From The Wall Street Journal July 23:
Atlantic salmon, though unremarkable in size, is a big fish in the culinary world. But producers face a pesky problem to keep salmon king.
Health-conscious consumers who covet its brain-enriching Omega-3 have helped make salmon one of the fastest-growing food sources on the planet. Victoria Beckham told The Wall Street Journal last year she considers it a dietary staple. She’s not alone. In America, salmon is the second-most popular seafood after shrimp.
The fish frenzy has driven prices higher and spawned new billionaires, such as Gustav Magnar Witzøe, a 31-year-old Norwegian heir to a salmon fortune and a fashion model who made a splash at this year’s Met Gala in a salmon-colored Versace cape.
Norway’s fjords and coasts are the farmed fish’s top habitat, with around 500 million salmon swimming in the chilly waters—a ratio of roughly 90 Norwegian salmon to every Norwegian human.
Atlantic salmon farming, introduced as overfishing and river pollution shrank the wild salmon population, increased 74 times from 1985 to 2022. Salmon are bred in tanks on land, then moved into the ocean, where they swim in giant ring-shaped nets until they’re ready for human consumption.
But these days, the industry is swimming upstream.
Crosscurrents
Atlantic salmon production dipped in 2022 and ’23, as disease outbreaks and a surge in jellyfish attacks ravaged the fish. Norway’s plentiful fjords have filled up. The coastlines of Chile—the world’s second-largest producer—are also saturated. There aren’t many new places to rear the fish, which require year-round cool temperatures and mild currents.Some analysts anticipate a sharp slowdown as governments move to curtail farming, concerned in part that farmed salmon—bred selectively to gain weight quickly—are escaping their nets and spreading their wonky genetics to their cousins in the wild. Canada, a top producer, recently stopped granting new licenses to coastal open-net salmon farms in British Columbia to protect the state’s wild salmon population.
Another big reason governments are clamping down: an explosion of bloodsucking, treatment-resistant fish lice.
These parasites are no small-fry. They lay hundreds of eggs at a time and quickly permeate shallow coastal waters, sucking at the flesh of cooped-up salmon.
To fight infestation, companies are employing an ever-expanding arsenal, from mechanical brushes that delouse fish to underwater lasers that zap these villains of the salmon-farming world.
“They are spending so much money trying to come up with new ideas and tools to combat the problems,” said Lars Daniel Garshol, lead salmonids analyst at Kontali, a Norwegian seafood analysis company. “But they’re having a hard time solving them.”
Lumpfish lunch?
Take, for example, this fishy solution: Some farmers began dumping lumpfish—stout, grumpy-looking creatures that snack on sea lice—into salmon pens. Only to have many of the fish take a liking to salmon food pellets over lice. Some also developed cataracts, making hunting the parasites harder.Researchers are now looking for ways to identify the most eager lice-eaters with the aim of selectively breeding them. A study at Swansea University in Wales concluded that personality tests could be used to build “elite” lines of cleaner fish. Part of the research involved dumping a yellow golf ball and a green Lego brick into lumpfish tanks, to see which fish would be bold enough to make an approach.
There’s also the question of what to do with the fish when their time is up. Researchers with close ties to the industry have tried to find markets that would fancy a lumpfish lunch. It’s a tough sell.
Participants in one study said the fish’s flesh was tasteless, and they were turned off by the fact the fish were raised on lice.
“They thought it was rather scary looking and very unappetizing,” said market researcher Gøril Voldnes of Nofima, a Norwegian government-owned research institute.
One of the more powerful tools being deployed in the battle against lice—laser death rays—didn’t seem like such a promising notion at the start.
When John Breivik, a veteran of Norway’s oil-and-gas industry, approached salmon farmers in 2010 with the idea of zapping lice with lasers, he was met with incredulity. “Every fish farmer that we met said: This is science fiction, this is ‘Star Wars,’ ” said Breivik.
Stingray Marine Solutions, the company he created with colleagues in 2012, used machine learning to teach underwater lasers to recognize the shape of lice and fire off pulses. Their maximum kill speed is three to five lice a second. Crucially, the beam is weak enough that if it hits salmon, it bounces off their scales.
A Stingray factory opened in November to produce over 1,000 laser sets annually. Each costs around $45,000 a year.
Alf-Gøran Knutsen, a third-generation salmon farmer and first-generation laser-user, is general manager of the Kvarøy Group, a Whole Foods supplier with a salmon farm on the Arctic Circle. A few years ago Knutsen dumped his lumpfish, which struggled with their health, and replaced them with an armada of 82 Stingray lasers.
“Right now we’re at 150,000-200,000 shots per laser a day,” he said. “That’s an insane number, and that also tells you we are able to control the lice situation at the moment.”....
....MUCH MORE
The fact they have to take so many shots tells us this is not an elegant solution.
We too have heard the siren call of laser de-lousing...
"Remote-controlled Salmon Farms to Operate Off Norway by 2020"
"And then Mr. Poisonnier, the robots massage the salmon..."
And it just got better and better:
Also at IEEE Spectrum:
Lice-Hunting Underwater Drone Protects Salmon With Laser
Sadly, The Fish Site reports:
Study shoots down sea louse laser
The efficacy of a laser-firing device that has been designed to reduce sea lice pressures on farmed salmon has been called into question by new research.
Innovative lice lasers developed by Stingray have been deployed by numerous salmon farming companies over the course of the last decade, but this newly published study – which took place at a commercial salmon farm operated by Bremnes Seashore in Norway – suggests they are not always effective....MORE
On the other hand lasers seem to work pretty efficiently against slower moving life forms:
2013: Dear Monsanto: "Weed Control Using Laser" (and robots) MON
"This startup says its new laser-armed weeding robot is already sold out for 2021"
"We should be careful to get out of an experience only the wisdom that is in it—and stop there; lest we be like the cat that sits down on a hot stove-lid. She will never sit down on a hot stove-lid again—and that is well; but also she will never sit down on a cold one anymore."