铜山源水库渔获物组成与美国大口胭脂鱼的资源量估算

The Catch Composition in Tongshanyuan Reservoir and Resource Assessment of Large Mouth Buffalo Ictiobus cyprinellus(Valenciennes)

2000～2002年每年的1月,在浙江省衢州市铜山源水库放养了前一年5月培育的美国大口胭脂鱼冬片鱼种,累计达1.6×105尾,于2004年11月,对用单层刺网捕获的渔获物进行了测量分析,并对所获渔获物中的美国大口胭脂鱼的年龄结构、可捕群体资源量、回捕率进行了分析估算.结果表明,铜山源水库渔获物中以白鲢为主,占总尾数的64.04%,总重量的78.2%;美国大口胭脂鱼次之,分别为29.55%和22.07%,而鲫鱼、鲤鱼等其他鱼类仅占7%左右.铜山源水库美国大口胭脂鱼由Ⅰ～Ⅳ龄4个年龄组组成,其年龄结构中以Ⅱ、Ⅲ、Ⅳ龄为主,其可捕资源量达6.1×104尾、4.29×104kg,回捕率达36.8%;Ⅰ～Ⅱ龄组为水库自然繁殖的子代群体,占所获美国大口胭脂鱼总尾数的40%,表明美国大口胭脂鱼在铜山源水库已自然繁殖并形成了一定的可捕捞资源量.

In January between 2000 and 2002, a total of 160 000 fingerlings of large mouth buffalo were stocked in Tongshanyuan Reservoir for breeding. An investigation and analysis on the resource of large mouth buffalo in Tongshanyuan Reservoir was carried out in November, 2004. The catch composition in Tongshanyuan Reservoir and the age composition of large mouth buffalo were studied and the resource assessment of large mouth buffalo was conducted. The results show that the fishing composition is mainly composed of large mouth buffalo of age Ⅱ , Ⅲ, Ⅳ and silver carp. The fishing resources of large mouth buffalo should be 4.29 × 104 kg and its recapture rate could be as high as 36.8%. Large mouth buffalo aged of Ⅰ and Ⅱ made up 40% of the totle sample. The result indicats that large mouth buffalo in Tongshanyuan Reservoir can reproduce naturally and resources of this type of fish have to some extend been available.