Yet other forms of aquaculture—some of them centuries-old—are proving to be more compatible with the environment. In California, Baja California, Oregon, and Washington, several varieties of seafood are being produced without harming wild marine life or wild waters. “Eco-friendly” entrepreneurs are growing oysters, sturgeon and caviar, striped bass, tilapia, and saltwater shrimp. Some farm leased tidelands, others cultivate their stock in closed land-based systems. Such sustainable aquaculture promises to play an important role in our seafood future.

In the northern part of Humboldt Bay, Coast Seafood Company raises oysters on longlines, polypropylene ropes that wind around vertical plastic pipes set in the substrate. Unlike farmed shrimp and salmon, these shellfish don’t require artificial feeds. They filter their food source, phytoplankton and nutrient-rich detritus, from the surrounding water column.

Coast used to grow on the bay bottom, as many oyster farmers still do, harvesting with hydraulic dredges. One of the major oyster growers in California, the company currently farms 370 acres of tidelands it owns or leases from the Humboldt Bay Harbor and Recreation District. Hydraulic dredging tears up valuable eelgrass beds, critical habitat for many bay creatures, and otherwise disturbs life on the bay bottom. Silt raised by dredging can reduce water clarity and clog gills of fish. Six years ago, as tighter federal and state regulations were imposed in an effort to prevent such habitat damage, Coast decided to shift to longlines. By so doing, Coast not only avoids harming eelgrass, it has also gained a significant economic advantage. The longlines put the oysters out of reach of rays, crabs, and other predators that feast on bottom-grown oysters. “We used to lose up to half our crop to bat rays,” recalls Coast operations manager Greg Dale. “We put a lot of effort into erecting underwater fences to deter the rays. With the longlines, we don’t worry about rays or underwater fences.”

The economic survival of oyster growers depends on clean water, because oysters are filter feeders. When excessive pollution is detected, harvesting is shut down. Oysters were cultivated in San Francisco Bay early in the last century, until sewage flows contaminated the crop and shut down the industry. Today growers only cultivate oysters in areas that the California Department of Health Services (DHS) has certified as safe. Growers in Humboldt Bay, Tomales Bay, Drake’s Estero, and Morro Bay work closely with DHS and with State regional water quality boards to identify and clean up sources of pollution, from leaky sewage lines to sloppy storm drains.

“The cities of Arcata and Eureka now use video cameras to spot leaks in sewer lines that can contaminate our oyster crop,” says Cole. “In a process called sliplining, they insert plastic liners in old clay sewer lines to stop damaging leaks.” By working together to maintain a high level of water quality, the growers, regulators, and bayfront communities like Arcata and Eureka ensure that California can produce over ten million pounds of farmed oysters annually, with a value of $7.5 million.

(State and local officials have not been as successful in controlling bacterial contamination in Carlsbad’s Agua Hedionda Lagoon. Farmed mussels and oysters harvested from this lagoon must be placed in trays and immersed in purified seawater for 44 hours to purge contaminants. In a March 2002 report, DHS recommended increased monitoring of storm runoff into the lagoon to see if further harvest restrictions, including rainfall closures, may be required.)

Oyster and mussel growers outside of California are just as interested in protecting water quality. Last year, thanks to a crackdown on polluting storm drains, Washington State growers regained a 30-acre shellfish-growing area in Puget Sound. On the Pacific coast some 180 miles south of the California-Mexico border—where you know you’re in oyster country when the dirt road becomes paved with oyster shells—growers recently teamed up with a cross-border environmental organization, Pro Esteros, to stop approval of a proposed massive resort that threatened to pollute the pristine waters of San Quintín Bay. One of the would-be developers was a U.S. realty firm, Century 21. “With our bay protected, we produce 1,200 metric tons of oysters each year,” says Vicente Guerrero of Agromarinos, one of the largest oyster growers. “We employ 120 people. We are one of the main employers in the San Quintín area. And our jobs are permanent, not temporary.”

Efforts to protect coastal water quality are paying off for West Coast growers. With disease and pollution plaguing native oyster grounds along the Atlantic coast and the Gulf of Mexico, the demand for farm-grown Pacific coast oysters has been rising. To capitalize even more on clean growing areas, Puget Sound growers are now branching out to other shellfish species. They are cultivating the world’s largest burrowing clam, the native geoduck (pronounced gweeduck), whose range extends into northern California. Wild stocks of this creature, which weighs up to 20 pounds, are under pressure from commercial divers and from illegal poaching rings, mostly for the Japanese market, where the geoduck fetches $10 a pound. Washington growers are also learning to cultivate a smaller oyster native to our Pacific coast, the Olympia, on a small scale.

