The potential impact of aquaculture on the genetic diversity and conservation of wild fish in sub‐Saharan Africa

Abstract

An increasing focus on aquaculture using introduced strains or species poses a serious threat to native wild species in sub‐Saharan Africa, yet almost no policies have been enacted or regulations put in place to address this environmental challenge. Aquaculture in these regions has traditionally been conducted on a relatively small scale but is currently expanding rapidly and is projected to continue increasing in the coming decades, with increasing use of genetically improved strains. This expansion is occurring in a region known for its high biodiversity, creating challenges for increasing fish production without damaging wild fish populations. However, few studies have yet assessed the impacts of changes in aquaculture practice on the genetic composition and diversity of wild populations. The use of non‐native improved strains for aquaculture could cause competition, gene introgression when there is interbreeding with native populations or species, displacement of species and possible extinction of the native wild populations. After providing historical context on African aquaculture, this review describes the current methods of fish breeding and genetic improvement programmes for the main species of cultured fishes, focusing on the potential conservation impacts of the use of introduced (and selectively bred) farmed species. Existing aquaculture policies, legislation and regulations regarding the import and farming of fish are then compared across the main fish‐producing countries. We recommend a regional policy framework considering fish introduction, risk analysis and risk management, human resources development and genetic monitoring that could be drafted into the existing policies to strengthen conservation efforts. We conclude by making recommendations for refining existing regulations and for future research aimed at minimizing the impacts of aquaculture on wild fish populations in sub‐Saharan Africa. Aquaculture in this region needs implementation of responsible guidelines to avoid genetic impacts on native populations of high conservation value.