可可托海水库江鳕个体的生物学研究

研究可可托海水库江鳕(Lota lota)个体生物学,丰富其基础生物学资料,可为其种质资源保护与合理利用提供科学依据。2012-2014年,从可可托海水库及入库河道采集江鳕样本共196尾,测量其生物学常规数据,以耳石为主要年龄鉴定材料,对其形态特征、生长和繁殖特性及食性进行分析。结果表明,江鳕体长与体重相关方程为W=0.011L2.926;von Bertalanffy的体长、体重生长相关方程分别为L_t=101.81-e~(-0.132(t+0.594))]、W_t=8 9821-e~(-0.132(t+0.594))]~(2.926),体长、体重生长速度和体重加速度方程分别为dL/dt=13.438e~(-0.132(t+0.594))、dW/dt=3 556.8721-e~(-0.132(t+0.594))]~2×e~(-0.132(t+0.594))和d~2W/dt~2=469.507e~(-0.132(t+0.594))×1-e~(-0.132(t+0.594))]~2×3~(e~(-0.132(t+0.594)-1))];肥满度为0.52~1.34,季节、性别和鱼体大小间肥满度数值基本一致;雌雄比1.4∶1,雌雄个体最小性成熟年龄均为2+龄,性腺Ⅳ期的雌、雄繁殖个体平均成熟系分别为(3.59±0.93)%和(7.93±2.50)%,绝对怀卵量为(274 445.06±98 039.81)粒,相对怀卵量为(417.49±112.30)粒/g。江鳕为肉食性鱼类,小型鱼类在食物中的重量比和出现率分别为94.73%和89.38%,全年平均摄食率和饱满度分别为(86.06±12.51)%和(3.72±3.44)%。人类活动对库区江鳕资源造成负面影响,防止过度捕捞、护幼捕大措施,可使其资源得到保护与合理利用。

Biological Characteristics of Lota lota in Koktokay Reservoir

Lota lota Linnaeus is the primary economic fish in Koktokay Reservoir, accounting for 58.0% of the total fish production and making a large contribution to the local economy. To enrich the basic biological data and provide a scientific basis for protecting L. lota, we investigated the biological characteristics of L. lota in Koktokay Reservoir. From 2012 to 2014, 196 specimens were collected from the reservoir and its tributaries. Biological parameters were measured for each individual and the otolith was selected as the material for determining age. The morphological features, growth and reproduction characteristics and feeding habits of L. lota were analyzed. The body length to weight relationship was described by the equation W=0.011L2.926. The Von Bertalanffy growth equations for body length and body weight were Lt=101.81?e?0.132(t+0.594)] and Wt=89821?e?0.132(t+0.594)]2.926. The growth rate equations for body length and body weight were dL/dt=13.438e?0.132(t+0.594), dW/dt=3556.8721?e?0.132(t +0.594)]2 ×e?0.132(t+0.594), and the growth acceleration equation of body weight was d2W/dt2 =469.507e?0.132(t + 0.594)×1-e?0.132(t + 0.594)]2×3e?0.132(t + 0.594)-1]. The fatness of L. lota ranged from 0.52 to 1.34, and there was little variation with season, gender or size. The ratio of female to male was 1.4:1 and both sexes reach sexual maturity at 2+ yr. The gonadosomatic index for males and females at gonad phase IV were, respectively, (3.59±0.93)% and (7.93±2.50)%. The absolute fecundity was (274445.06±98039.81) eggs/g and the relative fecundity was (417.49±112.30) eggs/g. L. lota is a carnivorous fish and the weight ratio and occurrence rate of small fish accounted for 94.73% and 89.38% of the food supply for L. lota. The average feeding rate and fullness were (86.06±12.51)% and (3.72±3.44)%. Human activities have negatively affected the L. lota resource in the reservoir area. To enhance protection and rational utilization of L. lota resources, we recommend prohibition of overfishing and conservation of juveniles.