Center for Biological Diversity

For Immediate Release, August 16, 2016

Contacts:  Dr. Abel Valdivia, (510) 844-7103,
Dr. Jake Allgeier, (502) 415-2298,

Study: Overfishing on Coral Reefs Reduces Nutrients Healthy Ecosystems Need

OAKLAND, Calif.— Overfishing of large and top predatory fishes on Caribbean coral reefs substantially reduces the amount of nutrients stored and recycled within the ecosystem by fishes, new interdisciplinary research published today in Nature Communications concludes.

Coral reef
Photo by Abel Valdivia. This photo is available for media use.

The study, by scientists at the University of Washington, the Center for Biological Diversity, the Smithsonian Institution and North Carolina State University, suggests that while avoiding local extinction of fish species is a conservation priority, management actions that preserve large fish groups such as sharks, groupers, snappers and jacks are needed to maintain an adequate flow of nutrients within ecosystems.

“We know that overfishing has wiped out most top predatory reef fishes and large fish species across the coral reefs of the Caribbean. But the potential consequences on crucial ecological processes were mostly unknown,” said Dr. Abel Valdivia, a marine ecologist at the Center for Biological Diversity and coauthor of the study. “We found that fishing not only reduces fish abundance and size, but also diminishes the flow of nutrients these fish release into the ecosystem, which is important for healthy reefs.”

The study analyzed more than 140 reef fish species, from small butterfly fishes to large reef sharks, across 110 coral reef fish communities throughout the Caribbean. Its objective was to determine how fishing influences fish biodiversity and the capacity of the fish community to store and supply nutrients into the ecosystem. Surprisingly, fishing had no effect on the number of fish species across sites, but significantly reduced the abundance and size of top predators and large fish species, substantially reducing nutrient storage and supply by fish communities in the reefs.

“Our study highlights the degree to which fishing intensity is altering a critical but widely overlooked ecological process: the storage and recycling of nutrients by fish communities on coral reefs,” said Dr. Jake Allgeier, a postdoctoral fellow at the School of Aquatic and Fisheries Science of the University of Washington and the study’s lead author. “Fishing can reduce the amount of nutrients stored and recycled within the fish communities by nearly half. This has negative consequences in coral reefs that we are just beginning to understand.”

The implications of the new findings may be crucial for coral reef conservation. The amount of nutrients flowing through fish communities into reef ecosystems is a piece of the puzzle that is rarely studied and may be important to protect these increasingly fragile ecosystems, already being hurt by climate change. The study calls for a broader perspective in coral reef restoration that incorporates fundamental ecological processes into management actions.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.1 million members and online activists dedicated to the protection of endangered species and wild places.

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