趋势和性别差异

TEMPORAL TRENDS AND SEX-SPECIFIC VARIATION IN GROWTH CHARACTERISTICS OF COILIA NASUS IN THE TAIZHOU SECTION OF THE YANGTZE RIVER

  • 摘要: 为评估长江十年禁渔政策对刀鲚(Coilia nasus)种群资源恢复的生态效应, 研究基于2005、2009、2012和2024年汛期在长江泰州江段采集的958尾样本, 运用基于信息准则的多模型推理方法, 系统分析了刀鲚群体生长特征的时序动态变化。研究结果表明: (1)种群年龄结构显著优化, 由以1—2龄为主的低龄化结构转向以3+龄为主的高龄化结构, 其中3—4龄个体所占比例从2009年的24.7%显著提升至2024年的72.4%, 雌雄性比从0.69﹕1恢复至2.66﹕1; (2)群体形态学指标呈现典型的"U型"恢复模式, 平均体长从2009年的历史低值24.2 cm增长至2024年的29.6 cm, 平均体重从58.4 g增加至105.0 g, 增幅分别达22.3%和79.8%; (3) Von Bertalanffy生长模型的拟合效果最优, 生长参数表现出显著的性别二态性: 雌性个体的渐近体长显著大于雄性(L: 雌性39.05 cm, 雄性32.63 cm), 但生长系数小于雄性(k值: 雌性0.41, 雄性0.56), 体现了"慢生长-大体型"的生活史策略, 而雄性则采取"快生长-小体型"策略; 时序分析显示, Lk分别呈"U型"和"倒U型"的恢复轨迹; (4)种群恢复存在性别差异, 雌性个体已完全恢复至2005年水平并有所增强, 雄性个体虽有改善但恢复程度相对滞后。研究证实长江十年禁渔政策对刀鲚种群保护与资源恢复产生了显著的积极效应, 为长江流域水生生物多样性保护成效评估提供了重要的实证支撑, 并为濒危洄游性鱼类的适应性管理策略制定提供了科学依据。

     

    Abstract: To evaluate the ecological effects of 10-year fishing ban policy in the Yangtze River on the population recovery of Coilia nasus, this study systematically analyzed the temporal dynamics of growth characteristics using multi-model inference approaches based on information criteria. A total of 958specimens were collected during fishing seasons in 2005, 2009, 2012, and 2024 from the Taizhou section of the Yangtze River. The results showed: (1) Population structure optimized significantly, with age composition shifting from younger to older cohorts. The proportion of 3-4 year-old individuals increased notably from 24.7% in 2009 to 72.4% in 2024, while the sex ratio (female: male) recovered from 0.69:1 to 2.66:1. (2) Morphometric parameters exhibited a typical U-shaped recovery pattern, with mean body length increasing from the historical low of 24.2 cm in 2009 to 29.6 cm in 2024, and mean body weight increasing from 58.4 to 105.0 g, representing increases of 22.3% and 79.8%, respectively. (3) The von Bertalanffy growth model showed the best fit, revealing significant sexual dimorphism in growth parameters: females exhibited greater asymptotic length than males, with L values of 39.05 cm for females and 32.63 cm for males, but lower growth coefficient, with k values of 0.41 for females and 0.56 for males, reflecting a “slow growth-large body size” life history strategy, while males adopted a “fast growth-small body size” strategy. Temporal analysis revealed U-shaped and inverted U-shaped recovery trajectories for L and k, respectively. (4) Population recovery exhibited sex-specific differences, with females fully recovering to 2005 levels and showing enhancement, while males improved but with relatively delayed recovery. This study confirms the significant positive effects of 10-year fishing ban policy in the Yangtze River on C. nasus population conservation and resource recovery, providing important empirical support for assessing the effectiveness of aquatic biodiversity conservation in the Yangtze River Basin and scientific basis for formulating adaptive management strategies for endangered anadromous fish species.

     

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