The Effects of Premature Hypersaline Acclimation Due to Climate Change on Pyrethroid Toxicity in Salmonids

Start/End: April, 2016 to March, 2018

Sea level rise and drought are expected to result in hypersaline waterways in the Delta. Endangered Chinook salmon and Steelhead trout go through smoltification to be able to live and mature in saline environments. However, with salinities and temperatures increasing in historically freshwater areas, these fish 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 Bay, can have endocrine disrupting effects on juvenile salmonids.

This project will examine the impacts of hypersaline conditions, various temperatures, and exposure to bifenthrin on the development and survival of juvenile Chinook salmon and Steelhead trout. Specifically, it will:

  • Test the impacts of premature hypersaline acclimation and temperature on the survivial and smoltification process of a range of juvenile salmonids;
  • Test the combined impacts of premature hypersaline acclimation, temperature, and bifenthrin exposure on smoltification, survival and behavior; and
  • Predict the population level effects of drought and pesticide runoff on the health of endangered salmonids

Additionally, this research will provide information to CA Department of Pesticide Regulation for potential pesticide management in the Delta, as well as to the CA Department of Fish and Wildlife for conservation practices of endangered juvenile salmonids in the Delta.