Integrated Assessment of Climate Change Impacts on Marine Fisheries Productivity Along the Nigerian Coastline

This research conducted an integrated assessment of climate change impacts on marine fisheries productivity along the Nigerian coastline, spanning the Gulf of Guinea from Lagos to Cross River states, using a multi-model ensemble downscaling approach combined with empirical fisheries production data. Climate change is projected to significantly alter the productivity and distribution of marine fish stocks in tropical West Africa, but Nigeria-specific projections with adequate spatial resolution and integrated bioeconomic modelling have been absent from the scientific literature. Sea surface temperature, primary productivity, and ocean current data from five CMIP6 earth system models were downscaled to a 0.1-degree resolution grid covering Nigerian coastal waters under RCP4.5 and RCP8.5 emission scenarios through to 2100. Projected physical-chemical changes were linked to fish species distribution models calibrated on 15 years of trawl survey and landing data. A bioeconomic model was constructed to translate fish production changes into household income and food security impacts for coastal fishing communities across 10 coastal local government areas. Results project a reduction of 23 to 38 percent in coastal pelagic fish biomass by 2100 under RCP8.5, with Sardinella aurita and small pelagics showing the largest declines. Demersal species showed more heterogeneous responses, with some deepwater species projecting modest poleward range shifts. Household food security impacts were projected to be most severe in communities with lowest livelihood diversification. The study provides an original integrated climate-fisheries-socioeconomic modelling platform for Nigerian coastal management and recommends its integration into national climate adaptation planning for the fisheries sector. Keywords: climate change, marine fisheries, productivity assessment, coastal Nigeria, bioeconomic modelling