Meanwhile, another form of eco-friendly aquaculture is flourishing amid the arid desert expanses of California’s Imperial County. In the shadow of the Chocolate Mountains, Pacific Aquafarms raises tilapia, a tropical freshwater fish native to Africa, in self-contained ponds of geothermal water. The use of this warm water not only “reduces the demand for Colorado River water,” says Aquafarms president Bill Engler, but also extends the growing season into the cooler winter months. Because tilapia is an herbivore and does well on feeds that use soybeans and other plant proteins, it costs half as much to feed as salmon and shrimp, which require feeds high in marine-animal proteins.

Down the road from Pacific Aquafarms, near the town of Niland, Fish Producers raises another natural herbivore, catfish, also in desert ponds. Although catfish growers in Mississippi and other southern states have been hit hard by cheaper imports of frozen basa fillets from Vietnam, (basa is a fish that tastes and looks like catfish) the cheaper imports have “no impact on us” according to George Ray of Fish Producers.

The desert growers sell their product live to some 100 Asian markets throughout southern California. Customers in these markets like their fish as fresh as possible. They even like to view their prospective meal live in display tanks before making a selection. Typically, the Asian markets have stocked their display tanks with Pacific rockfish. Now, however, with severe fishing restrictions making rockfish hard to get, the Asian markets are turning increasingly to farm-grown catfish, tilapia, and striped bass, another fish raised in desert ponds near the Salton Sea. Fish Producers and Pacific Aquafarms supply a combined two million pounds of live fish each year to the Asian markets. As Pacific rockfish winds up in the “avoid” column on environmental seafood lists, farmed catfish, tilapia, and striped bass earn a place on the “best choice” column.

Also in these display tanks and on “best choice” lists is farmed sturgeon raised in California’s Central Valley. For 15 years, Ken Beer of the Fishery has been raising white sturgeon, a California native, in tanks on his 600-acre farm complex 20 miles south of Sacramento. By reusing well water pumped into and then, as wastewater, out of his sturgeon tanks, Beer also raises catfish and carp. The wastewater is carried by canal from the tanks into the catfish and carp ponds. In some ponds, catfish and carp are raised together in a process called polyculture. The carp subsist on algae nourished by nutrient-rich catfish wastes. “The polyculture ponds have the highest production rates, but they are harder to harvest by net. You have to sort out the different fish species,” explains Beer. Wastewater that remains after the trip through the tanks and the ponds is used to irrigate and fertilize nearby corn and alfalfa fields. Besides selling to Asian markets, Beer sells his sturgeon to processors that distribute to restaurants.

More recently, in an agreement with nearby Stolt Sea Farms, Beer has been producing caviar from eggs harvested from his mature female sturgeon. Currently, his sturgeon produce about three tons of caviar a year, which Stolt processes and markets. (We will revisit Stolt below.) California’s farmed caviar now competes with imported Caspian Sea caviar that is produced from endangered wild stocks. Articles in Gourmet magazine and the New York Times have mentioned California farmed caviar as an eco-friendly alternative to the imported version. In San Francisco, upscale restaurants such as Jardinière will only serve the farmed roe. Russian caviar producers can expect increased competition. “In the near future, California growers expect to produce 75 tons of caviar, which is roughly equal to the amount the United States imports,” says Beer.

Double-crested cormorants, which tend to outwit “bird-dissuasion” tactics, are enjoying a population boom stimulated in part by the nationwide proliferation of nutritious fish ponds. Beer has a federal permit to shoot up to 50 cormorants a year if other control methods fail. (In 13 southern states, catfish farmers no longer need to obtain such permits from the U.S. Fish and Wildlife Service. The Service estimates that cormorants here consume about $20 million worth of catfish fingerlings each year.)

Land-based fish culture is an ancient practice, in which China has long been the leader. Today 65 to 70 percent of the world’s annual aquaculture production is in China.

Taking a cue from China’s experience, several U.S. states besides those already mentioned are learning to become players in aquaculture. Landlocked Arizona is growing saltwater shrimp in desert ponds. Growers there have learned to acclimate Pacific white shrimp to moderately saline groundwater. The shrimp pond effluent is then used to irrigate olive and citrus groves, instead of winding up in coastal waters. The isolated nature of the desert ponds and use of pathogen-free broodstock helps these growers avoid the disease outbreaks that plague coastal shrimp growers. The Aquatic Pathology Laboratory at the University of Arizona has assisted growers in developing pathogen-free stocks. To extend the growing season into the winter, the Laboratory is developing a pathogen-free coldwater shrimp stock originally imported from China.

