A study carried out by the University of Washington and the National Oceanic and Atmospheric Administration Fisheries’ Northwest Fisheries Science Center and published in the journal Global Change Biology has revealed that as carbon dioxide emissions are absorbed by the ocean, salmon may begin to lose their sense of smell.
Chase Williams, a postdoctoral researcher at the University of Washington Department of Environmental and Occupational Health Sciences, a lead author of the study, said salmon are highly dependent on their sense of smell and that the findings of the study are alarming.
“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,” Williams said in a press release.
Williams added that pollutants can also interfere with sense of smell, and as a result “salmon are potentially facing a one-two punch from exposure to pollutants and the added burden of rising CO2.”
“These have implications for the long-term survival of our salmon,” he said.
To carry out the study, the scientific team set up saltwater tanks with current ocean CO2 levels, as well as the predicted levels for 50 and 100 years from now. Juvenile coho salmon were exposed to the levels for two weeks. The fish were then exposed to the smell of salmon skin extract, which indicates a predator attack. While the fish that had been exposed to current CO2 levels responded naturally, the fish from the tanks with higher levels of CO2 were not able to detect the smell. Neural activities and gene expression pathways were also tested in the fish.
The researchers also plan to examine whether increased carbon dioxide levels will affect other species of fish in a similar manner.
