大麻哈鱼的年龄与生长

摘要

通过对2010和2011年采捕到乌苏里江大麻哈鱼洄游群体571个样本的鳞片观察和基础生物学测定,研究了大麻哈鱼的年龄判定和生长模拟.大麻哈鱼鳞片属于典型圆鳞,有明显的年轮特征,为一年一个周期,年轮特征表现为疏密型.部分鳞片有明显幼轮,幼轮和年轮根据鳞径大小能够区分.采集样本的雌雄组都分为2+,3+,4+三个年龄组,也都以3+龄组数量最多.采用特殊Von Bertalanffy、Logistic、Gompertz和幂指数生长方程分别模拟了大麻哈鱼1-4龄间的生长,通过最大似然法估计各模型的参数.采用残差平方和(Analysis of the residual sum of squares,ARSS)分析得出大麻哈鱼雌雄个体间生长无显著差异(P>0.05),故将雌雄个体放一起进行生长模拟.AIC和BIC检验结果显示特殊VBGF方程为最适生长模型,公式为:Lt=90.04× [1-e-0.3(ti+0.27)].大麻哈鱼的生长速度随着年龄增长逐年降低,且性成熟年龄小的个体生长速度大于性成熟年龄大的个体.应对大麻哈鱼年龄与生长进行长期监测,为增殖放流等渔业资源管理措施提供基础资料.%Chum salmon belongs to anadromous fish and it dies after spawning. In order to determine age and growth simulation of chum salmon, 571 homing chum salmons were randomly collected in Ussuri River in autumn of 2010 and 2011. Biological parameters, such as fork length and body weight, were measured in the field, and scales were taken into the laboratory for age determination. The results showed that the scale of chum salmon, which was thin and small, belonged to round scale. The scale had clear annuli that was formed once a year, the annuli belong to loose-close type. Young annuli, formed when chum salmon enters into the ocean from river, was observed in some chum salmons. Young annuli could be distinguished from annuli easily, as the young annuli diameter was shorter than the fist annuli obviously. The chum salmon samples were divided into 2+, 3+ and 4+ age group, and the individual number of the 3+ group was the largest, male and female group had the same character. In order to select the optimal growth function, Special Von Ber-talanffy (VBGF), Logistic, Gompertz and power exponential growth function were used to simulate chum salmon growth at the age of 1—4, respectively, and evaluate the effect of simulation. A maximum likelihood estimation procedure was used to fit the functions and calculate the function parameters. ARSS (Analysis of the residual sum of squares) was used to analyze the difference of growth, and the result suggested there were no significant differences in growth between male and female individuals among the four growth models (T>0.05). Therefore, male and female chum salmons were pooled together to analyze their growth. VBGF model was considered as the most appropriate growth model based on the Akaike's Information Criterion (AIC), and Bayesian information criterion (BIC), because it had the smallest value. The function is as follow: L,=90.04x[l-e~° 3(''+0 27)]. The relationship between AIC and BIC of other functions is as follow: Gompertz < Logistic < power exponential. Thus VBGF should be selected to simulate the growth of chum salmon when the scale was taken as the age determining material. With the increasing age of chum salmon, growth rate became lower, and the individuals whose maturation age was younger grow faster than the matured older ones. The study of the age and growth of chum salmon should be taken for ages, which can provide more basal data for enhancement and releasing of chum salmon for the fishery resource protection programs.