No abstract

ContentTo satisfy increasing demands for fish as food, progress must occur towards greater aquaculture productivity whilst retaining the wild and farmed genetic resources that underpin global fish production. We review the main selection methods that have been developed for genetic improvement in aquaculture, and discuss their virtues and shortcomings. Examples of the application of mass, cohort, within family, and combined between-family and within-family selection are given. In addition, we review the manner in which fish genetic resources can be lost at the intra-specific, species and ecosystem levels and discuss options to best prevent this. We illustrate that fundamental principles of genetic management are common in the implementation of both selective breeding and conservation programmes, and should be emphasized in capacity development efforts. We highlight the value of applied genetics approaches for increasing aquaculture productivity and the conservation of fish genetic resources.

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). In this paper we highlight the overarching challenges concerning the conservation and exploitation of FiGR for the long‐term development of aquaculture for food production in Africa. We address the major issues requiring attention in genetic improvement programs in order to take full advantage of the highly diverse wild FiGR in Africa, and we expand on strategies such as zoning, environmental risk analysis and molecular characterization approaches that can be used to minimize the potential harm to wild FiGR arising from aquaculture activities and future development. Finally, we discuss the challenge of strengthening local capacity. The enhancement of local capacity is essential because it will enable the fundamental link required to achieve the desired outcome of increasing the productivity of aquatic animals for food in Africa in a sustainable manner. We trust that this paper will provide a good basis for an in‐depth discussion of the subject, as well as guidance on future research and development priorities for the compatible exploitation and conservation of FiGR in Africa.

Intraspecific genetic diversity governs the potential of species to prevail in the face of environmental or ecological challenges; therefore, its protection is critical. The Indo-Australian Archipelago (IAA) is a significant reservoir of the world's marine biodiversity and a region of high conservation priority. Yet, despite indications that the IAA may harbour greater intraspecific variation, multiple-locus genetic diversity data are limited. We investigated microsatellite DNA variation in Pinctada maxima populations from the IAA to elucidate potential factors influencing levels of genetic diversity in the region. Results indicate that genetic diversity decreases as the geographical distance away from central Indonesia increases, and that populations located towards the centre of P. maxima's range are more genetically diverse than those located peripherally (P < 0.01). Significant partitioning of genetic variation was identified (F(ST) = 0.027; R(ST) = 0.023, P < 0.001) and indicates that historical biogeographical episodes or oceanographic factors have shaped present population genetic structure. We propose that the genetic diversity peak in P. maxima populations may be due to (i) an abundance of suitable habitat within the IAA, meaning larger, more temporally stable populations can be maintained and are less likely to encounter genetic bottlenecks; and/or (ii) the close proximity of biogeographical barriers around central Indonesia results in increased genetic diversity in the region because of admixture of genetically divergent populations. We encourage further genetic diversity studies of IAA marine biota to confirm whether this region has a significant role in maintaining intraspecific diversity, which will greatly assist the planning and efficacy of future conservation efforts.

No abstract