Fish caught at a popular fishing spot in the Laguna de Santa Rosa between Sebastopol and Santa Rosa had unacceptably high levels of mercury, well above the threshold where health officials normally recommend against eating them, according to a new state survey.
The State Water Resources Control Board surveyed fish caught in 63 well-known river fishing holes statewide during 2011 in an effort to get a better sense of how safe California's game fish species are for human consumption. The findings, released last week, largely confirmed what officials suspected: that except for a handful of spots, mercury levels are moderate to low, suggesting most fish are safe to eat.
The one unexpected finding, however, came in the 22-mile Laguna de Santa Rosa, the remnant of the sprawling wetlands that used to cover much of the west county. Bass caught at the fishing spot near the bridge along Occidental Road showed an average mercury level of .53 parts per million, well above the .44 ppm threshold at which the state recommends avoiding any consumption. Carp averaged .35 ppm, a level at which the state usually recommends limiting consumption to one serving per week.
"Everybody is caught a little by surprise," said David Bannister, executive director of the Laguna de Santa Rosa Foundation, a group dedicated to studying, preserving and promoting the waterway.
State and local officials have known for years that there is mercury in the water, he said, but it appeared to be from naturally occurring sources and was not high on the priority list for restoring the slow-moving, meandering waterway that drains into the Russian River. Mercury contamination certainly fell well behind other Laguna issues such as agricultural and urban runoff and pesticides, which are currently under study and discussion among regulators and area landowners.
But, Bannister said, "it appears that with these findings, there should be some signs warning people about consumption."