LEK-LIKE SPAWNING BEHAVIOR AND DIFFERENT FEMALE MATE PREFERENCES IN ROACH (RUTILUS-RUTILUS)

I studied the scarcely known mating system of roach. Individually mark ed fish were kept in a pond with a glass wall that allowed observation s of spawning. The roach showed a lek-like mating system which has not been described previously, with bourgeois males and reproductive para sites (i.e. simultaneous parasitic spawning), both tactics used by the same individuals. Females had the possibility to choose freely among the males but could probably hardly avoid multi-male fertilization. Mo st females spawned repeatedly during the observation period. They show ed strong individual preferences with different females preferring dif ferent males or spawning sites.