feature

Good Fish, Bad Fish

A Catch to the Catch of the Day

John McCosker

Commercial fishermen with a catch of rockfish. Photo by John McCosker.

Growing up, after the loss of a sweetheart or a baseball game, I was comforted when my parents said “Oh, don’t worry, there are plenty more fish in the sea.” That soothing aphorism may soon join the passenger pigeon in the Smithsonian as its veracity plummets, along with most of the world’s fish stocks.

In North America and Europe, except for an occasional meal of deer, duck, trout or bass, we have largely given up hunting for our food. Only from the sea do we still regularly capture our fare from nature. But two or three decades ago, we rapidly began to exceed the endowment income of this resource and are now consuming the precious capital. More than 70 percent of the world’s fish stocks are overfished, depleted, or worse—extinct—as a food resource.

To begin with one of the most egregious examples, where have all the orange roughies gone? Sounding like the flowers in a Peter, Paul and Mary tune, the orange roughy came and are now nearly gone in a generation. Previously known by the less-palatable name “slimeheads,” roughies are deepwater reef fish that first appeared in the New Zealand market in the early 1980s. With white, flaky, delicious meat, they rapidly ascended to the top of shopping lists and tony restaurant menus in both America and Europe.

After a decade of dragging trawls over the tops of deepwater seamounts, catches plummeted. When puzzled fishery biologists took a more careful look at the roughy’s life history, they discovered that it doesn’t mature until age 30 and can reach 170 years of age or more. Equally shocking was the discovery that some of the coral broken off by the trawlers was 500 years old.

Until recently, the Chilean sea bass, a species which is not related to true sea basses or other saltwater basses, was known as the Patagonian toothfish, another name which lacked cachet. Like the roughy, it is a deepwater fish with a slow growth rate. But its flesh is firm and tastes good, so it is experiencing gold rush fishing pressures. It, too, has a gloomy future. Caught mostly by illegal longline fishers who also drown more than 100,000 albatrosses and other seabirds each year as bycatch, its days on Western menus are numbered.

Learning that Pacific but not Atlantic swordfish can be eaten in good conscience, or some shellfish such as Olympic oysters and New Zealand green mussels are okay, but not quahogs or geoducks, you are probably rolling your eyes and asking how someone other than a marine biologist can tell the difference. Most can’t. The World Wildlife Fund and others are hoping to aid consumers by developing a “green label” to be attached to sustainable fish products. The program will run much like the successful “dolphin-safe tuna” label campaign. But until then, the best solution may be to cultivate a relationship with a trustworthy fishmonger or restauranteur.

What, then, can you consume from the sea in good conscience? Hold your lemon and read on. Generally, those aquatic creatures that are small, fast-growing, highly fecund, and mate while still young are the best food choices. Prime examples are sardines and squid. The least sustainable fisheries are slow-growing and late-to-mature species that produce few offspring, such as great whales, sea turtles, and pelagic sharks. The means of capture is equally important. If the method is targeted and unlikely to harm other fish, like crab pots, it’s good. If it’s a shrimper dragging a trawl that destroys the bottom like a highway grader, it’s ridiculous. Between these extremes lie many edible opportunities.

So are aquaculture and mariculture the solutions to the overfishing dilemma? Aquaculture has increased so dramatically in the last decade that nearly a fourth of the world’s fish products are purchased from farms and hatcheries. Aren’t farmed salmon and shrimp abundant, inexpensive, and a way to ease pressures on wild seafood?

Unfortunately, no.

At first blush, it would seem that hatchery-reared and farm-raised fish and invertebrates would relieve the pressure on wild stocks, but in reality they are far from a piscine panacea. For desirable species such as salmon and shrimp that reside high up the food chain, several pounds of fish flesh are required to raise a pound of product. As a result, ocean stocks are inevitably reduced in the process.

Aquaculture works best for species that consume plants or don’t require protein- rich diets, such as carp, catfish, and tilapia. Rearing some shellfish species can help purify water by filtering out algae and waste. If the impoundments are inland and well contained (rather than in or adjoining the sea), they cause only limited damage to the environment. When done well, fish rearing and processing jobs are created, the public is fed, and wild fish find relief.

But if aquaculture is done badly, consumers, the fish, and the environment are the poorer for it. While the pollution of nearby waters and the escape of farmed stocks into the wild are the biggest downsides of fish farming, the pitfalls of poorly planned, high-density aquaculture are many. These problems are graphically illustrated by two of the most popular types of farmed seafood: salmon and shrimp.

Perhaps the greatest ichthyological irony concerning salmon is their current abundance. Salmon are available in markets and restaurants year-round in most American and European cities, prompting incredulous consumers to ask, “what salmon problem?” The current glut is the result of pen-reared Atlantic salmon, an industry that’s practiced in British Columbia, Washington state, France, New England, Chile, Argentina, Tasmania, and Scandinavia. Some farms are making profits, but if the balance sheet honestly identified all the current and future costs, it is unlikely that buyers could afford these fish. The actual cost of raising them might well be an order of magnitude greater.

Atlantic salmon are raised in high-density populations in floating pens in bays and fjords. They are fed a high-protein meal laced with antibiotics that eventually end up in the sediments. When the sediments become anoxic from the accumulation of feces, uneaten food, and pesticide residues, which poison the adjacent water column, the pens are moved to a pristine location and the pollution process continues.

