Fog and fish: Stream temperature reduction due to coastal fog in central California’s anadromous salmonid habitat

Project Number
Project Date Range
Focus Area(s)
Healthy Coastal Ecosystems

Salmon and trout species are important to California’s ecology, culture, and economy. But climate change threatens these vital species, some of which are already endangered or threatened. Dryer and hotter summers are bringing lower stream flows and heat stress, both of which are directly related to low oxygen conditions in streams which can further stress fish populations.

Coastal fog events help to keep coastal regions cool by reducing solar radiation, which likely influences water temperature in streams. However, few studies to date have investigated how fog events affect stream temperature and fish survival.

This project aims to shed light on the relationships between coastal fog and stream temperatures in coastal California streams. The objective is to better understand where cool areas form that can serve as refuges for fish to survive hot and dry weather. The researchers will measure and compare stream temperature variation originating from three sources: coastal fog, riparian shading, and physical stream habitat.

The researchers plan to collect data from two central California stream systems: the Russian River and Pescadero Creek watersheds. This work will be completed in collaboration with the California Sea Grant Extension Program and the Resource Conservation District of San Mateo County.

This study will be one of the first to incorporate coastal fog events into predictions of stream temperature on seasonal and diurnal timescales, which will better inform management strategies at sub-watershed scales with the potential to improve the sustainability of the coastal California salmonid fishery.

Principal Investigators
Sara Baguskas
San Francisco State University (San Francisco State)
Co-principal Investigators
Alicia Torregrosa
U.S. Geological Survey (USGS)
Leora Nanus
San Francisco State University (San Francisco State)