鲢、鳙在天然条件下的摄食强度(Ⅱ)武汉东湖鲢、鳙周年摄食强度的研究

FEEDING INTENSITY OF SILVER CARP AND BIGHEAD UNDER NATURAL CONDITION. (Ⅱ) ANNUAL FEEDING INTENSITY OF SILVER CARP AND BIGHEAD IN DONGHU LAKE, WUHAN

武汉东湖的鲢(Hypophthalmichthy molitrix)鳙(Aristichthys nobilis)在天然条件下摄食强度具季节性变化。摄食强度高峰处于夏季,低谷处于冬季。在实验条件下,按周年采样期间水温变化范围,测定鱼的肠管排空率。食物通过鱼肠管时间(Y_p—h)与水温(X_t—℃)的关系为: 鲢Y_p=270.63 X_t^(0.6408) 鳙Y_p=280.46 X_t^(0.6642) 根据修正后Bajkov公式(D=C (24.A)/n),估算鱼的日粮。鱼日粮(Y_D)与水温(X_t)关系为: 鲢Y_D=0.2683e^(0.1503X_t) 鳙Y_D=0.0075X_t^(2.2715) 计算鱼在天然条件下周年月粮及年粮。鲢、鳙对天然饵料年消耗量分别为18.924公斤及17.39公斤,饵料系数分别为18.02及13.38。

The feeding intensity of silver carp and bighead varied with season under natural condition in Donghu Lake. With the increase in temperature, the fullness index of both fishes increases, and vice versa. The maximum feeding intensity appears in summer, and the minimum in winter. The evacuation rate of both fishes was determined under experimental condition. The relationships between the period of food passing through the fish intestine (Y_p, hour) and water temperature (X_t, ℃) are: Silver carp: (?)_p = 270.63X_t^(0.6408) Bighead: (?)_p = 280.46 X_t^(0.6642) According to the modified Bajkov's formula D = C(24·A)/n), the estimates of the daily ration of the two fishes were obtained. The relationships between the daily ration of the fish (Y_D,% wet weight of fish) and water temperature (X_t, ℃) are: Silver carp: (?)_D= 0.268 3e^(0.1503x_t) Bighead: (?)_D= 0.0075 X_t^(2.2715) The monthly and annual rations of both fishes were calculated. The annual consumption of natural food by silver carp and bighead was 18.924 kg and 17.39 kg, respectively. The food quotients are 18.02 for silver carp and 13.38 for bighead.