Fish are thriving near marine protected areas—and so are coastal communities

Limiting human activities in the ocean has numerous sustainability benefits.
A school of grunts and horse-eye jack fish swim above a reef in Hol Chan Marine Reserve near Ambergris Cay, Belize.
A school of grunts and horse-eye jack fish swim above a reef in Hol Chan Marine Reserve near Ambergris Cay, Belize. Pete Oxford

The world’s oceans are heating up at an alarming rate, threatening marine life, food security, and livelihoods. According to climate scientists and experts, the time to protect the oceans is now. In December 2022, nearly 200 countries agreed to the United Nations’ pledge of classifying 30 percent of the world’s maritime space as marine protected areas (MPAs) by 2030 and the High Seas Treaty signed in March aims to further protect marine life in the open ocean.

A study published June 22 in the journal Nature Sustainability finds that limiting human activity from fishing, boating, etc. in parts of the ocean can both enhance the health of marine environments, while also protecting the well-being of the coasting communities nearby. The researchers found that MPAs are part of the solution to reaching multiple sustainable development goals around the world.

[Related: Fish populations thrive near marine protected areas—and so do fishers.]

The National Oceanic and Atmospheric Association (NOAA) defines MPA’s as a defined region designated and managed for the long-term conservation of marine resources, ecosystems services, or cultural heritage. Roughly 26 percent of the waters in the United States are designated at MPA’s, including Papahānaumokuākea Marine National Monument in Hawaii. At 582,578 square miles, it is the world’s largest no-fishing zone and has also proven to be beneficial to both humans and marine life alike.

In this new study, researchers from the Smithsonian Environmental Research Center (SERC), looked at the impacts of MPAs in the Mesoamerican Reef region. This nearly 700-mile-wide region within the Caribbean Sea contains the largest barrier reef in the Western Hemisphere.

The team discovered that the MPA’s with the toughest fishing restrictions helped sustain critical fisheries. They also found a link between marine protections and increased income and the food security in nearby coastal communities in counties such as Mexico, Belize, Guatemala, and Honduras.  

“Marine protected areas are hailed as a way to protect fisheries and ecosystems and promote well-being in coastal communities simultaneously,” study co-author and SERC marine biologist Steve Canty said in a statement. “This is one of the first attempts to evaluate these benefits together. Our data critically shows that well-enforced, no-take zones help rebuild fish populations and that these zones are associated with higher well-being in nearby coastal communities.”

The team used a mix of data from ecological and social organizations in the area, including repurposed data on reef fish from the Healthy Reefs Initiative. Social datasets from the US Agency for International Development helped the team assess factors such as income, food security, and the likelihood of developmental issues in young children due to chronic malnutrition.

[Related: For marine life to survive, we must cut carbon emissions.]

The scientists calculated the presence of fish in terms of their biomass–the total mass of the fish population within a given area. The MPA’s with the highest protections had on average 27 percent more biomass than those without any restrictions. There was also a greater abundance of commercially valuable fish like grouper, with 35 percent more biomass.

Additionally, they found that young children living near an MPA were about half as likely to have stunted growth, which is a key indicator of food insecurity. The average wealth index was also 33 percent higher in communities near the best-protected MPAs.

“MPAs unquestionably help improve the health of reefs and fisheries and, in some cases, may positively impact the well-being of coastal communities,” study co-author and Penn State University PhD candidate in rural sociology Sara E. Bonilla-Anariba said in a statement. “However, there is an ongoing debate about the factors influencing their positive outcomes.”

The study was unable to discern which groups saw the most benefits from MPA’s—whether it was fishing households or those with income from tourism and other industries in the region. The power of community-led MPAs is also worth closer study.

 “The goals of sustainably managing marine resources, increasing food security and reducing poverty in local communities do not always lead to tradeoffs—these positive outcomes can occur in the same places,” study co-author and SERC research ecologist Justin Nowakowski said in a statement. “Under the right conditions, conservation interventions like MPAs may be central strategies for achieving multiple Sustainable Development Goals.”