网湖银鱼的繁殖、食性与生长

THE REPRODUCTION, FEEDING HABITS AND GROWTH OF SALANGID FISHES NEOSALANX TAIHUENSIS AND N.OLIGODONTIS IN WANGHU LAKE

研究了网湖太湖新银鱼和寡齿新银鱼的繁殖、食性和生长等生物学特性，并就网湖银鱼增殖的措施进行了探讨．两种银鱼的刚性征出现时间分别为10月和11月．平均绝对怀卵量为1506位和569粒，生殖期分别为3－6月和3－5月．生殖群体的体长组成，前者以56．0－64．gmm为主，后者以35．0－42．9mm为主．两种银鱼都以桡足类为主要食物．摄食强度在2—4月和10－11月有两个高峰．银鱼以4－6月和9－11月生长较快．捕捞宜在12月以后繁殖期前进行．

Thc present paper deals with the reproduction, feeding habits and growth of salangid fishes Neosalanx taihuensis and N. oligthentis in the Wanghu Lake, Hubei Province. The survey was conducted from 1992 to 1993 and the results are summarized as follows. The male secondary sex-ual characters of N. taihuensis emerge in October and those of N. olndontis in November. Both species spawn in batches. The N. taihuensis spawns from March to June, with an average abso lute individual fecundity of 1 506 eggs per female and dominant body-length groups of 56.0 mm to 64. 9mm;and for N. oligodontis, from March to May, 569 eggs per female and 35. 0mm to 42. 9mm,respectively. Both species feed mainly on Cladocera and Copepoda, with fceding inten-sities peaking twice, from October to November and from February to April. The juvenilcs grow fast before June and the adults grow fast between Septembcr and November. Based on the stud-ies, some propagation measurcs are suggested.