尼罗罗非鱼耗氧率的初步研究

PRELIMINARY STUDY ON THE OXYGEN CONSUMPTION OF TILAPIA NILOTICA

本文重点报道尼罗罗非鱼在成鱼阶段的群体耗氧率和窒息点的测定结果。尼罗罗非鱼的耗氧率,随着体重的增加而降低,在幼鱼阶段特别明显,但随着水温的上升而增加;在体重和水温相同的情况下,尼罗罗非鱼的耗氧率无显著的性别差异;在日夜间有明显的生理活动周期性有规律的变化。尼罗罗非鱼的窒息点是 0.07—0.23mgO_2/l。

The oxygen consumption of different size Tilapia nilotica were measured andstudied under temperatures ranging from 21℃ to 26.5℃, within 24 hours in succession.The results are summarized as follows: At body weight 0.00306 kg, it is 250.76mg/kg/hr at temperaturo of 24℃; attwo-month old, body weight 0.04053 kg and 0.04289 kg, it is 136.58mg/kg/hr and154.48 mg/kg/hr respectively at 24℃; at three and half-month old, body weight0.07150 kg, it is 91.61 mg/kg/hr at 21℃; at fifteen-month old, body weight0.23300 kg and 0.43330kg, it is 67.90mg/kg/hr and 123.10mg/kg/hr respectivelyat 22.5℃ and 26.5℃; at twentyfour-month old, body weight 0.47200 kg and0.56830kg, it is 88.58mg/kg/hr and 111.58 mg/kg/hr at 22.5℃ and 26.5℃respectively. The experiments show that oxygen consumption of T. nilotica decreases as the ageor the body weight increases. This indicates that the younger fish require higheroxygen consumption than do the older ones, and the rate of oxygen consumption ofthe fish increases as the water temperature rises. The rates of oxygen consumption between the male and the female T. nilotica areshows no significant difference at the same size and same water temperature. The fish can survive in very low oxygen content waters, and its the asphyxiatingpoint is 0.07-0.23 mg/l.