现场胃含物法测定鲐的摄食与生态转换效率

Determination of food consumption and ecological conversion efficiency of Pneumatophorus japonicus by stomach contents method

2000年7月至9月在山东半岛南部沿海鲐繁殖海域的鱼类养殖网箱中,应用胃含物法测定了渤海优势鱼种鲐的摄食、生态转换效率等生态能量学参数。结果表明,(1)在饵料不受限制时,鲐的摄食量和生长呈不规则波浪式变化,其波距比较恒定,但波高变化较大;(2)鲐的瞬时胃含物重量随时间变化可用指数模型St=9.0876e-0.1868t描述,瞬时排空率Rt=0.1868g·(100g)-1·h-1(按湿重计算);(3)按Eggers公式可求得鲐日摄食量Cd=(15.60±2.55)g·(100g·d)-1(按湿重计算)或(69.84±11.42)kJ·(100g)-1·d-1;(4)实验期间鲐体重随时间的变化可用线性方程Wt=2.23t+16.71描述,由该式可求得其相对平均日生长量Gd=3.72g·(100g)-1·d-1或30.00kJ·(100g)-1·d-1;(5)由于已知的平均日摄食量和平均日生长量,可求得鲐生态转换效率Eg=23.85%(按湿重计算)或42.96%kJ。

The ecological energetic parameters of Pneumatophorus japonicus (Houttyn), such as food consumption, growth and ecological conversion efficiency, were determined by gut content method in net cages which were situated in fish reproductive waters in offshore area of Shandong peninsula. The results indicated that,(1) under constant experimental conditions, the fish's maximum daily food consumption and daily growth change as irregular sine wave. The wave distance is constant, but the wave height's change is bigger;(2) the Relationship between instantaneous food content in stomach and corresponding time could be described as St=9.0876e-0.1868 t, and instantaneous gastric evacuation rate calculated by the formula was Rt=0.1868g·(100g)-1·h-1; (3) the daily food consumption calculated according to Eggers' formula was Cd=15.60±2.55g·(100g)-1·d-1=69.84±11.42kJ·(100g)-1·d-1; (4) the change of fish's body weight with time was linear, which could be described as Wt=2.23t + 16.71. The daily growth could be obtained by the linear formulae and average body weight at experiment period and was Gd = 3.72g·(100g)-1·d-1=30.00kJ·(100g)-1·d-1. So ecological conversion efficiency could be obtained as Eg=23.85%=42.96% kJ from known Cd and Gd values.