From expansion to overshoot: Policy risks in managing offshore fisheries expansion

Fishing grounds frequently expand as overfishing of the nearshore promotes policies to increase access and economic incentives to target offshore resources. Subsidies for boats, gear, and fuel have been introduced to shift effort offshore and compensate for declining catches. Therefore, I tested the hypothesis that fishing area expansion would increase the use of offshore-oriented gears and benthic catch losses would be compensated by increased pelagics. To evaluate these increased access strategies, I analyzed 23 years of effort, gear use, and catch data from 13 nearshore fisheries in Kenya, nine of which expanded spatially while four remained stable. Initially, expansion correlated with higher fishing effort and increased use of beach seines and ring nets. Beach seine use declined in the non-expanding and rose in the expanding fisheries, despite being made illegal 6 years after catch measurements began. Thereafter, effort and catch rates declined rapidly below the initial and non-expanding fisheries values. Pelagic catches rose cyclically after the decline but for 15 years failed to fully offset benthic losses. Although nearshore fishable biomass and production recovered modestly as fisher numbers fell, capture consistently exceeded local ecological production. Policies promoting offshore fishing access should consider that pelagic yields are potentially low and episodic and may not reliably replace the higher and more stable benthic production. To achieve nearshore fish recovery, enhanced resource protection coincident with offshore access will be required.