太湖大银鱼生长与食性的初步研究

大银鱼Protosalanx hyalocranius(Abbott)为太湖主要经济鱼类之一．为了合理利用太湖银鱼资源和探讨湖泊鱼类构成“小型化”问题提供参考，在1981年2月至1982年2月研究了太湖大银鱼的周年生长与食性，主要结果如下：大银鱼全年在太湖生长发育，属一年生的定居性小型鱼类，其生长较为迅速，经7个月平均体长可达到110毫米；大银鱼为肉食性鱼类，幼鱼阶段摄食枝角类与桡足类，成体在太湖中主要以湖鲚和太湖短吻银鱼等为食．为提高太湖银鱼产量和合理利用资源，建议大银鱼的起捕规格由全长40毫米提高到60毫米(体长约为52．4毫米)。

A PRELIMINARY STUDY ON GROWTH AND FEEDING HABITS OF ICE--FISH IN TAIHU LAKE

Ice-fish (Protosalanx hyalocranius Abbott) is an econmically important fish inTaihu Lake. Investigation on its growth and feeding habit was made from Fibrary1981 to Fibrary 1982 in order to understand the potentiality of the ice-fish resourceand the correlation among other fish resources in the lake.The results are summarized as follows:1. Ice--fish is a lake-dweller and has one-year lifespan. The fry grows relatively fastand the average body length may reach to 110 mm in seven months.2. Ice-fish is a predatory fish eating smaller fishes and sbrimps. The main food oflarvae less than 60 mm consists of cladocera tal copepod. 36 genera or species of foodorganism were found in the digestive tract of the fish of 5.4--181 mm in body length.3. The adult individuals feed mainly on lake ancovy (Coilia ectenes taihuensis)andanother ice-fish (Neosalanx tangkahkeii taihuensis) in Taihu and hence it has beenconsidered ss a potential danger to them.4. It is proposed that the catchable size of ice--fish should be increased to 60 mm intotal length (about 52.4 mm in body length).