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But a federal
Fisheries Department scientist questions the data
and says there is still too little evidence to
back the claims of the authors of the recently
published scientific paper. In an article in the
current issue of Science magazine, the authors say
raising salmon throughout their lives in a benign
environment like a hatchery leaves them
ill-equipped for the wild.
"By putting them in
a benign environment, they evolve to a state where
if they went back into the wild they wouldn't
compete very well with wild salmon and probably
wouldn't survive as well," says Daniel Heath, a
professor at the University of Windsor and expert
in conservation genetics.
The study,
undertaken by Heath, his brother John Heath, who
operates a salmon farm on Vancouver Island, and
three others specifically studied chinook salmon.
The principle,
however, could be applied not only to all salmon
but probably to any animal reared in a captive
environment, says Daniel Heath.
Why should the
public care about this study?
"In terms of salmon
in general, what it means is that the traditional
wisdom of putting them in a controlled, safe
environment doesn't shelter them from genetic
changes," says Daniel Heath.
He concedes there
is still no "hard data" on the precise effect of
small egg size in the wild, but their estimations
indicate the fish that began as small eggs "would
not do well."
What the study also
says - and what is disputed by Fisheries
Department scientist Terry Beacham - is that the
concern isn't only for salmon-farm fish but for
wild stocks that get only their beginnings at
federal government hatcheries.
"It's also wild
stocks through hatchery supplementation that also
appear to be evolving towards smaller eggs," says
Daniel Heath.
Beacham doesn't
necessarily have a problem with the fish farm.
"With respect to
the fish farm part, I think that's fine," he says.
"But the problem I have is when they make the
conclusion they do to the hatcheries. There, the
evidence is pretty sparse to support that claim.
"They're saying
just the mere fact of having the eggs in a
hatchery is going to cause the egg size to decline
in subsequent generations."
The study was
conducted primarily at Yellow Island Aquaculture
Ltd., a salmon farm in Campbell River, B.C.,
operated by John Heath and his wife.
"What (the study)
means is that whenever we try to rear animals in a
captive situation - in zoos or captive breeding to
restock wild - the animals are going to change
from the animals in the wild and they're going to
do it at a very rapid rate," says John Heath.
The rapid change in
egg size surprised the scientists the most.
"From a scientific
perspective, the thing that is most startling
about it is the speed with which this happened,"
says John Heath. "This happened with quite
breathtaking speed."
Jennifer Lash,
executive director of the Living Oceans Society on
Vancouver Island, calls the findings a wakeup
call.
"This is like a
warning bell going off, saying we're not playing
with fire, we're potentially in the fire now
because without intentionally doing it, we're
affecting the evolution of how salmon reproduce,"
says Lash, whose non-profit organization
specializes in research and public education of
marine issues.
"We need to be
saying that before we start farming indigenous
salmon we have to understand what we are doing.
And this paper is saying we don't understand it
yet."
Terry Glavin, who
has written books on salmon and has acted as a
consultant to environmental groups, also suggests
the study should serve as an alarm bell.
There has never
been a "comprehensive assessment of the
contribution that hatcheries make to maintain
salmon abundance," he says. "There is a lot of
evidence that hatcheries have produced no net
benefit in terms of salmon abundance.
"This study is just
more evidence that the potential for
cross-breeding of hatchery or enhanced populations
of salmon and naturally spawning populations of
salmon is such that it can reduce the fitness of
the offspring."
But Beacham says
the study won't prompt any change of policy by
Fisheries.
"I don't see strong
evidence in this paper that would cause a change
in the practices of the hatcheries," he says.
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