Ocean acidification has affected more than just the increase of pH in the ocean, but it also made salmon ability to sense predators decreasing. This makes salmon unable to avoid the predator, moreover, they become less afraid of the predator.

The increase of carbon dioxide uptake in the ocean from the atmosphere has resulted ocean acidification, which affected the sense of smell in the sea creatures, including salmon. This alters salmon ability to sense the predator and drawing them to the predator, according to the recent research from the University of Washington College of Environment.

Previously, salmon were able to smell their predator and avoided them. As the ocean become more acidic, they become unable to smell the danger. As a result, the salmon ability to sense predator has diminished.

The researchers, under principal investigator, the Professor from Department of Occupational and Health Sciences at the University of Washington, Evan Gallagher presented their findings of the decrease of salmon ability to sense a predator in the 2017 Ocean Acidification Symposium.The symposium was held on 22 May 2017 at the University of Washington Center for Urban Horticulture in Seattle, WA.

One of the researchers, Chase Williams, a post-doctoral student explained salmon ability to sense predator has significantly reduced. Salmon uses its sense of smell to navigate and to hunt its prey, as well as to avoid its predator.

“They can also smell a compound that’s released when a predator is eating one of their schooling mates,” Williams said in the symposium explaining the salmon ability to sense predator as their natural behavior. “In normal conditions, they would avoid the scent of danger."

In their research to analyze the effect of ocean acidification on the change of salmon ability to sense predator, the researchers examined two types of Salmons, the examined coho salmon, and sablefish, also known as black cod, the native salmon in Washington state. They found the change of seawater chemistry has affected the salmon ability to sense a predator. Watch the NOAA report on the ocean acidification below: