Reproductive Biology of Nile Tilapia, Oreochromis niloticus under the Brackish Water Culture Condition

Abstract

Tilapia is one of the most important cultured fish in the world. World production of tilapia is highly increased in recent decades. Reproductive strategies of tilapias cause their ability of living in different aquatic ecosystems. On the other hand, the gap between seed supplies and farmers' demand is one of the most serious limitations for tilapia culturists. Nile tilapia Oreochromis niloticus samples were stocked from September 2009 to January 2011. During the study period, water salinity, temperature, pH and oxygen saturate were fixed at 11.5ppt, 27±0.5°C, 7.6-8.1 and 100%, respectively. Fish were fed using 40% protein food under 18:6 (L:D) 2500lux light regime. Total length and weight of the spawners, absolute and relative fecundity, egg weight and diameter and spawning intervals were investigated. Pearson correlation coefficient between total length and weight of brooders against absolute and relative fecundity, wet weight of an egg, egg clutch and egg diameter were studied (p<0.005).