Gymnocephalus cernuus
System : Freshwater
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Actinopterygii
Perciformes
Percidae
  • General
  • Distribution
  • Impact
  • Management
  • Bibliography
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Common name
pope (English), river ruffe (English), Eurasian ruffe (English), blacktail (English), ruffe (English), redfin darter (English)
Synonym
Acerina cemua , (Linnaeus, 1758)
Acerina czekanowskii
Acerina fischeri
Acerina vulgaris
Perca cermua , Linnaeus, 1758
Similar species
Stizostedion vitreum, Perca flavescens, Percopsis omiscomaycus
Summary
Gymnocephalus cernuus is introduced into new locations in the ballast water of ships. Introductions also occur through escaped or discarded live bait. It has become a threat to the Great Lakes in North America and some lakes in Europe. Gymnocephalus cernuus has become invasive due to its reproduction ablity; its wide habitat range and its aggressive feeding habits.
Species Description
Gymnocephalus cernuus are small, reaching up to 20cm in length, with olive brown colouring on the back and pale sides. They have spiny dorsal and anal fins (Hajjar, 2002).
Notes
According to Hajjar (2002), \"Gymnocephalus cernuus have few predators in Europe and Asia, and most will only prey on G. cernuus when other prey is scarce. Predators include pike perch, northern pike, some eel, burbot, lake trout, small-mouth bass, black crappie, bullheads, walleye, Eurasian perch, yellow perch, cormorants, and kingfishers. To avoid predators, the ruffe prefers darkness, and uses special sensory organs called \"neuromasts\" to detect predators and prey. The ruffe also has a large, spiny dorsal fin likely unpalatable to predators.
Lifecycle Stages
According to Hajjar (2002), “the reproductive potential of G. cernuus is exceptionally high. It matures early, in two to three years, but males in some populations may mature in one year in warmer waters, reaching 11-12cm in length at maturity. G. cernuus spawn in a variety of habitats and environmental conditions. Spawning occurs at a wide range of temperatures, 4.9 to 20 degrees Celsius, and on a variety of substrates, including submerged plants, logs, branches, gravel, rocks, hard bottoms of clay, and sand. Eggs develop normally at pH 6.5 to pH 10.5, one of the widest ranges from a broad set of fish tested. Eggs hatch in 5-12 days. Young tolerate temperatures ranging from 7- 30 degrees Celsius. Females generally live for a maximum of 11 years, males for 7 years.”
Uses
Hajjar (2002) explains that Gymnocephalus cernuus fishery would only have minor commercial value. \"In some eastern European countries it is considered a delicacy, but is generally only used as a bait by anglers.\"
Habitat Description
G. cernuus can tolerate a wide range of ecological and environmental conditions. They are found in fresh and brackish water (with salinity up to 12ppt) and occur at depths varying from 0.25m to 85m. they are also able to thrive in eutrophic conditions (Hajjar, 2002).
Reproduction
According to Hajjar (2002), G. cernuus is a prolific breeder. \"Females produce up to 200,000 eggs in the first batch, and up to 6,000 eggs per subsequent batch.\"
Nutrition
Hajjar (2002) writes that “Gymnocephalus cernuus is an aggressive feeder. Depending on its life history stage and location, G. cernuus prey upon rotifer and copepod nauplii, cyclopoid copepods, cladocera, and chironomid larvae, macrocrustaceans, heleids, dragonfly and caddisfly larvae, zooplankton, mollusks, water mites, isopods, fly larvae and juveniles, and fish larvae (especially Coregonus spp.), and smelt. Larger G. cernuus will eat some small fish, including juvenile smelt, gobies, perch and nine-spined sticklebacks. According to Sea Grant (2002) \"G. cernuus spends its days in deeper water and moves to the shallows to feed at night.\" Nutrition includes eggs of whitefish (Coregonus spp.) (Adams & Maitland, 1998); C. lavaretus ( Schmid, 1998) and C. albula (Winfield et al. 2004).
Pathway
Introductions occur through escaped or discarded live bait.According to Hajjar (2002), the fish was introduced and is mainly spread by boats taking on ballast water and bring it to new locations.

