Salinity Tolerance and Preference of Hatchery Reared Nile Tilapia, Oreochromis niloticus (Linneaus 1758)

摘要

A study was conducted in fisheries laboratory of Department of Fisheries, Lagos State University, Nigeria on salinity tolerance and preference of hatchery reared Nile tilapia, Oreochromis niloticus, (Linneaus, 1758). Tilapias are important candidate species for aquaculture and are increasingly cultured in polyculture system with shrimp. Thus creating a demand for Tilapia genotypes well suited to elevated salinities. O. niloticus is a member of the Family Cichlidae and one of most cultured fish species in Nigeria. It is known for its high prolific rate of breeding and multiplication. Six hundred and sixty (660) fingerlings of the fish measuring between 53-140 mm TL and weighing 8.96 to 21.56 g BW were subjected to salinity regimes of 0-10? for 28 days. All the fish survived in 0-7?, and 100% death was recorded in 9 and 10?. Different levels of behavioural responses to threat and feeding were observed among the fish. Salinities 0-7? were tolerated by the fish, however the most preferred salinity was 1?. The present study as demonstrated in the laboratory therefore, suggests the possibility of culturing Nile tilapia, O. niloticus in both fresh and low brackish water environments and as added data to the existed reviews on this economically valued fish species. The salinity regimes well that were tolerated and preferred for optimal survival, growth and behavioural performances of O. niloticus are therefore investigated.