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August 29, 2018

Fishing pressure can surge before marine reserves are created, new study finds

The Phoenix Islands Protected Area has been a conservation success, but that's not the whole story.
R Gombarik / Shutterstock


Timing is everything, even when it comes to California-sized marine reserves. 

In 2015, the Phoenix Islands Protected Area, in the central Pacific, was put entirely off-limits to commercial fishing. The protected area, known as PIPA, has been a conservation success — but that success now comes with time-based caveat. 

Fishing pressure effectively doubled in the 16 months before the 2015 protection, according to a new study in the Proceedings of the National Academy of Sciences. Researchers used a trove of satellite data to track previously hidden boat activity in the reserve.

The finding suggests an additional factor scientists should consider when they estimate fish populations and then measure their recovery in marine protected areas, since the extra fishing resulted in an lower-than-normal starting point within the reserve.

PIPA, which is located within the Republic of Kiribati, is a UNESCO World Heritage site home to stunning coral reefs and uninhabited atolls. Study co-author Grant McDermott, an environmental economist at the University of Oregon, said previous research showed that the 2015 PIPA closure successfully stopped almost all commercial fishing, but didn’t look at what happened beforehand.

The team sought evidence for an ocean equivalent of the “green paradox.” That’s when human harms like logging or hunting accelerate in anticipation of environmental protections. After analyzing the satellite fishing data from the Phoenix Islands and nearby Pacific regions that weren’t closed, the scientists found a similar trend, and dubbed it the “blue paradox.”

This paradox is well-documented on land. In the southeastern United States, the paper notes, the once-rare red-cockaded woodpecker saw declines in its habitat when it was protected under the Endangered Species Act in 1973, as landowners cut down forests after realizing that woodpecker colonies would trigger costly land-use restrictions.

About 7 percent of the world’s oceans are now marine protected areas, or MPAs. The study found that if future marine reserve announcements trigger behavior similar to the woodpecker case, or to PIPA, it could temporarily increase over-exploited fisheries.

“It really shows how important it is to keep watch over those areas that are out of sight, out of mind,” McDermott said.

The new research “is a really good example of using technology to get at things that we haven’t been able to study before,” said Aaron MacNeil, a fisheries ecologist at Dalhousie University in Nova Scotia. “Fishermen have operated in a vacuum for centuries. They go to places and nobody really knows what’s going on.”

MacNeil, who wasn’t involved with the “blue paradox” paper, said that team addressed a key concern by using the same satellite data to measure fishing pressure in similar areas of the Pacific. “When you’re looking at MPA effectiveness, you want a comparison,” MacNeil said, and the new paper does that.

Kyle Meng of the University of California, Santa Barbara, another co-author of the paper, said in an email that detecting the “blue paradox” would not have been possible without the satellite monitoring data. The data was gathered using the Global Fishing Watch platform, originally created by Oceana, SkyTruth and Google.

McDermott added that measuring pre-closure fishing “has important impacts for understanding why these MPAs aren’t always as effective as we think they are, and how scientists should measure them.”

But just suggesting that marine reserves should be created more quickly is too simplistic, McDermott said. While some MPAs “take almost unduly long” to create, scientists and fishery managers need buy-in from local community stakeholders.

A 2017 study found evidence that both Kiribati citizens and community leaders were proud of the PIPA fishing closure decision and its conservation message. But that paper noted marine protected areas have been much more controversial elsewhere. In Bermuda, for example, a six-year bid to establish a new MPA “appears unlikely” to succeed.  

McDermott said a key point about the new paper is “being honest about the knowledge that this incredible data is providing us. We just have to be honest about the economic and political constraints.” The number of marine reserves has grown tremendously in recent years, he said, but they are “not the only arrow in the conservation quiver.”