Popova, O.A., Y.S. Reshetnikov, V.I. Kiyashko, Y.Y. Dgebuadze, and V.N. Mikheev, 1997.   Ruffe from the Former USSR: Variability Within the Largest Part of Its Natural Range, A.N. Severtsov Institute of Ecology and Evolution, Institute of Biology of Inland Waters

Ruffe from the Former USSR: Variability Within the Largest Part of Its Natural Range

ABSTRACT
A review of current data on the ruffe, Gymnocephalus cernuus L., range, variability of its meristic and morphological characters, diet composition and trophic relationships, habitats, behavior, growth rate and life cycle strategy, reproduction and abundance. Ruffe, a monotypic species is found from the Baltic Sea to the Kolyma River. Recent evidence extends its distribution as far as the Arctic coast both in Europe and Asia. In the south, the range is restricted by the Caucasus in Europe, and in Asia by the Aral Sea basin and upper reaches of several large Siberian rivers. Ruffe are a predominantly settled fish. Its seasonal migrations are related mainly to reproduction. In lakes and reservoirs, ruffe are found everywhere from shallow to the deepest zones. In rivers, they prefer sites with slow current. Larval ruffe feed mainly on zooplankton, but even adult fish can ascend from the bottom and consume large cladocerans and copepods. Fingerling ruffe feed mainly upon bottom and demersal prey (insects: chironomids, trichopterans, ephemeropterans; crustaceans: amphipods, isopods, and mysids). Ruffe larger than 10 cm often prey upon fish including young conspecifics. Eggs of whitefishes in Northern Europe and Siberia, and eggs of cyprinids in the temperate zone of Europe can be a supplementary food. Adults compete with bream, roach, benthivorous whitefishes, and prey of pikeperch, burbot, pike, large perch, and eel. Ruffe show flexible foraging, breeding, and migratory behavior. They mature very early, at 2-3 years, males sometimes in the first year. The age of maturation is almost the same from the northern to southern areas. Spawning is intermittent (usually 2-3 portions). Fecundity tends to increase north to south. Maximum age is 15 years, although in the south and temperate zone, usually not more than 10 years. Maximum length is about 20 cm, weight is 200 g. The highest growth rate is recorded in the first year. Daily specific growth rate is rather constant everywhere; the fastest growth was observed in the newly-impounded reservoirs. Ruffe variability to a larger extent depends on local ecological situations rather than on latitudinal factors. Attempts to control ruffe populations with small-mesh seines were unsuccessful and only caused a reduction in average age of populations. Introduction of some piscivorous fishes (eel, pikeperch) was more efficient.

Contact: O.A. Popova, A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow 117 071 Russia
Keywords: Ruffe, Basic_biology, Ecological_interactions
Product Type: Publications, Conference_proceedings
User Type: General