长江中游贝氏(鳖)繁殖生物学研究

2016年4-12月在监利长江何王庙故道采集591尾样本,对长江中游贝氏(鳖)(Hemiculter bleekeri)性比、初次性成熟大小、繁殖季节、产卵类型、产卵群体组成及繁殖力等繁殖生物学指标进行了分析.结果显示:贝氏(鳖)总体雌雄性比1.44:1,与1:1存在极显著性差异;繁殖期间雌雄比2.5:1,非繁殖季节雌雄比为0.91:1.繁殖群体年龄结构为1-3龄,以1龄补充群体为主,属于第Ⅱ类型.初次性成熟体长:SL♀50=8.08 cm, SL♂50=8.47 cm,最小观测性成熟个体分别为:雌性7.5 cm,体重6.65 g, 1龄;雄性8.2 cm,体重8.13 g, 1龄.根据成熟系数变化和性腺发育期观察,推测其繁殖季节为4-6月,可能延至7月份.贝氏(鳖)绝对繁殖力为1703~9601粒/尾,平均为(5876.6 ± 1837.8) 粒/尾,与体重、性腺重均呈线性关系,与体长呈幂函数关系.相对繁殖力(FW)为204.7~406.5粒/g,平均(322.3 ± 49.7) 粒/g,与成熟系数呈幂函数相关;相对繁殖力(FL)为212.0~827.6粒/cm,平均(552.4 ± 136.1) 粒/cm,与体重幂函数相关.

Reproductive biology of Hemiculter bleekeri in the middle reaches of the Yangtze River

The reproductive biology of Hemiculter bleekeri was studied based on 591 specimens collected from April to De-cember 2016 in Hewangmiao Oxbow, Jianli County, in the middle reaches of the Yangtze River.Several reproductive biol-ogy indicators including sex ratio, size at first sexual maturity, spawning season, spawning pattern, spawning stock and fecundity were analyzed in this study.The results showed that the total sex ratio (♀:♂) was 1.44:1, which was signifi-cantly different from 1:1.Females were dominated during spawning period with sex ratio of 2.5:1, while the sex ratio was 0.91:1 in anestrous season and had no significant difference from 1:1.The age structure of the spawning stock ranged from 1 to 3 years with the recruitment stock (1 year) dominant in the spawning stock, which indicated that the spawning stock belonged to type Ⅱ.The size of first sexual maturity for females and males were 8.08cm and 8.47cm, respectively.Moreover,the observed minimum mature individuals were 1 year old with the length and weight for females and males of 7.5cm, 6.65g, and 8.2cm, 8.13g, respectively.According to monthly variations of gonadosomatic index(GSI) and the gonad development stages, the spawning season might last from April to June, probably to July.The absolute fe-cundity (F) ranged from 1 703 to 9 601 eggs( (5 876.6 ± 1 837.8) eggs) per fish.The relations between F and weight (W), gonad weight (GW), standard length(SL) was in linear, linear and power function, respectively.Relative fecun-dity (FW) ranged from 204.7 to 406.5 eggs/g ( (322.3 ± 49.7) eggs/g) and was related to GSI in power func-tion.Relative fecundity (FL) ranged from 212.0 to 827.6 eggs/cm((552.4 ± 136.1) eggs/cm) and was in power corre-lation with W and in linear correlation with GSI, respectively.