扁担塘螺类生产力的研究Ⅱ.纹沼螺的周年生产量

PRODUCTION OF GASTROPODS IN LAKE BIANDANTANG Ⅱ.ANNUAL PRODUCTION OF PARAFOSSARULUS STRIATULUS

采用四种方法对扁担塘纹沼螺的周年生产量进行了测算 ,结果表明 ,四种方法得到的生产量吻合极好。生产量的去壳干重和带壳湿重分别是 :体长频度法 ,1 78.0 7mg·m- 2 ·a- 1 ,4998.40mg·m- 2 ·a- 1 ;减员累计法 ,1 74.50mg·m- 2 ·a- 1 ,4898.2 0mg·m- 2 ·a- 1 ;Allen曲线法 ,1 74 50mg·m- 2 ·a- 1 ,4898.2 0m- 2 ·a- 1 ;瞬时生长率法 ,1 78.1 4mg·m- 2 ·a- 1 ,50 0 0 .40mg·m- 2·a- 1 。对应的P/B系数分别为 4.3,4.4,4.4,4.5。

The production of Parafossarulus striatulus in Lake Biandantang was calculated by using four method.The results were:178.07 mg*m-2*a-1 of dry weight shell-free or 4998.40 mg*m-2*a-1 of wet weight with shell by size-frequency method;174.5 mg*m-2*a-1 of dry weight shell-free or 4898.20 mg*m-2*a-1 of wet weight with shell by removal-summation method;174.5 mg*m-2*a-1 of dry weight shell-free or 4898.20 mg*m-2*a-1 of wet weight with shell by Allen curve method;178.14 mg*m-2*a-1 of dry weight shell-free or 5000.40 mg*m-2*a-1 of wet weight with shell by instantaneous growth method.The corresponding P/B ratios are 4.3,4.4,4.4,4.5, respectively. Therefore,the results by the four methods are in well agreement,which might be of great significance in the estimation of invertebrate production.