1. Introduction
There is a growing consensus that tilapias can become the world’s most important
warmwater cultured fishes (FAO, 1980). Among all cultured tilapia species, Nile tilapia
(Oreochromis niloticus) has emerged as the single most important species. The attributes
which make Nile tilapia so suitable for fish farming are its general hardiness,
ease of breeding, rapid growth rate, ability to efficiently convert organic and domestic
wastes into high quality protein, and good taste (Stickney et al., 1979; Balarin and
Haller, 1982; Pullin and Lowe-McConnell, 1982).