Salmon Farming - Takes More than It Gives Back

However, in a report for Straight News, he says that this presumptive dietary shift, coupled with the fact that the bulk of seafood caught in Canadian waters is exported, serves as the raison d’être for the development of the salmon-aquaculture industry.

“We need to meet the seafood demand” is the mantra of eager government and industry representatives who are keen to reap the associated profits. But the first question is whether or not the demand for species such as salmon, tuna, halibut, and cod is actually sustainable. Is it really possible for these species to “feed the world”, as the industry’s proponents are wont to assert, he asks.

To farm salmon, harvesting of wild fish (for example, sardines, whiting, and anchovies) for fishmeal and fish oil is required to produce the feed. A recent report by the International Council for the Exploration of the Sea suggests that deep-sea fish in the North Atlantic are being fished at more than twice the rate they can withstand to provide food for farmed salmon. While the debate over local impacts continues, the global impacts of salmon farming have received little attention in British Columbia.

Genovali then considers the ecology of farming carnivore fish such as salmon and the impacts it has on natural food webs.

"Fewer organisms can be supported as you step up the pyramid, leaving only a few predatory species at the apex. In other words, there is a reason why we only see a few carnivores in the wild; nature only has so much energy to go around. Thus, when we consider the farming of salmon against the fundamental basics of ecology, it makes no sense to claim that this practice is sustainable,” he explains.

Unsustained Displacement

Recent estimates indicate that farming salmon requires anywhere from two kilograms to four kilograms of wild fish to produce one kilogram of farmed fish. In contrast, farming herbivorous species (like tilapia and carp) requires minimal inputs of fishmeal.

With the majority of the world’s fisheries in crisis, Genovali says that scientific evidence suggests that salmon farming is hurting more than helping the global fishery problem. For example, the volume of harvested fish required to support the salmon-farming industry in Europe is larger than the productivity of the entire North Sea, requiring the industry to depend heavily on fishmeal imported from South America.

He said that leading fisheries experts — such as Daniel Pauly of the UBC Fisheries Centre — are warning against “farming up the food web”. They say it is inefficient and a wasteful use of biological resources, all of which are already used by humans and other organisms, and some of which are commercially valuable.

He also makes reference to work by ecologist Corey Peet, who points out that more than 85 percent of the world’s aquaculture production (primarily in Asia) involves the use of noncarnivorous species (freshwater fish, shellfish, and seaweed. This has resulted in global aquaculture production adding to world seafood supplies. However, while the global industry is a net fish-protein producer, aquaculture of carnivorous fish is a net fish consumer. The rapid expansion of the farming of salmon and other high-value carnivorous species (tuna, halibut, black cod) is occurring mainly in industrialised nations where the fish are primarily consumed. The reality is that the salmon-aquaculture industry is being driven by short-term economic motives and not the lofty egalitarian goal of “feeding the world”.