Ray Hilborn: MPAs aren’t the answer to ocean biodiversity, sustainability efforts

A global movement to create additional marine protected areas (MPAs) has been steadily gaining traction in recent years, with the initiative picking up milestone victories in the past few months.

In January, newly inaugurated U.S. President Joe Biden signed an executive order committing to a “30 by 30” goal, whereby the United States would designated 30 percent of its land and territorial waters to conservation by the year 2030. The move heightened the potential that MPAs will be used as a tool to tackle climate change.

A recent study supports the hypothesis that MPAs could be beneficial for climate change, maintaining biodiversity, and boosting the yield of fisheries. According to the study, strongly protecting at least 30 percent of the ocean – primarily in the 200-mile exclusive economic zones of coastal nations – would result in substantial environmental and commercial benefits.

But University of Washington Professor of Aquatic and Fishery Sciences Ray Hilborn told SeafoodSource that the study – and the concept of MPAs – are both flawed. The study, he said, made some assumptions and contains inconsistencies that effectively invalidate the conclusions it reached.

“It’s a classic example of where the peer-review process totally failed to identify inconsistencies, bizarre assumptions, and improper conclusions,” Hilborn said.

The study, he said, made different assumptions on different types of fishing effort.

“It happens that each of the assumptions they made about fishing effort is the one that makes MPAs look better," he said.

A key example, Hilborn said, is how the study approaches trawling. The study made biodiversity calculations based on fishing effort shifting in geography as MPAs are put in place – which itself poses problems, he said. However, the study assumed that an MPA ban on trawling wouldn’t result in increased fishing effort in other areas.

“When it comes to the impact of trawling and the impacts on biodiversity, they assume when you close an area, the effort disappears,” Hilborn said.

The study found a ban on trawling in designated MPAs would have a carbon benefit – but that is true only if that trawling effort doesn’t move holds, Hilborn said.

“If you move the effort, the carbon benefit disappears,” Hilborn said.

Hilborn said the study also assumes an “instantaneous connection” between different species around the world – when in reality, species in separate oceans aren’t going to interact. And the analysis wasn’t actually global, as South Asia and Southeast Asia were not accounted for in the study.

“This isn’t a global analysis, because they don’t have trawl effort in Southeast Asia,” Hilborn said.

Protecting biodiversity is a key issue that needs to be tackled, and the core motivation behind MPAs and Biden’s 30 by 30 plan are sound, Hilborn said. 

“[The] 30 by 30 [movement] is not ambitious enough,” Hilborn said. “We need to protect the biodiversity of 100 percent of our [exclusive economic zone].”

Protecting biodiversity in the oceans is not best accomplished via MPAs, especially in light of climate change, Hilborn said. In fact, while advocates have touted MPAs as a means to fight climate change, in reality, they do little to help, he said.

“They want to see 30 percent of the oceans permanently closed,” Hilborn said. “That’s absolutely the wrong thing to do. With climate change, things are shifting.”

Hilborn used the interactions between fisheries and the critically endangered North Atlantic right whale as an example of how a proposed MPA might not work as intended. In recent years, the species has been the center of an ongoing push for increased protections, and recently NOAA outlined new regulations to protect the species.

Climate change has forced the 400 or so remaining North Atlantic right whales to chase food sources that are now located in parts of the ocean with more fishing effort, primarily in the Gulf of Saint Lawrence. That movement highlights how MPAs would struggle to protect species in the ocean, Hilborn said.

“If you had closed areas to protect northern right whales 20 years ago, they’d be in all the wrong areas,” he said.

Protected areas on land, he added, make sense because of the nature of human interaction with the land.

“The reason you want parks on land is that human use is transformative. If you put a city on it, or you farm it, it’s gone,” Hilborn said. “In the ocean, fishing doesn’t really change the structure of the ecosystem. We don’t kill the plants which is what farming does, we don’t harvest the second trophic level, we just harvest the top of the food chain.”

Plus, many of the actual threats to the ocean aren’t coming from the ocean itself, or from fishing.

“If you look at what the threats to the oceans are, they’re ocean acidification, climate change, invasive species, various kinds of pollution, land runoff, and none of those are impacted by MPAs,” Hilborn said.

A great example is the large dead zone that forms in the Gulf of Mexico every year.  The dead zone is created by excess nutrient pollution from agricultural areas – mainly related to fertilizers washed into the gulf through the Mississippi River and other inland waterways. NOAA makes annual predictions for how large the dead zone will be, based on things like rainfall. An MPA in the area to protect that environment, Hilborn pointed out, would have no effect on the biodiversity of the ocean in the region.

“You could make it an MPA and ban everything, you could ban shipping, you could ban mining, you could ban fishing, and you’d have no effect on the dead zone,” he said.

Protecting biodiversity is possible, but MPAs are the wrong tool for the job, Hilborn said.

“You don’t need no-take in order to protect the biodiversity. Again, high profile things, marine birds, marine mammals, turtles, sharks, those are things where there’s very specific – gear specific – things that impact them,” he said. “Closed areas aren’t going to help, because they’re all so mobile.”

The solution for those species, he said, is simple.

“Take sharks or turtles - all you have to do is stop killing them,” he said.

Current fisheries management agencies already serve as a tool for protecting biodiversity, and Hilborn said additional effort can be made using those existing agencies.

“What I would like to see is very explicit targets in what are we trying to achieve in biodiversity, and for each one of those targets, what’s the best tool to achieve it,” Hilborn said. “In almost every case, you’re going to be modifying fishing gear, and how fishing takes place, rather than closing areas to all fishing gears.”

MPAs, he said, are essentially just regulating a few activities in an area, without addressing wider issues.

“Fundamentally, all MPAs are doing is regulating fishing, and maybe oil exploration and mining,” he said. “It’s just the wrong tool. The illusion that you’re protecting the ocean by putting in MPAs, it’s a big lie.”  

Photo courtesy of Wikimedia