Co-authored by Erica Cirino
When thick sheets of sea ice began melting in the Arctic waters around Svalbard, Norway, a few years ago, a new expanse of sparkling blue sea opened up. As climate change continues to drive ice melt here on the previously untouched waters of the North Barents Sea, what many ocean conservationists consider to be unwelcome guests are starting to arrive in droves: trawling vessels.
And this trend toward more open sea and more ship traffic could have a harmful affect on the North Barents Sea ecosystem, according to Greenpeace. The conservation group is so worried about the detrimental effects of bottom trawling in the waters near Svalbard that they launched their own investigation into commercial fishing practices in the region.
“Industrial fisheries moving into newly accessible areas pose a serious threat to seabed communities,” says Greenpeace in its investigation report, This Far, No Further, published in March. The group cites a 2015 Norwegian Institute of Marine Research study on North Barents Sea seabed fauna that found a decline in biomass for all species in trawled areas as compared with those that are not trawled, with especially vulnerable species like sea stars, sea sponges and sea cucumbers experiencing the greatest losses.
The North Barents Sea lies above a continental shelf, a raised undersea boundary zone where an abundance of sea life thrives, fed off a steady stream of nutrients carried by ocean currents. So much sea life makes continental shelves especially appealing targets for trawling.
As our resident research scientist and sustainable seafood director Dr. Elizabeth Brown-Hornstein has explained in our Fishing Gear 101 series, fishing trawls act as the “bulldozers of the ocean, scooping up and destroying anything in their path,” especially when dragged along the sea floor. To trawl, fishers tow giant, cone-shaped nets (sometimes as wide as a football field and as high as a three-story house). These big nets can cause a lot of damage.
In the North Barents Sea, bottom trawlers target the cod that swim along the ocean floor. With more water free of ice, fishing boats are chasing cod and other fish farther and farther north. But it’s not just the North Barents Sea that’s losing ice. Sea ice around the Arctic Circle was measured at its lowest annual extent this January: a paltry 5.6 million square miles (compared to an average of 6 million square miles).
More open water is likely to mean more trawling in many vulnerable ocean areas throughout the Arctic. And this, according to researchers, could cause extreme devastation to the fragile deep-sea ecosystems of the Arctic.
“This study raises serious concerns about the future stability of continental shelves – the very source of the vast majority of the fish we consume,” said Dr. Ferdinand Oberle, visiting geological oceanographer at the U.S. Geological Survey and lead author of the studies. “A farmer would never plow his land again and again during a rainstorm, watching all his topsoil be washed away, but that is exactly what we are doing on continental shelves on a global scale.”
Oberle and his colleagues at U.S. Geological Survey conducted two studies on the consequences of bottom trawling in continental shelf habitats like that of the Barents Sea. In the first study, they developed a novel technique using computer models to quantify the total ecological harm caused, while in the second they analyzed sediment cores to find out how bottom trawling affects the quality of seabed sediment.
The researchers found that bottom trawling displaces an enormous amount of seabed sediment, nearly 22 gigatons (1 gigaton is equal to a billion tons!) globally each year. They also found that bottom trawling drastically altered the physical makeup of seabed sediment in the waters of northwest Iberia, churning up ancient layers of rock that lay beneath its surface.
In essence, trawling causes an enormous disruption to the lives of the organisms living on and in seabed sediments. And while many of the creatures living near the seafloor are small, according to Dr. Curt Storlazzi, research geologist and oceanographer with the U.S. Geological Survey, they are very important for the overall health of the oceans.
“Consider trawling impacts to be similar to clear-cutting a forest,” says Storlazzi. “You destroy the structure and plow-up the forest floor, and it will take years, if not decades, for the forest to recover and for all of the associated species to return.”
This means all sea creatures—not just those destined for our dinner plates—are likely to be affected by bottom trawling. The North Barents Sea—with its rich biodiversity—will inevitably experience species loss if bottom trawling isn’t stopped there.
Currently, Greenpeace and other conservation groups are pressuring the Norwegian government to prohibit trawling and other destructive fishing practices in Arctic waters. Instead, they encourage individuals to sign the Arctic Declaration, an agreement to protect the fragile Arctic ecosystem. These decisions will help decide whether the fate of the Arctic will be exploitation or conservation.