How fish production differs between reef environments, a fringing and island reef system, was explored for their influences of effort–stock–catch–revenue relationships and sustainability. Fisheries-independent fishable biomass, recovery rates, taxonomic composition, and fisheries-dependent metrics of effort, catch rates, and revenue were analyzed in the high production ocean exposed fringing reef and the low production ocean-sheltered island reef environments. Recovery rates of fish biomass in closures and catch rates supported the differential production predictions with the fringing reef fish ecological biomass-surplus production rate r of 0.22 ± 0.12 (± 95%CI) and the island reefs of 0.07 ± 0.03, which potentially produces a fisheries capture of 5.6 ± 0.91 and 2.8 ± 0.3 tons/km2/y estimated from Bmsy, respectively. Both reef types had high effort and yields below that estimated from Bmsy, which indicated overfishing by both fisheries-independent and -dependent metrics. Multiple lines of evidence indicate that fisheries catch was bounded by minimum acceptable or opportunity cost income thresholds rather than the reef’s natural productivity. For example, the higher production fringing reefs had lower biomass, exhibited higher production/biomass (P/B) turnover rates, and faster declining per area yields than the lower production island reefs. Fishing effort declined over the ~ 34-month study period to stabilize catch per unit effort (CPUE) in both reef types to income values between Kenya’s national poverty and minimum individual income thresholds. The more productive fringing reefs had a greater yield deficit than the sheltered reefs and would require a larger reduction in daily fishing effort (40% versus 15%) to achieve sustainability at censused stock levels. The less productive island reefs had considerable disproportionate losses of key vulnerable schooling taxa associated with a 25% yield deficit relative to the predicted potential yield. Protecting fish aggregations in the island and reducing fishing effort in both reef systems should increase the catch production and fisher's community wealth. Stock recovery required to recover ecological production and employment capacity is likely prevented by rising fish prices and resource extraction subsidies that have likely slowed the rate of decline in fishing effort.

Variation in coral reef fisheries production, employment, and living wage goals

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发表日期：

2025年11月7日

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T. R. McClanahan,
J. K. Kosgei

摘要

How fish production differs between reef environments, a fringing and island reef system, was explored for their influences of effort–stock–catch–revenue relationships and sustainability. Fisheries-independent fishable biomass, recovery rates, taxonomic composition, and fisheries-dependent metrics of effort, catch rates, and revenue were analyzed in the high production ocean exposed fringing reef and the low production ocean-sheltered island reef environments. Recovery rates of fish biomass in closures and catch rates supported the differential production predictions with the fringing reef fish ecological biomass-surplus production rate r of 0.22 ± 0.12 (± 95%CI) and the island reefs of 0.07 ± 0.03, which potentially produces a fisheries capture of 5.6 ± 0.91 and 2.8 ± 0.3 tons/km²/y estimated from B_msy, respectively. Both reef types had high effort and yields below that estimated from B_msy, which indicated overfishing by both fisheries-independent and -dependent metrics. Multiple lines of evidence indicate that fisheries catch was bounded by minimum acceptable or opportunity cost income thresholds rather than the reef’s natural productivity. For example, the higher production fringing reefs had lower biomass, exhibited higher production/biomass (P/B) turnover rates, and faster declining per area yields than the lower production island reefs. Fishing effort declined over the ~ 34-month study period to stabilize catch per unit effort (CPUE) in both reef types to income values between Kenya’s national poverty and minimum individual income thresholds. The more productive fringing reefs had a greater yield deficit than the sheltered reefs and would require a larger reduction in daily fishing effort (40% versus 15%) to achieve sustainability at censused stock levels. The less productive island reefs had considerable disproportionate losses of key vulnerable schooling taxa associated with a 25% yield deficit relative to the predicted potential yield. Protecting fish aggregations in the island and reducing fishing effort in both reef systems should increase the catch production and fisher's community wealth. Stock recovery required to recover ecological production and employment capacity is likely prevented by rising fish prices and resource extraction subsidies that have likely slowed the rate of decline in fishing effort.