Pollution May be Stalling Carp Invasion

Invasive silver carp are a problem just about everywhere they’re found here in the U.S. But according to Nora Schoenberg at the Chicago Tribune, pollution in the Illinois River may be slowing the silver carp down near Chicago.

Carp made it to the Illinois River, about 50 miles from Chicago, nearly ten years ago, but they haven’t moved into Lake Michigan. That’s surprising, since silver carp are known for quickly advancing through territory.

To understand what was keeping carp from moving into Lake Michigan, researchers took water from a polluted portion of the river and put a young silver carp in it.

“Instead of moving around and exploring, as they did in clean water, the fish slowed down almost immediately,” Schoenberg wrote. “The authors also found that the silver carp burned more energy in the polluted water, a sign that their bodies were fighting the effects of contaminants.”

While polluted rivers aren’t a good thing, this might be a slight silver lining, since preventing silver carp from entering Lake Michigan would be beneficial for the lake’s overall ecosystem.

Pollution might not be the only thing keeping carp from moving up river, according to Schoenberg.

“Other factors that could be causing the Illinois River carp to stall include shoreline changes such as walled river banks closer to the city; downstream carp fishing; and locks and dams.”

You can read the rest of the study, and learn more about the problem, here.