Fire / Feu

du saumon au Nouveau-

L’aquaculture s’est développée en réaction au déclin des populations de poissons. D’après 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 l’environnement.

Au rythme actuel de production au Nouveau-Brunswick, près de 3,7 tonnes d’antibiotiques sont intégrés dans la nourriture des saumons au cours d’une année. Les excrétions se déposent ensuite dans les sédiments marins et contribuent à l’accumulation et à la résistance bactérienne. En 1994 et 1995, afin d’éliminer une infestation de parasites marins communs, de nombreux produits toxiques ont été jetés dans la mer.

Il est très difficile de mesurer l’impact de telles pratiques dans la mer, ce qui n’est pas le cas avec l’élevage, d’où, sans doute, le peu d’attention portée au problème.

After the Gold Rush:
The Status and Future of Salmon Aquaculture in New Brunswick

Janice Harvey
Marine Conservation Director,
Conservation Council of NB
October 1998

w.gif (482 bytes)ith the global decline of many commercial fish stocks, fish farming is increasingly touted as the world’s 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 shelves.

aquac.jpg (18199 bytes)
(photo: Conservation Council of NB)

Principal environmental impacts of salmon aquaculture
in N.B.

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 L’Etang 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.

weir.jpg (28550 bytes)
(photo: Jimmy Brown)

Government Regulation

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.

Environmental Impact

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).

Aquaculture Cages

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(photo: Conservation Council of N.B.)

Sick Fish

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 Aquaculture’s 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 world’s 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 world’s population.

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.


The Conservation Council’s report, After the Gold Rush, can be ordered for the cost of copying and shipping by email: