This may be the best way to protect ocean life from being snared in nets

By Georgia Lambert via SWNS

Switching parts of the ocean closed to fishing is the best way to protect marine life from being accidentally snared in nets, according to a new study.

Sharks, sea turtles and other threatened species often perish after getting tangled in fishing gear.

The problem has become one of the biggest barriers to overcome when making global fisheries more sustainable.

Marine protected areas - sections of the ocean where biodiversity is conserved - are used to reduce the unintentional catch of animals among other conservation goals.

While the climate crisis looms over us, many nations are calling for the protection of 30 percent of the world's oceans by 2030 from the exploitation of sea animals, including fishing.

Building off this proposal, a new analysis led by the University of Washington has looked at how effective fishing closures are at reducing accidental catch.

While the researchers discovered that permanent marine protected areas are a relatively inefficient way to protect marine biodiversity, they found that "dynamic ocean management" is the way to go. This means that as the accidental catch hotspots shift, so should the closures.

Study senior author Professor Ray Hilborn, of the University of Washington, said: "We hope this study will add to the growing movement away from permanently closed areas to encourage more dynamic ocean management.

“Also, by showing the relative ineffectiveness of static areas, we hope it will make conservation advocates aware that permanent closed areas are much less effective in reducing accidental catch than changes in fishing methods.”

These techniques could include devices that keep sea turtles away from shrimp fishing, or streamer lines on boats to deter seabirds from getting caught in fishing lines.

The international team of researchers looked at 15 fisheries around the world, including Californian swordfish, South African tuna, and Alaskan pollock.

They then modeled what would happen to both the targeted fish and to species caught accidentally - known as bycatch.

They also predicted what would happen if 30 percent of fishing grounds were permanently closed, compared with dynamic management.

In practice, dynamic management works by tracking the real-time data of bycatch and in response, closing smaller areas that move year-to-year based on where species are most affected.

One of the critiques of permanent marine protected areas is that many of the species they are supposed to protect, such as marine mammals, turtles, seabirds, move around and may leave the protected area altogether.

This study found that on average for all fisheries studied, restricting fishing in 30 percent of a fixed area did reduce bycatch by about 16 percent.

But in dynamic closed areas, over the same fraction of the ocean, bycatch was reduced by up to 57 percent.

Lead author, Maite Pons, an independent fisheries consultant based in Uruguay who completed the work as a University of Washington postdoctoral researcher, added: “We found we can significantly reduce bycatch without decreasing the catch of target species by closing small fishing areas that can move year to year.

“This dynamic approach is increasingly valuable as climate change drives species and fisheries into new habitats, altering these interactions.”

The authors have acknowledged that goals differ for various marine protected areas, and if the main purpose is to protect critical habitat, a biodiversity hotspot, or a unique feature, static closures might be more effective and easier to enforce.

However, they said that all conservation goals should be broadly considered when determining which types of ocean protections to put in place.

Prof Hilborn added: “I hope this study encourages everyone to consider how best to reduce bycatch and protect marine ecosystems."

The study was published in the journal Proceedings of the National Academy of Sciences.