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Sea Lice on Farmed Salmon: Eco-Label Now Allows Far More

The Aquaculture Stewardship Council’s new standard means up to 1,550 per cent more parasites can live on the fish.

Michelle Gamage 14 Oct

Michelle Gamage is a Vancouver-based journalist with an environmental focus who regularly reports on climate for The Tyee. You can find her on Twitter @Michelle_Gamage.

In early September the independent non-profit Aquaculture Stewardship Council increased the amount of sea lice allowable on farmed salmon that is certified as “responsibly farmed.”

B.C. farmed fish are now allowed to have three motile (or 0.6 to 1.7 adult female) sea lice on them, when they used to only be allowed 0.1 mature females to qualify for the label. Motile sea lice is an umbrella term for pre-adult and both male and female lice.

This is a 540 to 1,550 per cent increase in the total allowable parasite limit.

Advocates say this won’t change anything in practice on B.C. fish farms because most farms were given exemptions from ASC sea lice limits and were operating under Fisheries and Oceans Canada limits, which are three motile lice per fish.

Sea lice are parasites native to B.C. that attach themselves to salmon and eat the fish’s mucous and skin layer, says Sean Godwin, a post-doctoral researcher at Simon Fraser University who specializes in sea lice. These parasites add stress to a wild fish, make them more susceptible to be eaten by predators and slow down their growth rate, he says.

Sea lice impact farmed salmon less because the fish are protected from predators and are regularly fed, he adds.

In their juvenile stages sea lice drift through the ocean in hopes of finding salmon to attach themselves to. Wild salmon shed the lice when they return to fresh water to spawn because sea lice cannot survive in fresh water, Godwin says. Because adult wild salmon tend to swim up rivers in the fall and juvenile salmon swim down rivers in the spring, sea lice transmission between the young and older fish are naturally prevented.

Salmon farms house a lot of fish — sometimes over one million salmon — in very close spaces “which provides the ideal conditions for pathogens and parasites to proliferate,” Godwin says. Farms act as “year-round reservoirs” for sea lice which then expose juvenile salmon to “high numbers of sea lice” as they swim close to farms during their migration.

“It's the juvenile salmon we worry about because they’re smaller and lack fully developed scales and immune systems to help protect them,” he adds.

The 0.1 sea lice limit was set in 2012 following a multi-stakeholder process that created limits to reduce the negative impacts of the industry while still allowing it to make money. The ASC launched a review of its sea lice criteria in 2019 and published its new standard on Sept. 5, 2022.

ASC spokesperson Sophia Balod told The Tyee the 0.1 limit emphasized the metric limit but omitted “various equally important measures,” and that the new standard “addressed all these concerns.”

The 0.1 standard was based off Norwegian legislation but didn’t consider “geographic region, sea lice species and wild salmon species,” she says. Norway has maintained its 0.1 limit.

As the ASC was trying to create a “credible global limit” for the many countries it operates in, it decided to defer to “existing metrics as set by the regulators in the understanding that these are based on available solid regional research and data,” she adds.

Godwin says he’s concerned that any eco-label would defer to local government regulations because in Canada those regulations are influenced by industry lobbyists, are not rooted in science and were written in the early 2000s before the impacts fish farms would have on local wild salmon were understood.

“There’s been a bunch of recent research that shows the threshold isn’t good enough for protecting wild salmon, especially with rising sea surface temperatures which are going to exacerbate sea louse outbreaks and resistance to the treatments used to control sea lice,” he says. “If they’re a sustainability label then their standards should go above and beyond what the government mandates.”

Balod says the ASC “strongly believe” this new standard “will deliver improved practice enabling protection of wild salmonids.”

A hand holds a a package of oysters with a turquoise "asc" certification label in the bottom right corner.
The ASC logo, seen here on a package of oysters, is meant to ‘[give] consumers confidence that they are choosing fish and seafood products that are fully traceable and have been independently certified as farmed responsibly.’ Photo by Michelle Gamage.

Several environmental organizations oppose the new standard.

Karen Wristen, executive director of Living Oceans Society, says locally her organization, the David Suzuki Foundation, Watershed Watch Salmon Society, Friends of Wild Salmon and Clayoquot Action are calling for the ASC to go back to the 0.1 standard.

Internationally, environmental groups in Tasmania, Scotland, Ireland, Chile and the Faroe Islands have also co-signed letters to the ASC demanding the same thing, she says.

Wristen says she believes ASC changed its allowable sea lice levels so it could certify more farms.

“Their revenue comes from fees paid by farmers for certification so it’s a money-making proposition, certifying farms,” she says.

She adds she’s heard the ASC say the change will allow it to bring more people into the program “so they can get them to improve their practices,” but that doesn’t make sense within the current certification structure, she says.

Kathleen McDavitt, the U.S. market development manager for ASC, told The Tyee “that's just plain false.”

The “ASC does not make money from audits,” she said in an email. “Our program uses independent, third-party auditing companies that farms contract with directly to perform the audits. Unlike other aquaculture certifications, we take no part in the auditing process and no money from farmers.”

