Science activity

Pyrethroids are a type of insecticide frequently detected in the San Francisco Bay and Delta (SFBD). They are highly toxic to fishes and may contribute to their decline. The Central Valley Water Resources Control Board has adopted regulations for many pyrethroids. These concentration goals for Delta surface waters are quite stringent. However, they do not take into account non-lethal effects in fishes, particularly during the early life stages and at the salinity conditions we see in the SFBD. Understanding non-lethal effects in fish is vital to influencing population health. This study investigates pyrethroid toxicity on Delta smelt and Inland Silverside embryos, while accounting for changing SFBD salinity and other factors such as sediment. Results will inform the development of pesticide regulation criteria and control efforts, furthering the protection of SFBD fishes.