MPAs and Commercial Fishing

A map showing the location of the Revillagigedo National Park Marine Protected Area.

For some time, the conventional wisdom has been that designating certain waters as Marine Protected Areas—where commercial fishing is off limits—hurts the fishing industry due to a corresponding reduction in catch, and that the reduction in turn drives seafood prices higher globally.

But is this really accurate? A new study published in the scientific journal Science Advances, says it is not.

According to the study, which was published in the magazine’s June 2023 issue, the largest Marine Protected Area (MPA) in North America, located in the Mexican Pacific, does not harm industrial fishing. In fact, the information uncovered by four researchers concludes that the protected area has actually helped commercial fishing in the long run.

The researchers, including a marine ecologist at the University of California, San Diego’s Scripps Institution of Oceanography, looked at fishing hauls before and after the establishment of Mexico’s Revillagigedo National Park, a 57,143 square-mile area (nearly five times the size of Hawaii) surrounding a four-island archipelago south of Mexico’s Baja California that was designated an MPA in November 2017.

While calculating the average daily haul from the 90 industrial fishing vessels that worked the region’s waters since 2007, the report found that not only did Mexico’s fishing industry not suffer, but that the catch actually increased by an average of 8% in the years after the MPA’s establishment.

“We found no statistical evidence of a significant, negative, causal impact of the MPA’s implementation on industrial fisheries in Mexico’s Pacific EEZ,” the authors wrote. “The average CPUE (catch per unit of effort) of the vessels that were historically active in the MPA … did not change significantly after implementation, nor did the CPUE of those who were never active within the MPA.”

“Implementing the 147,000-km2 Revillagigedo National Park had no negative effect on catches or caused Mexico’s industrial fleet to increase the area used for fishing,” the study states in part. “These findings refute the fishing industry’s argument that creating the Revillagigedo MPA would harm the fishery or directly cause the effort to move, thus increasing the fishing area.”

Similar results were recorded in other Pacific MPAs, according to the authors, but with less reliable data or in MPAs where fishing was already low.

A number of scientists have agreed that at least 30% of the world’s oceans should be declared off limits to commercial development and operation in order to protect fish stocks and marine biodiversity. But even if large, oceanic, fully protected MPAs reduce fishing effort without negatively affecting the fishing industry, they aren’t the only solution to ocean conservation, the story’s authors say.

“Industrial fishing vessels have the flexibility and potential to readily change their fishing grounds, which might be more challenging for artisanal fisheries, which tend to be limited in terms of their operating grounds,” the study states. “MPAs must be properly contextualized and complement other management measures, regulations, controls, and restrictions. Our work shows that it is possible to find common ground between area-based conservation and extractive activities like fishing and to foster cooperation between different sectors to achieve the global (30% MPA) target.”

According to a June 8 article in Time magazine, study lead author Fabio Favoretto of the Scripps Institution of Oceanography attributes the increase to what he calls a “fish bank” effect.

Because the ecosystem is protected, MPAs produce an explosion of marine life that eventually spills out of the protected area and into new territories that can be fished.

“This data,” Favoretto is quoted by Time as saying, “proves that MPAs work, and they don’t harm fishermen.”

The full study can be read and downloaded at  

Managing Editor Mark Nero can be reached at