Principal source: Hajjar, R. 2002. Ruffe (Gymnocephalus cernuus) Columbia University , New York, United States.

Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)

Review: Ian J Winfield. Centre for Ecology & Hydrology, UK

Publication date: 2006-03-31

Recommended citation: Global Invasive Species Database (2024) Species profile: Gymnocephalus cernuus. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=544 on 26-04-2024.

General Impacts
According to Sea Grant (2002), \"Gymnocephalus cernuus compete with native fish for food and habitat. Because of this, walleye, perch, and a number of small forage fish species are seriously threatened by continued expansion of the ruffe's range. Hajjar (2002), describes G. cernuus as prolific breeders and aggressive feeders. Their indiscriminate habitat requirements and selected life history traits are conducive to invasion. Their tolerance of different habitats and environmental conditions ensures successful introduction to novel locations.Their early maturation and high fecundity result in quick increases in abundance and quick establishment. G. cernuus have a competitive advantage over other bottom feeding fish, such as bream, Coregonus spp., roach, sturgeon, smelt, trout perch, Eurasian perch, and yellow perch, due to their flexible foraging abilities. They also “thrive in eutrophic conditions such as those associated with human disturbance, out-competing fish with narrower ecological requirements. They have been implicated in density declines of native fish by egg predation and competition for food in some European waters where they have been introduced. While the impact of G. cernuus on the Great Lakes ecosystem has not yet been considerable, the population is increasing and spreading, and has the potential to detrimentally effect highly valued commercial fishery species throughout the Great Lakes. And with the convenient mode of transportation of ballast water in ships traversing the Great Lakes, it is likely that G. cernuus will invade further habitats in the Great Lakes.\"
Management Info
According to Hajjar (2002), many physical, chemical, and biological methods have been suggested to contain the spread of the G. cernuus. In some Polish lakes, stocking of elvers and measures taken to protect pikeperch and eel resulted in an unintentional 5-7 fold decrease of G. cernuus. In 1989, attempts to control G. cernuus with a top-down predator control strategy failed. Northern pike and walleye were stocked in problem areas, but both species preferred native species and failed to control the G. cernuus population. Piscicides such as 3-trifluoromethyl-4nitrophenol (TFM) are now being suggested as an effective measure to control the G. cernuus population, but effects of such chemicals on other biota are questionable. Many believe that it is too late for eradication of G. cernuus, and instead are concentrating efforts on controlling the spread of the invasion. The Volunteer Ballast Water Management Program was enforced in 1993 for this purpose. In this joint effort among several Canadian and American coastal organizations and ocean lines, ships calling at ports in the western portions of Lake Superior were discouraged from taking on or discharging ballast water from these areas.\"\" According to Sea Grant (2002), \"fisheries managers have also considered a program to net and destroy as many ruffe as possible in the St. Louis River, on the theory that the ruffe's range would not expand as rapidly if populations were controlled.\" A modified design of the Windermere trap, (a useful collapsible tool in surveillance, monitoring, or control programs for ruffe or similar species, especially in situations where gillnetting or bottom trawling are not feasible) is found to be inexpensive and lightweight.
Countries (or multi-country features) with distribution records for Gymnocephalus cernuus
NATIVE RANGE
  • asia
  • europe
Informations on Gymnocephalus cernuus has been recorded for the following locations. Click on the name for additional informations.
