Are we risking our Pacific salmon heritage for Atlantic salmon aquaculture?
By John Volpe
Not since the days of Juan de Fuca and Cook has the thought of invasion
weighed so heavily on the collective conscience of people on our coast.
These current invasions are not ones of foreign cultures -- but of foreign
plants and animals. There is almost daily media coverage of the latest
species to land upon B.C. shores. If it's not mussel-devouring green crabs
then it's the Asian longhorn beetle, or the honey bee-destroying varroa
mite, or bullfrogs with a taste for ducklings.
Movement of species beyond their natural borders has invariably resulted in
negative consequences for native species in the target region. This is why
the United Nations has declared the introduction of exotic species as the
second greatest threat to global biodiversity after habitat destruction.
The latest invasion story to grab front page ink in B.C. is that of Atlantic
salmon. More than 32,700 ready-for-market adults escaped two weeks ago at a
Vancouver Island fish farm. The depressed state of our native salmon
populations and the commercial and sports fisheries that depend on them make
this potential invasion particularly worrisome. In the public's eye this is
one invasion story that should have and could have been avoided. Are we
risking our native salmon heritage for Atlantic salmon aquaculture?
Answers are not so straightforward. Salmon aquaculture is big money in B.C.,
and with it comes persuasive lobbying power. On the surface it's an easy
sell: stitch some nets together, fill your pens with young salmon, feed them
to maturity, and harvest for a handsome profit. You provide employment for
beleaguered coastal communities and reduce harvest pressure on
over-exploited Pacific salmon stocks. The program sells itself.
However, the reality is not quite so cheery. To satisfy the need for fish
meal, vast quantities of fish are being removed from southern oceans. Three
kilograms of wild fish (plus an unknown quantity of bycatch) are required to
produce one kilogram of salmon. This is not a sustainable enterprise.
Most fish farms are owned by offshore multinational companies and are
high-tech facilities geared towards minimizing on-site personnel. As
technologies mature, the industry will no longer be a significant coastal
Further, to be profitable, fish farms are run feedlot-style and like similar
land-based operations, rely on drugs to maintain a healthy population. The
inadvertent breeding of "superbugs" or drug-resistant bacteria is promoted
in this way, and the potentially devastating long-term ramifications of such
practices are only now becoming fully appreciated.
And the notion that salmon farming reduces harvest pressures on wild salmon
is a fallacy. For years, there's been an oversupply of salmon on the world
market due to aquaculture overproduction, and salmon prices have remained
correspondingly low. As prices dropped, commercial fishermen have had to
increase their harvests just to maintain their earning power.
The most immediate concern is the large number of fish being released from
fish farms. In B.C., more than 80 per cent of production is of Atlantic
salmon, which, as its name plainly states, is not native to the Pacific. An
estimated 60,000 to 100,000 Atlantic salmon escape into B.C. coastal waters
annually (in reality no one really knows how many escape). When escapes
occur, the big question on everyoneís mind is: What effect are the escapees
going to have on our native stocks?
Unfortunately for the uninformed, there is a variety of answers being
offered. Most are products of media-savvy organizations that have only
thinly veiled their particular slant on the issue. Last summer, I confirmed
the first natural spawning of escaped Atlantic salmon in a B.C. stream. The
response from the B.C. Fish Farmers Association was that this discovery
meant nothing. A few fish here and there does not make an invasion, it
claimed. Meanwhile, the federal Department of Fisheries and Oceans ignored
its primary mandate of conservation and parroted the words of industry
without a momentís hesitation, and provincial authorities cautiously sat on
The most recent escape at Port McNeill has again provided fodder for the
spin machines, resulting in a dog's breakfast of presentations to the
public. What does it really mean though?
The short answer is we donít know. Industry continues to hold up the 1997
provincial salmon aquaculture review as evidence of the benign nature of
fish farms. The outcome of the review was a set of volumes larger than the
Toronto phone book and a vague "cautious yellow light" for industry
Unfortunately, the review was just that -- a review. Data from the North
Atlantic and local historical anecdotes were seamlessly applied to
present-day B.C. without anyone questioning the soundness of the underlying
logic. To think that the current escapees will share the same fate as those
a continent away is hopelessly simplistic.
For similar reasons, because Atlantic salmon failed to colonize 70 years ago
bears no relevance to today. Lake Ontario was exposed to zebra mussels for a
century before they "stuck" in the mid-1980s. Ten years of consistent
releases were required to establish European starlings (in New York Cityís
Central Park) in the early days of this century. The natural world is a
dynamic place and in a constant state of flux. If a species is introduced
often enough, chances are that conditions will eventually swing in its
What may seem like subtle changes to our eyes may result in significant
biological effects. For instance, many Pacific salmonid populations are
augmented with hatchery fish. Yet it's now well documented that hatchery
fish can be deficient in a number of traits necessary for survival. Is it
possible that in our zeal to artificially augment wild stocks we've created
populations lacking the competitive ability to retard invaders such as
Atlantic salmon? Only time will tell.
Atlantic salmon have been reared in B.C. for nearly two decades, yet no one
has wondered what might happen if some escaped. The assumption of the public
is that someone, sometime must have addressed the ecological issues prior to
the importation of Atlantic salmon to B.C. But this is not the case. With
the exception of my work, there are no scientific investigations whatsoever,
past or present.
We urgently need more science to address these issues before it's too late.
My work has shown that escaped Atlantic salmon are capable of surviving in
the Pacific, do successfully spawn, and produce young that appear to be
every bit as capable of surviving as their native cousins.
A few fish here or there may not be a problem, who knows? But ask yourself
this: If an eight kilogram female Atlantic salmon can deposit 15,000 eggs,
how many spawners do you need in a river before you have a "problem"?
John Volpe is a PhD candidate in UVic's biology department. His work focuses
on the ecology of invading organisms, particularly Atlantic salmon.
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