Review confirms deadly impact of Salmon farms sited near wild Salmon migration routes; findings accompany shift in stance by Canadian Salmon-science committee
by Craig Weatherby
The corporate owners of Salmon farms would rather forget February, 2008… a month that’s delivered them one public relations disaster after another.
We're not opposed to aquaculture in principle. Fish farming probably is needed to supplement dwindling natural stocks of fish.
- Salmon farms suffered three big scientific blows this month.
- New review confirms that fish farms near Salmon rivers pose a grave threat to wild Salmon.
- Study affirms conclusions of recent Greenpeace report.
- Canadian science panel now acknowledges that some of British Columbia's Salmon farms pose a serious threat to wild Salmon stocks.
But aquaculture must be practiced much more carefully, to prevent the serious, ongoing problems caused by industrial Salmon farming.
To see our past reports on problems at Salmon farms and other aquaculture operations, search our newsletter archive.Let’s take a look at the three separate blows suffered by industrial Salmon farmers.
Salmon-farm strike #1—the Greenpeace report
The first blow that Salmon farms suffered this February came from a review of the current scientific literature by the Greenpeace Research Laboratories at Britain’s University of Exeter.
The Greenpeace scientists’ review documented, among other problems, the un-sustainability of current methods of farm-raising Salmon, and the coastal destruction wrought by farming of shrimp (See “Devastating Report Details Aquaculture Dilemmas”).
Among other problems, the report cites research proving that farming of Salmon is a grossly inefficient way to get protein from the sea. In fact, it takes from three to six pounds of small fish (herring, sardines, etc.) to produce one pound of Salmon.
As the authors wrote, citing UN data, “…farming of carnivorous species results in a net loss rather than a net gain of fish protein. Instead of alleviating pressure on wild fish stocks, therefore, aquaculture of carnivorous species increases pressure on wild stocks of fish, albeit of different species” (Greenpeace 2008).
Fish farmers can lessen this inefficiency by feeding their Salmon less fish meal and fish oil and more grain and vegetable oil.
A sustainability-driven shift toward plant-based feed can reduce the protein-wasting problem inherent to farming of predatory species like Salmon, Cod, Sablefish, and Tuna… but it remains to be seen whether it will totally eliminate it.
However, such a shift will worsen the fatty acid profile of farmed Salmon, which are high in omega-3s, but also—unlike wild Salmon—high in pro-inflammatory omega-6 fatty acids, which compete with omega-3s for space in our cell membranes.
This nutritional problem can be partially surmounted by giving the Salmon “finishing feed” that is high in fish meal or oil during the last two to three weeks of life.
But it is not certain that Salmon farmers will bother to blunt the negative nutritional impact of any shifts they might make to plant-based Salmon chow.
Salmon-farm strike #2 – Report affirms that wild Salmon harmed by nearby farms
Salmon farmers’ bad month peaked (they must hope) with the release last week of the first study to document the negative impact of Salmon farming worldwide.
Researchers Jennifer Ford and Ransom Myers of Canada’s Dalhousie University compared the survival rates of wild Salmon near Salmon farms to the survival rates of wild Salmon in areas with no Salmon farms (Ford JS, Myers RA 2008).
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Ford and Myers studied five species of wild Salmon and trout in five regions of Europe and Canada, including areas in British Columbia, New Brunswick, Nova Scotia and Newfoundland.
Their results showed that wherever wild Salmon come into close contact with Salmon farms, the numbers of wild Salmon decline by up to half, from one generation to the next.
As they wrote, “We show a reduction in survival or abundance of Atlantic Salmon, sea trout and pink, chum, and Coho [Silver] Salmon in association with increased production of farmed Salmon. In many cases, these reductions in survival or abundance are greater than 50 percent” (Ford JS, Myers RA 2008).
Although the differences between the farm-exposed and unexposed populations of wild Salmon were not statistically significant in every comparison, the scientists found large, statistically significant declines in survival and returns when they averaged the paired comparisons across all the regions and wild Salmon populations.
The Lenfest Foundation, which funded the research, published a summary that cited two reasons why Salmon farming harms wild Salmon (Lenfest 2008):
- “Aquaculture impacts wild Salmon populations in several ways. Large concentrations of fish can increase the presence of diseases and parasites that can be transmitted to nearby wild populations, and such transmission has been documented in all areas where Salmon farms and wild Salmon or trout co-exist. A recent study confirmed that wild Salmon in British Columbia are negatively impacted by sea lice emanating from fish farms" (Krkošek M et al. 2007).
- “Farmed Salmon also can escape from aquaculture farms. The escapees may compete with wild Salmon for resources and may also interbreed, reducing the genetic diversity of wild populations and producing hybrids with low survival.”
And the Foundation’s summary echoes the protein-inefficiency findings cited by Greenpeace: “Finally, Salmon farming uses large volumes of processed wild fish for feed, meaning that Salmon farming results in a net loss of fish, rather than a net gain.”
