The Effect of Saline Composition of Rearing Water on the Culture of Tilapia Fry (Oreochromis niloticus)

Abstract

18-days-old tilapia fry (Oreochromis niloticus) were raised for 15 days in various artificial aquaculture waters (AAWs), which are eight compositions of isotonic saline mediums (AAW-1 to 8) and an artificial freshwater (AAW-9). All of fry reared in isotonic mediums lack potassium (AAW-2 and 8) had been died until seventh day, although fry in the other AAWs exhibited high survival rates. It was suggested that tilapia fry can not tolerate low level of potassium at relative high salinity. The specific growth rate of tilapia in AAW-9 was slightly better than the others, but not significantly. The reason why fry in isotonic medium showed reduced SGR was assumed that increase of energy cost for saline adaptation exceeded decrease of energy cost for osmoregulation in 15 days of experimental period. The optimum age at transfer to AAW must be examined thoroughly to minimize energy cost of saline adaptation and enhance growth performance.