Kovac, 1998


Kovac, V. (1998) Biology of Eurasian Ruffe from Slovakia and Adjacent central european countries. J. Great Lakes Res., pp. 205-216

Associated characteristics

Species Development state Trait Primary Data Secondary Data
Gymnocephalus cernua Egg Egg size after water-hardening 0.97-1.07 [Activated egg] 1.02 mm
Gymnocephalus cernua Egg Egg adhesiveness Very adhesive Adhesive
Gymnocephalus cernua Egg Degree-days for incubation 136 136.0 °C * day
Gymnocephalus cernua Larvae Initial larval size 3.35-3.81 3.58 mm
Gymnocephalus cernua Larvae Larvae behaviour Most to the time they stay at the bottom Demersal
Gymnocephalus cernua Larvae Temperature during larval development At water temperature ranging from 16.2 to 23.2°C (mean 19.4°C), the larval period lasted 20 days 16.2 °C
Gymnocephalus cernua Female Age at sexual maturity 2 [Part of the population at 1] 2.0 year
Gymnocephalus cernua Female Length at sexual maturity 5.7-9 SL [All female exceeding 9 cm were mature] 7.35 cm
Gymnocephalus cernua Female Relative fecundity 585-1540 1062.5 thousand eggs/kg
Gymnocephalus cernua Female Oocyte development Polycyclic, with asynchrous ripening of eggs and protracted spawning Asynchronous
Gymnocephalus cernua Female Onset of oogenesis Between September and March, gonad weight increases slowly ['March', 'September']
Gymnocephalus cernua Male Age at sexual maturity 2 [Part of the population at 1] 2.0 years
Gymnocephalus cernua Male Length at sexual maturity 3.2-8 SL [All male exceeding 8 cm were mature] 5.6 cm
Gymnocephalus cernua Spawning conditions Spawning migration distance Ruffe do not make long migrations, however short diurnal and seasonal movements are common No data
Gymnocephalus cernua Spawning conditions Spawning season Mid-April to Mid-June ['April', 'May', 'June']
Gymnocephalus cernua Spawning conditions Spawning temperature 7.1-20.2 13.65 °C
Gymnocephalus cernua Spawning conditions Spawning water type Spawning of Eurasian ruffe in the the Baka side-arm system of the River Danube, in the Orava Reservoir, Lipno reservoir No category
Gymnocephalus cernua Spawning conditions Parity Most individuals atain a maximum age of 6 years, excepeionally 7 or 8 years No category