In comparison to the rest of the world, aquaculture in Africa is fairly insignificant. The continent as a whole contributed a mere 0.9 per cent (404 571 t) to the total world aquaculture production in 2000. The African continent, however, exhibits considerable potential in terms of land and water and in regard to inland, coastal and offshore resources. Genetic improvement of tilapias has a role to play in order to increase aquaculture production.
The GIFT Project is one of the longest multidisciplinary research and development program implemented by ICLARM and its partners. It began in March 1, 1988 and was successfully concluded in December 31, 1997. The focus ofthis report, as suggested by the principal donor of this initiative, the UNDP, has been on describing the major findings, recommendations and lessons learnt.
The present study is based on data recorded from fish of the third generation of the GIFT project (Genetic Improvement of Farmed Tilapias). The objective of the study was to compose a synthetic base population of Nile tilapia for further selective breeding, and to estimate phenotypic and genetic parameters in that population.
ADB RETA 5711 on the Genetic Improvement of Carp Species in Asia showed that the growth performance of carps, the most cultured fish in the world, could be improved by 10% per generation of selection, based on the preliminary studies of 4 carp species in the 6 Developing Member Countries (DMCs) participating (Bangladesh, the People's Republic of China, India, Indonesia, Thailand and Vietnam).
The information kit is the result of a workshop on farmer-proven integrated agriculture-aquaculture technologies held at the International Institute of Rural Reconstruction in Silang, Cavite, Philippines, on 2-15 February 1992. The kit contains materials on economic, sociocultural and environmental considerations in introducing integrated agriculture-aquaculture technology; integrated farming systems; animal-fish systems; rice-fish systems; rice-fish management, fish management and feeding; fish breeding and nursing.
Genetic change in the Genetically Improved Farmed Tilapia (GIFT) Nile tilapia (Oreochromis niloticus) was estimated by comparing the performance of the progeny produced from cryopreserved spermatozoa from the base population with that produced by freshly collected spermatozoa from the ninth generation. The comparison involved artificial fertilization of 13 males from each generation (base and ninth) with a random sample of 18 female brood stock. The progeny produced went through a 120 day grow-out period, after which live weight, standard length, body depth and survival were recorded.
Fifty-four participants from 20 countries representing national/research institutions in Africa, Asia and the Pacific, non-govermental organizations and regional/international organizations held an Expert Consultation on Ecological Risk Assessment of Genetically Improved Fish during 4-6 August 2003 in Dhaka, Bangladesh, under the auspices of the International Network on Genetics in Aquaculture.
The objective of this study was to estimate genetic parameters in GIFT (Genetically Improved Farmed Tilapia), especially focusing on the genetic correlation between trait expressions in both sexes and among measurements of body size. Body weight, length, depth and width data at harvest from 12,308 individuals, progeny of 232 sires and 340 dams, were analyzed by restricted maximum likelihood methods fitting a multi-trait animal model. To explore the genetic variation in sexual dimorphism the trait expressions in the two sexes were treated as if they were different traits.
Aquaculture in developing countries is largely based on unimproved fish strains. There is ample evidence indicating the potential of genetic improvement programs and a range of selection methods may be used. Examples of the application of mass, cohort, within family, and combined between-within family are given.The methods are discussed in terms of their effectiveness and suitability.
This document represents the report and contributed papers from the workshop Pioneering Fish Genetic Resource Management and Seed Dissemination Programmes for Africa: Adapting principles of selective breeding to the improvement of aquaculture in the Volta Basin, convened in Accra, Ghana 27-30 March 2007.