The Mysterious Decline of Coho Salmon

Coho salmon have a life cycle that involves spawning in freshwater, journeying into the open seas, and returning to their birthplace to spawn. However, researchers have observed a troubling trend over the years: many of these salmon die before they can spawn.

In the Pacific Northwest, Coho salmon were found dead in urban streams, exhibiting unusual swimming patterns before succumbing. This prompted concern about the species facing extinction unless the cause of the mortality was identified.

A team of experts, including biologists, environmental chemists, modelers, and community scientists, embarked on a quest to pinpoint the cause. They systematically ruled out common factors such as temperature fluctuations, oxygen levels, and known toxins. After exhaustive research, the team focused on chemicals found in tires as the prime suspect.

Despite identifying tires as a potential source, the exact chemical responsible remained undetermined. This ongoing mystery has driven researchers to continue their investigation to safeguard the future of Coho salmon.

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This episode’s production team included Jessica Yung, with Rebecca Ramirez as showrunner. It was fact-checked by Tyler Jones, and Kwesi Lee served as the audio engineer.