About This Project

The overarching goal of this experiment is to determine the carbon dioxide (CO2) concentration needed to cause movement of Faxonius rusticus and Procambarus clarkii away from the source. Time of exposure will also be evaluated, and depending on their size, some crayfish may need to be exposed to the CO2 longer than others in order to see an affect. This method may be further tested as a way to remove invasive species from small bodies of water without harming the crayfish.

Ask the Scientists

What is the context of this research?

Invasive crayfish like Faxonius rusticus and Procambarus clarkia have begun to displace and reduce the native populations of crayfish, reduce game fish populations, and their feeding habits reduce available habitats for amphibians. The growing rate at which these invasive species are spreading is troubling. Due to their invasive nature, F. rusticus and P. clarkia and thus negative effects on the environment, it is important to find was to control their abundance. Using CO2 to encourgae invasive crayfish to move to one area of a pond will allow their efficient removal and allow natives to be transplanted. If CO2 is too high the crayfish may lose consciousnous and thus not move to a site where they could be trapped and removed.

What is the significance of this project?

Faxonius rusticus and Procambarus clarkii are both considered to be invasive species. In the past, a variety of techniques have been used to help reduce the population of invasive crayfish. A new method of removal has been introduced that utilizes CO2. However, this method has only previously been tested on fish. This method has been used in small bodies of water in order to relocate the invasive crayfish to one localized point. From there, they can be trapped, removed and relocated elsewhere. However, due to this technique being relatively new and understudied, the exact amount of CO2 that is required to cause movement in the crayfish is undetermined. We also know little about the effect of crayfish size on their response to CO2.

What are the goals of the project?

The overarching goal of this experiment is to determine the CO2 concentration needed to cause movement of Faxonius rusticus and Procambarus clarkii away from CO2. The level of CO2 must be adequate enough to cause movement, however, it must not be elevated to the point where is causes the crayfish to lose consciousness or result in death. Time of exposure and crayfish size will also be evaluated, seeing as, depending on their size, some crayfish may need to be exposed to the CO2 longer than others in order to see an affect.