Stepien, C.A., A.K. Dillon, and M.D. Chandler, 1997.  Genetic Identity of Ruffe (Gymnocephalus cernuus) in the North American Great Lakes: DNA Evidence for a Southern European Origin, Case Western Reserve University

Genetic Identity of Ruffe (Gymnocephalus cernuus) in the North American Great Lakes: DNA Evidence for a Southern European Origin

ABSTRACT.
The objective of this study was to determine possible source regions for the newly invasive Great Lakes ruffe, Gymnocephalus cernuus (Percidae: Teleostei), and to compare relative levels of genetic variability in the new North American versus the established European populations. It has been postulated that high levels of genetic variability may be an indicator of invasive success. DNA sequences from the mitochondrial control region (or D-loop; 1050 bp = base pairs) and the 12S (small subunit; 500 bp) ribosomal gene from North American and Eurasian populations were tested. Degree of divergences were compared with the related European species, G. baloni and G. schraester, in order to provide a relative gauge for species-level separations. Samples included 10-15 individuals each from the St. Louis River/Lake Superior region (the North American origin), the Lake Huron population (Alpena, Michigan; first described in 1995), Bassenthwaite Lake (a recently introduced population in England, United Kingdom), St. Petersburg, Russia (near the Gulf of Finland/Baltic Sea), the Ob River (Siberia, Russia), and the Danube River (Gabcikovo, Slovakia). Results show that the North American population is invariable, supporting the hypothesis that the initial introduction consisted of a few individuals, showing a "founder" effect. Those from the new Lake Huron area appear genetically identical to those from the St. Louis River/Lake Superior region, suggesting spread. There are three very genetically divergent types of G. cernuus in Eurasia, a southern type (Danube River)-also introduced to Bassenthwaite Lake, a northern (Baltic Sea Area), and an eastern type (Siberia) which are separated by a large number of fixed sequence differences in both the control region and the 12S gene. The types are diverged by about 570,000 +/-100,000 years, representing early Pleistocene separations and are possibly different species. Surprisingly, the North American ruffe is the southern type (identical to those from the Danube River), which was previously also introduced to Bassenthwaite Lake and possibly to other regions in northwestern Europe. The origin is therefore not from the St. Petersburg/Baltic Sea area, as previously hypothesized by fishery scientists.

Contact: Carol A. Stepien, Department of Biology, Case Western Reserve University, Cleveland, Ohio 44106-7080 or cas20@po.cwru.edu
Keywords: Ruffe, Population_dynamics, Basic_biology
Product Type: Publications, Conference_proceedings
User Type: General