Exploitation and conservation of fish genetic resources in Africa: issues and priorities for aquaculture development and research

Africa harbours a rich biological diversity of native fish resources. Recognition of the potential to use these resources to make significant contributions towards improving African food security through aquaculture has existed for some time. A key challenge, however, is achieving compatibility between the two urgent, but sometimes conflicting, goals of reducing poverty and food insecurity in Africa through aquaculture development while paying due attention to the conservation of natural biodiversity and fish genetic resources (FiGR).

Donor-oyster derived heritability estimates and the effect of genotype X environment interaction on the production of pearl quality traits in the silver-lip pearl oyster, Pinctada maxima

The aim of this study was to estimate donor-oyster derived heritability and genetic correlations for pearl quality traits in the silver-lipped pearl oyster, P. maxima; namely pearl size, colour, lustre, shape and complexion. As future breeding programs for pearls are likely to involve oysters that will be reared in geographically disparate locations we also evaluated the potential impact environment G × E interactions may have on the realization of genetic gains for pearl quality traits.

Considerations about effective dissemination of improved fish strains

Aquaculture production systems in developing countries are largely based on the use of unimproved species and strains. As knowledge and experience are accumulated in relation to the management, feeding and animal health issues of such production systems, the availability of genetically more productive stock becomes imperative in order to more effectively use resources. For instance, there is little point in providing ideal water conditions and optimum feed quality to fish that do not have the potential to grow faster and to be harvested on time, providing a product of the desired quality.

A comparison of communal and separate rearing of families in selective breeding of common carp (Cyprinus carpio): Responses to selection

The genetic response in growth traits in a selection program for increased harvest weight in a common carp population in Vietnam is reported. A base population (G0) was established from six carp stocks using single pair mating. Selection was based on high breeding values for body weight at harvest, with a corresponding control group selected on average breeding values of the population.

Quantitative genetic basis of fatty acid composition in the GIFT strain of Nile tilapia (Oreochromis niloticus) selected for high growth

The quantitative genetic basis of fatty acid composition was examined in the Genetically Improved Farmed Tilapia (GIFT) strain of Nile tilapia selected for high breeding value for body weight and in the contemporaneous control selected for average breeding value. Gas chromatography analysis of 514 frozen fillet samples, obtained from the offspring of 104 sires and 154 dams from two generations in 2006 and 2007, showed that the fish possess all important fatty acids (FA), with the amount of omega-3 polyunsaturated fatty acids being 3.6%.

Progress toward a global genealogy of common carp (Cyprinus carpio L.) strains using mitochondrial nucleotide sequences data

As part of a study of genetic variation in the Vietnamese strains of the common carp (Cyprinus carpio L.) using direct DNA sequencing of mitochondrial control and ATPase6/8 gene regions, samples from a number of other countries were analyzed for comparison. Results show that the levels of sequence divergence in common carp is low on a global scale, with the Asian carp having the highest diversity while Koi and European carp are invariant. A genealogical analysis supports a close relationship among Vietnamese, Koi, Chinese Color and, to a lesser extent, European carp.

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