Socio-Oceanographic Drivers of Vulnerability in Artisanal Fishing Households of the Lake Chad Basin

The Lake Chad Basin fishing communities of Borno and Yobe States in North East Nigeria represent one of the most multiply vulnerable populations in sub-Saharan Africa, exposed simultaneously to catastrophic lake shrinkage, armed conflict, extreme climate variability, and collapsing freshwater fisheries. Understanding the socio-oceanographic drivers of vulnerability at the household scale is essential for designing effective adaptation interventions, yet integrated empirical research linking environmental dynamics to social vulnerability outcomes in this context is rare. This dissertation advances a socio-oceanographic vulnerability framework and applies it through a longitudinal mixed-methods study of 480 artisanal fishing households in eight communities across the Nigerian Lake Chad Basin during 2022 to 2024. Environmental exposure is characterised using a 35-year retrospective analysis of lake surface area change, water level variability, rainfall anomalies, and fish stock abundance indices constructed from satellite imagery, hydrological records, and fisheries landing data. Household survey rounds at 12-month intervals measure livelihood diversification, income stability, food security (Household Dietary Diversity Score and Food Consumption Score), social capital, and adaptive strategies (migration, occupational change, social network activation). Structural equation modelling tests hypothesised pathways linking environmental exposure dimensions to social vulnerability and food security outcomes, with household asset endowment and community governance quality as moderating variables. Network analysis of fishing cooperative structures examines how social capital buffers environmental vulnerability. The dissertation's theoretical contribution is the development of a socio-oceanographic vulnerability model that formalises the interaction between freshwater environmental dynamics and human system resilience in inland water-dependent communities. Keywords: socio-oceanographic vulnerability, Lake Chad fisheries, artisanal households, environmental exposure, social capital