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Species
Gymnocephalus cernuus (Linnaeus, 1758)
IUCN
NCBI
EOL Text
Habitat and Ecology
Eutrophic lakes, lowland and piedmont rivers. Prefers still or slow-flowing water with soft bottom, without vegetation. Most abundant in estuaries of large rivers, brackish lakes with salinities up to 10-12 and reservoirs. Generally increases in abundance with increased eutrophication.
Biology:
Females live up to 10 years, males up to seven. Spawns for the first time at 1-3 years, males one year earlier than females. Spawns in March-May, until July in the north, on a variety of substrates at depths of about 3 m or less. Spawns at temperatures above 6C in the north and above 10C in the south. Usually, a single female spawns with several males. Eggs become adhesive on contact with water and stick to stones or plants. Females may spawn intermittently, laying eggs in two or more portions, usually separated by about 30 days in summer. Eggs of first portion are larger than those of second portion. Larvae without, or with only a brief, pelagic larval stage, switching early to benthic life, secretive and solitary, not forming schools. Survival of larvae is poor below 10C and above 20C. Crepuscular or nocturnal. The well-developed cephalic lateral line system and tapetum lucidum in eyes makes it an efficient predator at night and in turbid waters. Usually feeds on benthic chironomid larvae and amphipods, which can be detected in the top layers of the substrate by sensory canals on head. Pelagic in coastal lakes and tidal estuaries, feeding on zooplankton and fish. When they coexist in deep lakes, Perca fluviatilis and G. cernuus partly occur at different depths, G. cernuus being more abundant in deeper layers.
Systems
- Freshwater
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | International Union for Conservation of Nature and Natural Resources |
Source | http://www.iucnredlist.org/apps/redlist/details/9568 |
Red List Criteria
Year Assessed
Assessor/s
Reviewer/s
Contributor/s
History
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1996Lower Risk/least concern (LR/lc)
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | International Union for Conservation of Nature and Natural Resources |
Source | http://www.iucnredlist.org/apps/redlist/details/9568 |
Habitat Type: Freshwater
Comments: In Europe, occurs in fresh and brackish water and in all types of lakes (eutrophic to oligotrophic); prefers turbid areas and soft bottom, usually without vegetation. In rivers, prefers slow-moving water. Spends day in deeper water and moves to shallows to feed at night. Tolerant of a wide range of conditions. Entered Lake Superior in the ballast water of a ship.
Ruffe is a freshwater fish commonly found in the IJsselmeer and other large open waters and canals in the Netherlands. It can grow up to 25 centimeters in length. During the day, it hunts in the water column for freshwater plankton, such as insect larvae and water fleas. It rests on the bottom at night. During spawning season from around April till June, ruffes form large schools. They spawn in shallow water. Together with roach, ruffe is the most important food source for cormorants in the IJsselmeer region.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Ecomare |
Source | http://www.ecomare.nl/index.php?id=3922&L=2 |
demersal; potamodromous (Ref. 51243); freshwater; brackish; pH range: 7.0 - 7.5; dH range: 8 - 12; depth range 10 - ? m (Ref. 9696)
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Crispina B. Binohlan, FishBase |
Source | http://www.fishbase.org/summary/SpeciesSummary.php?id=4474 |
Rounded Global Status Rank: G5 - Secure
Pos is een zoetwatervis die algemeen voorkomt in het IJsselmeer en andere grote open wateren en kanalen. Ze kunnen 25 centimeter lang worden. Overdag jagen ze in de waterkolom op zoetwaterplankton, zoals insectenlarven en watervlooien, 's nachts rusten ze op de bodem. In de paaitijd vormt pos grote scholen. Ze paaien van medio april tot juni in ondiep water. Pos is, naast blankvoorn, het belangrijkste voedsel voor de aalscholvers in het IJsselmeergebied.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Ecomare |
Source | http://www.ecomare.nl/index.php?id=3922&L=2 |
Depth range based on 9115 specimens in 1 taxon.
Water temperature and chemistry ranges based on 607 samples.
Environmental ranges
Depth range (m): 0.3 - 38
Temperature range (°C): 4.258 - 7.898
Nitrate (umol/L): 1.212 - 1.795
Salinity (PPS): 5.681 - 6.914
Oxygen (ml/l): 8.114 - 8.768
Phosphate (umol/l): 0.114 - 0.274
Silicate (umol/l): 12.053 - 14.880
Graphical representation
Depth range (m): 0.3 - 38
Temperature range (°C): 4.258 - 7.898
Nitrate (umol/L): 1.212 - 1.795
Salinity (PPS): 5.681 - 6.914
Oxygen (ml/l): 8.114 - 8.768
Phosphate (umol/l): 0.114 - 0.274
Silicate (umol/l): 12.053 - 14.880
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
License | http://creativecommons.org/publicdomain/mark/1.0/ |
Rights holder/Author | Ocean Biogeographic Information System |
Source | http://www.iobis.org/mapper/?taxon_id=449331 |
Population
Population Trend
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | International Union for Conservation of Nature and Natural Resources |
Source | http://www.iucnredlist.org/apps/redlist/details/9568 |