Worse is the damage to native salmon populations. Farm pens are not escape-proof, and damage caused by seasonal storms and marauding seals have resulted in hundreds of thousands, perhaps millions, of salmon escaping—with disastrous results. Nightmare scenarios are already occurring. Farm-raised salmon bred for qualities other than the hardiness needed in the wild have interbred with and so sullied the genomes of wild salmon in Maine and Norway that entire stocks may not urvive. This, combined with the precariously low populations of wild fish from runs in Maine and other areas, supports the report of Andrew Goode of the Atlantic Salmon Federation that wild fish were outnumbered 1,000 to 1 after two escapes last fall.

Infectious salmon anemia, an incurable virus, has spread from salmon farms in Norway to Scotland, New Brunswick, and Maine. Diseases of Atlantic salmon have recently infected Canadian Pacific species unable to resist the pathogens. Independent Canadian researcher Alexandra Morton has reported that in 1991, Atlantic salmon escaped from Vancouver Island farms and passed furunculosis, a bacterial infection, to native coho salmon stocks. Two years later, cohos were found infected with antibiotic-resistant furunculosis—the inevitable consequence of the massive quantities of antibiotics applied to high-density aquaculture operations. Tragically, the cohos, along with wild king salmon stocks, crashed and have yet to recover.

Finally, the development of transgenic Atlantic salmon has entered the ecological equation. By inserting the genes of Pacific salmon and ocean pout (a distant salmon relative) into Atlantic salmon, researchers have succeeded in creating a fish that grows twice as fast. These so-called “Frankenfish” produce growth hormones year-round, unlike the normal pattern of their species that limits hormone cycling to the warmer summer months. Purdue University biologists William Muir and Richard Howard have hypothesized a worst-case scenario about transgenic salmon known as “the Trojan gene effect.” Their model predicts that escaped transgenic males would attract a greater share of wild female mates when they escape from their pens because they are bigger and initially healthier. But because their offspring would be less resistant to disease and genetically unfit to survive, the interbreeding would result in the extinction of wild salmon populations.

Farming transgenic salmon raises many of the same fears and concerns associated with genetically modified crops. The long-term consequences to health and the environment remain undemonstrated.

At $8 to $10 billion a year, shrimp and prawns account for the largest category of the world’s seafood market. About half of the shrimp on world markets is caught by trawler boats that drag their nets across the bottom. The remainder is farmed in bays and along shorelines, largely in the tropics of the Third World. A small percentage of the market includes prawns captured by traps in a sustainable manner. These include California spot prawns and Atlantic northern pink shrimp, and are appropriate to consume. Shrimp trawling, a century-old tradition, has declined as shrimp farming, barely 30 years old, undergoes an explosive expansion. Both practices contribute to widespread environmental damage.

Mike Hagler of Greenpeace recently completed an extensive study entitled “Shrimp—The Devastating Delicacy.” He concluded that the true costs of “all the shrimp you can eat” markets in America, Europe, and Japan are being paid by poorer people living in coastal areas in countries such as India, Bangladesh, Thailand, Honduras, and Ecuador. Japan and America currently consume one third of the world’s marketed shrimp, but as prospects for China’s growing middle class improve, an increase in this burden is inevitable.

The destructive nature of shrimp rearing is compounded by its disastrous effects on mangroves, tropical trees whose stiltlike roots form dense thickets along tidal shores. Mangrove forests offer key nursery grounds for many fish and invertebrates. By the year 2000, more than half of the world’s mangrove forests had been destroyed; half of that was due to shrimp farming, a practice equivalent to the clearcutting of coastal forests. The destruction is accelerating even as you read this. Nils Kautsky from the University of Stockholm says that the “footprint,” or sphere of influence, of a fish or shrimp farm on the local environment can be 50,000 times larger than the farm itself. And the chemical and mineral modifications caused by the shrimp make the abandoned farms useless for other crops.

The downside of shrimp trawling is less apparent than that of shrimp farming, but equally depressing. Imagine a fleet of 13,000 boats dragging nets that scrape the bottom of the Gulf of Mexico. Besides the shrimp, a wasteful bycatch of mackerel, snapper, croaker, and a host of other creatures is netted, causing them to steadily decline. A more appropriate term would actually be “bykill.” Worldwide, shrimp fisheries discard 9.5 million metric tons of dead and dying non-shrimp creatures—including many endangered marine turtles—at a ratio often as great as ten pounds of bycatch to one pound of shrimp.

So until these practices change, avoid eating shrimp entirely unless you can be sure they were caught with traps. They cost more, but the alternative is a higher price to pay.

Many conservation-minded organizations are leading the charge to inform consumers about the ecological significance of their next meal. The National Audubon Society’s Living Oceans Program, the Natural Resources Defense Council’s “Give Swordfish a Break” program, the Environmental Defense Fund’s Environmental Scorecard, the Monterey Bay Aquarium’s Seafood Watch, and the Marine Stewardship Council provide timely brochures and advice on the Internet. The recently formed Seafood Choices Alliance provides an exhaustive listing of appropriate seafood for both consumers and restaurateurs on the web at www.seafoodchoices.com.

Retail seafood outlets are beginning to take notice of fishing’s environmental costs. Although Chilean sea bass has been one of its most popular items, Whole Foods Market announced that they would stop selling the fish until fishing methods and fish stocks improve. And some of the country’s finest restaurants now subscribe to Seafood Choices so they can make informed decisions about the seafood they serve.

The current list of sustainable, edible marine species is not long. Unless consumers convince fisheries and the governmental agencies that manage them to respond wisely, the list is likely to become even shorter. And as more and more species approach commercial extinction, they will come to be found only in the most exclusive restaurants—and aquariums.

Eat wisely. And bon appetit.

John McCosker is the former director of Steinhart Aquarium and the chair of Aquatic Biology at the California Academy of Sciences.