Wednesday, December 26, 2018

Higher Carbon Levels May Threaten Salmon’s Sense of Smell

New research from the University of Washington and NOAA Fisheries shows that the sense of smell critical to survival of salmon may be in trouble as carbon rises in the ocean.

Salmon depend on their sense of smell to avoid predators, sniff out prey and find their way home to natal streams to spawn and die at the end of their lives.

Researchers from UW and NOAA Fisheries’ Northwest Fisheries Science Center note that ocean acidification is changing the chemistry of ocean water. Higher levels of carbon dioxide in the water can affect the ways in which coho salmon process and respond to smells.

The study, published online in December in the Global Change Biology journal, is the first to show that ocean acidification affects the sense of smell of coho salmon. Researchers said 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, and how that loss of smell changes their behavior.

Lead author Chase Williams, a postdoctoral researcher in the UW Department of Environmental and Occupational Health Sciences, said that “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.”

Researchers said that Puget Sound’s waters are expected to absorb more CO2 as atmospheric carbon dioxide increases, contributing to ocean acidification. Their tests involved a series of behavioral and neural test to see whether the fishes’ sense of smell was affected in laboratory tanks with three different pH levels.

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