Scaling the fish issue
According to the United Nations, approximately 75 percent of the world’s fish stocks are fully exploited, overexploited or depleted, and at least one quarter of U.S. fisheries are overfished, writes Lauren Lindstrom.
Her article, published in the American Dietic Association, says that another study predicts that if this trend continues, 90 percent of all wild fisheries will be depleted by the middle of this century.
"The diminishing of wild stocks has catalyzed large-scale growth in aquaculture, which supplies more than 40 percent of fish eaten by consumers." She writes. "Although theoretically aquaculture should help to relieve pressures on wild fisheries, the realities of some farming practices often fall far short of these promises. In fact, certain types of aquaculture can contribute to biological, nutrient and chemical pollution."
"Certain types of aquaculture can contribute to biological, nutrient and chemical pollution."
For instance, typical salmon farms raise Atlantic salmon in open pens on coastal waters, allowing fish waste to pollute the surrounding waters.
Additionally, much like conventionally raised terrestrial livestock, farmed fish are often very densely stocked, creating conditions for parasites and diseases to readily multiply. To remedy this, antibiotics and other chemical treatments are administered into the water or through feed.
And because Atlantic salmon are natural predators, they are fed high levels of fish oil and meal, which primarily consist of wild-caught fish. For these reasons, salmon farming contributes to, rather than alleviates, the pressures on global fish stocks. Well-run aquaculture facilities are designed to minimize their environmental impact. These kinds of farms often stock species low on the food chain, use closed systems to recycle water and do not discharge untreated wastes. Seafood from such facilities includes mollusks (clams, oysters, mussels and bay scallops), tilapia from US farms, striped bass, arctic char and catfish.
While fish farms strive to supplement the world’s fish supply, wild-caught fish can still be on the menus of conscientious consumers. Well-managed fisheries utilize sustainable capture practices, do not damage fragile marine ecosystems and provide conservation incentives for fishers. And wild fish such as Atlantic mackerel and Alaskan salmon make healthy and environmentally friendly meals.
According to Mrs Lindstrom tne misconception is that “local” or domestic food is automatically an environmentally preferable choice; however, seafood from an unsustainable local fishery may actually leave a larger ecological footprint than fish that have been transported from further away.
Transportation mode is a critical factor. According to the US Department of Commerce, more than 80 percent of the country’s seafood is imported, she says, making local seafood difficult to actually procure. "Flying fresh fish by air freight contributes substantially more to greenhouse gas emissions than sending frozen fish across the ocean by container ship."