In 2002, the number of pink salmon returning to the Broughton Archipelago was only 3% of normal. Alexandra Morton subsequently co-authored a study reporting that 68 – 98 % of the fish tested in this area had the sea louse “L. salmonis.”[1.] A University of Toronto study links the 2015 sea lice epidemic to fish farms in the same area. The article that follows is based on Marine Harvest Canada’s (MHC) Ian Roberts’ response to anti-salmon farm critics.
The 2015 Sea Lice Epidemic
The University of Toronto study said, “Because farmed salmon are in open net pens and share water with nearby wild salmon, the parasites can transmit to young wild salmon who wouldn’t normally encounter sea lice until later in life.”
To which Roberts responded, “2015 was a bit of an anomaly, and that is where that U of T study came from … If you only look at an area near salmon farms and found sea lice, then you would come to the conclusion that sea lice is only found near salmon farms. But we had the benefit of doing four studies that found sea lice prevalence was higher far away from the farms than near the farms. “
The BC Salmon Farming Association’s summary of these studies concluded “Sea lice prevalence is not related to the presence or absence of a salmon farm in the vicinity of the sample site.” A sampling of 22 sites in the Broughton Archipelago, for example, found that 65% of all the sea lice came from an area not located next to a salmon farm. Similarly, the amount of lice were “5 times higher in the Goletas Channel (away from salmon farms) than in the Queen Charlotte Strait (next to farms).”
Roberts offered an alternative explanation for the 2015 epidemic, “Salmon runs were extremely high in the fall of 2014 and with that you get an average of 41 sea lice per adult returning Pink salmon and you get a lot of sea lice into the coastal area. Combine that with low salinity and high temperatures, because we saw a jump of a degree or so in the Spring of 2015, and you have perfect conditions for sea lice. If wild juvenile fish are seeing high levels of sea lice, we are probably going to see that in our salmon as well because they kind of mirror what is happening in the wild environment.”
Wild Salmon Infect Fish Farms Too
A Fisheries and Oceans Canada report suggests that there are times wild salmon infect fish farms:
- “Sea lice abundance on farmed Pacific salmon increases during the autumn, and is most likely associated with wild salmon returns, but declines soon after.”
- “Evidence suggests that farmed fish most likely derive L. salmonis sea lice from wild returning salmon (primarily Pink and Chum Salmon)” .
Flawed Research Pointing To Salmon Farms?
In their original study, Morton and Williams (2003) observed bleeding at the base of fins on infected juvenile Pink Salmon – but subsequent studies state these lesions did not appear on Pinks infected in “controlled laboratory trials, nor has this been observed in any other reports.”
Gary Marty, from UC Davis, was the lead author of a 2010 PNAS article faulting the original Broughton Archipelago study because, “No diagnostic investigation was done to rule out other causes of mortality.” They concluded “all published field and laboratory data support the conclusion that something other than sea lice caused the population decline in 2002.”
The Cohen Commission
The controversy continued after the disastrous Fraser River sockeye run of 2009. Morton and Marty both testified in the federal inquiry. In his subsequent recommendations, Justice Bruce Cohen called for:
- a freeze on fish farm expansion in the Discovery Islands, an important salmon migratory route;
- a removal of farms if impacts aren’t addressed by 2020;
- remove promoting fish farming from Fisheries and Oceans Canada’s mandate, as this conflicts with its duty to regulate it (Fisheries and Oceans Canada continues to regulate and promote fish farms .)
Morton’s film Salmon Confidential Documentary is what Roberts calls a one-sided depiction of those hearings.
Morton’s Recent Court Victory
To paraphrase her lawyers, Morton’s more recent court victory confirms that “the Department of Fisheries and Ocean’s duty to protect and conserve wild fish and the marine environment.”
Gleaning the essential facts from the judges decision:
- In March, 2013, Marine Harvest transferred salmon smolts, that subsequently tested positive for piscine reovirus (PRV), from its Dalrymple hatchery to the Shelter Bay fish farm.
- The causal relationship between PRV and the lethal salmon disease HSMI “has not been conclusively established”, and Marine Harvest vigorously contests it, but “the weight of the expert evidence before this Court supports therited view that PRV is the viral precursor to HSMI.”
- While “the Court is not arbitrating on the PRV/HSMI debate,” it found that “the Minister sheltered behind Marine Harvest’s evidence” and was not taking “a precautionary approach” in the performance of its’ duties..
Morton recently wrote, “In the ongoing saga of what I view as a coverup of the effect of farm salmon disease on wild salmon, I have written to Canada’s newest Minister of Fisheries. Recent internal CFIA emails reveal that the agency only wants only one lab in all of Canada to test for ISA virus in BC farmed salmon and that lab is shrouded in controversy due to its chronic inability to find diseases and pathogens that other labs are reporting. This is not acceptable and threatens not only wild salmon, but Canada’s reputation, again.”
MHC’s Director of Fish Health and Food Safety, Dr. Diane Morrison, stated, “ The body of research now tells us that PRV has been ubiquitous in the Pacific Northwest for many decades, and that it isn’t linked to any fish disease or mortality … no cases of HSMI have ever been confirmed in fish with western North American PRV.”
MHC Continues To Clean Up Its Act
Meanwhile MHC is continuing to clean up its act. Regular diagnostic testing, and treatments (when called for), are carried out at each of its 30 British Columbian fish farms. They found that farmed salmon are usually lice free during their first year, but will become infected with sea lice after the second autumn run. They near the limit of three lice per fish over the winter.
At the moment a drug called “slice” is the mainstay of their cleansing programs. They are also trialling a “cleaner” fish to “pick sea lice off Atlantic salmon and eat them.”
Another alternative is the 75-metre “freshwater well boat” that will soon be visiting each farm twice a year.
“It is such a large ship that we can do one full pen, of small and even large fish, in a few hours. Our local trials showed that freshwater baths over 3 hours removed up to 85% of the sea lice,” says Roberts.
These baths will be conducted in the Spring and fall. Roberts says they primarily concerned about infection spreading from pens to wild salmon during the spring. This is when the juveniles pass through on their way out to sea. “Our goal is to (eventually) have no impact on this migration.” This is not a serious problem in the fall, when fish are returning home to spawn.
“There is so much natural influx of sea lice into the area that you are better off to just wait until the salmon are through,” he explained.
Roberts predicts the well boat, “will be very effective, when combined with the other tools we’ll use as well. And, of course, our certification demands that we continue to reduce drug and antibiotic use. That’s something our customers will agree is just good management.”
(Ian Roberts invited me to look at their Phillips Arms facility, and I posted a report here.)
All photos courtesy of Marine Harvest Canada; Map adapted from Google by Roy L Hales
-  S. Saksida et al, Population ecology and epidemiology of sea lice in Canadian waters, Fisheries and Oceans Canada, Table 3: Reported sea lice levels on juvenile wild salmon in the Pacific.]
-  A Sea Lice Report, BC Salmon Farming Association, January 6, 2016 p 4.
-  S.Saksida et al, p 14
-  ibid, p 23
-  ibid, p 6
-  Gary D. Marty et al, “Relationship of farm salmon, sea lice, and wild salmon populations” PNAS vol. 107 no. 52 ]
-  ALEXANDRA MORTON vs MINISTER OF FISHERIES AND OCEANS and MARINE HARVEST CANADA INC, paragraph 1]
-  ibid, para 37, but “the weight of the expert evidence before this Court supports therited view that PRV is the viral precursor to HSMI.”
-  10. ibid, para 35
-  ibid, para 35