白缘[鱼央]的年龄结构与生长特征及生活史类型

Age Structure,Growth Characteristic and Life-history of Liobagrus marginatus

为丰富白缘[鱼央](Liobagrus marginatus)的基础生物学资料,在金沙江支流黑水河采集白缘[鱼央]244尾,分析其年龄结构、生长特性和生活史类型,并通过脊椎骨进行其年龄鉴定。结果显示,黑水河白缘[鱼央]由5个年龄组构成,其中以2龄个体为主,占50.4%。全长与体重的关系式为W=3×10^(-5)L^(2.78)(R^(2)=0.947),全长与体重的Von Bertalanffy生长方程分别为L_(t)=133.13[1-e-^(0.24(t+1.92))]和W_(t)=24.02[-e^(-0.24(t+1.92))]^(2.78)。体重生长速度和加速度均具有拐点,拐点年龄为2.34龄,拐点体长85.19 mm,拐点体重6.30 g。通过模糊聚类法分析,确认白缘[鱼央]属于r-选择鱼类。研究表明,白缘[鱼央]的种群结构呈现低龄化,水电开发和过度捕捞是影响其种群结构的主要因素;白缘[鱼央]的捕捞规格应该高于其拐点年龄,即体长大于85.19 mm,体重大于6.30 g。

Liobagrus marginatus,inhabiting the upper Yangtze River and its tributaries,has high nutritional and economic value.In this study,the age structure,growth characteristics and life-history pattern of L.marginatus were analyzed,based on a field investigation carried out in the lower Heishui River in July,2014.The objectives were to supplement the basic biological data for L.marginatus and provide a theoretical basis for resource conservation.A total of 244 L.marginatus specimens were collected from the Qiaojia reach of Heishui River,with a body length range of 58-110 mm and body weight range of 2.60-26.70 g.Vertebrae 1-5 were used to determine age.Results show that the L.marginatus specimens ranged in age from 1 year to 5 years and were dominated by two-year-olds,accounting for 50.4%of the total.The relationship between body weight(W)and total length(L)was described as W=3×10^(-5)L2.78(R^(2)=0.947),indicating that L.marginatus growth is allometric.The Von Bertalanffy equations for total length and body weight in L.marginatus were L_(t)=133.13[1-e^(-0.24(t+1.92))]and W_(t)=24.02[1-e^(-0.24(t+1.92))]2.78.The growth inflexion point of L.marginatus was 2.34 years,with corresponding total length and body weight of 85.19 mm and 6.30 g.Based on fuzzy cluster analysis,the life-history pattern of L.marginatus belongs to r-selection.This study shows that the population structure of L.marginatus is tending towards younger,and hydropower development and overfishing were identified as the primary factors affecting the population structure.We recommended that the capture size should be larger than that at the inflection point,i.e.,a length longer than 85.19 mm and weight heavier than 6.30 g.