du saumon au Nouveau-
Laquaculture sest développée en
réaction au déclin des populations de poissons. Daprès le rapport produit par le
Conseil de conservation du Nouveau-Brunswick en 1997, « The Status and Future of
Salmon Aquaculture in New Brunswick », cette riposte à la dépopulation des
poissons engendre cependant, doit-on le rappeler, des conséquences sur
Au rythme actuel de production au Nouveau-Brunswick, près de 3,7 tonnes
dantibiotiques sont intégrés dans la nourriture des saumons au cours dune
année. Les excrétions se déposent ensuite dans les sédiments marins et contribuent à
laccumulation et à la résistance bactérienne. En 1994 et 1995, afin
déliminer une infestation de parasites marins communs, de nombreux produits
toxiques ont été jetés dans la mer.
Il est très difficile de mesurer limpact de telles pratiques dans la mer, ce qui
nest pas le cas avec lélevage, doù, sans doute, le peu
dattention portée au problème.
After the Gold
The Status and Future of Salmon Aquaculture in New Brunswick
Marine Conservation Director,
Conservation Council of NB
the global decline of many commercial fish stocks, fish farming is increasingly touted as
the worlds best chance of meeting protein needs into the next century. Comparisons
are made with the advent of agriculture, which displaced hunting and gathering as the
primary means of securing food supplies. Advocates of aquaculture see it as inevitable
that wild or hunted fish would be replaced by cultured fish on our store and market
(photo: Conservation Council of NB)
Principal environmental impacts of salmon aquaculture
Yet fish farming brings with it a whole host of issues which, if not resolved
responsibly, will simply add one more polluting and unsustainable industry to our already
beleaguered coastal region. The experience of salmon farming in New Brunswick provides a
cautionary tale of inevitable problems if the natural rules and limits of marine
ecosystems are ignored.
In November 1997, the Conservation Council of New Brunswick published a major report
called "After the Gold Rush: The Status and Future of Salmon Aquaculture in New
Brunswick". It outlines the public policy issues to which the development of this
industry has given rise, including environmental impacts, conflicts with traditional
fisheries, lack of government regulation, and the larger ecological context of fish
farming. Here are some highlights.
Salmon Farming in New Brunswick
Introduced in New Brunswick in 1978, Atlantic salmon farming, located exclusively in
Charlotte County, began with one salmon farm producing $46,000 worth of Atlantic salmon.
Ten years later, there were 52 farms in operation in the LEtang Estuary, Deer
Island, Campobello, Grand Manan, Beaver Harbour and Passamaquoddy Bay. By 1997, a total of
83 sites were licensed (not all sites are active at this point). Another 33 sites operate
in adjacent Cobscook Bay (between Eastport and Lubec, Maine), the highest concentration of
aquaculture activity in that State, bringing the total number of large salmon farms
impacting the marine ecosystem in the relatively small Quoddy region, as the marine area
is called, to between 110 and 120 (some adjustments in this number have been made in 1998
as the industry has restructured to deal with a deadly virus). Another 45-50 applications
remain to be processed.
Industry analysts suggest that salmon farms need to produce from 200,000 to 300,000
fish to remain profitable in today's flooded market. In 1997, the average number of fish
per NB site was 70,000, although many farms are already in that "ideal" range.
One farm is reported to hold nearly half a million fish.
With annual sales now approaching $120 million and representing 95 percent of the total
value of aquaculture products in Atlantic Canada, salmon farming has been considered an
economic miracle to a region beset by seasonal employment fluctuations and declines in
wild fish stocks. As a result, governments have been reluctant to examine the ecological
costs of the industry and have failed to put into place a regulatory and policy framework
to govern the industry that would meet even minimal sustainability criteria.
(photo: Jimmy Brown)
For the first ten years salmon aquaculture was virtually unregulated. The federal
Fisheries Act gives federal DFO the theoretical power to limit or deny a proposed
aquaculture operation that may harm fish habitat, or to charge a farm for releasing
substances "deleterious to fish" into the water column. However, DFO has never
exercised those powers. It wasn't until December 1988 that the provincial government
introduced the Aquaculture Act to be administered by their Department of Fisheries and
Aquaculture. Despite the urgent need for a regulatory framework, the Act was not given
Royal Assent and declared in force until October 1991, when the Regulations to the Act
were finally prepared. By that time, there were 56 licensed farms. Even so, the Act and
Regulation do not include environmental performance standards or marine environmental
quality standards to be met by the industry.
No environmental monitoring of the industry was done until 1991. That year, underwater
monitoring by the Department of Environment of 48 farm sites confirmed all farms have some
impact on the environment. Thirty-seven of the monitored sites had moderate (29 sites) to
high (8 sites) environmental impact ratings. Subsequent monitoring by DOE (1992-93) and by
the industry itself (1995-97) had similar results. The eight worst sites (less than 17%)
were also the largest, occupying 24% of the 34.6 hectares of seabed directly impacted by
sea cages. (The impact zone used in this monitoring program included the area immediately
under the cages plus a 10 metre "zone of influence" around each cage site. Other
studies suggest this is an insufficient distance for monitoring impact.)
