牡丹江上游(含镜泊湖)江鳕年龄、生长、食性和繁殖的研究

本文汇集了1981～1987年捕获的1,800余尾江鳕标本的观测数据。以耳石为材料对年龄和生长作了鉴定分析。探讨了该水域江鳕食性变化特点。记述了镜泊湖江鳕冰下溯江作生殖洄游的时间规律。揭示了江鳕属一次性产卵类型的鱼类,产卵期明显集中。少数性腺发育与产卵群体不同步的初次性成熟个体,产卵活动有不规则地延后现象。此与国内流行的卵分批排出,产卵期为11月至翌年3月的文献记述显著有别。

AGE, GROWTH,FEEDING HABITS AND REPRODUCTION OF THE BURBOTS LOTA LOTA, IN THE UPPER REACHES OF THE MUDAN RIVER INCLUDING LAKE JINGSO,CHINA

This paper deals with the data of 1,800 Burbots (Lota lota) specimenscontinusly collected from 1981 to 1987. Age composition, feeding habits and repro-duction of the Burbots were studied. The composition in age of Burbots in the upperreaches of the Mudan River was 0~ -6~ . The relation between body length and theredius of earstone is described by the equation: L=0.9542 166.8599R(r=0.8655).The length-weight relation of the burbots is computed from the equation: W=3.6262~(-08)L~(3.2175)(r=0.9803). The fastest growth rate of the fish is at 1-2 years old.Maturating and spawning begins at 3~ -4 years old. The growth rate reducesafter maturation. Burbots still take food while upstream reproductive migration.But feeding suspends during spawning. The peak of feeding and fattening is afterspawning and downstream migration. The principal food of young Burbots 0~ -1~ years old is naiad of stonfly, plecoptera, the diet changes in 2 years old and the principal food is other small fishes. Regression equations were developed forfecundity VS body length and body weight respectively as follows: N=15.5778 L~(2.727?)(r=0.8588) and N=4145.536 596.7289W (r=0.8929). The migrating habit of burbots in this River section was narrated. The spaw-ning period was concentrated on January 12-25. But some first matured youngfish may delay to February even the first ten days of March. It is revealed that thespawning type of burbots belong to ovulating only once. Those the former reportsabout spawning in batches and spawning period from November to next year Marchare all invalid.