Climate change poses a significant threat to African marine and freshwater fisheries . Fisheries provide the main source of protein for approximately 200 million people in Africa and support the livelihoods of 12.3 million people. At 1.5℃ global warming, marine fish catch potential decreases 3-41%, and decreases by 12-69% at 4.3°℃ by 2081-2100 relative to 1986-2005 levels, with the highest declines for tropical countries. Under 1.7℃ global warming, reduced fish harvests could leave 1.2-70 million people in Africa vulnerable to iron deficiencies, up to 188 million for vitamin A deficiencies, and 285 million for vitamin B12 and omega-3 fatty acids by mid-century. For inland fisheries, 55-68% of commercially harvested fish species are vulnerable to extinction under 2.5℃ global warming by 2071-2100. 
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report