珠江河口棘头梅童鱼的资源评估

STOCK ASSESSMENT OF COLLICHTHYS LUCIDUS IN PEARL RIVER ESTURARY

  • 摘要: 本文应用ELEFAN Ⅰ和ELEFAN Ⅱ技术分析了1986年珠江河口区棘头梅童鱼每月的体长资料,推算了生长参数K、L、自然死亡系数M、总死亡系数Z和利用率E。单位补充量的产量Y/R和单位补充量的产值Yv/R的分析表明,该群体未出现过度渔捞现象。如果适当放大开捕体长Lc,则可相应地增加产量和产值,但是调整捕捞死亡水平,则收效不明显。本文还应用ELEFAN Ⅱ技术分析了珠江河口区棘头梅童鱼的补充类型,并讨论它的适用性。

     

    Abstract: The monthly 1ength-frequency data of Collichthys lucidus collectedduring 1986 in Pearl River Estuary was analysed by applying the ELEFAN Ⅰand Ⅱtechnique (Pauly et al., 1981). The growth parameters were estimated to be K=1.8,L=171mm and t0=-0.12, and the approximate longevity to be 1.5 years. A length-converted catch curve was then constructed, from which total mortality, Z=7.36,and mean sclection length, Lc=82mm, were calculated. Natural mortality, M=2.68,was estimated by using the empirical relationship between M, the growth parametersand mean environmental temperature (Pauly, 1980), and the exploitation rate, E= F/Z=0.636, was then obtained. Yield-per-recruit analysis and the value of yield-per-recruit analysis indicatedthat the stock of Collichthys lucidus in Pearl River Estuary is moderatly exploited.An increase in yield-per-recruit and the value of yield-per-recruit may be expected ifthe size of first capture have a moderate increase. However, no significant increase inyield-per-recruit and value of yield-per-recruit could be expected from regulating offishing mortality. This analysis also provided the optimin management alternative forthe short-lived fishes in the tropical waters. A recruitment pattern in the Collichthy lucidus stock was derived when using theELEFAN Ⅱ technique, and its appropriateness was discussed.

     

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