Development of Bioeconomic Models for Optimising Harvest Strategies in the Artisanal Fisheries of the Benue River Basin

Bioeconomic modelling offers the analytical foundation for designing harvest strategies that simultaneously maximise economic returns and maintain long-term ecological sustainability in artisanal fisheries, yet no bioeconomic model calibrated to the Benue River basin in Nigeria has been published. This study develops original bioeconomic models for the Benue River artisanal fishery in Benue and Kogi States, integrating biological production models with economic modules representing fishing costs, market prices, and fisher household decision-making. Biological data inputs were derived from a three-year catch monitoring programme at 14 landing sites, providing length-frequency data, catch per unit effort, and species composition time series for six target species. Surplus production models were estimated using ASPIC and compared against age-structured models where ageing data were available. An economic module incorporating heterogeneous fisher types with different cost structures, risk preferences, and gear portfolios was coupled to the biological model using a dynamic optimisation framework. Three harvest scenarios were modelled: open access equilibrium, maximum sustainable yield, and maximum economic yield. Results showed that current exploitation rates exceeded maximum sustainable yield for four of six species, with open access equilibrium resulting in significant economic rent dissipation. Transition to maximum economic yield harvest rates would reduce total fishing effort by 28% while increasing aggregate economic returns by 34%. The study provides an original applied bioeconomic modelling framework for the Benue River fishery and recommends its adoption by the Benue and Kogi State fisheries agencies as the quantitative basis for effort management.

Keywords: bioeconomic model, harvest strategy, Benue River, maximum economic yield, effort management