Identification and Comparison of Three Tilapia Nilotica Strains for Selected Aquacultural Traits
Ali Abd El-Aziz Khater
A Dissertation Sumitted to the Graduate Faculty of Auburn University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy
Auburn. Alabama 1985
Tilapias are members of the family Cichlidae (perch-like African fishes) and are among the most important cultivable fishs pecies in the world (Bardach et al., 1972). They possess several desirable characteristics which recommend them for culture on wider scale in the tropics (Lowe, 1955; Kelly, 1956; Hickling, 1960, 1963; Swingle, 1960; Lovshin, 1975).
The most commonly cultured species are Tilapia aurea, T. hornorum, T. mossambica, and T. nilotica. T. hornorum and T. mossambica are less desirable: T. hornorum has dark color and is not very hardy, while T. mossambica is extremely hardy but has a low growth rate. The T. Niltica and its relative T. aurea have been widely introduced due to their reportedly good growth rate (Chimits, 1957; Bardach et al., 1972; shehadeh, 1976). T. nilotica is a preferred species because it feeds on plankton and detritus, but also utilizes agricultural by-products and animal wastes as well as pelleted feed (Nerrie, 1979).
A number of studies have documented yields of T. nilotica in different locations with different aquaculture systems (Smitherman et al., 1978; Burns and Stickney, 1980), but no research has focused on the potentials which may exist variations among the many geographical populations.
The general objective of this research was to compare three T. nilotica populations (strains) of know geographical origin (Egypt, Ghana, and Ivory Coast). Specific objectives were:
- to identify the three strains using electrophorises, color meristics and morphometrics, and
- to evaluate the three strains for the following traits: (a) cold tolerance, (b) reproduction, (c) growth, and
- to compare growth of nine possible crosse among the three straints.
Table of contents
- Literature Review
- Materials and Methods
Tilapia nilotica (Egypt
Tilapia nilotica (Ghana)
Tilapia nilotica (Ivory Coast)
Color and Morphology
Cold Tolerance – Reproduction - Growth Statistical Analyses
- Results and Discussion
Color and Morphology
Cold Tolerance – Reproduction - Growth Reproduction
Fry to Subadult
Subadult to Marketable size
- Summary and conclusions