Seasonal occurrence of actinosporeans (Myxozoa) and oligochaetes (Annelida) at a trout hatchery in Bavaria, Germany.

A systematic inventory of actinosporeans and oligochaetes conducted over 3 years at a trout fish farm in Bavaria, Germany, allowed the identification of 12 actinosporeans from five collective groups: four Triactinomyxon (Triactinomyxon nov. types 1-4), two Raabeia (Raabeia nov. types 1, 2), two Echinactinomyxon ( E. radiatum, Echinactinomyxon nov. type 1), two Aurantiactinomyxon ( A. pavinsis, Aurantiactinomyxon nov. type 1) and two Neoactinomyxum (Neoactinomyxum nov. types 1, 2). Nine forms are novel but can be placed within existing collective groups. All 12 forms were detected in the laboratory in aquarium water associated with farm sediment. However, only four of these could be linked with an oligochaete host. Three families of oligochaetes were identified from the sediment: Tubificidae, represented by eight species, Lumbriculidae with one species and Naididae with two species. Only tubificid oligochaetes were found to host actinosporeans.