Coho salmon are severely affected by toxic runoff from urban highways, a new study suggest, drawing attention on the loss of salmon population runoff may cause.
This alarm signal was raised after the research team comprising scientists from federal institutions, tribal authorities and other research institutions exposed coho salmon to water infected by toxic runoff to study these exact effects.
Urban streams located along the West Coast are home to the coho salmon. Rainwater that gathers all the toxic runoff from developed surfaces in the vicinity of these streams runs directly here. Coho salmon are severely affected by toxic runoff from these surfaces, which include parking lots or highways.
Salmon survival is crucial for a balanced ecosystem in these streams. In southwestern Washington, as well as in Oregon and California coho salmon is protected by the Endangered Species Act. As adult salmon are prone to being affected by toxic runoff, mating and breeding a new generation becomes more difficult.
Julann Spromberg with NOAA Fisheries Northwest Fisheries Science Center, Seattle stated:
“Untreated urban runoff is very bad for salmon health. Our goal with this research is to find practical and inexpensive ways to improve water quality. The salmon are telling us if they work”.
In reaching this conclusion, the research team exposed coho salmon to a chemical brew of substances that would imitate the approximate composition of toxic runoff from highways.
Nonetheless, the effects on the salmon population sample weren’t as severe as when it was exposed to water containing real toxic runoff. The water sample that was found to have disastrous effects on the coho salmon was collected from a pipe draining one onramp on Highway 520 in the vicinity of Montlake.
Exposed to this sample, the coho salmon became ill and died in less than 24 hours. Nevertheless, the researchers also found an easy to implement solution. Filtering toxic runoff with the help of sand and soil columns captures almost all of the toxic waste, greatly reducing the impact on the coho salmon population.
The team recommends that such filters are taken into account in future transport development projects as a green alternative for filtering toxic runoff. Improving conditions for survival of the coho salmon is vital.
The research paper features in the Journal of Applied Ecology.
Photo Credits: Flickr