Risk analysis for species introductions: forecasting population growth of Eurasian ruffe ( Gymnocephalus cernuus)

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Author: Drake, John M
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2005
• Subjects: Eurasian ruffe; Gymnocephalus cernuus
• Online Access: http://dx.doi.org/10.1139/f05-014; http://www.nrcresearchpress.com/doi/pdf/10.1139/f05-014

The North American distribution of the Eurasian ruffe (Gymnocephalus cernuus), an ecologically important and costly invasive fish, is presently limited to the Laurentian Great Lakes. Risk analyses for accidental introductions of ruffe to inland lakes should focus on the chance of establishment for small introductions such as those that would result from transporting ruffe as bait. Here I use Akaike's Information Criterion to select a population growth model for ruffe based on observed population dynamics during the invasion of Loch Lomond, Scotland. This population is regulated by a high carrying capacity and Allee effects were undetected. Parameter estimates obtained from this population forecast that the chance of establishment for possible introductions of ruffe to inland lakes in North America is high. A model for ruffe winter survival suggests that survivorship between introductions and spawning may be an important determinant of establishment success, but that the chance of establishment is high for introductions of only a few individuals. To prevent invasions of ruffe in inland waters, release of ruffe, whether intentional or accidental, should not be tolerated.