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Gymnocephalus cernuus in Finland
Ruffe

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Gymnocephalus cernuus   (Linnaeus, 1758)
Family:	Percidae (Perches) , subfamily: Percinae			picture (Gycer_u0.jpg) by Zienert, S.
Order:	Perciformes  (perch-likes)
Class:	Actinopterygii (ray-finned fishes)
FishBase name:	Ruffe
Max. size:	25.0 cm TL (male/unsexed; Ref. 556); max. published weight: 400 g (Ref. 556)
Environment:	demersal; potamodromous; pH range: 7 - 7.5; dH range: 8 - 12 ; depth range - 10 m
Climate:	temperate; 10 - 20°C; 74°N - 43°N
Global Importance:	fisheries: minor commercial; bait: usually
Resilience:	High, minimum population doubling time less than 15 months (K=0.4-0.48; tm=1-2)
Distribution:	Europe: France to eastern Siberia and to Kolyma river. Recently established in Lakes Superior and Michigan, USA (Ref. 3814). Several countries report adverse ecological impact after introduction.
Diagnosis:	Dorsal spines (total): 12-19; Dorsal soft rays (total): 11-16; Anal spines: 2-2; Anal soft rays: 5-6; Vertebrae: 35-36. Caudal fin with 16 to 17 rays (Ref. 40476). Dorsal fins are fused. Color brownish with dark spots (Ref. 35388).
Biology:	Inhabits lakes, quiet pools and margins of streams. Prefers deep water with deposits of sand and gravel (Ref. 9696). The membranous external walls of the head canals of this species provide high directional sensitivity; can feed at night in the dark using the lateral line system; feeds on zooplankton, chironomids, oligochaetes and amphipods (Ref. 10999). White to yellow eggs in sticky strands are found on rocks and weed in shallow water (Ref. 41678). Used as bait for pike (Ref. 6258). Can tolerate some degradation of the environment (Ref. 30578)
Threatened:	, (Ref. 36508)
Dangerous:	potential pest
Coordinator:
Main Ref:	Kottelat, M.. 1997. (Ref. 13696)
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Finland country information
Common names:	Kiiski		Ref:  Koli, L., 1990
Status:	native		Ref:  Winkler, H.M., K. Skora, R. Repecka, M. Ploks, A. Neelov, L. Urho, A. Gushin and H. Jespersen, 2000
Salinity:	freshwater, brackish
Abundance:	abundant (always seen in some numbers)		Ref:  Koli, L., 1990
Importance:	subsistence fisheries		Ref:
Regulations:	no regulations		Ref:
Uses:	no uses
Comments:	Occurs through the country except in the northern Lappland.
Country Information:	www.cia.gov/cia/publications/factbook/geos/fi.html
Occurrences:	Occurrences    Point map
Main Ref:	Koli, L., 1990
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More information:	Countries FAO areas Occurrences Introductions Ecosystem Ecology Diet Food items Food consumption Ration Predators Ciguatera Fish loss Common names Synonyms Pictures Sounds Reproduction Maturity Spawning Eggs Egg dev. Larvae Larval dynamics References Growth L-W relationship L-L relationship Length frequencies Recruitment Max. age & size Metabolism Morphology Morphometrics Gill area Brains Vision Collaborators Genetics Allele frequencies Heritability Strains Aquaculture Aquaculture profile Diseases Ecotoxicology Processing Speed Swim. type Stamps
	Note: No data are available if label is black .
Tools:	Biogeographic modelling | Bio-Quiz | E-book | Field guide | Identification keys | Length-frequency Wizard | Life-history tool | Point map |
Internet sources:	Alien/Invasive species database | BiOSC Point Data | CISTI | Google | GOBASE | GenBank ( genome, nucleotide ) | National databases | PubMed | Scirus | Public aquariums | Tree of Life | Zoological Record FishWatcher | Other web sites |
	Note: use the Back button of your browser to return to FishBase.
	Modified:  Sampang, Arlene G.	Entered:  Froese, Rainer

	Ref.:				Glossary
		(e.g. 9948)				(e.g. cephalopods)
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Page created by: Eli, 20.10.03, last modified by Eli, 26.06.07