Dependence that the community structure of the roach Rutilus rutilus (L.) parasites has on the host age

The changes that take place in the structure of the parasite communities of two roach populations as the hosts grow older have been studied in the Chivyrkuiskii Bay of Lake Baikal and the estuary of the Selenga River. The parasite communities are analyzed at the levels of host individuals (infracommunities), host age groups (sets of infracommunities), and host population (component community). The number of parasite species regularly increases as the roaches age in both aquatic bodies, whereas the evenness of the parasite communities decreases. The Berger-Parker dominance index of the parasite communities changes with the roach age in different directions, increasing in the Chivyrkuiskii Bay and decreasing in the estuary of the Selenga River. The changes in the Shannon diversity index for sets of infracommunities of roach parasites are the opposite of those in the Berger-Parker index.