Populations of largemouth bass, bluegill, catfish and other sportfish are at the highest levels recorded in more than a century in the Illinois River, according to a new report. Their dramatic recovery, from populations close to zero near Chicago throughout much of the 20th century, began just after implementation of the Clean Water Act, the researchers say.
Populations of largemouth bass, bluegill, catfish and other sportfish are at the highest levels recorded in more than a century in the Illinois River, according to a new report. Their dramatic recovery, from populations close to zero near Chicago throughout much of the 20th century, began just after implementation of the Clean Water Act, the researchers say.
The new findings, reported in the journal BioScience, add a more hopeful chapter to the ecological history of the Illinois River, which was one of the most productive rivers of the Mississippi Valley until it began receiving Chicago’s human and animal waste on a large scale in 1900.
“The biggest single negative change that happened to the Illinois River in the 20th century was the opening of the Chicago Sanitary and Ship Canal in 1900,” said Illinois Natural History Survey researcher and fish biologist Daniel Gibson-Reinemer, the lead author of the study. “After that, a lot of the untreated sewage from Chicago started flowing right down the canal and into the Des Plaines River, which is the headwaters of the Illinois River.”
Before 1900, the Illinois River had been extraordinarily productive.
Read more at University of Illinois at Urbana-Champaign
Image: Researchers from the Illinois Natural History Survey have surveyed fish in the Illinois River since 1957. Here, the team uses electricity to stun the fish for capture. (Credit: Photo by Aaron Yetter)
