达里湖鲫的年龄和生长

AGE AND GROWTH OF CRUCIAN CARP IN DALI LAKE

根据４７８尾标本研究了生活在盐碱性达里湖中鲫的年龄和生长，并提出资源合理利用意见。采用臀鳍第三枚鳍条与鳞片相结合鉴定年龄，高龄个体以鳍条为主。生长模式可用ＶｏｎＢｅｒｔａｌａｎｆｆｙ生长方程来描述，渐近体长Ｌ∞＝３０．１ｃｍ，渐近体重Ｗ∞＝８３２．３ｇ、体重生长拐点ｔｒ＝５．６龄。与７０年代比较，目前湖中鲫的生长速度加快、产量下降，资源呈衰退状况。改善产卵条件，控制捕捞规格是恢复资源的重要措施。

Age and growth of crucian carp (Carassius auratus) in Dali Lake, a saline alkaline lake situated in the Inter Mongolia plateau were studied. Both the third ray of anal fin (Spinous soft ray) and scale were used as the material for age determination. The result showed that the scale was a better material for age determination at the age below 5, while the third ray of anal fin was a superior one at the age 5 and above. The Von Bertalanffy growth equations as follows: L t=30.1[1-e -0.179 7(t+0.558 9) ]; W t=832.3[1-e -0.179 7(t+0.558 9) ] 3 which were established based on the age,length at age and weight at age, which indicated a higher growth speed than that in 1970's. Considering the declining of the yields in recent years, we suggest here two management measures of improving spawning condition and control the capture size for the conservation of resource.