Salmon may lose the ability to smell danger as carbon emissions rise

December 18, 2018, University of Washington

The ability to smell is critical for salmon. They depend on scent to avoid predators, sniff out prey and find their way home at the end of their lives when they return to the streams where they hatched to spawn and die.

New research from the University of Washington and NOAA Fisheries' Northwest Fisheries Science Center shows this powerful sense of smell might be in trouble as carbon emissions continue to be absorbed by our ocean. Ocean acidification is changing the water's chemistry and lowering its pH. Specifically, higher levels of carbon dioxide, or CO2, in the water can affect the ways in which coho salmon process and respond to smells.

"Salmon famously use their nose for so many important aspects of their life, from navigation and finding food to detecting predators and reproducing. So it was important for us to know if salmon would be impacted by future carbon dioxide conditions in the marine environment," said lead author Chase Williams, a postdoctoral researcher in Evan Gallagher's lab at the UW Department of Environmental and Occupational Health Sciences.

The study, appearing online Dec. 18 in the journal Global Change Biology, is the first to show that ocean acidification affects coho salmons' sense of smell. The study also takes a more comprehensive approach than earlier work with marine fish by looking at where in the sensory-neural system the ability to smell erodes for fish, and how that loss of smell changes their behavior.

Read more at: