Remote Ocean Wilderness Is as Important as Marine Reserves

A new study finds that some remote ocean wilderness areas support fish populations better than marine reserves dedicated to sheltering them.

Researchers found that remote marine reefs protect three times as many fish stocks as marine reserves. They also keep safe many threatened and other key species that need large spaces to thrive, such as sharks, groupers, and snappers.

Lead author Tim McClanahan, senior scientist for the Wildlife Conservation Society, says he has been studying the recovery of fish populations in no-fishing marine reserves near the shore in order to understand important numbers for fisheries management and conservation.

“As I was doing this, it became clear from the work of the other authors in remote wilderness areas that what I was studying and the numbers were quite different from what these people found in remote areas,” McClanahan tells Treehugger. “Thus, it dawned on us that there were essentially two different seascape biomass and probably growth rates in nearshore areas with heavy fishing and more intact seascapes.”

Environmental influences weren’t as important as the nature of the seascape, McClanahan explains. It mattered whether the seascape was intact or divided or whether some areas were closed off to fishing.

A recent environmental initiative called to conserve at least 30% of the world’s land and oceans by 2030, a policy called 30x30. On the ocean front, the policy focuses on creating and maintaining highly protected marine areas where no activities like fishing and mining can take place. So far, only about 2% of coral reefs are being fully protected in marine reserves.

But the researchers wondered about what they call “best-practices seascape” (BPS) now that they saw remote ocean wilderness areas offered some advantages over marine reserves.

“What might be the consequences of this in terms of whether or not this 30% was distributed among the two seascapes?” McClanahan says. “In many ocean ecoregions, there was essentially no wilderness, so that would mean that this 30x30 policy would result in an outcome that is reflected in a best-practice seascape for large areas of the Earth’s oceans.”

Better Protection

For their study, researchers examined coral reefs located four hours or more from people and those located 9-plus hours of travel distance away from regional cities. They found that the mean biomass of fish in remote wilderness areas was about one-third higher than those populations in even the largest, oldest, and most well-managed marine reserves that are located nearer to shore and closer to people.

“This study confirmed that wilderness areas protect fish far better than even the most sustainable fisheries and reserves,” says McClanahan. “It scares us to think what is being lost when wilderness is reduced. The findings are a call to designate the last remaining marine wilderness as areas needing special status and protection—global ocean strongholds. To ensure that all coral reef fish species are protected from fishing and possible extinction, we need to focus on wilderness alongside 30 percent closures in nearshore areas.”

The findings were published in the journal Fish and Fisheries.

Particularly, researchers found that species that need more space are more affected.

“The large-bodied species compose a large part of the total biomass, their populations are greatly reduced as the seascape becomes dissected by zoning areas as fishing and no-fishing,” McClanahan says. “This loss and outcomes may not be noticeable in terms of fisheries production, as the production is conserved relative to the stock biomass in the marine reserves of BPS.”

Marine reserves protect smaller, more resilient species while large, remote wildlife marine areas are successful in sheltering larger species.

“These big species require space to access resources and complete their life cycles. So, this space is only available to them in large undisturbed or undissected seascapes,” McClanahan says.

But these marine wildlife habitats are disappearing due to widespread fishing. Because these natural areas complement marine reserves, it’s important to protect both seascapes, researchers conclude.

“Observing and surveying fishes for many years has made it clear to me that many, and particularly big fishes, require lots of space to survive and thrive. This collaboration and analyses with my colleagues have made it clear how this need for open marine wilderness is so pervasive,” said study co-author Alan Friedlander of Pristine Seas.

“This robust and extensive dataset has allowed us to confirm what many of us have observed for year, that remote marine wilderness are like time machines that allow us to observe the ocean of the past in order to protect the future.”