California is issuing its first statewide warning about toxic contamination of sport fish in lakes and reservoirs.
A new health risk advisory says children and adult women under the age of 45 should not consume carp, bass, or larger brown trout caught in several hundred bodies of water around the state. Everybody else should only eat those fish once a week.
The problem is methyl mercury – a toxic metal that can harm the brain and nervous system.
“Some of the mercury contamination comes from prior mining or other industrial operations,” says Sam Delson, a spokesman for the Office of Environmental Health Hazard Assessment. “Some of it is deposition from atmospheric mercury.”
Rainbow trout and smaller browns are slightly safer – women of childbearing age and children can eat them twice a week.
The health advisory is based on studies at 272 lakes and reservoirs. Environmental health officials have posted it on their website, and it will be included in the regulatory handbook offered by the Department of Fish and Wildlife with California fishing licenses.
“In some cases, local officials distribute our site-specific advisories more widely, post signs, and translate them into various languages,” Delson says. “Some have been translated into various Asian languages because many subsistence fishers speak those languages and may not speak English.”
California’s Department of Fish and Wildlife stocks many bodies of water; it’s not immediately clear whether the advisory applies to any of the lakes or reservoirs where that department is active.
OEHHA’s Delson acknowledges that Fish and Wildlife’s hatchery program stocks “catchable sized” fish. “We believe these are likely to be less contaminated than other fish in the lakes where they are stocked,” Delson says. “We are planning a study with DFW to test fish from their hatcheries to confirm whether this is true.”
California had previously warned fishermen about eating their catch at about 60 bodies of water. Regulators say more lake-specific advisories are on the way.