Kentucky encourages its farmers to grow catfish, tilapia, and freshwater shrimp in ponds, as an alternative to growing tobacco. And in Florida, saltwater shrimp ponds are popping up next door to inland citrus groves and sugarcane fields. Using pathogen-free groundwater pumped up from limestone strata, OceanBoy Farms is producing a million pounds of shrimp annually. One enthusiastic OceanBoy customer is Wegman’s, one of the state’s large supermarket chains. David McMahon, a former Army ranger and investment banker, is principal investor and CEO of OceanBoy. He stocks his shrimp ponds with tilapia that graze on plankton nourished by shrimp effluent. He is also working with a major feed company to develop a shrimp feed that contains no marine-animal protein. (Soybean growers in the United States would benefit handsomely if plant protein displaced fishmeal in feedstocks.) McMahon’s goal is to become owner-operator of the largest shrimp farm in the United States by 2003.

Some of the biggest investors in salmon net-cage culture are beginning to appreciate the advantages of land-based aquaculture. As farmed salmon production soars and salmon prices decline, salmon growers find themselves in a financial squeeze. Stolt Sea Farms, a subsidiary of the Norwegian conglomerate Stolt-Nielsen, operates a global network of salmon farms. Because of the price squeeze and disease outbreaks in its farms in Canada, Maine, and Chile, Stolt Sea Farms reported a loss of $11 million during its second business quarter in 2002. However, its sturgeon farm venture near Sacramento is turning a modest profit. (On its website, Stolt extols its farmed sturgeon caviar as an eco-friendly alternative to Caspian Sea caviar.) Also doing well is a tank farm in Spain that grows a premium marine flatfish, turbot. To offset its big-time losses on salmon, therefore, Stolt plans to expand its land-based farm ventures.

A high-tech version of aquaculture promises to encourage the shift to sustainable land-based fish farms. In an industrial building in Huntington Beach, Scientific Hatcheries produces up to 20 million fish a year in a closed-cycle or recirculating system. In this system, water flows through fish-growing tanks and then into biofilters that cleanse the water of fecal material, feed particles, and other pollutants; the purified water is then re-oxygenated and returned to the growing tanks. A recirculating system conserves water, avoids wastewater discharges, and minimizes the transmission of disease. By being indoors, this system avoids the problem of fish-eating birds. The system, however, requires more energy than pond culture. To help pay for rising energy bills, Scientific Hatcheries specializes in a niche market. “We raise ornamental fish for the aquarium trade and small fish used in research and science education,” explains owner Dallas Weaver. What happens to his indoor fish crop during a power blackout? “We have an emergency system to pump oxygen into the tanks to keep our fish alive,” says Weaver.

Closed-cycle systems are being used worldwide to raise seafood that fetches a premium price. In the Netherlands, growers raise marine eels, a European delicacy, in closed-cycle systems. In Australia, growers have adapted the Dutch system to raise a popular saltwater fish, the barramundi. In June 2002, Agrimarine Industries of Campbell River, British Columbia, sold its first harvest of salmon raised in a land-based, closed-cycle system to a supermarket chain on Vancouver Island. The 28,790 tank-raised salmon fetched a premium price—20 percent more than salmon raised in ocean pens. In California, UC Davis researchers are rearing juvenile California halibut in a closed-cycle system. A larger prototype system that could foster commercial culture of this popular fish will be built at the UC marine laboratory on Bodega Bay in 2004, according to UC Davis Professor Douglas Conklin. The environmental advantages of closed-cycle systems even impress leading seafood buyers. Bill Herzig, a vice president of Darden Restaurants (the Red Lobster chain), writing in a trade publication, the Advocate (August, 2000), observed, “It would appear that an industry evolution toward closed systems is the solution to eliminate pollution and reduce the risk of disease.”

Regulatory reforms that crack down on the environmental shortcomings of marine aquaculture will soon make closed-cycle systems and pond culture even more competitive. The Environmental Protection Agency is developing national guidelines to regulate aquaculture discharges into our waterways.

As America’s taste for seafood expands, so does the need for sustainable aquaculture that can help meet this demand. As shellfish growers along the Pacific coast and fish growers in the desert demonstrate, we can grow healthy seafood without sacrificing critical habitat and polluting our waterways.

WESLEY MARX enjoyed barbecuing live oysters from San Quintín Bay on an impromptu beachside grill while preparing this article. He is author of The Frail Ocean, rev. ed. 2000. His e-mail address is wmarx@primenet.com.