Effects of Ocean Acidification on Salmon Olfactory Function and Magnetoreception

Examined whether ocean acidification impairs salmons’ ability to smell.

Principal Investigator

Evan Gallagher, University of Washington, Department of Environmental and Occupational Health Sciences

Co-Principal Investigators

Andrew Dittman, NOAA NWFSC

Chase Williams, University of Washington


With funding from Washington Sea Grant, researchers studied the effects of elevated carbon dioxide on salmon magnetoreception, which is used for navigation. The purpose of the study was to determine if ocean acidification (OA) affects magnetoreception in pink and chum salmon. Pink salmon immediately migrate to the marine environment as fry, so this additional time in the sea could put them at increased risk to OA. This work builds upon previous WSG-funded research on the olfactory responses to decreased pH in coho salmon and sablefish.

Research Updates


As the oceans absorb an increasing amount of atmospheric carbon dioxide, the water chemistry is acidifying. Previous Washington Sea Grant-funded research has demonstrated that ocean acidification (OA) negatively impacts the sense of smell in coho salmon, which the fish use to find food, avoid predators and find their way back to their home rivers to spawn. Salmon also rely on another sense for navigation, especially when out in the open ocean: magnetoreception. This research addressed the question: Does OA also affect magnetoreception in salmon?


Over the first year of the project, 2018, the researchers worked with collaborators at the Northwest Fisheries Science Center Mukilteo Research Station to construct a large Helmholtz coil capable of generating magnetic fields that mimic the geo-locations of the research station, southern Oregon, and the northern Gulf of Alaska. The researchers conducted a pilot experiment in which 100 juvenile pink salmon were exposed to control and high carbon dioxide waters, and then tested within the magnetic coil. The pilot project helped researchers refine experimental protocol and methodology.