Impacts of Akosombo Dam Spillage on Fisheries and Livelihoods in Keta Lagoon, Ghana. A socio-ecological mixed-methods study for sustainable livelihoods.

Spillage from the Akosombo Dam in 2023 altered downstream hydrological regimes. While the spillage impacts were documented in downstream areas, short- to medium-term impacts on fisheries in the Keta Lagoon Complex received little attention, despite receiving freshwater inflows from the Volta River via the Anyanui Creek. This study investigated the impacts of dam spillage on the lagoon fisheries through fieldwork (December 2023-July 2024) and questionnaires (December 2024-January 2025) administered to 420 full-time lagoon fishers, to assess changes in species composition, hydrology, and fishery outcomes. A total of 96.43% of respondents reported high freshwater inflows and flooding as the major immediate impacts. Although 66.67% reported observing freshwater fish during the initial inflow, these fish suffered stress-induced mass mortalities and washed ashore. Subsequent management interventions, such as opening the flood-control gates and breaching of the lagoon sandbar, restored brackish conditions. This led to increased landings of high-value Blue crab (Callinectes amnicola) and Southern rose shrimp (Farfantepenaeus notialis) a few weeks after the event, as validated by field data. Of the 21 species recorded from field sampling, Farfantepenaeus notialis was the second most dominant by number (20.73 %), while Callinectes amnicola was the fourth most dominant (6.60 %).  The results of the study indicate that coastal brackish water ecosystems connected to rivers may experience short- to medium-term changes in species composition due to shifts in inflow dynamics and human management interventions. Hence, adaptive management is needed to maintain ecosystem stability and support coastal livelihoods in dynamic lagoon systems. 

Keywords: Keta Lagoon Complex, dam spillage, species composition, inflow