Adding carbon dioxide gas to water could help control the movement and behavior of invasive carp in the Great Lakes basin, according to a recent study.

Scientists with the University of Illinois and the U.S. Geological Survey (USGS) tested the effectiveness of infusing water with recycled CO2 gas to discourage the movement of bighead and silver carp. Both carp species avoided CO2-infused water in a research pond at the USGS Upper Midwest Environmental Sciences Center, in La Crosse, Wisconsin.

Bighead carp are a large and troublesome invasive species from Asia found in the great rivers of the central United States. Image credit: USGS. “This study demonstrates the ability of carbon dioxide to act as a non-physical barrier on a large scale,” says University of Illinois researcher Cory Suski. “Work on this topic to date has primarily been performed in small laboratory studies, and so this work showed the potential for CO2 to be effective at larger scales more relevant to field applications.”

Non-native Asian carp have the potential to damage ecosystems in the Great Lakes basin by competing with native fish and mussels for food. Large silver carp are also hazardous to boaters because they can leap up to 10 feet out of the water when startled.

Attempting to develop methods to thwart this menace, the scientists gradually added light plumes of CO2 gas to one end of the USGS test pond. They monitored the behavior of individual bighead and silver carp, as well as the behavior of native fish species such as bigmouth buffalo, channel catfish, paddlefish and yellow perch before, during and after the addition of CO2.

The findings include:

· Each fish species except for paddlefish avoided the areas of the pond with CO2-infused water.

· Certain bighead and silver carp movements slowed down after CO2 was injected.

· Bighead carp used a smaller area of the pond farthest from the injection sites after CO2 was added.

“Further tests are needed before CO2 can be used in Asian carp management,” says Jon Amberg, a USGS scientist and co-author of the study. “Understanding the effects of long-term, elevated CO2 exposure on fish and other organisms can help assess its risks to native species.”

The scientists will next test the usefulness of CO2 gas in controlling bighead carp movement in a natural river.