辽东地区北方须鳅种群结构分析

Population Structure Analysis of Loach Barbatula nuda in Eastern Liaoning Province

为探明辽宁东部地区北方须鳅的种群结构,2018—2019年在鸭绿江支流和太子河上游用网目1.5cm地笼网采集到161尾北方须鳅,以脊椎骨为鉴定材料,分析年龄组成。调查结果显示:渔获物中雌性全长62~124mm,体质量1.7~13.6g;雄性全长71~130mm,体质量2.1~14.6g;年龄组成均为1~3龄,雌雄比为0.916∶1。全长50%方法估算结果显示,北方须鳅种群雌鱼初次性成熟全长79.3 mm,雄鱼初次性成熟全长98.9mm,对应的初次性成熟年龄分别为0.69龄和1.19龄。调查结果表明,北方须鳅是一种个体小、年龄组成简单、初次性成熟较早的鱼类,种群的生态对策偏向r选择类型。虽然r选择类型鱼类在遭受资源开发时种群恢复力较快,但过度捕捞可导致北方须鳅的种群恢复力不足,种群资源衰退。必须加强渔业管理措施,如设立最小捕捞规格、开展驯化繁育和人工增殖放流活动等加以养护。

In order to explore the population structure of loach Barbatula nuda in eastern Liaoning,the total length,body weight,age and first maturity performance were investigated in 161 samples collected from the tributaries of Yalu River and the upper reaches of Taizi River from 2018 to 2019 by a 1.5 cm mesh size trap to probe the population structure with vertebrae as the identification material.The results showed that the females had total length from 62 mm to 124 mm,and body weight from 1.7 g to 13.6 g,and that the males had body length from 71 mm to 130 mm,and the body weight from 2.1 g to 14.6 g,with age composition of 1—3 a and ratio of male to female of 0.916∶1.The estimation results of total length(TL)50%method showed that the female was first sexual maturity at total length of 79.3 mm,and the male was first sexual maturity at total length of 98.9 mm,corresponding to the first sexual maturity age of 0.69 a and 1.19 a,respectively.In conclusion,B.nuda is a fish with small size,simple age composition and early sexual maturity,and the ecological strategy of the population is an r selection type.Overfishing will lead to deficiency in the population recovery of B.nuda and the decline of population resources,although the population recovery of this fish is fast when suffering from exploitation.Therefore,it is necessary to strengthen fishery management measures,such as setting up the minimum fishing specifications,domestication,breeding and releasing activities for conservation.