Croatian Journal of Fisheries (Dec 1995)
WATER QUALITY AND ECTOPARASITE DISEASES OF CY- PRINIDAE FISH
Abstract
On large carp fish farms water from larger surface streams is used, which have been affected by industrial and urban pollution, making the zoohygienic conditions bad for the culturing region. The quality of the culturing region directly affects the growth, condition and health of the fish. The aim of this work was to investigate the components of phytoplankton and the physico-chemical indicators of water quality on the occurrence of ectoparasites on the cyprinidae fish farms. Investigation were carried out from May to September 1992 on the fish farms Narta and Blatnica. The main stock of the farms were there year old carp fry. Qualitative and quantitative analysis of phytoplankton, as well as the basic physico-chemical indicators were carried out by methods used in limnology. The health examination of the fish was carried out in view of the general clinical, microscopic and path anatomic examination. In the components of phytoplankton the species which participated in the group s were: Cyanobacteria (Cyanophyta), Euglenophita, Phyrrophyta, Chryso- phita and Chlorophyta. Eventhough there were indicators of greater and lesser water pollution, the betamesosaprobic representative were dominant. The obtained values of physico-chemical indicators ranged in the limitis characteristic of the cyprinidae fish farms. An exception was in the concentration of disolved oxygen in the water, which was relatively lower that the optimal concentration for cyprinidae, amounting to 1.4 mg.l-1 (pond 9). Based on the health examination of the ectoparasite fish, determined were representatives of the families: Trichodina, Argulus, Dactylogorus and Gyrodactylus, ectopara sites which mainly occur when there is low water quality, bad zoohygienic conditions in the ponds and an increase in water temperature. A higher invasion of ectoparasites was determined in the fish from ponds 9 and 10.
