草海鲫鱼的年龄和生长

Age and Growth of Crucian Carp Cauratus auratus in Caohai Lake

以生活在高寒湿地草海中鲫鱼的鳞片作为鉴定年龄的材料,对其种群开展年龄结构与生长特性研究。研究结果表明,草海鲫鱼种群由1-5龄共5个年龄组组成,以低龄个体为主,1-3龄个体占96.34%,体长分布主要集中在90-150mm（81.97%）,体质量分布主要集中在30-120g（83.89%）。群体总性比为♀∶♂=8∶1,体长和鳞径呈幂函数关系,体长和体质量呈幂函数关系且幂指数接近3,属于匀速生长类型,因此可用Von Bertalanffy方程来描述其生长特性,相关生长参数分别为：渐近体长L∞=259.67mm,渐近体质量m∞=481.94g,k=0.1537,t0=-0.6506龄,体质量生长拐点Ti=6.28龄。与20世纪80年代相比,目前草海中鲫鱼的年龄组成简单,低龄个体比例偏大,种群数量下降,资源呈衰退状况。

The age and growth of crucian carp Cauratus auratus found in alpine wetland Caohai Lake,Guizhou province,were studied by scales as annual ring method.The results showed that there were 5age classes ranging from 1to 5in the population of the crucian carp in CaoHai Lake,with preponderant age classes of 1-3years old,accounting for 96.34%of the total population.Most of the crucian carp had body length of 52.0-240.0mm,primarily within the range between 90.0mm and 150.0mm（81.97%）,and body weight ranging from 4.8g to 582.4g,mainly between 30 g and 120g（83.89%）.The ratio of♀to♂was found to be 8∶1,more females than males in the crucian carp in CaoHai Lake,and length-weight power function relationship of the crucian carp showed the exponent b=s with isometrical growth by scale annulus.The growth of the crucian carp was described as Von Bertalanffy equation,with L∞=259.67 mm,m∞=481.94 g,k=0.1537,t0=-0.6506 and body weight growth inflexion point of 6.28.Compared with 1980＇s,the simple age structure of the crucian carps in CaoHai Lake is featured by more small individuals and the declined population in the resources.