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Details of Gymnocephalus cernuus in information
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Occurrence
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Species notes for this location
Location note
Management notes for this location
Impact
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Outcome:
Ecosystem services:
Impact information
According to Sea Grant (2002), \"Gymnocephalus cernuus compete with native fish for food and habitat. Because of this, walleye, perch, and a number of small forage fish species are seriously threatened by continued expansion of the ruffe's range. Hajjar (2002), describes G. cernuus as prolific breeders and aggressive feeders. Their indiscriminate habitat requirements and selected life history traits are conducive to invasion. Their tolerance of different habitats and environmental conditions ensures successful introduction to novel locations.Their early maturation and high fecundity result in quick increases in abundance and quick establishment. G. cernuus have a competitive advantage over other bottom feeding fish, such as bream, Coregonus spp., roach, sturgeon, smelt, trout perch, Eurasian perch, and yellow perch, due to their flexible foraging abilities. They also “thrive in eutrophic conditions such as those associated with human disturbance, out-competing fish with narrower ecological requirements. They have been implicated in density declines of native fish by egg predation and competition for food in some European waters where they have been introduced. While the impact of G. cernuus on the Great Lakes ecosystem has not yet been considerable, the population is increasing and spreading, and has the potential to detrimentally effect highly valued commercial fishery species throughout the Great Lakes. And with the convenient mode of transportation of ballast water in ships traversing the Great Lakes, it is likely that G. cernuus will invade further habitats in the Great Lakes.\"
Red List assessed species 2: CR = 1; EN = 1;
View more species View less species
Locations
Lake Superior
UNITED KINGDOM
UNITED STATES
Upper Lake Constance
Mechanism
[2] Competition
[3] Predation
Outcomes
[3] Environmental Ecosystem - Habitat
  • [3] Reduction in native biodiversity
[1] Environmental Species - Population
  • [1] Population size decline
Management information
According to Hajjar (2002), many physical, chemical, and biological methods have been suggested to contain the spread of the G. cernuus. In some Polish lakes, stocking of elvers and measures taken to protect pikeperch and eel resulted in an unintentional 5-7 fold decrease of G. cernuus. In 1989, attempts to control G. cernuus with a top-down predator control strategy failed. Northern pike and walleye were stocked in problem areas, but both species preferred native species and failed to control the G. cernuus population. Piscicides such as 3-trifluoromethyl-4nitrophenol (TFM) are now being suggested as an effective measure to control the G. cernuus population, but effects of such chemicals on other biota are questionable. Many believe that it is too late for eradication of G. cernuus, and instead are concentrating efforts on controlling the spread of the invasion. The Volunteer Ballast Water Management Program was enforced in 1993 for this purpose. In this joint effort among several Canadian and American coastal organizations and ocean lines, ships calling at ports in the western portions of Lake Superior were discouraged from taking on or discharging ballast water from these areas.\"\" According to Sea Grant (2002), \"fisheries managers have also considered a program to net and destroy as many ruffe as possible in the St. Louis River, on the theory that the ruffe's range would not expand as rapidly if populations were controlled.\" A modified design of the Windermere trap, (a useful collapsible tool in surveillance, monitoring, or control programs for ruffe or similar species, especially in situations where gillnetting or bottom trawling are not feasible) is found to be inexpensive and lightweight.
Locations
UNITED KINGDOM
UNITED STATES
Management Category
Prevention
Control
Bibliography
25 references found for Gymnocephalus cernuus

Management information
Bernstein, N.P and Olson, J.R., 2001. Ecological problems with Iowa s invasive and introduced fishes. Journal of the Iowa Academy of Science. 108(4). 185-209.
Brown, W. P; Selgeby, J. H and Collins, H. L, 1998. Reproduction and early life history of ruffe (Gymnocephalus cernuus) in the St. Louis River, a Lake Superior tributary. Journal of Great Lakes Research, 24(2):217-227.
Summary: The reproduction and early life history of the ruffe (Gymnocephalus cernuus) in the St. Louis River tributary of Lake Superior is examined. Spawning period and corresponding water temperatures are reported as is timing of protolarval emergence. Diel movements of larval ruffe are also reported. Characteristics of ruffe reproduction and the activity of larval ruffe are used to estimate the most probable times of larval infestation of ballast water and subsequent translocation of larval ruffe. The authors suggest that this information may be useful to fishery managers developing ruffe control methods as well as determining possible interactions between ruffe and native species during early life stages.
Centre for Environment, Fisheries & Aquaculture Science (CEFAS)., 2008. Decision support tools-Identifying potentially invasive non-native marine and freshwater species: fish, invertebrates, amphibians.