Wristen says the ASC’s certification model does not encourage farmers to improve their business practices.

“There’s no beginner level followed by silver level, gold and platinum,” she says. “It’s just, ‘We’re platinum and you don’t get the certification unless you meet this high bar.’ And all they’ve done since they started business is lower that bar time after time after time.”

Living Oceans Society has been advocating for the ASC to enforce the 0.1 sea lice standard on its certified farms since 2016, “but the farmers managed to convince them that it would put them out of business,” Wristen says.

Farmers were allowed to make “variance requests” for sea lice standards which let them follow local regulations set by Fisheries and Oceans Canada while still being certified “responsibly farmed,” Godwin adds.

“The requests were always granted so actual ASC limits were never actually applied in B.C.,” he says. In a way this recent change is “making more explicit what was already happening.”

DFO requires salmon farms to keep within the three motile sea louse per salmon limit between March 1 to June 30, during the juvenile salmon migration.

If farms exceed the three-lice limit they have 21 days to bring sea lice numbers back down under ASC limits to maintain the “responsibly farmed” certification. This is lower than the 40-day limit set by DFO, Wristen says.

Three weeks gives farmers enough time to treat or harvest their salmon, Godwin says.

To better encourage industry to adhere to limits set by the ASC or any other eco-labeller, Godwin says thresholds should be hard cutoffs, “not guidelines,” and that the thresholds should be based on the total number of sea lice on the farm, not on a per-fish average. “Three lice per fish on a 10,000-fish farm is very different than three lice per fish on a 1 million-fish farm,” he says.

There’s also likely more lice on the fish than are being counted, Wristen says.

B.C. has two types of sea lice, Lepeophtheirus salmonis and Caligus. L. salmonis attaches itself to salmon, trout and char while Caligus is more generalist and infects near-shore fish, like herring, anchovies and stickleback, Godwin says. In B.C. regulations around sea lice are all based off of L. salmonis because it is thought to affect its host more, he says.

But in his research he’s shown Caligus makes juvenile Fraser river sockeye grow slower and impacts their ability to compete for food, he says.

The DFO and ASC require salmon farmers to count both types of sea lice, but the limits are only applied to L. salmonis, he adds.

An outbreak of Caligus would not trigger treatment requirements, Wristen says.

“Nothing about the distinction between the two species of lice matters to a tiny, wild smolt: both species attach to the fish and eat their way through the skin to get at the blood,” Wristen says. Both species can create “large, open sores” on the fish which make them more susceptible to diseases; can spread disease between farmed and wild fish; and reduce a smolt’s “competitive ability to forage,” she says.

“There is simply no reason to treat them differently, from an ecological perspective,” Wristen says.

It’s important for B.C. to improve its regulations around sea lice because warming sea temperatures and sea lice treatment resistance are going to exacerbate louse populations, Godwin says.

If the ASC is deferring to local governments to set allowable sea lice limits it should defer to First Nation’s regulations, says Dan Lewis, executive director for Clayoquot Action.

Many First Nations oppose fish farms in their territories. The Dzawada'enuxw First Nation took the federal government to court for granting fish farm licences in their territory in the Broughton Archipelago. More than 100 First Nations, wilderness tourism operators and commercial and sport fishing groups have demanded the government remove all open net pen salmon farms from around Campbell River on Vancouver Island. Hereditary Chief Tsahavkuse of the Laichwiltach Nation wants to kick all fish farms out of the country.

It’s not clear how long fish farms will be in B.C. waters.

In June 2022 the federal Minister of Fisheries and Oceans Joyce Murray said B.C. would transition away from open-net pen salmon aquaculture over the coming years, but both Wristen and Godwin say the DFO appears to be positioning itself to “transition” rather than “wind down” the industry, which could mean adding new technology but leaving the farms in the water.

Even before the ASC recently changed its sea lice limits, its stamp of approval didn’t convince everyone.

As of December 2021, for example, the Monterey Bay Aquarium Seafood Watch recommended customers "avoid" buying Atlantic salmon farmed in marine net pens in B.C. The program gave the aquaculture industry a score of 3.6 out of 10, with disease and chemical use being the top concerns. But the program also recommends buying ASC-certified salmon, regardless of farming method or location.*

SeaChoice recommends avoiding buying any open net-pen farmed salmon, regardless of if it is certified or markets itself “best practice” or “responsible practice.” Buying sustainably caught wild Pacific salmon or Atlantic salmon grown in land-based, closed containment is best, it adds.

Consumers can check fish farm’s lice levels themselves through the DFO website, but reports are published half a year after they’re prepared.

Most farms in B.C. are ASC-certified farms; these farms are also required to publish their lice numbers on their websites, but finding the data often requires some digging, Wristen says.

* Story corrected on Oct. 17 at 10:45 a.m. to clarify that Monterey Bay Aquarium Seafood Watch advised specifically against buying Atlantic salmon farmed in marine net pens in B.C., and recommended buying farmed Atlantic salmon that had been ASC-certified.  [Tyee]

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