东海北部和黄海南部鲐鱼生长特性及合理利用

Growth characteristics and rational exploitation of Scomber japonicus in the north of the East China Sea and the nouth of the Yellow Sea

采用2002年11月～2003年8月在东海北部和黄海南部区域（30°～34°N、126°E以西范围）所获取的鲐鱼（Scomber japonicus）样品，通过观察鲐鱼耳石生长轮和基础生物学测定，研究了鲐鱼的年龄和生长；再依据不完全β函数渔获量方程，计算、分析在不同开捕年龄和不同捕捞强度下的单位补充量渔获量（Yw／R）的变化情况。结果表明，采用Walford方法拟合的鲐鱼生长方程，其生长参数K、L∞、t0分别为0．320、451．4和-1．203。比较不同时期鲐鱼的生长情况显示，20世纪60、80年代和21世纪初期鲐鱼的生长较接近，而20世纪70年代的鲐鱼生长情况与其他3个时期的鲐鱼生长相差较大。比较不同海域鲐鱼的生长情况显示，随着纬度的增加，鲐鱼的个体有增大的趋势，经分析很可能与海水温度有关。根据历史资料推算出鲐鱼的最大年龄（tλ）为9龄；根据最近的采样，推算出鲐鱼的开捕年龄和补充年龄都为0．4年，鲐鱼的自然死亡率为0．355，捕捞死亡率为2．27。利用上述参数，动态综合模型模拟的结果显示，该资源过度捕捞已很严重。若保持当前捕捞强度，则必须把开捕年龄限制在2．9龄；若能同时改变捕捞强度和开捕年龄，则可以把当前的开捕年龄限制在2．0龄，捕捞死亡率降到1．3，这样鲐鱼资源才能够得到保护与合理利用。

Based on the samples from bottom trawl surveys from November 2002 to August 2003 in the north of the East China Sea and the south of the Yellow Sea, Scomber japonicus＇s age and growth were studied by observing Scomberjaponicus＇s otolith and measuring their biological characters. The catch equation including incomplete β function is adopted to analyze catch weight per recruit（Yw/R ） at different first capture age and with different fishing mortality coefficient. The results show that： by Walford＇ s method, the parameters of Scornber japonicus＇s growth equation are, K, L∞, to are 0. 320,451.4, - 1.203 respectively. By comparing Scomber japonicus＇ s growth status of different periods, the growths of 1960＇, 1980＇ and 2000＇ are similar, but that of 1970＇ is obviously different. By comparing the growth status of different areas, it is a trend that Scomber japonicus＇s body length increases with the latitude increase probably for the water temperature＇ s decrease. Based on historical data, the maximum age of Scomber japonicus, 9 years old, is got. Based on the recent data, it is got that both the first capture age and the recruiting age are 0.4 year old, the natural mortality rate is 0.355, and the fishing mortality coefficient is 2.27. On above parameters, the utilization situation is simulated by dynamic synthetic model, and the result show that the stock of Scornber japonicus has been severely overfished. To protect and exploit rationally this resource, if the current fishing intensity is kept on, the first capture age should be put off till 2.9 years of age;and if the first capture age is kept on, the current fishing intensity should be reduced to 0.44; in another way the first capture age should be put off till 2.0 years of age and the fishing mortality coefficient must be reduced to 1.3 simultaneously.