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Aquaculture: Key to Sustainable Fisheries?

US - Supplies of wild fish from rivers and oceans around the globe are dwindling, even as the demand for fish worldwide is growing. Aquaculture, or fish farming, is fast becoming the most convenient way for consumers to get fish. But, as Jan Sluizer reports, aquaculture is a new frontier in the modern world, fraught with promise and with challenges.

Corey Peet sits in front of a tank holding tuna at the Monterey Bay Aquarium

Scientists, researchers, environmentalists, and fishermen are all in agreement with Corey Peet, an aquaculture research analyst at California's Monterey Bay Aquarium. There is a global fisheries crisis and if current practices continue, wild fish will be completely gone from the oceans in 40 years.
"Seventy to 80 percent of fisheries are fished to capacity or over-exploited and one strategy to try to mitigate this problem is to grow the fish ourselves," he explains.

Enter aquaculture

Thousands of years old in Asia, only within the past six decades has the West looked towards fish farming. Seen as a key to solving the increasing global demand for fish, it's an industry that has been growing very quickly, nine to 10 percent a year since 1950. Right now, half the world's fresh fish come from aquaculture and it's a trend experts say will surge as ocean fish sources continue to dwindle.

But Peet notes that there is a growing resistance to farm-raised fish: "I often find consumers saying, 'Well, all farmed fish is bad,' when the reality is the vast majority of aquaculture or farmed fish is actually pretty good. It's just these few bad actors that have tainted the whole thing," he adds.

Those 'bad actors' are carnivorous ocean fish, like tuna, halibut, and salmon. One environmental concern is that they are raised in huge open net pens and cages in the ocean. The concentration of thousands of fish in these floating farms produces large amounts of waste matter, including nitrogen and feces. Antibiotics used to control disease leak into the ocean and can spread to wild fish. Some aquaculturalists believe that the solution to the problem is dilution, making sure fish farms are not too dense and placing them far apart in the ocean.

Concerns

Those concerns can be more easily handled by inland operations, like Ken Beer's, which typically grow freshwater fish, and shellfish. For 30 years, Beer has cultured sturgeon for its caviar and largemouth bass in huge tanks, and catfish and carp in some 250 hectares of ponds.

His environmentally sustainable farm recycles groundwater through the containers, and into the ponds, which act as natural water treatment plants. Algae and bacteria feed off the nitrogen, bugs and little fish eat the algae, and the carp and bass eat the bugs and little fish. What water is not re-circulated back into the closed tanks is used to irrigate nearby fields where corn is grown to feed cattle. Beer says good hygiene is the key to keeping fish disease-free.

 

An aquaculture operation in North Carolina

Beer attributes the bad press surrounding the young aquaculture industry to an uninformed public.
"Farmed fish in and of itself is not the demon," he insists. "Over time I think the pendulum will probably switch back a little bit. I mean it's inevitable. Where else are the fish going to come from?" he asks.

Because more and more of the world's fish supply is farm grown, and the US government has not yet formulated industry regulations, California lawmakers took action on their own. The Sustainable Oceans Act, passed two years ago, sets forth strict requirements on aquaculture to protect the state's coastal environment… and it's become the standard for many fish farmers all across the United States.

There are almost 400 registered commercial fish farms in California. Tom Moore, an associate marine biologist with the California Department of Fish and Game, is in charge of its aquaculture division. Moore says he or a colleague has visited each operation to certify the health of the fish being grown. He says fish farmers work hard to meet the state standards.

"You want to protect the environment but the industry, itself, wants to protect its investments in what they're doing, too."

Cultured country

Israel is one country where cultured fish is a growing industry closely regulated by the Federal government. Dr. Sheenan Harpaz, with the Department of Aquaculture, says he prefers farmed fish to wild-caught. "The reason for that is that farmed fish are very carefully monitored," he explains. "They are checked by vets. They are regulated. They cannot sell fish on the market that do not meet certain standards. While fish that are caught, wild-caught, there is no regulation. There might be very high levels of heavy metals in them."

 

At the Dor Aquaculture experimental station in northern Israel, Sheenan Harpaz shows the large tanks holding tilapia

Harpaz points to a large tank where farmed tilapia is being cultured. Despite the high density of fish, he says they are healthy because they are grown under controlled conditions. "Since the water is circulated, purified, and oxygenated, oxygen added to water here, you can reach these high levels of production. In a relatively small area, we can grow large quantities of fish," he adds.

By controlling what fish are fed, they can be made healthier. Farmed fish can also be grown according to need, supplementing the food supply during the months when storms prevent fishermen from going to sea or during the months when there is more demand.

Source: VOA News

Ellen Hardy

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