Protection efforts have resulted in ~10% of existing fish biomass on coral reefs

Caldwell, Iain R. and McClanahan, Tim R. and Oddenyo, Remy M. and Graham, Nicholas A.J. and Beger, Maria and Vigliola, Laurent and Sandin, Stuart A. and Friedlander, Alan M. and Randriamanantsoa, Bemahafaly and Wantiez, Laurent and Green, Alison L. and Humphries, Austin T. and Hardt, Marah J. and Caselle, Jennifer E. and Feary, David A. and Karkarey, Rucha and Jadot, Catherine and Hoey, Andrew S. and Eurich, Jacob G. and Wilson, Shaun K. and Crane, Nicole and Tupper, Mark and Ferse, Sebastian C.A. and Maire, Eva and Mouillot, David and Cinner, Joshua E. (2024) Protection efforts have resulted in ~10% of existing fish biomass on coral reefs. Proceedings of the National Academy of Sciences of the United States of America, 121 (42): e230860512. ISSN 0027-8424

Abstract

The amount of ocean protected from fishing and other human impacts has often been used as a metric of conservation progress. However, protection efforts have highly variable outcomes that depend on local conditions, which makes it difficult to quantify what coral reef protection efforts to date have actually achieved at a global scale. Here, we develop a predictive model of how local conditions influence conservation outcomes on ~2,600 coral reef sites across 44 ecoregions, which we used to quantify how much more fish biomass there is on coral reefs compared to a modeled scenario with no protection. Under the assumptions of our model, our study reveals that without existing protection efforts there would be ~10% less fish biomass on coral reefs. Thus, we estimate that coral reef protection efforts have led to approximately 1 in every 10 kg of existing fish biomass.