L'aquaculture du saumon: n'est pas un entreprise qui peut être maintenu

Aquaculture Finfish est devenue une importante industrie agro-alimentaire avec des clients sur le marché mondial; cette compagnie est capable de faire compétition aux entreprises chiliennes faiblement réglementées qui offrent de bas salaires, ainsi qu’aux gigantesques producteurs de la Norvège et de la Grande-Bretagne. 

À part les brutales rationalisations économiques imposées par la bourse des marchandises, la production industrielle de Finfish confronte de sérieuses questions environnementales et de qualité de la nourriture.

Cage of Our Own Making

Salmon Aquaculture: Not a Sustainable Venture

Janice Harvey
June 2006 

l.gif (280 bytes)n May 2006, the New Brunswick government approved the 97th salmon aquaculture site in the lower Bay of Fundy. These 97 submerged Crown land leases now stretch from the New Brunswick - Maine border including Campobello, Grand Manan and Deer Island, to just above Chance Harbour (the latest approval, Haley’s Cove, is the easternmost site).

(photo: Image Express)

From the small scale cottage industry of its origins (circa 1980), finfish aquaculture, primarily salmon but now including cod and haddock, has grown into an agri-food industry which sells its product on the world market and competes with low-wage, sparsely regulated operations in Chile and gigantic producers in Norway and Great Britain.

As it has grown, most independent producers have been driven out of business as product price plummeted and disease and parasite problems plagued the densely packed fish farms.  Through consolidations and buy-outs, Cooke Aquaculture, a St. George-based company, has emerged at the top of the pack, now owning about 60 of the 97sites (including the new approval at Haley’s Cove).

The industry’s troubles are the hallmark of all industrial agriculture operations that sell into the world market. It is no place for the small or the faint of heart.  In New Brunswick, even the mighty have fallen.  Heritage Salmon, a subsidiary of Weston Foods, and Stolt Sea Farm, a Norwegian salmon aquaculture giant recently merged with Nutreco, the world’s largest, both sold their east coast operations to Cooke Aquaculture.  Because Cooke is a private company, it is not obvious who is financing their phenomenal expansion, but all bets are on overseas money.

Besides brutal economic rationalization imposed by a commodity market, industrial production of finfish (as opposed to shellfish), like that of hogs or other livestock, brings with it serious environmental and food quality issues.  The two drivers of these impacts are scale and technology.

First, scale.  When this industry began in the early 1980s, a large salmon farm was 30,000 fish.  Today, one cage on a multi-cage farm can contain this many fish.  As with most human activity, Mother Nature can absorb and recycle waste products at a certain scale.  However, the bigger the scale, the more difficult such recycling becomes.  Eventually, Nature’s so-called carrying capacity is outstripped and the environment becomes degraded, habitat is lost, and biodiversity and productivity follow.  That is what has happened in the lower Bay of Fundy.

Second, technology.  Salmon and other marine finfish are grown in nets suspended from floating frames, usually plastic, in coastal waters.  This is referred to as open net pen systems.  Anyone wandering along the shore in the lower Bay of Fundy will have seen the ubiquitous plastic piping of all sizes, either as whole cages or in remnants, strewn about, sometimes hauled up for storage, sometimes abandoned as industrial debris.  A salmon farm is made up of several so-called cages each holding 20,000 or 30,000 fish.  Farms range in size from a few hundred thousand fish to a million fish or more.

(photo: CBC)

The problem with open net pen technology is that all the waste from these industrial operations is discharged directly - untreated and undiminished – into the coastal waters. This waste is made up primarily of fish faeces and urine, and waste feed.  This is not an unsubstantial waste stream.  For every tonne of salmon raised, 200 kg of solid waste is produced, most of which is faeces.  Liquid waste is completely unaccounted for.  Total annual production in New Brunswick has ranged in recent years between 30,000 and 40,000 tonnes, which in turn generates between 6,000 and 8,000 tonnes of solid waste discharged directly into little coves and bays along the lower Fundy coast.

This waste creates several problems.  The organic material settles out on the bottom, and where currents don’t keep it scoured, builds up forming bacterial mats which deplete oxygen and kills the little critters that live on and in the bottom sediments - the base of the marine food chain.  This bacteria creates the conditions under which hydrogen sulfide gas, which is toxic to fish, forms and off-gasses into the water column.

Further, solid and liquid waste from fish farms contains high levels of nitrogen compounds. Like phosphorus in fresh water, nitrogen fertilizers the marine environment, creating algal blooms in the water.  When these blooms die, the decomposition process uses up oxygen, robbing it from marine species that need it. This so-called eutrophication process results first in species changes and then species loss as the nitrogen loading continues. DFO research has revealed that the Bliss Harbour - Lime Kiln Bay area near L’Etete, where salmon aquaculture sites are most dense, is eutrophied and has suffered a measurable loss of biodiversity.

Other signs of eutrophication in fish farming areas include the loss of the red species of seaweed and the presence of bright green mats of enteromorpha, a nitrogen-fed fast growing annual algae that wreaks havoc on the intertidal zone and beaches. A recently published study has also demonstrated that under eutrophic conditions, elemental mercury which is relatively inert, changes to methyl mercury which is quickly absorbed by animals, creating mercury accumulation in the marine food chain.  This process has been found in Passamaquoddy Bay in particular.

(photo: Boris Worm)

DFO research has also revealed the presence of antibiotic resistant bacteria in the vicinity of salmon farms. This is the result of antibiotics which have been administered to control salmon diseases being excreted by the salmon and discharged into the water column. Sea lice, a parasite which flourishes in a fish farm situation, is generally treated with systemic drugs of the ivermectin-avamectin-emamectin family which are also excreted into the environment with the potential to harm marine life.

Scientists have also found that only 10 percent of all solid waste discharged from salmon farms actually remains within the farm site.  The vast majority drifts offsite.  Yet environmental regulations only require fish farmers to monitor bottom conditions on the farm site itself.  Most of the impact remains unmonitored and therefore unquantified.

Even so, the annual monitoring program which measures oxygen and sulfide gas levels under the cage sites, routinely finds about one-third of all sites to be hypoxic or anoxic.  These are levels at which 60 to 90 percent of the different species found in the sediments are wiped out.

Salmon aquaculture is only viable economically as long as companies can discharge waste untreated directly to the ocean.  While the cost is externalized to the industry, there is a steep price to pay – polluted water, loss of marine biodiversity, coastal dead zones, and a contaminated marine food chain.