稀有鮈鲫的繁殖生物学

根据野外调查与室内养殖的结果,稀有鮈鲫的繁殖季节为3—11月,在人工控制条件下可周年繁殖。在适宜的水温和充足的饵料条件下孵出后4个月左右即可达性成熟并产卵。对7对鱼共136批次产卵进行了观察统计,平均每尾雌鱼5.4d产卵一次,平均每次产卵300.3粒。根据卵母细胞发育进程、卵径分布、产卵频次以及年产卵量大于怀卵量、含卵量等特征,建议将稀有鮈鲫的特殊产卵类型命名为连续产卵类型,并与生态学上常用的“多次产卵”、“分批产卵”加以区别。最后就稀有鲍鲫作为一种新的实验鱼等应用前景作了展望。  

REPRODUCTIVE BIOLOGY OF GOBIOCYPRIS RARUS

Reproductive biology of the rare minnow, Gobiacypris rarus, was studied both in the field (Liusha River, Hanyuan County, Sichuan Province) and in laboratory experiments from March 1990 to May 1991. Spawnings may occur throughout the year in the aguarium under controlled conditions (temperature, food etc.), though the breeding season in the field lasts from March to November only, when the water temperature is above 14℃. Fingerlings attain sexual maturity when they are 4 months old under favorable cultured conditions. The eggs are adherent, with transparent membrances. The diameter of the egg membrance is between 1.25 and 1.70 mm. Spawning. often begins at dusk and usually finishes before midnight. Observations on 136 spawnings by 7 pairs of rare minnows showed that the interval between successive spawnings ranged from 3 to 20 days, (usually 3 to 6 days); the mean spawning interval was 5.4 days and the mode was 4 days. The number of eggs produced per spawning ranged from 2 to 768 (average 300.3). Based on the unsynchronous development of oocytes, distribution of egg diameters, frequency of spawnings, and continuous recruitment of oocytes, the rare minnow is reguarded as a continuous batch spawner. A discussion was made on the classification of spawning patterns in fish and the potential uses of the rare minnow.