长江干流长鳍吻鮈(Rhinogobio ventralis)繁殖生物学

The Reproductive Biology of Rhinogobio ventralis in the Main Stream of the Yangtze River

关键词:  长鳍吻鮈  繁殖生物学  性成熟  繁殖力

Key words:  Rhinogobio ventralis  Reproductive biology  Sexual maturity  Fecundity

摘要:

2012年3月–2014年12月对长江上游宜宾江段采集的521尾野生长鳍吻进行了繁殖生物学研究。结果显示，长鳍吻鮈种群雌雄比为1.41∶1，繁殖期为3–5月，盛期为4月上旬至5月上旬。繁殖季节可通过吻端细小“珠星”鉴别雌雄，雄鱼最小性成熟年龄为2+龄，最小成熟体长为173 mm，体重为90.4 g，成熟系数为0.36%；雌鱼最小性成熟年龄为3+龄，最小成熟体长为185 mm，体重为119.6 g，成熟系数为11.30%。繁殖群体中，雌性优势龄组为3+龄，雄性优势龄组为2+龄和3+龄。统计结果显示，长鳍吻绝对繁殖力(F)为16399–39835(26816±±7875)粒/尾，体重相对繁殖力(FW)为162–234(189±±23)粒/g，体长相对繁殖力(FL)为877–1659(1231±±246)粒/cm。通过对性腺成熟系数、卵径分布频率以及性腺组织切片结果的综合分析认为，长鳍吻属于完全同步产卵类型。

Abstract:

Rhinogobio ventralis is an endemic fish species in the upper stream of the Yangtze River that has high commercial values. However, a series of hydroelectricity projects dramatically changed the aqua environment and damaged the habitat of this species. In order for the protection of R. ventralis resource, we conducted the reproductive biology research on 521 R. ventralis collected in the upper Yangtze River (Yinbin section) from March 2012 to December 2014. The overall sex ratio of female to male was 1.41:∶1. Females outnumbered males except for the groups in which the fish body lengths were in the ranges of 161–190 mm and 221–250 mm. The monthly average gonadosomatic index of females varied between 0.78% and 18.22%. A GSI peak value appeared in April，and the ovary stage was IV or V from April to May. The hepatosomatic index (HSI) also changed over the development of gonad, which indicated that liver might play an important role in the maturity of R. ventralis. Analysis on the monthly gonadosomatic index (GSI) and the percentage of females at different gonadal stages revealed that the breeding season for R. ventralis was from March to May, and the optimal time window was from the beginning of April to the beginning of May. During the breeding season the nuptial organs was a prominent sexual characteristic. The mature age of males started at 2-year old, and the minimum size of a mature male was 173 mm in length and 90.4 g in weight. The females became sexually mature at 2-year old, and their minimum size was 185 mm in length and 119.6 g in weight. The predominant age groups were 3 years for females, and 2 years and 3 years for males. The absolute fecundity of R. ventralis was 16399–39835 (26816±7875). The relative fecundity to the body weight was 162–234 (189±23), and it was 877–1659 (1231±246) in terms of the body length. The egg diameters of R. ventralis exhibited a unimodal distribution pattern. In conclusion, our study suggested that the reproduction of R. ventralis could be one-time spawning.