碧流河水库陆封型香鱼生物学特性的演变

Evolution of biological characteristics in landlocked Ayu, Plecoglossus altivelis, in Biliu Reservoir

198 2年碧流河水库建成后 ,被陆封在水库中的香鱼 (Plecoglossusaltivelis)经 10余年适应后 ,其生物学特性发生了很大变化。其中一部分个体春季水温上升后暂不进入河道 ,而留在水库中生活 ,至 7月份才进入河道。与刚陆封时不同 ,在其植物食性阶段 ,消化道内有大量浮游植物出现 ;繁殖期也由 9～ 10月提前到8～ 9月 ,性腺发育速度明显加快 ;个体进一步变小。

Ayu, Plecoglossus altivelis, has been recorded as a species of sea-river migration. But when the Biliu Reservoir (Dalian, Liaoning Province) was built up in 1982, the stock born in Biliu River was restricted to the reservoir, forming a landlocked population. The investigation from May to September in both 1995 and 1996 showed that after more than 10 years of adaptation in the reservoir, the population of Ayu in Biliu Reservoir has changed a lot in their biological characteristics that part of them did not go up stream into the Biliu River in spring even when the water temperature got to 14℃ till July, which was different from those at the beginning of the landlocking. Abundant phytoplankton was found in their digestive tracts during their vegetable feeding period. A further test showed that the sexual glands in them developed more rapidly and the ovaries developed from stage III to V in less than a month. The spawning water temperature was 26～18℃, higher than before, and the breeding period was from August to September , a month earlier than the beginning. Due to the shortening of the growth period and the changing of food, the body size of P. altivelis in this reservoir became smaller.