“新吉富”罗非鱼、“吉丽”罗非鱼及萨罗罗非鱼耐寒力的测定

Determination on the cold tolerance of NEW GIFT Nile tilapia，GILI tilapia and Blackchin tilapia

摘要:

在上海地区室外自然降温条件下，连续3年观察测定了“新吉富”罗非鱼、“吉丽”罗非鱼（“新吉富”罗非鱼♀×萨罗罗非鱼♂）及萨罗罗非鱼对低温的耐受力，计算和分析了平均半致死水温。2008年，“新吉富”罗非鱼死亡水温范围是7.5～5.8 ℃，平均半致死水温是6.8 ℃，对水温降低过程中罗非鱼行为活动的变化进行了观察；2009年，“新吉富”罗非鱼和“吉丽”罗非鱼的死亡水温范围分别是10.8～7.6 ℃、12.4～9.2 ℃，平均半致死水温分别是9.2 ℃和11.4 ℃；2010年3种实验鱼的死亡水温范围分别是11.0～7.0 ℃、12.8～11.4 ℃、13.8～12.4 ℃，平均半致死水温分别是8.3 ℃、12.5 ℃、13.1 ℃，且3者间差异显著(P<0.05)。综合3年实验结果，开始死亡和100%死亡的水温为“新吉富”罗非鱼11 ℃、5.8 ℃，“吉丽”罗非鱼12 ℃、9.2 ℃，萨罗罗非鱼13.8 ℃、12.4 ℃。3种遗传型罗非鱼耐寒力之间存在显著或极显著的种间差异，杂交能一定程度地改良耐寒能力。

Abstract:

Cold tolerances of three tilapias（NEW GIFT Nile tilapia，GILI tilapia and Blackchin tilapia）to low temperatures naturally decreased in Shanghai area were studied and the average lethal temperature of 50% individuals has been calculated continuously for 3 years. It is found that low lethal water temperatures ranged from 7.5℃ to 5.8℃，and the average lethal temperatures of 50% individuals was 6.8℃ for NEW GIFT Nile tilapia in 2008. Meanwhile,behaviors of tilapias under decreasing water temperatures were observed. The range of low lethal water temperatures were 10.8-7.6℃，12.4-9.2℃ for NEW GIFT Nile tilapia and GILI Tilapia in 2009, and the average lethal temperatures of 50% individuals were 9.2 ℃ and 11.4 ℃. But they were 10.8-7.6 ℃，12.4-9.2 ℃ and 13.8-12.4 ℃ for NEW GIFT Nile tilapia，GILI tilapia and Blackchin tilapia in 2010. The average lethal temperatures of 50% individuals were 8.3 ℃, 12.5 ℃ and 13.1 ℃，separately，also there were significant differences among them. The comprehensive results showed that：water temperatures that began to die and 100% die were 11 ℃，5.8 ℃ respectively for NEW GIFT Nile tilapia, 12.4 ℃，9.2 ℃ respectively for GILI Tilapia，13.8 ℃，12.4 ℃ respectively for Blackchin tilapia. There were significant or highly significant species/strainspecific differences among these three genotypic tilapias in cold tolerance. The hybridization could improve cold tolerance to a certain extent.