All News & Blogs
Shift manager Daryl Jenkins sends tilapia into a frenzy after pouring food into one
PHOTOS BY Steve Sheppard/
View More Images from this story
Visit the Photo Place
Date published: 3/2/2008
Closed systems that treat and recirculate wastewater cost more to set up, but Staniford contends they're more economical because less food is wasted, fish burn less energy and grow faster, and there is little chance of disease transfer.
Blue Ridge Aquaculture relies on technology developed by MariCal Inc. of Portland, Maine, that lets fish typically harvested from salty coastal environments grow in tanks fed by freshwater sources. MariCal discovered a way to control proteins called calcium receptors that allow fish to sense and respond to changes in salinity and nutrients.
David E. Guggenheim, who formed the 1planet1ocean conservation group, consults for Aquaculture Developments LLC of Pittsburgh, another firm bringing more closed-containment technology to the U.S.
Such farms are needed if seafood suppliers are to keep up with demand, he argues. And if more U.S. operations thrive, the technology will spread.
"And it only makes sense," he says. "We've domesticated chickens and cows and pigs, but we're still hunting wild animals in the ocean."
Land-based farms will never replace water-based operations because some fish, including tuna, are too large to grow in tanks. But advocates say they could reduce reliance on offshore farms and relieve pressure on wild stocks.
The Seafood Choices Alliance says three-quarters of the world's fisheries are being fished at or beyond capacity, and the health of the oceans is declining globally. Joey Ritchie Brookhart, a senior project manager in Monterey, Calif., says companies like Blue Ridge help address concerns about environmental sustainability.
"The question is whether it will work," she says.
Not all conservation groups believe closed containment is proven technology, and not all land-based aquaculture is created equal.
Bivalves--mussels, clams, oysters and scallops--are raised "in a benign way," Brookhart says, because they require no feed or chemicals.
In the middle of the sustainability spectrum are species that can thrive on plant life like tilapia, catfish and barramundi, a species native to Australia but now being raised in Massachusetts by Australis Aquaculture LLC.
Then there are meat eaters like salmon, which require protein to grow and produce the most waste.
Even if Blue Ridge is successful, Brookhart says it's unlikely net pen operators will follow suit.
"They've been doing it that way for many, many decades," she says, "and to tell them their operation is not sustainable and it should be done on land is going to create a lot of resistance."