Distribution and seasonal occurrence of glochidia on the host fishes.
|Year of publication||2000|
|Type||Article in Proceedings|
|Conference||Acta Parasitologica, Abstracts: VIII European Multicolloquium of Parasitology|
|MU Faculty or unit|
|Keywords||Seasonality; spatial distribution; glochidia|
|Description||Objectives: Glochidia are the parasitic larvae of freshwater mussels (Mollusca:Unionidae); they parasite mostly on the fins and the gills of fish. Glochidia belonging to two genera, Unio and Anodonta, were observed on the host fishes. Altogether 2388 speciments of 22 fish species from three families were found; they were gathered from April 1997 to November 1999. For the distribution and seasonal pattern of occurrence, three host species (Rutilus rutilus, Perca fluviatilis and Rhodeus sericeus) have been investigated. Methods: Changes of prevalence and intensity of infestation were used to characterize infection. In the case of other fish species, presence or absence of glochidia were considered. Spatial distribution on the fins and gill apparatus was analyzed. Results: Unio glochidia were observed on the fish host from April to October with the highest prevalences during May and June. Anodonta glochidia attached fish from October to June, and prevalences reached maximum in November in winter and in March and April in spring. Glochidia of Unio, Anodonta were observed on 17, 10 fish species, respectively. The perch seemed to be the most susceptible host for both mussel genera, and on the contrary, bitterling was probably not a susceptible host for glochidia. Unio glochidia were mostly located on the gills, and Anodonta glochidia on the fins of the fish. The highest numbers of glochidia were observed on the second and third gill arch and pectoral fins. Conclusions: There was a difference in spatial distribution and seasonal occurrence among glochidia on the host fish.|