大口黑鲈幼鱼低温耐受、耗氧率和窒息点研究

Determination on the low lethal temperature tolerance,oxygen consumption rate and asphyxiation point of juvenile largemouth bass

对大口黑鲈北方亚种(N)、佛罗里达亚种(F)及其正交子代(N♀×F♂)和反交子代(F♀×N♂)幼鱼的耐低温限度、耗氧率和窒息点进行了测定。结果表明:在驯化温度为20℃,降温速率为2h/℃时,北方亚种的半致死低温最低为(3.10±0.17)℃,佛罗里达亚种最高,为(5.05±0.21)℃,正、反交子代介于两亲代群体之间,分别为(4.80±0.06)℃和(4.20±0.17)℃,对4种鱼的半致死低温进行单因素方差分析,显示4种大口黑鲈的半致死低温具有显著性差异(P<0.05)。采用封闭式流水装置测定大口黑鲈北方亚种、佛罗里达亚种及正反交子代的昼夜平均耗氧率分别为0.136 8 mg/(g.h)、0.181 1 mg/(g.h)、0.168 1mg/(g.h)和0.138 8mg/(g.h),4个群体的昼夜平均耗氧率差异不明显。窒息点测定显示佛罗里达亚种的窒息点最高为0.4mg/L,北方亚种的最低为0.33mg/L,4个群体在窒息点上差异不显著(P>0.05)。

The tolerance to low water temperature,oxygen consumption rate and asphyxiation point were compared among northern largemouth bass,florida largemouth bass and their reciprocal hybrids.The results were as follows： when the acclimation temperature was 20 ℃ and the rate of temperature decrease was 2 h/℃,the low semi-lethal temperatures of northern largemouth bass was the lowest（3.1±0.17） ℃,florida largemouth bass was the highest（5.05±0.21） ℃.One-way ANOVA analysis indicated that there were significant differences（P0.05） in the tolerance to low temperature of four largemouth bass species.The oxygen consumption rate and asphyxiation point of four largemouth bass species were studied.The result demonstrated that,under the natural water temperature（24-27℃）,the oxygen consumption rate were 0.136 8 mg/（g·h）,0.181 1 mg/（g·h）,0.168 1 mg/（g·h） and 0.138 8 mg/（g·h）,respectively.There were no significantly difference for the oxygen consumption rate at the four groups in day and night.Under constant temperature 15 ℃,the asphyxiation point of them were 0.33 mg/L,0.40 mg/L,0.38 mg/L and 0.34 mg/L,respectively.There was no significantly difference between the oxygen consumption of the four largemouth bass species（P0.05）.