Summary: The electronic tool kits made available on the Cefas page for free download are Crown Copyright (2007-2008). As such, these are freeware and may be freely distributed provided this notice is retained. No warranty, expressed or implied, is made and users should satisfy themselves as to the applicability of the results in any given circumstance. Toolkits available include 1) FISK- Freshwater Fish Invasiveness Scoring Kit (English and Spanish language version); 2) MFISK- Marine Fish Invasiveness Scoring Kit; 3) MI-ISK- Marine invertebrate Invasiveness Scoring Kit; 4) FI-ISK- Freshwater Invertebrate Invasiveness Scoring Kit and AmphISK- Amphibian Invasiveness Scoring Kit. These tool kits were developed by Cefas, with new VisualBasic and computational programming by Lorenzo Vilizzi, David Cooper, Andy South and Gordon H. Copp, based on VisualBasic code in the original Weed Risk Assessment (WRA) tool kit of P.C. Pheloung, P.A. Williams & S.R. Halloy (1999).
The decision support tools are available from: http://cefas.defra.gov.uk/our-science/ecosystems-and-biodiversity/non-native-species/decision-support-tools.aspx [Accessed 13 October 2011]
The guidance document is available from http://www.cefas.co.uk/media/118009/fisk_guide_v2.pdf [Accessed 13 January 2009].
Dawson, V.K; Bills, T.D; Boogaard, M.A., 1998. Avoidance behavior of ruffe exposed to selected formulations of piscicides. Journal of Great Lakes Research. 24(2). 343-350.
Eckmann, R and Roesch, R., 1998. Lake Constance fisheries and fish ecology. Ergebnisse der Limnologie. 0(53). 285-301.
Fullerton, A.H., G.A. Lamberti, D.M. Lodge, and F.W. Goetz, 2000. Potential for Resource Competition between Eurasian Ruffe and Yellow Perch: Growth and RNA Responses in Laboratory Experiments, Transactions of the American Fisheries Society 129: 1331�1339
Mayo, K. R, Selgeby, J. H., 1996. Trophic relations of ruffe and the status of ongoing research in the St. Louis River estuary, Lake Superior. Presented at Great Lakes Fishery Commission Lake Superior Committee Meeting, 19 March, , Duluth, MN. 10 p
Mendoza, R.E.; Cudmore, B.; Orr, R.; Balderas, S.C.; Courtenay, W.R.; Osorio, P.K.; Mandrak, N.; Torres, P.A.; Damian, M.A.; Gallardo, C.E.; Sanguines, A.G.; Greene, G.; Lee, D.; Orbe-Mendoza, A.; Martinez, C.R.; and Arana, O.S. 2009. Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species. Commission for Environmental Cooperation. 393, rue St-Jacques Ouest, Bureau 200, Montr�al (Qu�bec), Canada. ISBN 978-2-923358-48-1.
Summary: In 1993, Canada, Mexico and the United States signed the North American Agreement on Environmental Cooperation (NAAEC) as a side agreement to the North American Free Trade Agreement (NAFTA). The NAAEC established the Commission for Environmental Cooperation (CEC) to help the Parties ensure that improved economic efficiency occurred simultaneously with trinational environmental cooperation. The NAAEC highlighted biodiversity as a key area for trinational cooperation. In 2001, the CEC adopted a resolution (Council Resolution 01-03), which created the Biodiversity Conservation Working Group (BCWG), a working group of high-level policy makers from Canada, Mexico and the United States. In 2003, the BCWG produced the �Strategic Plan for North American Cooperation in the Conservation of Biodiversity.� This strategy identified responding to threats, such as invasive species, as a priority action area. In 2004, the BCWG, recognizing the importance of prevention in addressing invasive species, agreed to work together to develop the draft CEC Risk Assessment Guidelines for Aquatic Alien Invasive Species (hereafter referred to as the Guidelines). These Guidelines will serve as a tool to North American resource managers who are evaluating whether or not to introduce a non-native species into a new ecosystem. Through this collaborative process, the BCWG has begun to implement its strategy as well as address an important trade and environment issue. With increased trade comes an increase in the potential for economic growth as well as biological invasion, by working to minimize the potential adverse impacts from trade, the CEC Parties are working to maximize the gains from trade while minimizing the environmental costs.
