Building on remote sensing and coral reef mapping work conducted by the Asner Lab in Hawaiʻi, a new study by researchers at the Arizona State University Center for Global Discovery and Hawaiʻi’s Department of Land and Natural Resources examines the impacts of different types of marine management, human activities, and habitat drivers on reef-dwelling resource fish abundance and biomass. Understanding how local pressures, such as pollution and fishing, affects groups of reef fish can help state managers improve measures associated with MPAs to better sustain coral reef systems and the fish that depend on them.
The researchers found an alarming 45% decrease in fish biomass over a decade of surveys. However, reefs that banned spearfishing contained significantly greater fish abundance and biomass compared to reefs without a ban, likely due to the fact that four of the five most common species from the surveys are primarily caught by spears. Additionally, marine management areas with multiple bans on spearfishing, aquarium collection, and lay nets had the highest overall fish biomass compared to other managed or unmanaged areas, especially for herbivorous fish.
Findings suggest that marine management that prohibits a combination of lay nets, aquarium collection, and spearfishing, along with regulation of land-based nitrogen pollution, can be effective in maintaining or increasing resource fish biomass. Overall, the paper recommends that regional management that better balances multiple factors including habitat, pollution, and fisheries, is most important for managing sustainable resource fish biomass off Hawaiʻi Island.