Behavior of juveniles of roach Rutilus rutilus (cyprinidae), produced by breeders from a tributary of the Rybinsk Reservoir and from a nonfreezing area of the Moskva River at variable temperatures

Abstract

The study has revealed differences in search behavior among juvenile individuals of the roach Rutilus rutilus produced by breeders from a tributary of the Rybinsk Reservoir and from nonfreezing areas of the Moskva River. It has been shown that differences in behavioral responses of juveniles are minimal at a stable temperature (approximately 20°C). Gradually rising or falling temperatures lead to an increase in the variation of behavioral parameters. Response to rising temperature is more pronounced in juvenile roach individuals produced by breeders from the Rybinsk Reservoir tributary, while response to decreasing temperature is, on the contrary, more pronounced in individuals produced by breeders from the nonfreezing Moskva River area. Year-round occurrence in zones with heated water in the nonfreezing Moskva River area has probably contributed to a change in the roach population’s adaptation to cold, consolidated by selection at the genetic level over several generations.