State advises Oso Flaco Lake fishers on friendly eats



On the menu of edible fresh fish caught at Oso Flaco Lake are blue gill and hitch. If it’s gigantic goldfish you want, though, you should probably drop your hook elsewhere.

And as far as Oso Flaco Lake bass are concerned, the California Environmental Protection Agency (CEPA) recommends only eating one a week. CEPA’s Office of Environmental Health Hazard and Assessment released a health advisory about the body of water in early August. The advisory outlines what’s safe to eat out of the Guadalupe-Nipomo Dunes lake based on a number of studies that found higher-than-normal levels of mercury in the lake’s bass and extremely high levels of DDT in the goldfish.

In fact, the amount of DDT—which is a pesticide that was banned in the United States decades ago—in Oso Flaco Lake’s goldfish is 10 times higher than what’s been found in any other lake in California.

Sam Delson, a health hazard office spokesperson, said the office started working on the health guidelines in April. He said that in addition to the overall state advisory for mercury levels in fish, the advisory for Oso Flaco Lake is one of more than 50 specific lake advisories his department has released.

Guidelines released for specific lakes usually stem from oddities found consistently through a number of studies that gather information on a variety of species in the water.

“Oso Flaco was kind of unusual because of those large amounts of contaminants found in the goldfish,” Delson said. “There’s obviously something going on there that’s not happening in other California lakes.”

Data collected over the last decade went into the advisory; information from the State Water Resources Control Board’s Toxic Substances Monitoring Study and the Surface Water Ambient Monitoring Program was included. California State Parks also provided funding to have species collected and analyzed.

Chris Rose, a program manager with the Central Coast Regional Water Board, responded to a request for comment by referring New Times to the board’s recently completed Total Maximum Daily Loads document for Oso Flaco Lake. The document sets out methods that will help decrease the amount of pesticides and chemicals that run into the lake. Rose said he expects the document to be approved in December.

New Times spoke with water board environmental scientist Mary Hamilton in April for a cover story about contamination in Oso Flaco Lake. At the time, Hamilton was collecting samples from the lake as part of this year’s round of testing on water bodies in the Santa Maria water basin.

The water board doesn’t normally test lake water, but Hamilton said they made an exception.

“It’s so polluted; I insisted,” she said. “Oso Flaco is my highest priority in this whole region.”

Hamilton told New Times she was concerned that people who fished out of the lake were eating toxic fish. She said she was waiting for the office of health hazard assessment to publish a health advisory. As a stop-gap measure, the Central Coast water board and California State Parks posted signs around the lake cautioning people about the danger: “WARNING: PESTICIDE CONTAMINATED FISH.”

The advisory for Oso Flaco Lake as well as other health hazard advisories are available online at

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