Invasive Asian Carp Respond Strongly to Carbon Dioxide

Adding carbon dioxide gas (CO₂) to water, a process similar to making carbonated soda water, could help control the movement and behavior of invasive carp in the Great Lakes basin, according to a recent study published in Transactions of the American Fisheries Society.

Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix are species of invasive Asian carp that threaten the Great Lakes. Scientists with the University of Illinois and 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.

“These fish responses provide evidence that CO₂ could be used as a tool to deter the movement of Bighead and Silver Carp,” said Michael Donaldson, a University of Illinois researcher and the study’s lead author. “The results are encouraging because there is a need for additional methods to prevent the entry of Asian carp into the Great Lakes.”

The scientists gradually added light plumes of CO₂ gas throughout 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 Ictiobus cyprinellus, Channel Catfish Ictalurus punctatus, Paddlefish Polyodon spathula, and Yellow Perch Perca flavescens, before, during, and after the addition of CO₂. The scientists found that:

• Each fish species except for Paddlefish avoided the areas of the pond with CO₂-infused water;
• Certain Bighead and Silver Carp movements slowed down immediately after CO₂ was injected; and
• Bighead Carp used a smaller area of the pond furthest from the injection sites immediately after CO₂ was added.

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

The next research step is to test the usefulness of CO₂ gas in controlling Bighead Carp movement in a natural river.

Nonnative Asian carp can 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.

The new study is published in the journal Transactions of the American Fisheries Society.

For more information about Asian carp research, please visit the University of Illinois, USGS UMESC, and asiancarp.us websites.