Norwegian salmon farming company, Kvarøy Fiskeoppdrett, has ruled out a move to closed-containment fishing pens, insisting that lumpsuckers provide the solution for them to sustainable open-net salmon farming.
A row broke out last week after Canadian Prime Minister Justin Trudeau pledged to end all open-net salmon farming in British Columbia, instead moving to land-based closed containment facilities by 2025.
The move was slammed by local fish farming groups, who branded it ‘careless’ and ‘destructive’.
Sea lice threat
But one of the benefits of this move will be on sea lice. Chile recently reported its highest sea lice statistics in six years.
But it’s not just Chile, as all countries who farm salmon in the ocean have been looking at how to better keep and supply their salmon because of the threat from sea lice.
Closed-containment pens are just one solution. Sea lice cannot, for example, attach to salmon when they are not raised in open-net pens.
But closed-containment facilities have their own problems, so must be considered as a whole.
One family-run business in Norway says the costs involved in operating closed-containment pens would be ‘enormous’. Kvarøy Fiskeoppdrett launched in 1976 and has 23 staff working across five sites. They produce roughly 8,000 metric tonnes of salmon each year, and their biggest market is the US-based Whole Foods supermarket chain.
Whole Foods only sell products that are free from preservatives and colours, and are known for their organic range of food. They have 500 stores in America and the UK.
Speaking to Salmon Business from his boat in Norway, the general manage of Kvarøy Fiskeoppdrett, Alf-Gøran Knutsen, said: “With the way we’re doing farming, it’s sustainable, the cost of taking it on land, the energy costs, would be enormous.”
Kvarøy Fiskeoppdrett chooses to salmon farm using a cleaner-fish called lumpsuckers. These are small marine fish found in the cold waters of the Arctic, North Atlantic and North Pacific oceans. They work on cleaning salmon by eating the sea lice that can affect them after they are placed in the salmon pens.
“We have only the lumpsucker we use for lice treatment,” he said.
“We have a feed that exceeds all the goals. We’re cleaning the fish. We have a natural colourant in the feed. We also don’t use soy from the Brazilian rainforest, just European soy.”
“The lumpsucker is quite amazing. It’s not a wild, caught fish that you need a stock from. We catch 10 from the wild, we milk them, breed them on a land-based farm.
“We use a percentage compared to the salmon. We have a special feed for them. We go round the pen every day and feed them. They have a special hiding place that they can swim into. We have a lot of mechanisms to make sure the lumpsucker has the same welfare as the salmon. The reason why we succeed with using lumpsuckers, is because we have the same amount of people watching the lumpsucker as the salmon.”
Other varieties of cleaner-fish include wrasse, who peck the parasites on the fish.
“We were using the wrasse fish before,” Mr Knutsen said.
“They were caught in the wild and fished in the south of Norway, transported up to the north of Norway. In salmon farms, we saw the fishing was too expensive. They were taking out too many fish, so they tried breeding the wrasse fish, but it’s not an easy fish to breed.”
“Then we got an idea that the lumpsucker was good. It was a great success breeding them and farming them, and eating the lice. So it was just an idea that became a success.”
Even though the use of lumpsuckers has been a success, it’s a challenge to maintain their welfare.
“If it’s only going to eat lice, you need to feed it with a feed and do a good job, and maintain a good and healthy diet for it so it survives the whole life cycle,” Mr Knutsen said.
Other ways to fight sea lice
But cleaner-fish is not the only solution in the fight against sea lice. There are also many other ways. Sea lice skirts, anti-sea lice feed, snorkel cages, thermal treatments, strategic site management, flushers, lasers, sea lice traps, deep lights, bubble curtains and hydrogen peroxide are all techniques that can be applied. There are also newer treatments which include ultrasound, vacuuming, different breeding practices, vaccinations and freshwater.
So how do some of these work? A thermolicer, which is a thermal treatment, works by putting salmon through heated water which kills the sea lice.
Another option include a Stingray laser, which fires beams out whenever it detects sea lice. The fish go on unharmed because of their scales, which reflects the beam. But the sea lice end up fried.
Other options include a snorkel sea cage. These keep salmon at lower depths than the larvae of sea lice, helping to prevent them attaching to the salmon.
Hydrogen peroxide has been tried. It works by temporarily paralysing the sea lice, causing them to fall off the salmon. But it’s not widely used because it’s known to cause stress on the salmon.
Vaccinations were first started in Chile in 2015. It works by improving the abundance and quality of mucus in the skin of the salmon. That helps protect against sea lice. It has had some success, but is still in its early stages of development.
The other newly-developed device that gets rid of sea lice has been made by supplier Vard Aqua. It’s a vacuum which works by collecting sea lice and filtering them through large amounts of sea water. The device can also clean up during the de-lousing stage.
Separately, an anti-sea lice feed antimicrobial called emamectin benzoate can be fed to the fish to poison the sea lice who are feasting on the tissue of the salmon. It works by being fed to the salmon, passing through to the tissues, and then is absorbed by any attached lice.
But Dr Martin Jaffa, a fish farming consultant from Manchester, in England, questions why the fish feed can’t be placed at the bottom of the cages so the fish don’t travel to the top where they encounter sea lice.
He told Salmon Business: “What we should be doing is passing the feed through the water column but make sure it does not go out of the cage. Instead of sending it down the water column, send it up the column, and introduce it at the bottom of cage and let it flow to the surface.
“If it doesn’t work, you know to stop feeding. The real benefit is if you feed from the bottom of the cage, the fish don’t come to the surface. When you’re feeding from the surface, you’re encouraging the fish to come to the area where the sea lice larvae are settling. Surely having an existing feed system in a cage is better.”
Less sustainable solutions include using colouring supplements, antibiotics or medicines.
There have been concerns that giving too many antibiotics to the salmon can make them develop a resistance to it, effectively making the antibiotics useless. For that reason, many salmon farmers choose not to use them.
How ever a farmer chooses to treat their sea lice problem, the issue is likely to persist while the salmon remain in the open waters. Moving from open-net pens to closed-containment facilities represents one of the only ways to eradicate the problem completely. But, as that opens up a can of worms itself, it isn’t a very popular option at all, so the threat of sea lice will continue.
Still, Mr Knutsen hopes to continue being a sustainable farmer and vows to do all he can in the ongoing threat from sea lice.
“We just want to be in front and continue being one of the most sustainable farmers,” he told Salmon Business. “And find customers who appreciate what we do and how we do it.”
