Evaluation on salinity-alkalinity tolerance and growth of thefirst selection generation of Oreochromis niloticus

In order to assess the tolerance and growth performance of the first selection generation of Nile tilapiain salinity-alkalinity waters，chronic lethal experiment was carried out in juvenile fish and the average growth ratesof young fish in different salinity-alkalinity waters（S0A0，S10A0，S10A2，S10A4，S10A6）were compared during60 days culture experiment. The results showed that the median lethal salinity was 53.95（±1.29），53.36（±1.53），56.25（±2.12）g/L，the median lethal alkalinity was 19.18（±1.24），18.73（±1.20），20.05（±1.37）g/L for Shanghai，Shandong，Hebei strain，respectively. The results of growth performance showed that the average growth ratesignificantly decreased with the elevation of salinity-alkalinity，there was no significant difference between S10A0 andS10A2 groups，but significantly higher than that in S10A4，S10A6 groups. There was no significant difference amongdifferent strains within the same treatment，except that Shandong strain showed a relatively higher growth rate thanShanghai，Hebei strains in S10A6.