东海中部鲐鱼相对体质量指数的计算

Calculation of Relative Body Weight Index of Chub Mackerel in Central East China Sea

为描述东海中部鲐鱼资源的健康状况,反映鱼类所遭受的外界压力情况,基于2009-2010年在东海中部捕获的鲐鱼的叉长和体质量数据,通过建立鲐鱼的标准体质量,计算得到东海中部鲐鱼的相对体质量指数值。根据叉长和体质量对数中值建立的标准体质量方程为：lgms=0.104574L2＋2.945479L-2.014981。相对体质量与叉长的分布情况显示,当叉长小于10cm时,相对体质量指数为45~166,而当叉长为15cm时,相对体质量指数变化范围较小,为82~109。虽然在叉长小于10cm或叉长在20cm时,相对体质量指数的变动性较大,但其频率趋于正态分布。东海中部鲐鱼相对体质量指数的计算为不同海域间鲐鱼资源的相互比较研究提供了便利,也为今后更全面、准确地了解该研究海域鲐鱼群体的资源状况提供了研究基准。该指数不受体长大小所引起的误差的影响,能够较准确地在具有不同时空特征以及来自不同种群的鱼类个体之间进行相互比较,从而能够更好地为鲐鱼资源的开发与管理提出科学建议。

The relative body weight index （m,） was calculated in chub mackerel （Pneumatophorus japonicus） based on the fork length and body weight data collected during 2009 and 2010 in the Central East China Sea in or- der to evaluate the pressure of surrounding environment on chub mackerel stock. The equation obtained by standard weight （m,） was established as lgm, =0. 104574L2 ＋2. 945479L-2. 014981 based on the mid-values of lgl0-trans- formed fork length and body weight. The frequency of relative body weight and fork length showed that the range of mr was varied from 45 to 166 at fork length of below 10 cm,and the range of mr was varied between 82 and 109 at fork length of about 15 cm. The frequency of the variation of mr tended to follow normal distribution,although the variation of mr was relative large when the fork lengths were within smaller than 10cm and close to 20 cm. The calculation of mr of chub mackerel in the Central East China Sea provided convenience for the comparison of chub mackerels among different seas,and provided baseline of the status of chub mackerel stock in surveyed area for fu- ture studies. The index is not affected by the errors of the variation of fish body size, and can be used in accurate comparison of the individuals derived from different populations with different temporal and spatial characteristics for future exploitation and management.