At heavily degraded sites, impacts included "moderate to heavy gas bubbling [these
are noxious gases such as ammonia, hydrogen sulphide, methane and carbon dioxide], the
absence of fish, invertebrates and sediment-dwelling organisms, the accumulation of fish
faeces and fish feed on bottom...or thick bacterial mats, and in severe cases, anoxia
[absence of oxygen]...." Conditions in the remaining area ranged from slight
[nutrient] enrichment to "conditions which limit the use of the sea floor solely to
low-oxygen [tolerant] species such as worms". Ten percent of the moderate impact
sites reported noxious gases being released from the sediments under the sites.
A 1997 study demonstrated nutrient enrichment/oxygen depletion problems extending far
beyond the actual cage sites, largely due to accumulated fish faeces and uneaten feed.
Such releases from salmon farms in the L'Etang Inlet, West Isles and Passamaquoddy Bay
contribute nitrogen and phosphorus to receiving waters equivalent to that contained in raw
sewage from 87,000 to 200,000 people, depending on the type of feed used (the population
of Charlotte County is 30,000).
(photo: Conservation Council of N.B.)
Diseases are an ongoing problem on fish farms. Most are treated with antibiotics. (The
only viral disease to hit NB fish farms is Infectious Salmon Anaemia (ISA) for which a
vaccine is under development). In 1989, 1.6 tonnes of antibiotics (400 grams/tonne) were
used by NB salmon farmers. By the early 1990's, average use had dropped to about 200
grams/tonne (compared to Norway's 165 grams/tonne). At current production levels of over
18,500 tonnes, 3.7 tonnes of antibiotics would be administered in fish feed. Much of this
is excreted unchanged by the fish and is deposited in marine sediments, giving rise to
problems of accumulation and bacterial resistence.
Pesticides in Salmon Farming
In 1994 and again in 1995, a serious infestation of sea lice (a naturally occurring
external parasite) in most of the farms cost the industry between $25 and $30 million in
lost salmon. The standard response to sea lice infestations is to treat salmon with
pesticides. The fish are drawn up to the water surface in tarpaulins and there bathed in
solutions of these chemicals. Once treatment is completed, the used bathing solution is
then dumped into the sea.
At the onset of the infestation, no pesticides were registered for use in the marine
environment. After intense lobbying, federal emergency registrations were granted for
hydrogen peroxide and pyrethrin (an Agriculture Canada directive says pyrethrin is
"highly toxic to fish and other cold-blooded animals" and should be kept out of
water). Cypermethrin, a pesticide toxic to crustaceans and which never received an
emergency registration in Canada, has been used illegally by some farmers. The veterinary
drug Ivermectin, a parasiticide commonly used in livestock, was also used as a feed
additive (veterinary drugs can be prescribed on a case by case basis by individual
veterinarians without prior regulatory approval. The manufacturer of Ivermectin opposes
its use in marine fish farms because of ecological and resistance concerns). Recently, an
organophosphate pesticide, azamethiphos (trade name Salmosan), has been registered for use
on salmon farms. Emergency registrations of other products have been discontinued.
In July 1996, 60,000 lobsters (over 80,000 lbs valued at $700,000) being held in a
tidal pound, before being shipped live to markets, mysteriously died. After traces of
cypermethrin were detected in samples of lobster from the pound, four companies which
owned the lobster filed notice of legal action against several individual salmon
operations, the federal and provincial departments of fisheries, and the industry
association. The case has recently completed the discovery process.
Marine Aquacultures Bigger Impact
The effect of farmed salmon on wild stocks is a topic of ongoing debate and study. In
1983, 5.5 percent of the Magaguadavic River's salmon run was comprised of escaped cultured
salmon. In 1994 and 1995, the number was 90 percent. Fish farming is also displacing
commercial fishing activity. Lobster fishermen have lost fishing ground for about 1000
lobster traps in the L'Etang Estuary alone due to the ongoing allocation of new salmon
farm leases. Scallop grounds have also been taken over.
On a more abstract level, salmon aquaculture is a net consumer of ecological support.
Primary productivity over one square kilometre of ocean surface and 5.3 tonnes of herring
or other feed fish are required to produce one tonne of salmon. Thus production of 18,500
tonnes (current) in one small area of the Bay of Fundy is already drawing down ecological
support from an area more than three times larger than the entire Bay.
Worldwide, low cost sources of protein, such as herring, jack mackerel and anchovy, are
being converted into feed to raise high cost fish such as salmon. Besides the loss of
protein inherent in this conversion process, food fish affordable to worlds most
needy are being diverted to more luxury food products. Such inefficiencies and inequities
diminish rather than enhance the role of marine fish farming in providing protein to the
Raising finfish such as salmon in open sea cages is no different than raising livestock
intensively under feedlot conditions. Inevitably, environmental and health problems will
arise on an ongoing basis. There is one important difference. The impacts of terrestrial
operations can be measured and described, and a strong lobby for alternative agricultural
models has developed as a result. The marine context is largely invisible, much less
predictable, and poorly understood. Problems are less readily observed and therefore
largely ignored by the public. Until this changes, aquaculture development is destined to
result in a net loss to marine ecosystems and to global food production.