Possible New Methods To Control Spread Of Round Goby

Sep 2: Scientists have discovered that certain chemicals may be useful in slowing the spread of the round goby, an invasive fish species that is threatening parts of the Great Lakes and Mississippi River. When released near the bottom of a river or lake, two fish pesticides are effective in controlling this bottom-dwelling invader, particularly where dissolved oxygen is low, while leaving native species unharmed. Theresa Schreier, lead author of this research, published in the Journal of Great Lakes Research said, "Selective removal of round gobies may be possible with bottom-release pesticides. This work shows the value of understanding how an invasive species differs from native populations in the way that it lives in an ecosystem and basing control measures on a unique vulnerability of the invader."

Researchers at the U.S. Geological Survey (USGS) Upper Midwest Environmental Sciences Center in La Crosse, WI evaluated four currently registered fish pesticides (antimycin, rotenone, 3-trifluoromethyl-4-nitrophenol (TFM), and Bayluscide) for their toxicity to round gobies. Round gobies were sensitive to all four chemicals; unfortunately, the level of sensitivity was similar to native fish species tested. Further testing revealed that formulations of Bayluscide and antimycin that can be released near the bottom of a body of water showed promise as control agents because round gobies did not react or appear to detect the presence of these chemicals.

USGS scientists also evaluated the effect of dissolved oxygen concentrations on toxicity to determine if a modification of the current design of the Illinois Waterway could be an effective tool in the management and control of round gobies. Round goby can withstand low dissolved oxygen concentrations, and during lab tests gobies showed increased sensitivity to bottom-release fish pesticides at lower oxygen levels. Some portions of the Illinois Waterway have low oxygen levels and are mechanically aerated, providing an option to manage a segment of the waterway as an anoxic barrier. USGS said managers could explore the option of maintaining a low dissolved oxygen zone that could be treated with selective fish pesticides to control congregations of the bottom-dwelling round goby.

Access a release from USGS with links to additional information (click here). Access more information on the Invasive Species Research Program at the USGS Upper Midwest Environmental Sciences Center (click here).