If you eat salmon, odds are that it comes from a salmon farm, with a fifth of the salmon that Americans eat coming from Norway. NPR's Rob Schmitz went to Norway's west coast recently, visiting fishing villages and fish farms to see how the growth of salmon farming is affecting the wild population.
Jorgen Wengaard has worked most of his life on salmon farms — he says the Norwegian coastline is perfect for farming Atlantic salmon because of the optimal temperature, salinity and oxygen levels.
As Norway exports more salmon across the world, the industry has come under criticism from environmental groups who say salmon farms are irreversibly impacting the pristine environment of Norway's fjords.
In many of these salmon farms, the fish are kept in open water pens — with the only thing separating them from the open ocean of the fjords being a thin nylon net.
Wengaard says they inspect the net every day and look for holes, because they don't want the salmon to escape:
"So even though this salmon comes from wild salmon originally, we don't want them to mix the genes and destroy the spawning places for the wild salmon."
But according to industry experts, it's too late for that.
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Population decline.
Author Simen Saetre says Norway's wild salmon population has been cut in half in the past two decades, largely due to the impact of tens of millions of farmed salmon, Saetre coauthored The New Fish, a book about Norway's farmed salmon.
Each year, an average of 200,000 farmed salmon escape from their open net pens, and then they mate with Norway's remaining 500,000 wild salmon, says Saetre.
"These farmed salmon are made to be fat and slow and be effective for the industry," Saetre says. "When they mate with the wild salmon, then also the wild salmon becomes slow and fat and easy to catch for predators."
The mixing of the salmon populations has dangerous consequences: Norway's wild salmon stock is rapidly dying out.
A study this year by the Norwegian Institute for Nature Research and the Institute of Marine Research found that nearly a third of wild salmon in Norway have "significant genetic changes" due to interbreeding with escaped farmed salmon. But Saetre says there is a bigger problem with Norway's farmed salmon - sea lice. They're tiny crustaceans that attach themselves to salmon, feed on them and reproduce.
"These sea lice, they have lived for ages just on wild salmon swimming by. They attach to it. And then when you gather millions of big salmons in the fjords and sea lice get into that, it's like a heaven for the sea lice," says Saetre.
Solutions.
In a four-year study ending in 2020, Norwegian scientists discovered that in the fjords of western Norway, mortality rates among farmed salmon from sea lice infestation reached more than 30%. Salmon farms use chemicals like pesticides to treat their fish, but scientists have discovered that sea lice have evolved to become resistant to the chemicals. One salmon farmer, however, says he has an answer to all of these problems.
Sondre Eide, the young third-generation CEO of his family company, Eide Fjordbruk, says he has built the salmon farm of the future.
It's a black cylinder barely sticking out of the water, surrounded by floating gangplanks. It's the cap of a 72 meter deep tank – with 200,000 salmon swimming inside.
This is closed-pen salmon farming — no escaped salmon and no salmon lice.
"This is all about giving the optimal life for the fish inside," Eide says. "And then, of course, when you take away the salmon lice, you have no lice treatment. So you don't have the handling. And that's responsible for 60, 70% of all the mortality in the industry. So then you can focus on 'how can we create the best day for the fish?'"
Eide and a team of his company's engineers put years of work and hundreds of millions of dollars into this closed pen, which circulates ocean water into it and keeps lice out. It also filters out salmon waste, a big contributor to rising nitrogen levels in the fjords. This waste creates biogas, which, in turn, creates energy. Eide is now working on using that energy to power this facility. Eide's closed-loop project raises the question - why isn't the entire industry farming salmon this way? Eide says when he and his team looked for the technology to do this, it wasn't there. He had the money to try to create it, so he did it.
"For me, it's like, it is the right thing to do, and I 100% believe it from the bottom of my heart. And I know my father would have done the same," he says.