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There are
scores of fish farms, with many more applications before the
provincial government for new developments.
Meanwhile, the neglected pink salmon has become the target
fish of a major sports fishery. Especially, in odd-numbered
years, once summer comes around and fishing drops off
elsewhere, the pinks return to the coast in their millions.
Fly fishers find them in the shallows of estuaries and in
beach areas, and particularly off the shallow bars of the
Fraser River. Pinks may not have the reputation of Coho and
Chinook, let alone the glamour of steelhead, but they are
numerous, fun to catch, and they come at a time when other
fishing is slow.
From the
establishment of the first fish farms on the Pacific coast
there has been strong concern over their possible impact on
wild native salmon. Disease transfer, escapement and possible
gene pool contamination, possible introduction of exotic
species, and impact on the value of wild fish were all major
worries.
The most
attractive sites for fish farms are protected waters with
enough current to provide flushing action and clean water, but
without so much as to create problems in mooring the net cages
holding the fish. The Broughton Archipelago, near the
mainland north of Campbell River, has the required water and
protection and, consequently, has extensive fish farm
activity. These are also waters used extensively by pink
salmon, both going to the spawning rivers in the area and
returning, as smolts, to the sea. Concentrations of sea lice,
present naturally in wild fish and in farmed fish alike, have
been high at the fish farm sites.
Pink salmon
smolts migrate to the ocean after a very brief time in fresh
water, so the outbound fish from the rivers are of much
smaller size than most other salmon species. They are,
therefore, more vulnerable to damage by lice in the ocean.
The fish
farming industry maintains that there is little transfer of
lice from farmed fish to wild fish and, further, the type of
sea lice on farmed fish is of a different type than those
affecting the pink salmon smolts--Lepeophtherius salmonis
on the one and Caligus clemensi on the other.
The
Department of Fisheries and Oceans has been caught in the
middle of the dispute. Its 2003 studies, done early in the
year when lice are in less mobile stages, relied on a test
based on the weight of smolts (the Fulton Condition Factor).
This did not show that there was a causal relationship between
the lice on farmed fish and smolt mortality. On the other
hand, it did not, as industry spokespersons sometimes claim,
show that the farms were not affecting the fish. More
detailed DFO studies took place in 2004 and last year, and are
continuing.
As is so
often the case with fish science, new studies revealed new
issues. As recently as four years ago, salmon were considered
the only host of sea lice. However, the studies done by DFO
in 2003 determined that the stickleback, an abundant species
in the Broughton Archipelago area, is also host to the
parasite. So there is a whole new possible source of sea lice
contamination of pink smolts, which is, as yet, unstudied.
To add
further complexity to the debate, earlier this year a paper by
researchers from Simon Fraser University was published in
The American Journal of Fisheries Management.
Their study concluded that the Fulton test used by DFO did not
correctly measure impact of sea lice on smolts, as the body
weight remained close to normal until shortly before death..
Their research indicated substantial smolt mortality from sea
lice, and further, a dramatic increase in sea lice on smolts
as they passed through the waters where the fish farms are
located.
In late
March, another paper, written by three academics from the
University of Alberta and the University of Victoria, was
published in The Journal of the Royal Society B of the
United Kingdom. That study indicated that the sea
lice numbers on wild juvenile pink salmon near the fish farms
was 70 times higher than background or natural levels, and
that the impact stretched for thirty kilometers of the wild
migration route past the fish farms.
In their
turn, these studies have been criticized publicly for poor
research methodology, by industry position supportive
academics, Dr. Patrick Moore of Greenspirit in British
Columbia and Dr. Alasdair McVicar, an aquaculture industry
consultant in the United Kingdom.
Where will
this dispute between the experts wind up? Probably with the
work of the Department of Fisheries and Oceans scientists.
The critical questions DFO is attempting to answer are:
1. How
much of the transfer of sea lice to smolts is because of the
proximity of salmon farms,
2.
Given that even without salmon farms ninety to ninety nine
percent of pink salmon smolts do not live to return to spawn,
how significant is this mortality to the subsequent adult pink
salmon populations returning in later years.
For a fish
that no one cared much about a few years ago, in a place few
had heard of, pink salmon and the Broughton Archipelago have
certainly taken center stage.
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