ABSTRACT
The fauna of parasitic protozoans of the bream (Abramis brama) from different reachs of the Rybinsk water reservoir was investigated. 350 fish specimens have been examined by the method of total dissection. The greater number of parasites and diversity (33 species) were observed in the Volzhski reach: infusoria--16 species, myxosporidia 12, flagellata--4, dermocystidia--1. In the breams of Sheksninski reach 18 species of parasites were recovered: infusoria--8, myxosporidia--8, flagellata--1, dermocystidia--1. Parasite protozoans from the Molozhski reach were represented by 14 species: myxosporidia--8, infusoria--5, flagellata--1. Statistic analysis of the morphological variability of spores of the myxosporidians from gills (Myxobolus muelleri and M. exiguus) has displayed the decrease of spore size in the row Molozhski-Volzhski-Sheksninski reachs. Some parasitic protozoans could be used as indicators of local fish herds.
Subject(s)
Eukaryota/isolation & purification , Fishes/parasitology , Animals , Eukaryota/classification , Fresh Water , Russia , SeasonsABSTRACT
The mass infection of larvae and youngsters of carp fishes with the peritrichoid Ambiphrya ameiuri has been recorded in natural condition in the Rybinsk water reservoir. The uneven localisation of ambiphyrans on the body surface has been observed on the hosts Blicca bjorkna and Abramis brama. Most high density of parasites was on the breast, back and tail fins. The morphological variability of ambiphyrans in dependence upon their localisation on the fish body has been observed. Details being significant for the taxonomy have been studied by means of the scan electron microscope. It has been found that the scopulae (greatly developed attaching organ of A. ameiuri) in cases of heavy infection cover about 50-60% of the skin epithelium of fish larvae. In these cases the significant part of skin epithelium, which performs the respiratory function is excludes of the active oxygen supply that cause the illness and death of young fishes.
