Re: "Aquaculture is the big fish that got away," Nov 25.
Wild salmon roam the seas feeding on smaller fish. Farmed salmon are fed fish meal made from sardines, anchovies and other small fish. The production of one kilogram of farmed salmon requires three to five kilograms of fish meal. The over-harvesting of this important link in the marine food chain deprives sea birds and marine mammals of their major food source, contributing to their population decline.
It makes neither economic nor ecological sense to burn fuel and generate greenhouse gases catching food for farmed salmon when wild salmon can be harvested cheaply and sustainably on their return to their native streams to spawn.
Nor is salmon farming analogous to land-based agriculture, as suggested. Farm animals are herbivores feeding on plant material, salmon are carnivores requiring animal products.
Moreover, as human populations expand and global warming affects agriculture, human meat consumption must diminish.
The open sea is more like a vast desert than an untapped cornucopia of food to be farmed to support future human populations.
And the most productive areas of the sea are near shore, where the negative impact of human activity is greatest.
Salmon farming offers an economic opportunity for a few, but its long-term impact on the human food supply will always be negative.
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