青菱湖中长春鳊生物学的研究

1983-1985年对通长江的青菱湖中长春鳊的年龄与生长、食性、繁殖及其鱼群江湖交流等生态习性进行了调查。发现相当部分标本的鳞片上有明显的幼轮标志;性成熟后,雌鱼的生长较雄鱼迅速;摄取的食物种类与湖中各种水生植物的季节性盛衰相适应,但有一定的选择性;亲鱼能在湖中成熟产卵,但鱼卵因受自然条件限制,不能发育成活。湖中鱼群的补充仍依靠数量不定的1龄幼鱼由长江干流逆水或顺水伺机窜入湖内。江湖之间闸门的启闭主要根据农田水利的需要,因此,长春鳊鱼群规律性的江湖交流仍然受到阻碍。  

ON THE BIOLOGY OF THE PARABRAMIS PEKINENSIS(BASIL.)IN LAKE QINGLING,WUHAN

An Investigation was made on the biology of the P.pekinensis,a semi-migratory fish bet- ween rivers and lakes,from Nov.1983 to Dec.1985 in Lake Qingling,which is linked with the main stream of the Yangtze River by a canal.The results are summerized as follows: (1)The “fry check” and “spawning check” were clearly obverved on the scales. (2)The fish reached a mean body length of 83 mm in the first year,164 mm in the se- cond year and 260 mm in the third year.The weight gain by adult females is much greater than that by adult males. (3)Over 10 vegetable food species were found in the intestine of the fish.The main spe-cies were Myriophyllum spicatum,Hydrilla verticillata and Spirogyra sp.The fish hardly ate Potamogeton crispus and Ceratophyllum demersum,which spread seasonally all over the lake,showing the habits of selective feeding. (4)During the spawning season,most mature fish were hindered from migrating into the river to spawn by the sluice gate between the river and lake.However,the tempo- rary flowing water caused by heavy rains and overflow near the inlet or outlet of the lake could still stimulate the parent fish to spawn in the lake.Owing to lack of the condition of constant flowing water in the lake,the drifting eggs then sank onto the bottom and died. (5)The population in the lake is recruited by the young fish from the river.These young individuals frequently aggregate outside the gate and may occasionally swim into the lake during the temporary lifting of the sluice gate.