The California Office of Environmental Health Hazard Assessment (OEHHA) has published a recently updated advisory on fish consumption in the San Francisco Bay.Their report contains recommendations on which fish are suitable for human consumption and in what quantities. Toxins that end up in the bay also end up in fish through the food they eat. It is important to limit human consumption of fish due to these toxic substances.

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Contaminants such as mercury, which comes from natural sources, mining runoff, and air pollution, end up in fish in the form of methylmercury. Methylmercury affects brain development in fetuses, babies, and children. Sharks and bass in the Bay contain the highest levels of mercury among the fish sampled. Methylmercury compounds are a known carcinogen and are listed under Prop 65, which contains all the chemicals known to the state to cause cancer or reproductive toxicity.

Another common contaminant in the Bay is Polychlorinated biphenyls (PCBs). PCBs were widely used in light ballasts of light fixtures until the EPA phased out their use 1979. PCBs are a known carcinogen that have entered the Bay from spills, leaks, and improper disposal. PCBs accumulate in fish skin and organs, thus it is recommended to eat only the fillet portion of the fish, cook the fish thoroughly, and drain the juices away after cooking. OEHHA also recommends not eating any fish from the Lauritzen Channel in Richmond Inner Harbor because of high concentrations of PCBS in addition to the pesticide dieldrin.

Despite these harmful toxins found in fish, eating certain types of fish on a limited basis is still recommended because of their positive health benefits. Fish contain protein, vitamins, and heart-healthy omega-3 fatty acids. Children and women of child bearing age should eat less fish than men over 17 and women over 45 due to the impacts on reproduction and development. Women of child bearing age are still encouraged to eat limited weekly servings of salmon because they are especially rich in omega-3 fatty acids which help fetus development.

The guidelines OEHHA established for San Francisco Bay fish also apply to migratory fish whether they are caught in the ocean, Bay, Delta, or rivers flowing into the Delta. In general, it is also recommended that people eat smaller, younger fish, since they have had less time to build up chemicals in their bodies. Additionally, it was found that larger predatory fish accumulate more mercury because they eat higher up on the food chain and bioaccumulate persistent organic chemicals. OEHHA recommends that predatory fish found in the bay, such as striped bass and sharks, should never be consumed by children and women of child bearing age, and consumed in very small quantities by adult males and women over 45. Some fish found in the Bay are still healthy for human consumption, but only in limited quantities.

To read the full report on San Francisco Bay advisory and safe eating guidelines follow this link.
To find out more information on OEHHA fish advisories for water bodies in California near you follow this link.