ruffe
(Gymnocephalus cernuus)
This species is Introduced in the United States
Eurasian Ruffe
Scientific NameGymnocephalus cernuus (Linnaeus, 1758)
AppearanceTotal length is usually 11-15 cm (approx. 4-6 in.) and up to 25 cm (approx. 10 in.). Head has no scales and mouth is terminal to slightly subterminal (snout overhangs the mouth opening).
FinsDorsal fin (on back) has two lobes: the anterior lobe is long with spines and it is attached by a membrane to a soft posterior lobe with 1 spine and numerous soft rays.
ColourColour is green-brown above, light brown sides with dark patches, yellowish below with black spots on the dorsal and caudal (tail) fins.
HabitatHighly adaptable and may live at a wide range of depths and conditions in lakes and rivers. Spawns at water temperatures between 4.9-20° C.
Introduced RangeIn Ontario: in Lake Superior near Thunder Bay, ON in the north and in the eastern part of the province in the St. Lawrence River east of Kingston, ON. In the United States: in Lake Superior, Lake Michigan and Lake Huron.
Native RangeNorthern Europe and Asia.
Pathway of Introduction and SpreadTransported to North America in the ballast water. It was first detected in the Lake Superior harbour of Duluth, Michigan. They may spread through ballast water exchange within the Great Lakes and may be unintentionally spread through the use of live baitfish.
ImpactsCan reach high densities and may compete with native game and forage fishes for habitat and food (zooplankton and benthic insects). May prey on eggs and larvae of native fish species.
ReferencesOntario Ministry of Natural Resources. 2010. Field Guide to Aquatic Invasive Species, 3rd Edition. Queen's Printer for Ontario. Ontario, Canada.
Selected Images
Maps
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Lists - This map identifies those states that have this species on their invasive species list or law.
Invasive Listing Sources
- Alberta Fisheries Act
- Idaho Invasive Species Act
- Maryland Invasive Species Council - Invasive Species of Concern in Maryland
- Michigan’s Prohibited and Restricted Species
- Minnesota DNR invasive species list
- New York Regulated and Prohibited Invasive Species - Regulated
- Ontario’s Invading Species Awareness Program Tracked Species List
- Pennsylvania's Field Guide to Aquatic Invasive Species
- Unlisted Species of Interest
- Wisconsin's Invasive species rule – NR 40
Taxonomic Rank
| Domain: Eukarya |
| Kingdom: Animalia |
| Phylum: Chordata |
| Subphylum: Vertebrata |
| Class: Actinopterygii |
| Subclass: Neopterygii |
| Order: Perciformes |
| Family: Percidae |
| Genus: Gymnocephalus |
| Gymnocephalus cernuus |
References
Common Name Reference: Integrated Taxonomic Information System on-line database.
Scientific Name Reference: Integrated Taxonomic Information System on-line database.