Mother Jones Magazine
November / December 2001
Title: Aquaculture’s Troubled Harvest
Author: Bruce Barcott
PEW Oceans Commission Report on Marine Aquaculture, 2001
Title: Marine Aquaculture in the United States: Environmental Impacts and Policy Options
Authors: Rebecca J. Goldburg, Matthew S. Elliott, Rosamond L. Naylor
Faculty evaluator: Bill Crowley
Synopsis by: Anthony Sult, Adam Cimino
Farmed fish provide one-third of the seafood consumed by people worldwide. In the US, aquaculture supplies almost all of the catfish and trout as well as half of the shrimp and salmon. In the early 1990s, the fledgling aquaculture industry was hailed as a remedy to the problem of marine over-fishing and the subsequent decline in jobs for fishermen. Unfortunately, aquaculture’s harm to people and surrounding environments may be greater than its highly anticipated benefits.
A recent Canadian study found that a single serving of farmed salmon contains three to six times the World Health Organization’s recommended daily intake limit for dioxins and PBCs. A salmon farm of 200,000 fish releases an amount of nitrogen, phosphorus, and fecal matter roughly equivalent to the nutrient waste in untreated sewage from 20,000 to 25,000 people. Farmed salmon (usually called Atlantic or cultured Atlantic salmon) are genetically modified to be larger and have a 50 to 70 percent higher metabolic rate. When these super-fish get into the wild they compete unfairly for food resources, causing an increased rate of starvation among wild fish.
There is also a wide range of chemicals used in aquaculture, including antibiotics, parasiticides, pesticides, hormones, anesthetics, minerals, and vitamins. The use of these antibiotics is a health risk for fish as well as people, since it promotes the spread of antibiotic-resistance in both human and fish pathogens.
Canada is a major target for salmon farming. At first, salmon farms were welcomed for the jobs they would bring. Within a few years, however, large foreign corporations bought out many of the smaller operators. As the new operators took control, farms expanded and anchored their net pens in places where wild salmon smolts rested and fed on their way out to sea. Shrimp fishermen began pulling up traps full of back muck – a gooey mixture of feces, excess antibiotic-laden fish feed, and decayed salmon carcasses that had drifted out of the pens.
Other problems persist. Piercing acoustic sirens have been installed over salmon pens to keep seals and sea lions away, the noise has caused killer whales to flee the Canadian archipelago. To rid their fish of sea lice, farmers dose them with ivermectin, a potent anti-parasitic known to kill some species of shrimp. Farmed fish contracted antibiotic-resistant stains of furunculous, a fatal disease that produces ugly skin ulcers; wild salmon that migrated past their pens also contacted the disease. Said one Canadian fishing guide, “I’ve been catching salmon up here all my life. I’d never seen a fish with a lesion until the farms came in.”
Glen Neidrauer, a game warden who patrols the archipelago for Canada’s department of Fisheries and Oceans, said,” I can appreciate the values of the jobs, but why would you jeopardize a place so pristine? We’re not just talking fish. All the birds, bears, and sea mammals depend on the wild salmon. I wonder how long you can mess with that until they finally don’t return.”
COMMENTS BY ERVAND PETERSON, PROFESSOR OF ENVIRONMENTAL STUDIES, SONOMA STATE UNIVERSITY: Human numbers continue to grow exponentially and feeding ourselves is an ever-expanding venture. The oceans today are experiencing impacts never before seen. Evidence of overfishing’s impacts continues to mount. Aquaculture has been the industrialized technology employed to grow and harvest numerous aquatic resources.
For the past 40 years, beginning in Norway, salmon have been farmed in ocean pens. Environmental regulations in Norway have driven many to the Western Hemisphere. Today the inlets of British Columbia are caged off for the farming of salmon – Atlantic salmon to be accurate. Despite promises to contain the fish, an estimated 40,000 to 1 million have escaped and are spawning in streams native salmon use. Other impacts that have been documented show “dead zones” immediately adjacent to the salmon pens. A pen of 200,000 fish produces as much fecal waste as a city of 64,000 people.
We have seen this problem before with land grown livestock. Swine farms are notorious for their environmental impacts. Now we are seeing these impacts from aquaculture in the US and Canada.
UPDATE BY AUTHOR BRUCE BARCOTT: This is merely one answer to the question that will dominate both environmental and consumer reporting in the next decade: What’s in our food?
In the case of farmed salmon, the answer is too many antibiotics and a legacy of polluted marine waters. I came away from the story fairly hopeful, because this is an issue where individual consumers, not bought-off politicians, hold the power. The equation is simple, if strangely counterintuitive: Eat wild salmon to save wild salmon. Because the farmed stuff is junk, through and through.
In early 2002, the Canadian government lifted its 7-year moratorium on expanding British Columbia salmon farms. Multinational corporations could add 10 to 15 new B.C. farm sites every year, effectively doubling the industry’s footprint over the next decade. Chile continues to dump below-market-price farmed salmon into the U.S., driving down worldwide prices and making it nearly impossible for Alaskan wild salmon fishermen, who operate sustainable, well-managed fisheries, to make a living. Meanwhile, Canadian researcher Michael Easton published a study in May 2002 that found elevated levels of PCBs in British Columbia farmed salmon. “Depending on whether you are a child or not,” said Easton, “you would be advised not to eat farmed salmon more than once a week.”
Before you get active on this issue, the best thing you can do is eat the stuff. Try a farmed salmon side-by-side with the real wild thing. You will become well informed with every forkful. Best info, pro and con, starts at Canada’s David Suzuki Foundation and the B.C. Salmon Farmers Association websites.