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Salmon Safe from Lice

BC Salmon Safe from Science Scare

April 5, 2005
By Dr. Patrick Moore, PhD

The David Suzuki Foundation and its anti-aquaculture allies are bamboozling global media into believing sea lice from salmon farms are killing B.C.’s wild salmon stocks.

In a report published in the Proceedings of the Royal Society of London, David Suzuki Foundation-funded scientists claim they have “proof” the farms cause massive sea lice infestations and salmon declines. Well, at least that’s what the authors have stated during media briefings.

In fact, the pink salmon population is far from declining. The 2004 returns in B.C.’s Broughton Archipelago were well above the 50-year average. Aquaculture opponents would have us believe low 2002 returns were caused by sea lice from salmon farms. Yet the Department of Fisheries and Oceans recorded lower returns for five years prior to 2002, and three of those years — 1960, 1972 and 1978 — occurred before the first salmon farm was introduced to the Broughton.

John Volpe, one of the report’s authors, was quoted in The Vancouver Sun: “Absolutely… this is the silver bullet.” Why then, one might ask, is the following statement contained on line 547 of his report? “No general conclusion can be made on the transmission dynamics of lice from farm to wild salmon based on this study alone.” Because the authors haven’t proven anything, that’s why.

What Volpe and company appear to have found is a correlation between the position of a salmon farm in Tribune Channel and the infestation of pink salmon by sea lice. They have offered no proof these lice originated from the farm. They have not demonstrated any damage to wild fish by the lice. They used no control location to see what happens in the absence of a salmon farm.

Sea lice are virtually everywhere on the coast and always have been. Nowhere does the report acknowledge that the farmed salmon get their sea lice from wild fish in the first place. The report glosses over the crucial distinction between different species of sea lice, some of which are rarely found on farmed salmon but are common on wild fish. This failing in itself is a sufficient reason for a reader to question the conclusions reached by the researchers. And they did not seem to understand the very basics of sea lice biology or the oceanography of the region.

The life cycle of a sea louse begins when a mature female, attached to a fish, sheds thousands of microscopic eggs into the sea. The eggs float near the surface at the whim of tides and currents until they hatch six to eight days later. Only then are they able to attach themselves to a fish, where they survive on the mucous secreted by the skin.

In coastal inlets such as Tribune Channel, a net outflow of water on the surface always occurs as a result of the freshwater coursing in from rivers and streams at the head of the inlet. If the lice infesting pink salmon fry were indeed coming from the farm in the Channel, those lice could not hatch until they had been carried some distance seaward during the six to eight days of incubation.

Lice that are hatching and attaching to wild fish near the farm very likely originated well up the inlet, possibly from adult lice living on wild sticklebacks and other native species. In contrast to agenda-driven activist scientists and their activities, which receive such wide coverage, credible experts studying the Broughton issue are preparing to report in the scientific literature that pink salmon actually depend on the larvae of sea lice for some of their food supply. It may turn out that in balance the sea lice are good for wild salmon. I can already hear the shrieks of derisive horror coming from the true believers.

The fundamental problem in all this sensationalistic “science” is that “correlation” is being equated with “causation.” Correlation occurs when two events or things happen in the same place or time. The classic case is ice cream consumption and shark attacks in Australia. Of course the strong correlation between the two is not because one causes the other, rather it is because warm weather causes both. Otherwise they are not related. The very first line of the Royal Society report is “Marine salmon farming has been correlated with parasitic sea lice infestations and concurrent declines of wild salmonids.” This one statement should have disqualified the paper from being printed. Science journals themselves seem to have forgotten the difference between correlation and causation.

Activists take the term correlation and substitute it with the term “link,” as in “a link has been shown between salmon farms and sea lice infestations on wild salmon.” This is also highly misleading since most people think the word “link” implies some kind of causal relationship. It does not.

This report, funded by activists and Canadian taxpayers, has been broadcast around the world on everything from CNN to The Associated Press to The New York Times. To say it was a highly orchestrated release with many activists involved would understate the situation. The goal appears to be the destruction of one of British Columbia’s cleanest industries, which produces what is arguably the most nutritious source of protein and good fats on Earth.

Patrick Moore, co-founder of Greenpeace, is chairman and chief scientist of Greenspirit Strategies Ltd. in Vancouver. http://www.greenspiritstrategies.com/.

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