Abstract
Mercury contamination in the San Francisco Estuary (Estuary) is a significant concern due to its bioaccumulative potential in aquatic ecosystems and toxicological effects on humans and wildlife. Small forage fish species are commonly used in monitoring and assessment activities as indicators of bioavailable mercury and subsequent risk to wildlife, but limited research has been conducted evaluating the impacts of growth rate variation on the dynamics of mercury bioaccumulation in these fish. This study addressed this by examining mercury concentrations and growth rates in six populations of a commonly used bioindicator fish species, Inland silversides (Menidia beryllina), found in the southern region of the Estuary. Whole fish total mercury and back-calculated growth rates varied significantly among sites. However, no significant effect of growth rate on mercury concentration was found. This study addressed a concern regarding the accurate use of bioindicator fish, and the results show that growth rate analysis may not be necessary in future monitoring spatial trends with inland silversides.