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Shell Fish Farming: Is it Sustainable?

Food

By Hannah Norman

An otter backstrokes past the damp walkway as sea lions bark, resting on adjacent planks. Sunlight filters into the shaded labyrinth of mesh-lined cages that hang in the water column beneath Monterey's Municipal Wharf No. 2. Inside the suspended cylinders, thousands of California red abalone are munching on freshly harvested kelp.

"Welcome to our world under the wharf," said Art Seavey, co-owner of Monterey Abalone Company.

The historic pier is more than 90 years old; its wooden troughs were severely rotted out before the farm refurbished them and took up residence in the unused space. A built-in ladder eases the descent through a trapdoor from the bustling office and touristy marketplace above, where the company sells fully grown abalone for roughly $21 to $23 per pound. Local, high-end restaurants, as well as individuals, purchase the delicacy straight off the wharf.

Aquaculture provides more than half of all fish consumed globally, as wild fish catches are slowly diminishing. Experts say that seafood is an integral part of supplying food security, as well as sufficient protein and nutrition, to a global population that is expected to reach 9.7 billion by 2050. A major battle for environmentalists and many aquaculture proponents alike is ensuring the industry moves away from environmentally harmful techniques, which have painted the growing sector with a negative brush.

Monterey Abalone Company hopes to help catalyze this shift. Founded in 1992, the company is one of six abalone farms in California, and it takes pride in its sustainable aquaculture practices. Monterey Bay Aquarium's Seafood Watch, a program that helps consumers and businesses choose sustainable seafood options, gives abalone—when farmed in enclosed systems such as that of Monterey Abalone Company—a green, "best choice" ranking.

Trevor Fay, Seavey's partner, points out that the sea snails are indigenous to the Pacific coastline, as is their regular meal of hand-harvested kelp. One of the fastest growing plants on the planet, giant kelp expands 10 to 12 inches per day, providing a renewable, fresh resource to feed the abalone. "It all comes back to us relying on a healthy kelp bed," said Fay. "We need a healthy planet to continue our farming."

Still, kelp harvesting has been the most controversial aspect of their operation, even though the company is one of only two hand harvesters in the entire U.S., according to Fay. During the 1990s, the Monterey abalone outfit came under fire after an out-of-town kelp harvester unrelated to the company mechanically clear-cut a giant kelp bed just offshore. It wasn't until after a 2000 Monterey Bay National Marine Sanctuary study, which concluded that Fay and Seavey's business only harvested about one-tenth of one percent of the bay's kelp, that tensions subsided.

Corey Peet, a sustainable seafood consultant, said that across the U.S. and Canada, the pendulum has swung too far toward the anti-aquaculture side, propelled in part by the notoriously bad byproducts of salmon farming, such as waste excretion from net pens, the overuse of antibiotics and the spread of disease to wild populations. Another problem with finfish farming is the feed conversion ratio. Salmon and other finfish, which are predators by nature, feed on harvested smaller fish that are ground into fishmeal. It can take up to five pounds of wild fish to produce one pound of salmon.

"There are shades of gray in which the sustainability of our species will be determined," Peet said. "Clearly, aquaculture has a role to play, but it's not going to be salmon or tuna feeding the masses."

That's where shellfish, and species like abalone that are lower on the food chain, come in. Bivalves, such as mussels and clams, are filter feeders, which means that they don't require any additional feeding, according to Judith Weis, a member of the Sierra Club's Marine Action Team and a professor of biological sciences at Rutgers University. They also absorb excess nutrients from the ocean, which can actually be beneficial to water quality and local ecosystems.

Just like with finfish farming, however, not all shellfish aquaculture embraces best practices, notes Weis. Bivalve culture can be an avenue for introducing invasive species—and their diseases—to a new area, along with smaller hitchhiking critters such as oyster drills, limpets and algae. Cultivating species in a native habitat prevents these negative impacts on local ecosystems. "Aquaculture is a necessary thing because we are depleting wild stocks, but let's learn to do it right," she said.

Aquaculture can also be integral in restoring local species decimated by overfishing and coastal degradation.

California's once plentiful abalone population succumbed to a combination of overharvesting and a disease called withering foot syndrome. In 1997, the U.S. Department of Fish and Wildlife closed both sport and commercial abalone fishing for all seven species of the sea snail. Today, only freediving for red abalone, the most abundant variety, is permitted on a short stretch of coast above San Francisco.

Though the Monterey Abalone Company raises their abalone for eating, Fay said they contribute to restoration and environmental efforts through their educational partnerships. In 2008, the company started a hatchery in a joint project with Moss Landing Marine Laboratories, a consortium campus for seven California state universities, where students can study the species' early life cycle. It has also hosted groups from the restaurant industry, such as the Culinary Institute of America, to raise awareness about the environmental benefits of sustainable seafood. The farm regularly invites elementary and high school classrooms from around Monterey County in for discussions about California's depleted abalone population, as well as aquaculture best practices.

"It's very important to educate the public about how and why we're doing it," Fay said. "Most people aren't aware of where the food comes from."

The company is doing a few experiments of their own, too, in order to minimize their environmental impact even more. The marine farmers have begun growing purple hinged rock scallops, which hang underneath the abalone in the water column and feed off of extra nutrients excreted from the abalone above.

"The idea of cultivating species with different ecological roles together, multiaquaculture, is a really clever idea," Weis said. "That's really good."

Reposted with permission from our media associate SIERRA Magazine.

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