Mercury levels in Delta fish reason to think before you chew

Alex Breitler
The Stockton Record
11/06/2007

THE DELTA - Dylan Service motored up the Mokelumne River on Monday morning, asking fishermen along the way the familiar question: "Any luck?"

Not a nibble, they replied.

But within an hour, the Department of Fish and Game marine technician and his partner had netted more than two dozen largemouth bass, suckers and other species.

In the largest study yet conducted on mercury contamination in the Delta, researchers over the past two years have used electric shocks to stun fish and collect them for testing. Early conclusions, contained in a report released today, include:

• While the Sacramento and San Joaquin rivers carry high levels of mercury, the place where they meet - the central Delta - typically does not.

• Fish such as largemouth bass and the Sacramento pikeminnow appear to be most dangerous.

• Many people are confused by the mixed message that fish are nutritious but hazardous at the same time.

Bottom line: Anyone who eats fish from the San Francisco Bay, the Delta or its Central Valley tributaries should be careful, said researcher Jay Davis of the San Francisco Estuary Institute.

"It's up to people to make smart choices with the information that's out there," he said.

The ongoing studies are part of a three-year, $4.5 million project by a handful of government agencies and organizations. Their findings are important for thousands of people in Stockton who rely on fish for a large portion of their diets.

Fish are healthy. They contain fatty acids that strengthen the heart, assist in brain development and might even help your vision.

But millions of pounds of mercury used in the Gold Rush days linger in streams that drain from the Sierra Nevada into the Delta.

Once in the environment, mercury converts to a more toxic form and accumulates in tiny organisms that are eaten by fish. It can then spread up the food chain to humans, attacking the nervous system and potentially harming unborn children.

Officials involved in the mercury project want to step up public education efforts. They've posted 60 multilingual signs around the Delta warning of the dangers, but that approach will only go so far.

"There's hundreds of miles of Delta levees where people fish. Some of the best fishing spots, I don't know about them and you don't know about them," said Jeff Carruesco of the San Joaquin County Environmental Health Department.

So groups such as Stockton's United Cambodian Families and Vietnamese Voluntary Organization are now working on their own outreach efforts.

Longtime striped bass fisherman Jay Sorensen eats his catch at least once a month, sometimes raw. "It's excellent," he said.

But Sorensen laments the widespread contamination that prevents him from partaking more often.

"Man can be the ruination of all creation," he said. "What took millions of years to put there can be totally dismantled and destroyed by the human race for the almighty dollar."

Mercury is likely to remain a serious problem in California for decades more, today's report says.

Plenty of time to answer more questions, such as why mercury appears to be less of a problem in the central and south Delta than other places. More than 4,000 fish have been tested, Davis said.

"We're gathering tons of information every year," he said.