4 YEARS RESEARCH ON THE REPRODUCTIVE-BEHA VIOR AND HYBRIDIZATION OF BARBUS-BARBUS AND BARBUS-MERIDIONALIS

This paper reviews the main results of 4 years studies on the reproduc tive behaviour of Barbus barbus (L., 1758) and Barbus meridionalis (Ri sso, 1826) under controlled conditions in aquarium. The reproductive b ehaviour is described as well as the behavioural mechanisms of hybridi zation. During the spawning act - sometimes preceded by <<forehead swi m>> in which two fish swim together, at high speed, head against head the female and the few accompanying males rise from the gravel and mov e their genital papilla in the gravel while releasing ova or sperm (fi g. 1 and 2). The reproductive behaviours of Barbus barbus and Barbus m eridionalis appear to be similar and hybridizations were observed, sho wing that no complete behavioural barrier blocks the mating of the two species (fig. 2). The daily rhythms of activity are compared within t he two species. The influence of temperature and daylength on the dail y rhythms of activity is discussed. in winter conditions, barbels exhi bit a night activity rhythm. Spawning occurs during daytime or during the night (fig. 3). The influence of spawning stimuli is analysed usin g dummies of different sizes and colors (photo I). Barbels seem to pre fer white, grey, yellow and brown colors to red or black colors.