温台渔场龙头鱼的生长、死亡及最适开捕规格

Growth, mortality and optimum catchable size of Bombay duck (Harpadon nehereus) in the Wentai fishing ground, East China Sea

  • 摘要: 在传统渔业资源衰退的情况下,龙头鱼等次要的经济种类逐渐成为东海海区的优势种群,具有重要的经济价值和生态地位。根据2015年11月—2016年8月在温州台州外海(120.93°~122.95°E,27.21°~28.97°N)调查采集的2 611尾龙头鱼的生物学数据,用ELEFANⅠ方法对其生长、死亡参数进行估算,并通过不完全β函数渔获量方程动态综合模型确定最适开捕规格,评估种群资源的利用状况。结果显示,温台渔场龙头鱼体长—体质量关系为W=0.000 5L3.87(R2=0.906 7),雌、雄个体间的体长—体质量关系无显著性差异;龙头鱼的Von Bertalanffy生长方程参数LKt0分别为32.13 cm、0.39和–0.69龄,体质量生长拐点年龄为2.78龄;根据体长组成资料的线性渔获量曲线估算出龙头鱼的总死亡系数2.55,用Pauly经验公式估算出自然死亡系数0.66,捕捞死亡系数1.89和开发率0.74;动态综合模型评估表明,应适当提高开捕年龄,增大开捕体长,最适开捕年龄tc为1.15龄,相应开捕体长为16.5 cm。

     

    Abstract: Some traditional fishery resources in the East China Sea have showed an apparent decline trend over years and therefore, those subordinate economic species, such as Harpadon nehereus, have gradually became dominant species, which also has important economic value and plays a key role in local eco-system. During the period from November 2015 to August 2016, a total of 2611 samples of H. nehereus were collected in the Wentai fishing ground. Based on the length information recorded, an ELEFAN I technique was used to estimate growth and mortality parameters of H. nehereus, and an incomplete β function dynamic pool model was adopted to determine the catchable size and evaluate the exploitation conditions for H. nehereusresources. The results show that: the length-weight relationships of H. nehereus in the Wentai fishing ground was W=0.000 5L3.87 (R2=0.906 7), and this relationship was insignificantly different between females and males. The parameters of Von Bertalanffy Growth function for H. nehereus were L=32.13 cm, K=0.39 and t0=–0.69, with the inflexion for body weight growth estimated at 2.78 years. The total mortality coefficient calculated with linear catch curve based on body length structure was 2.55, and the natural mortality coefficient estimated by Pauly’s empirical equation was 0.66. Meanwhile, the fishing mortality coefficient was found to be 1.89 and the exploitation rate was 0.74. The dynamic pool model indicated the age of capture and the first catchable size should be increased, and the first catchable age and the corresponding capture length should be set at 1.15 years, and 16.5 cm, respectively.

     

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