In its article on the new study, Toronto’s The Globe and Mail newspaper quoted Professor John Reynolds, who holds a chair in Salmon conservation at B.C.'s Simon Fraser University:
“It's very significant… basically the first time anybody has put the global data together… we really are going to have to think about the way we are doing Salmon farming… I don't think we have to give it up. But people will have to make some choices.”
Salmon-farm strike #3—Canadian science panel supports sea lice study
The third blow against Salmon farms struck sites in British Columbia, just south of where we get our wild Alaskan Sockeye Salmon.
This blow was especially painful because it came from the Pacific Salmon Forum … a generally pro-farm research group funded by the Canadian government.
On February 7, a scientific committee of British Columbia’s semi-official Pacific Salmon Forum acknowledged that sea lice from Salmon farms are devastating pink Salmon populations in Broughton Archipelago, as argued in a peer-reviewed study published the prestigious journal Science (Krkošek M et al. 2007).
That landmark study was co-authored by researchers from the University of Alberta and Alexandra Morton, M.S., of the Raincoast Research Society. They estimated that wild pink Salmon could vanish from B.C.’s central coast within four years, due to sea lice swarms generated by Salmon Farms in that area.
We profiled Ms. Morton last week. See “Help Support a Wild Salmon Heroine.”
When the study was released last December, members of the Pacific Salmon Forum suggested that the study overstated the seriousness of the situation.
But two weeks ago, the Forum invited Morton and her co-authors to a meeting, during which they successfully defended the solidity of their research and findings.
Ms. Morton told The Vancouver Sun that the discussion seemed to reflect a pro-farm bias on the part of the Forum’s representatives.
As she told the Sun, “They were very reluctant to admit there were no flaws they could find with the paper.”
But Morton and her fellow researchers won the day, and the Pacific Salmon Forum’s science committee now expresses “general agreement” that preventing pink Salmon extinctions will depend on changes in the way Salmon farms are managed and sited.
Scientists’ pleas go unheeded by Canadian politicians
Alexandra Morton and other researchers have urged B.C. authorities to compel Salmon farmers to remove any sites located near the birth-rivers of wild pink Salmon.
And last year, a committee of the B.C. provincial legislature recommended that Salmon farms switch from using open-net sea pens to closed-containment pens that would prevent lice infestations from spreading to wild fish migrating in the vicinity.
Sadly, both recommendations have been ignored by provincial officials, even though economic activity related to wild Salmon—commercial and sport fishing and tourist businesses that support the latter—is estimated to be twice as large as that generated by Salmon farms.
Upon release of Ms. Morton’s sea lice study last December, the University of Alberta issued a press release that included some cogent comments by fisheries biologist Ray Hilborn, Ph.D., of the University of Washington (UA 2007):
- “It shows there is a real danger to wild populations from the impact of farms. The data for individual populations are highly variable. But… it is pretty persuasive that Salmon populations affected by farms are rapidly declining.”
- “This paper is really about… the impacts of net pen aquaculture on wild fish. This is the first study where we can evaluate these interactions and it certainly raises serious concerns about proposed aquaculture for other species such as cod, halibut and sablefish.”
We share Dr. Hilborn’s fears, and hope that our readers will keep let their legislators—and supermarkets—know that they will not support fish farming unless it is practiced in ways that do not significantly harm the coastal environment, wild fish stocks, and the people whose livelihoods depend on them.
- FAO (2007). The state of world fisheries and aquaculture 2006. FAO Fisheries and Aquaculture Department. Food and Agricultural Organization of the United Nations, Rome, Italy. 162 pp.
- Ford JS, Myers RA (2008) A global assessment of Salmon aquaculture impacts on wild Salmonids. PLoS Biol 6(2): e33. doi:10.1371/journal.pbio.0060033
- Greenpeace. Challenging the Aquaculture Industry on Sustainability. Accessed online February 5, 2008 at http://www.greenpeace.org/raw/content/usa/press-center/reports4/challenging-the-aquaculture.pdf
- Hume M. Salmon farms killing wild stocks: study. Globe & Mail, February 12, 2008. Accessed online February 14, 2008 at http://www.theglobeandmail.com/servlet/story/LAC.20080212.BCSALMON12/TPStory/Environment
- Krkošek M, Ford JS, Morton A, Lele S, Myers RA, Lewis MA. Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon. Science 318 (5857), 1772, 14 December 2007. [DOI: 10.1126/science.1148744]
- Lenfest Foundation. Global assessment of Salmon aquaculture impacts on wild Salmon: A summary of new scientific analsyis. February 2008. Accessed online February 14, 2008 at http://www.lenfestocean.org/publications/FordMyersLOPRS2.08.pdf
- University of Alberta (UA). Fish Farms Drive Wild Salmon Populations Toward Extinction. December 13, 2007. Accessed online February 14, 2008 at http://www.lenfestocean.org/newsroom/pr_2007_12_14_wildsalmon.pdf