A fish kill incident has wreaked havoc on native brook trout in a Minnesota stream. On August 2nd, a fish kill was reported on Tischer Creek, which runs through the small city of Duluth, Minnesota.
Several hundred brook trout were found in the Hunters Park neighborhood, as well as other fish species and aquatic invertebrates. Around 1,000 fish were killed in total in the shocking incident, which impacted two miles of Tischer Creek.
Brook trout are the only native trout species in the area. Don Schreiner, a University of Minnesota fisheries biologist, told the Star Tribune that it could take up to three years for the stream, which is managed as a wild trout fishery, to repopulate from the fish kill.
Officials haven't reveled the cause of the incident. It is under investigation by both the Minnesota Pollution Control Agency and the Minnesota Department of Natural Resources. That said, reporting from the Duluth News Tribune indicates that the cause may have stemmed from the city of Duluth’s water treatment reservoir.
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City staff released 400,000 to 500,000 gallons of chlorinated water from the reservoir on August 1. While the city maintains that the water was “clean, potable” and not a threat to public safety, it’s possible that the chlorine impacted the fish. Toxicology tests are underway but have not yet been completed.