Salmon steak at $7 a pound is the kind of grocery bargain that makes consumers smile. It’s a slab of protein, it’s heart healthy and the price seems to keep dropping.
Americans are buying more seafood than ever, but they may not know that the bargain-priced salmon or the all-you-can-eat shrimp dinner at the chain restaurant is raised on a fish farm.
As aquaculture has become the wonder child in U.S. agriculture, environmentalists and concerned chefs are voicing concerns about the hidden costs of raising seafood.
Aquaculture simultaneously spawns big hopes and equally big fears. Water is plentiful and free, but is easy to abuse and difficult to keep clean, observers say. Because fish have extremely high reproductive rates (a catfish lays up to 3,000 eggs at a time), they are an easy commodity to raise. But their waterborne wastes can quickly spread to the surrounding ecosystems.
“The health of aquaculture is an indicator of the health of our existence on the planet,” said chef Greg Higgins, owner of Higgins Restaurant & Bar in Portland, Ore. “It’s connected to water quality. It’s a deeply complicated system.”
Higgins addressed a recent conference here of Chefs Collaborative 2000, an organization of 1,200 chefs and growers dedicated to sustainable agriculture and cuisine.
Aquaculture has boomed worldwide, fueled by demand in the United States and other affluent countries. Almost all catfish and rainbow trout consumed in the U.S. are farmed within the country, according to the USDA. Half of the shrimp and a third of the salmon consumed in the U.S. come from fish farms, agricultural economists say. Farmed shrimp comes almost exclusively from overseas. Fish farms are found in all 50 states, raising more than 100 species, but most concentrate on catfish, trout, salmon, tilapia and hybrid striped bass. In shellfish, the top farmed categories are oysters, crawfish and clams.
Aquaculture can be a source of chemical and biological pollutants and nutrient wastes, Rebecca Goldburg of the Environmental Defense Fund said at the same conference. The dumping of wastes from tanks or the free flow of wastes from open ocean systems, called net pens, play havoc with the environmental balance by depleting oxygen, stressing or killing surrounding marine life.
Goldburg warned that fish waste, like livestock waste, might create elsewhere the same kind of “dead zone” that exists in the Gulf of Mexico. “There is evidence that the zone is due to huge amounts of nutrient waste from hog and chicken farming,” she said.
Net pens are especially harmful. “Building a net pen is like building a very tall smoke stack,” Goldburg said.
Government and industry officials do not take such a dire view, saying that the industry is regulating itself. But aquaculture waste is “a concern for industry and government,” said LaDon Swann, aquaculture extension specialist with Purdue University and the University of Illinois.
“There’s a lot of research going into more efficient feed,” he said, to minimize nutrient waste. In addition, the federal government does have discharge guidelines, and some states’ standards are even tougher, he said. In some cases discharge from fish farms is cleaner than stream water, he said. But Swann acknowledged that current filtration systems are too expensive for small farms.
Aquaculture is here to stay, the experts said. In many cases, it helps local economies and the environment. Shrimp aquaculture in developing countries is “taking pressure off the land by giving a better way of life to farmers. They’re not clear-cutting (forests) and subsistence farming,” said David Wills of the Peat Institute Environmental Programs. Wills, who consults on environmental issues for corporations, says these companies look for sustained growth and therefore are farming fish in ways that maintain the environment and social growth.
Intensive fish farming increases the use of antibiotics, pesticides and colorants, said Portland chef Higgins. Residues of those chemicals may be on seafood and left in the water, he said. Goldburg said antibiotics are used to control disease, and pesticides are used to control weeds, algae and parasites. Often, farmers apply these chemicals by putting them directly in water, she said.
Higgins posed the question: “What are the residuals brought to our tables, and are we returning water the way we found it?”
There is also the danger of so-called “biological contamination.” Farmed fish escape from net pens and breed with or compete with wild stock, Higgins said. “Non-indigenous fish can escape and dilute the local gene pool. They can disrupt the spawn cycle of native salmon,” he said.
Farmed Atlantic salmon have escaped from net pens to breed with the wild salmon, threatening their survival. The wild species may soon be listed under the Endangered Species Act, Goldburg said.
Salmon farming is more of a problem because the fish is a carnivore. It has to be fed anchovies, herring and sardines, all wild food fish. Estimates of the fish protein needed to raise 1 pound of salmon range from 3 to 5 pounds, Goldburg said.
“Feeding fish to fish leads to a net loss of protein in a protein-short world,” she said. Furthermore, catching wild fish to feed farmed fish leaves less food for wild, predatory fish, Goldburg said.
Aquaculture can be environmentally friendly, profitable and feed the world at the same time, Goldburg believes. The aquaculture industry should learn from countries such as Norway, Ireland and Chile, which have halted salmon aquaculture from time to time because of disease, overproduction or environmental degradation.
According to Norwegian fisheries consul Stein Owe in Washington, Norway has limited licensing for salmon fisheries as well as the sale of feed since the 1980s to control production. Norway is the largest producer of farmed salmon in the world: In 1997 it sold 320,000 metric tons, Owe said. But the issue of interbreeding between domesticated and wild species is still a controversy there, he said.
Regulation teamed with science may be able to unlock the potentials of a sustainable aquaculture. The World Bank continues to invest in shrimp farming, as it has since 1984, especially in Asian countries, said Ron Zweig of the bank’s Rural Development and Natural Resources Unit. In 1997, it spent $450 million on shrimp farming, the bulk of which was directed at reclamation, Zweig said.
The governments of India and Thailand, for example, are creating controls since they halted shrimp farming because of disease, abandoned sites, salinization of drinking water, loss of mangrove forests and the undercutting of fishermen’s livelihoods. Some of the bank’s assistance goes toward new, sustainable ventures.
