Parasitoses in the Fry of Selected Freshwater Fish Species Under the Conditions of Stripping and Rearing

Abstract

Navratil S.: Parasitoses in the Fry of Selected Freshwater Fish Species under the Conditions of Stripping and Rearing. Acta vet. Bmo. 60. 1991: 357-366. During the period from 1984 to 1989. the problem of parasitic invasion into the artificially reproduced and reared fry of the freshwater fish species (Barbus barbus, Chondrostoma nasus. Leuciscus cephalus, Aspius aspius) were- investigated at a specialized fish breeding farm ofthe Czech Angler's Union in Tfeb1C!-PouSov situated on the river Jihlava (the Danube river basin). The invasion with parasites was investigated in 979 fish specimens (846 juvenile. 133 adult) of the selected species and in 257 fish of other species. The reared fry of the selected fish species were found to be' endangered already in their first days ofHfe. predominantly by ectoparasitic protozoa with not definitely formed host specificity. Thus optimal rearing conditions have to be assured. along with regular exa­ mination of the health status. Efficient preventive antiparasitic baths have to be applied. It is advantagenous to complement these measures with an effective way of sanitation of the fish-rearing farms. by the investigation of the health status of fish in the feeder of the fish-hatchery and rearing pond with its regulated stocking, . or possibly by declaring relevant areas as being protected with the introduction of a closed turnover of the parent fish shoal. Barbus barbus. Chondrostoma nasus. Leuciscus cephalus. Aspius aspius. ectoparasitic protozoa. zoooeterinary measures