Using an ecosystem model to evaluate fisheries management options to mitigate climate change impacts in western Indian Ocean coral reefs

Abstract

A coral reef ecosystem simulation model, CAFFEE, was developedto evaluate the effects of fisheries management measures on coral reef ecosystem services and functioning, independently or combined with climate change impacts. As an example of the types of simulations available, we present model outputsfor temporaryfishing closures and the switchingof fishing gears on fish biomass, fisheries yields, and coral recovery after bleaching events.In this case CAFFEE was calibrated to simulate Kenyan coral reef ecosystems and fisheriesbased on long-term observational data sets.The temporary closuresimulationsindicated thathandline fisheries benefited from an increase in total annual catch over time but gill net fisheries did not.Closures in gill net fisheries had less trophic level impacts on hard coral than in handlines and corals recovered faster in the gill net fishery after a simulated bleaching event. Using spearguns or gill nets after bleaching helped coral recovery and promoted greater fisheries yields whereas handlines promoted sea urchins by reducing their predators and reduced coral recovery. Ecosystem models combined with empirical surveys can assist managers in evaluating the effects offisheries management options on ecosystem services where climate change mitigation strategies are required.