Scientists have discovered a chemical used to prevent tire cracking is wiping out coho salmon populations.
The study indicates that tires expel a chemical known as 6PPD-quinone through dust, which gets washed into creeks and streams when it rains.
Watersheds near busy roads can see the chemical kill 40 to 90 percent of coho before spawning.
Another study suggests that the chemical causes fish to swim in circles, lose equilibrium, and stop moving, before dying.
The lead researcher is a doctor at the University of Washington.