Available from: English version: http://www.cec.org/Storage/62/5516_07-64-CEC%20invasives%20risk%20guidelines-full-report_en.pdf [Accessed 15 June 2010]
French version: http://www.cec.org/Storage/62/5517_07-64-CEC%20invasives%20risk%20guidelines-full-report_fr.pdf [Accessed 15 June 2010]
Spanish version: http://www.cec.org/Storage/62/5518_07-64-CEC%20invasives%20risk%20guidelines-full-report_es.pdf [Accessed 15 June 2010].
Ricciardi, A and Rasmussen, J.B., 1998. Predicting the identity and impact of future biological invaders: A priority for aquatic resource management. Canadian Journal of Fisheries & Aquatic Sciences. 55(7). 1759-1765.
Schmid, W., 1998.Coregonus lavaretus ova predation by newly introduced ruffe (Gymnocephalus cernuus L.) in Lake Constance, Germany. Ergebnisse der Limnologie. 0(50). 179-183.
Winfield, I.J and Durie, N.C., 2004. Fish introductions and their management in the English Lake District. Fisheries Management and Ecology, 11, 195�201.
Winfield, I.J; Fletcher, J.M and James, J.B., 2004. Conservation ecology of the vendace (Coregonus albula) in Bassenthwaite Lake and Derwent Water, U.K. Annales Zoologici Fennici. 41(1). 155-164
General information
Adams, C. E and Maitland, P.S., 1998. The ruffe population of Loch Lomond, Scotland: Its introduction, population expansion, and interaction with native species. Journal of Great Lakes Research, 24(2):249-262.
Summary: The introduction of the ruffe (Gymnocephalus cernuus) into Loch Lomond, Scotland in 1982 and the subsequent expansion of the population are discussed. The population is reported to have grown exponentially between 1982 and 1992, and then stabilized at a very high level. Food habits of the ruffe are examined with emphasis on diet overlap between this exotic species and native species including perch (Perca fluviatilis) and brown trout (Salmo trutta). Results suggest that feeding resource competition does not occur between ruffe and perch or ruffe and brown trout during their adult lives. Possible disruption of predator-prey interactions is also discussed focusing on the use of ruffe as prey by cormorants, herons, and northern pike (Esox lucius). The effects of this diet shift on native fish populations is commented on.
FishBase, 2005. Species profile Gymnocephalus cernuus Ruffe
Summary: FishBase is a global information system with all you ever wanted to know about fishes . FishBase on the web contains practically all fish species known to science. FishBase was developed at the WorldFish Center in collaboration with the Food and Agriculture Organization of the United Nations (FAO) and many other partners, and with support from the European Commission (EC). Since 2001 FishBase is supported by a consortium of seven research institutions. You can search on Search FishBase
This species profile is available from: http://www.fishbase.org/summary/speciessummary.cfm?id=4474i [Accessed 21 March, 2005]
Freyhof, J. & Kottelat, M. 2008. Coregonus pennantii. In: IUCN 2012. IUCN Red List of Threatened Species.
Summary: Available from: http://www.iucnredlist.org/details/135518/0 [Accessed 25 May 2012]
Hajjar, R. 2002. Ruffe (Gymnocephalus cernuus) Columbia University , New York, United States.
Summary: Contains common names, scientific name, taxonomy, description, native and non-native distribution, mode of introduction and spread, benefits, impacts, and control methods.
Available from: http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Gymnocephalus%20cernuus.html [Accessed 2 November 2003]
ITIS (Integrated Taxonomic Information System), 2005. Online Database Gymnocephalus cernuus
Summary: An online database that provides taxonomic information, common names, synonyms and geographical jurisdiction of a species. In addition links are provided to retrieve biological records and collection information from the Global Biodiversity Information Facility (GBIF) Data Portal and bioscience articles from BioOne journals.
Available from: http://www.cbif.gc.ca/pls/itisca/taxastep?king=every&p_action=containing&taxa=Gymnocephalus+cernuus&p_format=&p_ifx=plglt&p_lang= [Accessed March 2005]
Maitland, P.S and East, K., 1989. An increase in numbers of ruffe, Gymnocephalus cernua (L.), in a Scottish loch from 1982 to 1987.
