洞庭湖花■的年龄、生长和资源评估

根据2017-2019年在洞庭湖采集的228尾花鱼骨](Hemibarbus maculatus)样本,使用耳石和鳞片研究其年龄、生长和资源现状。结果显示:耳石和鳞片是良好的年龄鉴定材料,鳞片上年轮特征以普通切割型为主,耳石重量可用于粗略、快速年龄鉴定。样本体长90~262 mm,优势体长组120~180 mm;体重11.0~399.0 g,优势体重组为20.0~80.0 g;年龄组成1~4龄,1龄为优势年龄组。体长体重关系:W=7.434×10^-6 L s 3.165,b值显著大于3,为异速生长鱼类。Von Bertalanffy生长方程:L t=301.41-e-0.471(t+0.341)],W t=522.01-e-0.471(t+0.341)]3.165,拐点年龄2.11龄(体长206.2 mm,体重156.9 g)。花鱼骨]为典型的r-选择鱼类,总死亡系数3.321,自然死亡系数0.823,开发率为0.752,种群处于过度开发状态。建议起捕体长为172.2 mm,开发率降至0.601,同时在繁殖季节设置人工鱼巢,以恢复洞庭湖花鱼骨]种群资源。

Assessment of age,growth and stock for Hemibarbus maculatus in Dongting Lake

A total of 228 Hemibarbus maculatus specimens were collected in Dongting Lake from December,2017 to January,2019.Otoliths and scales of these specimens were studied to investigate the age,growth and stock assessment.The results showed that both of the otoliths and scales were good age identification characteristics for H.maculatus.The main annuli pattern was common cut on scales.It was a rapid and cursory method to estimate the age of specimens through otoliths weight.Standard length of specimens ranged from 90-262 mm,mainly between 120-180 mm;body weight ranged from 11.0-399.0 g,mainly between 20.0-80 g.Estimated age ranged from 1 to 4,and the dominant age group was 1 year old.The length-weight was described by W=7.434×10^-6 L s 3.165.There was a significant difference between the heterotrophic growth index(b)and the theoretical value(3),which indicated that H.maculatus was a kind of heterotrophic fish.The Von Bertalanffy growth equations were:L t=301.41-e-0.471(t+0.341)],W t=522.01-e-0.471(t+0.341)]3.165.Growth inflexion point was 2.11 years with the standard length of 206.2 mm,and weight of 156.9 g.The life-history pattern was r-selection on H.maculatus,which had the total mortality of 3.321 and the natural mortality of 0.823.The resource development rate was 0.752,which meant the stock was overexploited.In order to recover and rationally develop the stock,the minimum catchable size should increase to 172.2 mm,the development rate should be reduced to 0.601.During the breeding season,artificial fish nests could be laid in lake.