2024 | Using Population Genetics to Inform Sustainable Aquaculture Governance

FACULTY SEED GRANT | Global Change Center

Using Population Genetics to Inform Sustainable Aquaculture Governance in Lake Victoria, Uganda

INVESTIGATORS:

• Dr. Elizabeth Nyboer, Fish and Wildlife Conservation
• Dr. Emmanuel Frimpong, Fish and Wildlife Conservation
• Dr. Meryl Mims, Biological Sciences
• Dr. Eranga Galappaththi, Geography
• Dr. Papius Tibihika, National Fisheries Resources Research Institute (NaFIRRI), Uganda
• Dr. Eric Hallerman, Fish and Wildlife Conservation

Growing global demand for aquatic foods amid declining wild fish stocks has propelled aquaculture to become the world's fastest-growing food production sector. Research is urgently needed to inform sustainable governance of this industry, and there are growing calls for approaches that balance sectoral growth with the prevention and mitigation of social and ecological risks.

In Lake Victoria (East Africa) wild fisheries are showing signs of overexploitation, and the motivation to intensify aquaculture production (primarily of Nile tilapia, Oreochromis niloticus) is high. Current aquaculture research in the region is thus focused on maximizing production, and information on potential social and ecological effects is lacking. Interbreeding between wild and escaped domesticated fish is a major concern as it can lead to diminished genetic diversity and reduced fitness within and among wild populations. Few studies have investigated which genetic strains are currently being produced in cage aquaculture in Lake Victoria and fewer still have investigated potential biodiversity impacts.

The goal of our research is to understand the degree to which interbreeding between wild and farmed tilapiines needs to be prioritized in Uganda’s aquaculture governance. We will characterize the genetic profiles of O. niloticus in Ugandan fish farms and investigate levels of admixture and introgressive hybridization among farmed and wild O. niloticus and endemic Oreochromis species. High levels of admixture and hybridization and low genetic diversity of farmed fish may signal the need for enhanced regulatory frameworks within aquaculture governance. We will follow this work with a social study to understand community concerns on regulation of genetic strains and risks posed by non-native strains to native species. Our findings on the social and ecological impacts of cage aquaculture on Lake Victoria’s fish and fishing communities will provide evidence-based recommendations for responsible governance of this industry.