Coral reefs are the breadbaskets of the ocean, home to an outsized amount of the fish that wind up on people’s plates.
But reefs could be producing a lot more food. With careful management, these places could generate enough additional fish to feed millions more people, many in places wracked with malnutrition, according to new research in the Proceedings of the National Academy of Sciences.
The results “reinforce that effective reef fisheries monitoring and management has substantial and measurable benefits beyond environmental conservation; it has food security and public health implications,” said Jessica Zamborain-Mason, the lead author and a marine scientist at the King Abdullah University of Science and Technology in Saudi Arabia.
But it will be no easy task making good on this promise. Coral reefs are being buffeted by underwater heat waves, with scientists warning climate change threatens much of the world’s coral. Many of these reefs have little oversight, so regulatory infrastructure such as scientists and managers is lacking. Perhaps most daunting is the difficulty of restricting fishing in places where people rely on it to survive day-to-day.
“If you’re going to reduce fishing pressure to give yourself more fish protein in the long run on a sustainable basis, you need some way to meet the nutritional shortfall in the short term. I think that’s the biggest challenge,” said Sean Connolly, an ecologist at the Smithsonian Tropical Research Institute who worked on the study.
To estimate the gap between what reefs produce today and what they could produce, the scientists built a model of fisheries productivity at reefs around the world. It relied on sampling done at more than 2,000 sites. Of those, 150 were protected or remote, uninhabited reefs, providing a reference point for how many fish would be at a particular kind of reef if it weren’t subject to fishing.
To determine the maximum amount of fish that could be harvested from these reefs if they were sustainably managed, the scientists adopted a widely-used metric that fishers should take no more than half the total biomass of what would be found in an untouched reef. If the biomass fell below that 50% benchmark, it was overfished.
The calculation revealed a yawning gap in many places between how much fish should be in the water in a well-managed fishery, and how many fish were actually there. In the most extreme cases, less than 10% of fish biomass was found on reefs in Kenya, Mauritius and Oman. But they weren’t alone. Overfished reefs globally had a 32% fish deficit compared to what could be swimming there if the reefs were fished to maximum level while still remaining sustainable, the scientists reported.
The work “quantifies how much is being lost by having overfished reef fish communities in terms of food provisioning and, in turn, how much could be gained from rebuilding reef fish stocks and managing them at sustainable levels,” said Zamborain-Mason.
If all those fisheries were allowed to recover, the additional fish would translate into a staggering 9,000 extra meals for every square kilometer of coral reef, the scientists found. Much of the benefit would come in the developing world, in countries with high levels of hunger. In Indonesia, an additional 1.4 million people would get the recommended amount of fish in their diet. In the Philippines it would meet the needs of more than 800,000. More than 500,000 Tanzanians would experience similar gains.
“Countries with higher malnutrition indexes could benefit more from recovered reef fish stocks,” said Connolly.
But it would take years of careful management, and disruptions to people’s current ways of life, to translate these calculations into reality. With the most draconian regulations – a ban on fishing – the median time to recovery for a reef would be 6 years. A more measured approach, by contrast, would take nearly half a century for the median fishery. Some of the most battered places could take up to 70 years. And that’s without accounting for how habitat loss from dying coral might diminish fish productivity.
Such measures could require wrenching changes in people’s way of life. While the scientists don’t spell out detailed reforms, they note that fishing reductions would have to be paired with alternative food production such as farming. In the cases of small islands with little available land, it could require finding other seafood or importing food from abroad.
In other words, making reef fisheries both more sustainable and more productive sounds appealing. Making it happen could be very hard.
Zamborain-Mason, et. al. “Potential yield and food provisioning gains from rebuilding the world’s coral reef fish stocks.” Proceedings of the National Academy of Sciences. Dec. 16, 2025.
Photo by Filip Milovac/WorldFish via Flickr
