长白山头道白河上游北方条鳅种群结构分析

2011年4月中旬至5月下旬,在长白山头道白河上游捕捞北方条鳅样本846尾,对其种群结构进行了分析,结果表明:捕捞群体的体长为2.2～14.6 cm,平均8.8 cm,以10～12 cm体长组和2～4 cm体长组的数量最多,两者所占的比例合计达75.3%,呈明显的双峰型分布格局.雌性和雄性群体的体长组成相似;捕捞群体的总体性比接近1∶1,但不同体长组的性比不同,个体小者(体长小于8 cm)雌性所占比例较低,个体大者(体长大于13 cm)雌性所占比例则明显偏高;春季迁移过程一般是大个体在先,小个体在后.

On Population Structure of Nemacheilus nudus in the Upper Reaches of Toudaobaihe River in Changbai Mountain

846 samples of Nemacheilus nudus was caught in the upper reaches of Toudaobaihe River in Changbai Mountain from mid April to late May,2011,and the population structure was analyzed.The results showed that the body length of population is from 2.2 cm to 14.6 cm with an average of 8.8 cm,and most in 10~12 cm length group and 2~4 cm length group,which account for 75.3% of the whole population totally,assuming obviously a bimodal distribution pattern.The body length composition of the female is similar to that of the male ones.The sex ratio is close to 11 in the overall caught population,but it is different in different body length groups.The female proportion is lower in the smaller groups(body length less than 8 cm) while it is obviously high in that of the larger ones(body length more than 13cm).Generally the larger individuals migrate first while the smaller ones later in the spring migration process.