山美水库两种入侵罗非鱼繁殖生物学比较

为比较山美水库两种入侵齐氏罗非鱼(Coptodon zillii)和伽利略罗非鱼(Sarotherodon galilaeus)种群的繁殖生物学特征,于2021年3—10月份在山美水库逐月采样,分析了繁殖时间、性比、绝对繁殖力、相对繁殖力和成熟卵径等特征。结果表明,两种罗非鱼均于4月份开始繁殖,齐氏罗非鱼繁殖高峰为7月, 10月结束繁殖;伽利略罗非鱼繁殖高峰为6月, 9月结束繁殖。齐氏罗非鱼平均绝对繁殖力为(4009.85±1305.69)粒、平均体重相对繁殖力为(67.32±15.63)粒/g、平均体长相对繁殖力为(31.31±5.03)粒/mm;伽利略罗非鱼平均绝对繁殖力为(1701.85±591.29)粒、平均体重相对繁殖力为(6.46±0.87)粒/g、平均体长相对繁殖力为(8.22±2.33)粒/mm;齐氏罗非鱼的绝对繁殖力、体重相对繁殖力和体长相对繁殖力均显著高于伽利略罗非鱼,平均成熟卵径则显著小于伽利略罗非鱼。齐氏罗非鱼和伽利略罗非鱼繁殖群体的雌雄性比分别为1.59和1.83,两个种群的雌雄性比无显著差异,但均显著偏离1﹕1。研究表明两种共同入侵的罗非鱼种群具有不同的繁殖...

COMPARATIVE STUDY ON REPRODUCTIVE BIOLOGY OF TWO CO-INVASION TILAPIA SPECIES IN THE SHANMEI RESERVOIR

The redbelly tilapia Coptodon zillii and the mango tilapia Sarotherodon galilaeus are two invasive fish species in the Shanmei Reservoir, which have become dominant species of the fish community in the reservoir. In order to compare their reproductive traits for developing invasive control measures for the two tilapia species, we monthly sampled fishes from March to October 2021 in the Shanmei Reservoir, and analyzed their reproductive period, sex ratio, absolute fecundity, relative fecundity and egg size. We also analyzed the reasons for their stable coexistence after co-invasion through the reproductive biology of two species of tilapia. Results showed that both populations started to spawn in April, but the spawning activity was peaked in July and June, and ended in October and September for C. zillii and S. galilaeus, respectively. The absolute fecundity of C. zillii was (4009.85±1305.69) eggs, the body weight relative fecundity was (67.32±15.63) eggs/g, and the body length relative fecundity was (31.31±5.03) eggs/mm for C. zillii, which were significantly higher than those of S. galilaeus (1701.85±591.29) eggs, (6.46±0.87) eggs/g, and (8.22±2.33) eggs/mm]. However, the mature egg size of C. zillii was significantly smaller than that of S. galilaeus. The sex ratios (female/male) of C. zillii (1.59) and S. galilaeus (1.83) showed non-significantly difference and females outnumbered males in these two species but both ratios were significantly biased with 1﹕1. This study suggested that the two co-invasive tilapia exhibit different reproductive strategies, which should be key factors explaining their dominant abundance and stable coexistence after successful co-invasion. This study can provide implications for the management of the two co-invasive tilapia populations, which contribute to the sustainable development of fisheries resources management in the Shanmei Reservoir.