Expanded Marine Protections Benefited Hawaii Tuna Fishery, Study Shows

Major fleet’s catch and revenue rose after enlargement of two marine monuments

Navigate to:

Expanded Marine Protections Benefited Hawaii Tuna Fishery, Study Shows
Fabien Forget
Tuna swim in a purse seine net. The expansion of two large marine protected areas in the Pacific Ocean led to increases in catch and revenue of bigeye and yellowfin tuna for the Hawaii longline tuna fleet, a new analysis shows.
Fabien Forget ISSF

Contradicting concerns from longline commercial fishing operators in the Pacific region, tuna industry revenue actually increased following the expansion of two large U.S. marine protected areas (MPAs) in the Pacific Ocean, a new analysis shows. The work builds upon a study published in the journal Nature Communications last year, which is one of only a few studies to apply rigorous scientific methods to this issue.

In the original study, the authors looked at longline commercial fishing by the Hawaii fleet around two of the largest protected areas on earth: The Pacific Remote Islands Marine National Monument (PRI), south and east of Hawaii, which was expanded in 2014, and the Papahānaumokuākea Marine National Monument (PMNM) in the northwestern Hawaiian Islands, which was enlarged in 2016. The expansions quadrupled the size of each of these MPAs, which together prohibit commercial fishing and oil and gas exploration across more than 2.7 million square kilometers (about 1.1 million square miles) of ocean.

Prior to the enlargement of both PRI and PMNM, the fishing industry warned that expanding the MPAs would reduce catch and increase travel costs for fishermen, resulting in the loss of tens of millions of dollars and driving seafood prices higher at Hawaiian retail markets. The original study assessed “catch per unit effort”—which measures the number of fish caught as a factor of the effort and cost expended to catch them—as a proxy for profitability. It found no net impact on profitability following the PMNM expansion and increased profitability following the PRI expansion.

In response to a comment by National Oceanic and Atmospheric Administration researcher Jonathan R. Sweeney, the study’s authors reanalyzed their approach using a more robust outcome measure—revenue per unit effort. The revised analysis weighted species by their economic value, rather than by the number of fish caught for all species, allowing the researchers to capture the market value of the two most commercially important species that are the focus of the fishery. Although one of them—yellowfin tuna—had the fourth-largest catch, it was second only to bigeye tuna in revenue. The updated analysis found that fishing profitability increased for these two species following both expansions.

The data shows that revenue per unit effort generally increased since the expansions began in 2014 and further increased for the 16 months following the Papahānaumokuākea monument expansion. “It now appears that the Papahānaumokuākea expansion actually benefited” Hawaii’s tuna fishery, the researchers explained.

The reanalysis provides compelling data contradicting previous findings that revenue per unit effort declined following the expansion of the PMNM. In addition, the new findings reinforce the important role that MPAs can play in both protecting biodiversity and providing economic benefits to nearby fisheries.

Matt Rand is a senior director and Rebecca Jablonski-Diehl is an associate manager working on The Pew Charitable Trusts’ marine habitat conservation efforts.

Note: The descriptions in the legend included with the graphic below were updated on May 13, 2021, to clarity that the data relate to revenue. 

Spotlight on Mental Health


A Way to Safeguard Biodiversity and Protect Ocean Habitat

The Case for Marine Protected Areas
Quick View

A Way to Safeguard Biodiversity and Protect Ocean Habitat

The Case for Marine Protected Areas
Papahānaumokuākea Marine National Monument
Papahānaumokuākea Marine National Monument
Press Releases & Statements

U.S. Creates World’s Largest Protected Area

Quick View
Press Releases & Statements

HONOLULU—The Pew Charitable Trusts joins partners in Hawaii and the scientific community in praising today’s announcement by President Barack Obama that the United States has expanded the Northwestern Hawaiian Islands Marine National Monument, also known as Papahānaumokuākea, to 582,578 square miles (1.5 million square kilometers).

Composite image of modern city network communication concept

Learn the Basics of Broadband from Our Limited Series

Sign up for our four-week email course on Broadband Basics

Quick View

How does broadband internet reach our homes, phones, and tablets? What kind of infrastructure connects us all together? What are the major barriers to broadband access for American communities?

Pills illustration
Pills illustration

What Is Antibiotic Resistance—and How Can We Fight It?

Sign up for our four-week email series The Race Against Resistance.

Quick View

Antibiotic-resistant bacteria, also known as “superbugs,” are a major threat to modern medicine. But how does resistance work, and what can we do to slow the spread? Read personal stories, expert accounts, and more for the answers to those questions in our four-week email series: Slowing Superbugs.

Explore Pew’s new and improved
Fiscal 50 interactive

Your state's stats are more accessible than ever with our new and improved Fiscal 50 interactive:

  • Maps, trends, and customizable charts
  • 50-state rankings
  • Analysis of what it all means
  • Shareable graphics and downloadable data
  • Proven fiscal policy strategies


Welcome to the new Fiscal 50

Key changes include:

  • State pages that help you keep track of trends in your home state and provide national and regional context.
  • Interactive indicator pages with highly customizable and shareable data visualizations.
  • A Budget Threads feature that offers Pew’s read on the latest state fiscal news.

Learn more about the new and improved Fiscal 50.