Abstract:

In order to improve the ability of cold resistance of Oreochromis niloticus, in this experiment, we did some researches on low-temperature tolerance of Nile tilapia under 0, 5, 12, 25‰ four salinity gradients with indoor aquarium farming methods. The results showed that, as for temperature, the mortality rate showed a trend of increased and then decreased as the temperature decreases, When the temperature reached at 9.1°C, the mortality rate reaches its maximum of 38.7%; in terms of salinity, salinity is 5 ‰ when mortality rate was the lowest, when the salinity increased to 25 ‰, means the highest mortality, according to Salinity, the survival time of 50% of individuals ranked as follows: 5‰＞12‰＞0‰＞25‰; Under different salinity gradients, the low-temperature tolerance of Nile tilapia has increased, when the temperature reached at 8℃-11℃, salinity 12 ‰, the mortality rate did not reach half of the total, when the temperature was below 8°C, the death rate rised sharply, they all died at 7℃; with statistical analysis, half of the lethal low temperature at the salinity of 12‰ was significantly lower than the other three groups. These results suggested that a certain degree of salinity could increase the low-temperature tolerance of Oreochromis niloticus.