The effects of premature hypersaline acclimation due to climate change on pyrethroid toxicity in salmonids

Chinook salmon and steelhead trout go through a series of physiological changes known as smoltification to be able to live and mature in saltwater. However, with salinities and temperatures increasing in historically freshwater areas, these fish, which are already endangered in the Bay-Delta, may be facing new stressors. Pesticide runoff into the Delta is common due to the urbanization and agriculture of many regions and can adversely affect fish. Additionally, previous research has shown that salinity exposure increases the toxicity of contaminants in anadromous fish, and it is had been demonstrated that bifenthrin, a common insecticide in the Delta, can have endocrine disrupting effects on juvenile salmonids.