华南地区外来鱼类革胡子鲶的繁殖生物学

Reproductive biology of exotic fish Clarias gariepinus (Burchell,1822) in south China

2011年8月—2015年8月在华南地区主要河流收集255尾革胡子鲶(Clarias gariepinus)样本,对其繁殖生物学特征进行研究。结果表明:革胡子鲶繁殖季节为5—8月,繁殖旺季为6—7月,卵径分布呈现明显的多峰型;成熟系数与脂肪系数和肥满度的周年变化存在相反的趋势;绝对繁殖力为2850~605720粒,均值234232±175498粒,与体长、体重和年龄呈正相关;相对繁殖力为20~445粒·g^(-1),均值165±99粒·g^(-1),随体长、体重和年龄的增加呈先增加后趋于稳定趋势;绝对繁殖力和相对繁殖力均大于常见的鲶科鱼类。繁殖群体性比为1∶1.12,符合1∶1比例;雌、雄鱼最小性成熟个体均为1龄,Ⅳ期性腺;雌鱼体长174 mm,体重119.5 g,成熟系数为8.50%;雄鱼体长205 mm,体重116.2 g,成熟系数为0.45%;繁殖群体以1和2龄鱼为主,分别占繁殖群体总数的42.28%和51.68%,以补充群体占优势;华南地区革胡子鲶野生种群具有分批产卵、相对繁殖力高、卵径小、性成熟年龄低的特征,有利于其迅速建立稳定的种群,应加强对革胡子鲶野生种群动态的监测力度,并进一步采取防控措施。

A total of 255 fish specimens of invasive species Clarias gariepinus were collected from the main rivers of south China,to analyze its reproductive characteristics. The results showed that females spawned from May to August,and the spawning peak occurred in June and July. The distribution of egg-diameter presented a multi-peak pattern. Fat coefficient and fullness coefficient had obvious seasonal changes,and had an opposite trend with gonadosomatic index. The absolute fecundity ranged from 2850 to 605720 eggs with an average of 234232 eggs,and had a positive correlation relationship with body length,weight and age. The relative fecundity varied from 20 to445 eggs·g-1with an average of 165 eggs·g-1,and initially increased with body length,weight and age,and then became stable. Absolute fecundity and relative fecundity of C. garipinus were greater than those of other Siluridae fishes. Sex ratio of C. garipinus was 1 ∶ 1.12 in breeding season,and had no obvious difference with 1 ∶ 1. The shortest mature females（ body length： 174mm; weight： 119. 5 g; gonadosomatic index： 8. 50%） and males（ length： 250 mm; weight：116.2 g; gonadosomatic index： 0.45%） were 1 year old with Ⅳ period gonads. The age composition of breeding population mainly consisted of ages 1 and 2,which accounted for 42.28%（ age1） and 51.68%（ age 2） of the total specimens. The results suggested that reproduction characteristics（ i.e. multiple batch spawning,highly relative fecundity,small eggs,mature at early age） ofC. gariepinus might be conducive to its invasion in south China. It is necessary to strengthen monitoring for the wild populations of C. gariepinus,and take further measures to prevent and control this fish species in the invaded regions.