Protecting Ocean Ecosystems

New CAP Report Discusses Fisheries Benefits of MPAs

An octopus in the Northeast Canyons and Seamounts Marine National Monument. Image via NOAA.

Last week, just in time to celebrate World Oceans Day and National Ocean Month, the Center for American Progress (CAP) released a new report titled, “How Marine Protected Areas Help Fisheries and Ocean Ecosystems.” In the report, the authors discuss the need to protect specific areas and habitats as our ocean waters warm due to climate change and as new technologies provide increasing access to the ocean. The report also provides a current status of MPAs in the United States.

Generally, there are four types of marine protected areas (MPAs): minimally protected, lightly protected, highly protected, and fully protected. As discussed in the report, “Both highly and fully protected MPAs prohibit any industrial extractive activities within their boundaries, including oil and gas drilling, seabed mining, and commercial fishing.” Importantly, as the authors note, “Even the best fisheries management cannot provide all the benefits of a highly or fully protected MPA,” such as increased biodiversity, enhanced resilience to ecological change, increased opportunity for education and research as well as other economic opportunities.

Here in New England, the Northeast Canyons and Seamounts Marine National Monument is the only highly protected MPA along the East Coast, but it only protects about 1 percent of the U.S. Atlantic Ocean. In the spirit of World Oceans Day (though a belated celebration) and National Ocean Month, we wanted to highlight the fisheries benefits, identified by CAP, that MPAs like this can provide:

1. Biomass. MPAs are known to increase the total mass of living biological organisms. CAP reports, “One meta-analysis of scientific studies showed that biomass of whole fish groups in highly and fully protected MPAs is, on average, six to seven times greater than in adjacent unprotected areas and three to four times greater than in lightly protected MPAs.”

2. Numerical Density. The number of individual species increases. For example, on Georges Bank, “after just five years of protection, the densities of legal-sized scallops reached nine to 14 times those of scallops in fished areas.” Increases in numerical density can lead to the spillover effect, meaning that species move beyond the boundaries of the MPA and become available for harvest.

3. Organism size. Organisms within highly and fully protected MPAs are on average larger in size compared to organisms outside. This provides direct benefits to fisheries because larger females often produce more, higher quality eggs compared to smaller females.

While emphasizing these various benefits, the report also addresses potential concerns – and possible solutions – about the impacts of highly and fully protected MPAs on fishermen, coastal communities, and ocean-related businesses. Ultimately, CAP concludes, “Just as MPAs cannot replace fisheries management, fisheries management cannot replace MPAs. Both systems must be used in concert to achieve sustainable and economically viable ocean protections.”

We encourage you to read the full report here.


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