Summary: An increase in the abundance of the ruffe (Gymnocephalus cernua), a species recently introduced into Loch Lomond, is reported. Concerns about the impact of increasing ruffe predation on existing species, particularly the powan (Coregonus lavaretus) are discussed.
Maitland, P.S; East, K and Morris, K.H., 1983. Ruffe Gymnocephalus cernua (L.), new to Scotland, in Loch Lomond.
Summary: The occurrence of the ruffe (Gymnocephalus cernua (L.)) in Loch Lomond, Scotland is reported. Historically robust native populations have prevented invading species from becoming established, however disruption in native species may provide an opening for newly introduced species and adverse effects on existing fish populations in the Loch are feared. Steps to prevent further introductions are discussed.
Moyle, P.B., 1991. Ballast water introductions. Fisheries, 16(1):4-6.
Pratt, D.M; Blust, W.H, Selgeby, J. H., 1992. Ruffe, Gymnocephalus cernuus: Newly introduced in North America. Canadian Journal of Fisheries and Aquatic Sciences, 49:1616-1618.
Summary: The first known occurrence of the Eurasian ruffe (Gymnocephalus cernuus) in North America is reported. Possible mechanisms of the introduction of this exotic species are mentioned. Aspects of basic ruffe biology are reported including physical description, habitat, fecundity, and food habits. The possible ramifications of the introduction of G. cernuus are speculated including impacts on native fish.
Sea Grant, 2002. Ruffe (Gymnocephalus cernuus) Exotic Aquatics On The Move [Online Database].
Summary: Includes information on description, impacts, orgin, distribution, and control methods.
Available from: http://www.iisgcp.org/EXOTICSP/ruffe.htm [Accessed 2 November 2003]
Selgeby J., 1998. Predation by ruffe (Gymnocephalus cernuus) on fish eggs in Lake Superior. Journal of Great Lakes Research, 24(2):304-308.
Summary: The food habits of ruffe (Gymnocephalus cernuus) in the St. Louis River estuary, Lake Superior, are examined to assess predation on native species� eggs. Food items found in stomach analysis denoted an entirely benthic foraging behavior and showed fish eggs to be one of the most frequently consumed items. Using genetic characterization (PCR-RSLP) the eggs were determined to be lake herring (Coregonus artedii). Based on reports of ruffe predation on eggs and the effects on populations in other areas the authors speculate that ruffe predation could play a role in overwinter mortality for fall spawning fish in the Great Lakes.
Winfield, I. J., 1992. Threats to the lake fish communities of the U.K. arising from eutrophication and species introductions. Netherlands Journal of Zoology, 42:233-242.
Summary: The direct and indirect effects of eutrophication on U.K. fish communities is briefly discussed with references cited for more in depth discussions. Also included is a discussion on how species introductions can effect U.K. fish communities. Attention is focused on pike-perch (Stizostedion lucioperca L.), ruffe (Gymnocephalus cernuus L.) and roach (Rutilus rutilus L.) in regard to their roles as predators, competitors and environmental degraders.
Winfield, I. J., Adams, C. E. & Fletcher, J. M. (1996). Recent introductions of the ruffe (Gymnocephalus cernuus) to three United Kingdom lakes containing Coregonus species. Annales Zoologici Fennici 33, 459-466.
Contact
The following 1 contacts offer information an advice on Gymnocephalus cernuus
Winfield,
Ian J
Organization:
Centre for Ecology & Hydrology, UK
Email:
Address:
Centre for Ecology & Hydrology
Lancaster Environment Centre
Library Avenue
Bailrigg
Lancaster
Lanchashire LA1 4AP
U.K.
Phone:
(0) 1524 595846
Fax:
(0) 1224 62536
Gymnocephalus cernuus
pope, river ruffe, Eurasian ruffe, blacktail, ruffe, redfin darter
Date assessed
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Recommended citation
(2024). Gymnocephalus cernuus. IUCN Environmental Impact Classification for Alien Taxa (EICAT).