Seasonal dynamics of occurrence and reproduction of some parasites in four cyprinid fish cultured in ponds. II. Monogenea

The occurrence and reproductive activity of 10 monogeneans, parasitizing four herbivorous fish (common, grass, silver and big head carp) in pond culture were analyzed in relation to three seasons of the year (spring, summer, autumn). The population dynamics of autochthonous species showed the features characteristic for other European monogeneans: a high level of frequency and reproductive ability in the spring, probably connected with a distinct rise of ambient temperature in this season. Among acclimatized species, Dactylogyrus lamellatus and D. nobilis seem to be well adapted to the temperate climatic conditions, manifesting a high level of occurrence and reproductive activity at the beginning of spring. The occurrence of D. aristichthys, D. hypophthalmichthys and D. suchengtaii seem to retain the behavioural features connected with the climatic conditions of the region of their provenance. They probably do not reproduce in colder seasons, and develop better in the higher temperatures of summer.