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Arcata Project Is Flush With Fish

Science: University study uses wastewater to raise oceangoing freshwater trout, which have been found to be hardy and healthy.


ARCATA, Calif. — A soft odor of raw sewage permeates the air, competing with the sharper salt smell of the Pacific Ocean.

Humboldt State University student Mike Shoemaker tosses fish food pellets into two wastewater ponds, which burst into a simmering boil as nearly 10,000 steelhead trout and coastal cutthroat trout roil to the surface.

Shoemaker is wearing a "Flush with Pride" T-shirt, featuring a fish leaping out of an open toilet -- the official logo of the Arcata Wastewater Aquaculture Project.

It's believed to be the only one in the world studying the use of wastewater to grow oceangoing freshwater fish, although studies elsewhere have centered on everything from catfish to carp.

"Those are really hardy fish, where trout are really known to be sensitive. So a lot of people don't even try it, but we haven't found any problems," said Kristine Brenneman, a Humboldt State fisheries biologist who also heads the city's wastewater utilization program.

The sewage-raised trout emerge clean of all the nasties, including significant levels of cholera and fecal bacteria, Brenneman said.

Indeed, research by graduate student Andrew Jensen found that steelhead hatchlings raised in wastewater filtered through the treatment center's marshes grew significantly larger, were more likely to survive and had fewer abnormalities than those raised in Arcata's drinking water, which picks up higher copper levels while passing through pipes.

Wastewater, by contrast, "is very high in nutrients," Brenneman said.

The research holds potential for hatcheries that grow great numbers of notoriously finicky salmon and steelhead to replenish natural stocks, Brenneman and Jensen said.

Each year, the university releases into the wild several thousand wastewater-raised fish that aren't needed for research.

But the thought of using wastewater to raise fish that people may eat is innately troubling to Americans, Brenneman acknowledged, although other cultures have used human waste for fish and fertilizer for centuries.

The U.S. Department of Interior sent representatives to inspect the project this spring, and Minnesota flew out observers last summer. Other hatcheries have also toured the program.

If wastewater-raised fish never catch on in the United States, the research could help in other countries that have a scarcity of water and protein, Jensen said.

"It's all controversial," Brenneman said. "We just do the experiments; if anyone wants to do it commercially, they can."

Until a few decades ago, cities saw nothing wrong with pumping raw sewage into wetlands.

Since the mid-1960s, however, state and federal governments have gone to great lengths and expense to protect wetlands from sewage.

In 1975, Arcata residents were confronted with plans for a new sewage treatment plant that would drastically raise their sewage rates. So they proposed building their own plant that would use the marshes to help filter wastewater before spilling it into Humboldt Bay.

Research by Humboldt State University professor emeritus George Allen, who started the aquaculture research project in 1971, helped persuade the state that the marsh treatment was not only safe, but beneficial.

All the fish died during Allen's first attempt to raise coho. By 1977, however, he successfully released 12,000 coho, some of which returned to spawn as adults. He continued experimenting through the late 1990s, with increasing success, although the program has since switched from endangered salmon to steelhead and cutthroat.

But proposals for "ocean-ranching" salmon at the wastewater treatment plant were rejected because of opposition from commercial fishing and environmental groups, as were previous proposals by two commercial fish-hatchery projects, Allen writes in a trilogy of reports titled "Aquatic Hoop Dreams Revisited."

Arcata's pioneering use of wetland filters for wastewater, completed in 1986, has since spread worldwide, wherever it's warm enough so the marshes don't freeze in winter.

The system was several times cheaper than the proposed mechanical sewage treatment system that Arcata residents rejected. And with it, Arcata got a wildlife and recreation area frequented by bird watchers, joggers and dog-walkers, and thousands of waterfowl.

Through the mid-1990s, Allen hosted annual fish barbecues where his students snacked on their research subjects with no ill effects.

More recently, the only ones eating the wastewater-raised fish are otters that sampled the captive population until researchers installed netting and an electric fence to keep them out.

Although Shoemaker is satisfied that there is nothing wrong with the fish, he and other researchers still can't stomach the idea of eating them.

But it's not because the fish have grown up in human waste.

It's because after raising the fish from eggs to adulthood, he said, it's as if "they're your children."

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