The large body of information available on tilapia biology and culture presents a confusing picture to the prospective culturist. Further stock improvement and standardization of intensive culture methods are needed. Concentration on a few species - Oreochromis aureus, O. niloticus, their hybrids and the 'red' tilapias will facilitate progress. the macrophyte-feeder Tilapia rendalli may also have potential particularly for polyculture with microphagous tilapias. International cooperation is recommended for establishing research facilities and programs.
The sea cucumber Holothuria scabra (sandfish) has been commercially exploited over a wide tropical and subtropical range for centuries. It can produce a high-value grade of beche-demer if processing is carried out well. In many cases sandfish have made up the most valuable fraction of the total sea cucumber trade from particular producing countries, both in terms of price per kilogram and of total value.
The characteristics, food and feeding, reproduction and breeding of sea horse and pipefishes (Synanthidae) are presented together with the aspects of syngnathid culture.
This paper describes the present status of artificial propagation of the grey mullet (Mugil cephalus) including manipulation of breeding time and induced breeding. Predictable spawning can be induced by administration of piscine pituitary gonadotropin and human chorionic gonadotropin. The synthetic steroid, deoxycorticosterone (DOC) can also be used when oocytes have reached the subperipheral germinal vesicle stage (dosage 120 mg/kg fish) following a priming injection of gonadotropin, which is essential for bringing oocytes at yolk globule stage to final maturation.
A simple and low-cost breeding technology for breeding the striped murrel, Channa striatus in hapas in ponds was developed in India.
We mainly (but not exclusively) draw upon research and development work carried out by The WorldFish Center (WorldFish). We review the current state of development of selection programs that have had a main focus on growth rate and body traits. There is evidence of sustained gains of 10 to 15 per cent per generation over more than six generation. To date, these gains have not been accompanied by any undesirable correlated response. The prospects for altering sexual dimorphism and the shape of the fish appear to be very limited, however.
From the history of introductions and the development of successful aquaculture elsewhere, it appears that the use of exotic species to speed up the rate of aquaculture development in Africa is unlikely to be an efficacious strategy. The major sustained aquaculture industries worldwide evolved from close working relationships between pioneering investors and local research-and-development institutions.
Aquaculture in Africa is fairly insignificant by world standards and accounts for a mere 0.4 per cent of global aquaculture production. The application of genetics can play an important role in efforts to increase aquaculture production in Africa through methods such as selective breeding, hybridization, chromosome manipulation and use of YY “supermales”. Other issues that need to be addressed are limited genetic research facilities, funding, human capacity and suitable species for aquaculture.
The International Network on Genetics in Aquaculture (INGA) was established in 1993 and is being coordinated by the International Center for Living Aquatic Resources Management (ICLARM), with the objective to contribute through collaborative research, to the domestication and sustainable performance of tropical finfish species farmed in developing countries and to strengthen national capabilities for genetic enhancement of farmed fish through exchange of germplasm, methodologies and through training and interactive forums.
Gathering and recording of biological data vital to experiments in a genetic improvement program should be carried out with efficiency, precision and accuracy. This is important in order to avoid marking erroneous conclusion about the results. The GIFT team has so far standardized the methods of measuring some of the important phenotypic traits in tilapia. These traits are noted and measured during breeding and fry collection, stocking, rearing and harvesting activities. This manual lists the guideline required for sampling and recording of phenotypic traits.