While genetic engineering is a pervasive affront to the wildness that surrounds us, humans have manipulated Mother Nature's bounty for some time. In particular, we've developed a talent for cultivating and mixing the nearest and dearest elements of the natural world: our food. Crossing different varieties of crops and livestock has long been used to create hybrid flora and fauna that better meets our needs, suits our tastes and fills our stomachs (and wallets).
How do these subtle changes in color, texture and yield affect the other members of the ecosystem? Could an innocuous supermarket salmon steak really impact anything other than your gut? You be the judge.
*The following was adapted from "Behind That Farmed Salmon Steak," by Seth Zuckerman, in Salmon Nation: People and Fish at the Edge (Ecotrust, 1999; Edward C. Wolf and Seth Zuckerman, editors).
The sight of a whole salmon in the supermarket conjures up the feral power of these fish, which range the high seas for years until they zero in on their home river for the final chapter of their lives. They evade sea lions and grizzly bears, leap cascades and waterfalls, and couple in streams too small to contain their robust bodies. Ingest a morsel of this fish, the word "salmon" seems to promise, and it will imbue you with some of that wild strength and perseverance.
But if you eat salmon these days, you may well be consuming a product that's no wilder than a grain-fed steer. A glut of farmed salmon - amounting to roughly half of the world's supply - has flooded the market from fish feedlots around the globe. These factory farms consist of mesh pens anchored in cold-water bays and inlets in places such as Norway, Scotland, Chile, Washington State and British Columbia. The ingredients in the salmon they produce are quite different from what goes into their free-ranging cousins captured by nets or hooks.
In captivity, salmon are raised on a diet of oily brown fishmeal pellets made from inexpensive fish such as anchovetas, sardines and mackerel. Raising each pound of farmed salmon takes four pounds of those smaller fish, in effect wasting three-quarters of the catch that is processed into fishmeal. In this way, B.C. farms alone account for a loss of nearly 90 thousand tons of edible protein each year. Wild salmon flesh gets its color from the fish's prey, particularly krill, tiny shrimp-like crustaceans. But the fishmeal pellets turn the flesh of farmed salmon a pale gray. Fish farmers know that gray salmon won't sell well, so they add dye to their feed. And because salmon are natural-born predators, smaller native fish (including juvenile wild salmon) that stray into the farms don't stand a chance. Salmon farmers notice that when native oolichan (minnow-sized smelt that are important to indigenous people's diets) pass by the pens, the salmon stop eating their fishmeal pellets but "mysteriously" continue to gain weight.
Farmed fish are so densely confined that a typical one-pound Atlantic salmon is within fifteen inches of its neighbors. Diseases can spread rapidly through such packed quarters, so the fish are fed antibiotics, just like most domestic chicken or cattle. About 30 percent of the medicated feed goes uneaten; from uncontained net pens it enters the sea's food chain, where it has been found to kill natural marine algae and bacteria and cause deformities in halibut larvae. Nonetheless, the farmed fish still contract infections and are attacked by parasites. Wild stocks pick up those diseases in two ways - either from escapees, or as they pass by the fish farms en route to their spawning streams. Norwegian authorities have poisoned 24 rivers with rotenone - which kills all aquatic life - in an attempt to eradicate sea lice and a lesion-causing disease spread there by farmed salmon.
The excrement from one large B.C. fish farm equals the sewage of a city of 10,000 people - all of it flowing straight into the surrounding waters, fouling nearby clam beds and other sea habitat, at too high a concentration to be assimilated easily by natural forces. Salmon excreta are one reason that environmental activists are pushing for fish to be raised only in closed-containment systems, allowing the wastes to be treated before being discharged into the water.
Atlantic salmon have become a favorite of West Coast fish farmers, in part because they can be raised at higher densities than native chinook. These fish frequently escape from their pens into the wild. In 1997, one Washington State farm lost 360,000 Atlantic salmon in a single incident. Alien Atlantic salmon have been found to spawn successfully in Vancouver Island streams, and fishery advocates are concerned that they will compete with threatened populations of native Pacific salmon.
Instead of conjuring wildness, these farmed fish are subverting it - fouling the waters, harming native fish, and demanding that oceans be strip-mined of cheap sardines to feed aquatic livestock. But it gets worse: feedlot owners want to introduce a strain of Atlantic salmon that has been genetically engineered to mature in 18 months, half the time now needed. Some of these "Frankenfish" would escape and probably displace slower-growing wild salmon from their native streams. In time, instead of evoking the wild, salmon might come to mean destructively raised protein in a faux-wild package. The gonzo growth gene that has been spliced into the salmon distances us further from an era when fish were wild, and cooling off in the summer meant a dip in the lake, not cranking up the air-conditioner. There comes a time to decide we have strayed too far, and, like the salmon, to find our way home.