Parasitic nametodes of Prussian carps (Crassius gibelio Bloch, 1782) from the waters of Kopački rit Nature Park

Uzorkovanje babuški (Carassius gibelio Bloch, 1782) provedeno je u rujnu 2018. godine na tri različite postaje unutar Parka prirode Kopački rit: jezero Sakadaš i kanali Čonakut te Novi kanal. Od uzorkovanih 198 babuški, u njih 20 je utvrđena prisutnost ličinki trećeg stadija oblića roda Contracaecum Railliet i Henry, 1912 dajući iznos prevalencije od 10,1 %. Ni jedna druga svojta nametnika nije pronađena u inficiranim babuškama. Brojnost i ukupna biomasa oblića pozitivno su korelirali s masom inficiranih riba. Zabilježena je znatna varijacija u intenzitetu infekcije, pri čemu je minimalni broj izoliranih oblića po pojedinoj ribi iznosio 2, a maksimalni 952 (u prosjeku 180). Nije uočena značajna razlika u vrijednostima Fulton-ovog faktora kondicije i dužinsko-masenih odnosa između inficiranih i zdravih riba. Dobro opće stanje inficiranih babuški naznačuje visoku otpornost na infekciju oblićima roda Contracaecum, kao i na minimalni negativni utjecaj samih nametnika na domaćina.Sampling of Prussian carp (Carassius gibelio Bloch, 1782) was conducted in September 2018 at three different sampling sites located within Kopački rit Nature park: lake Sakadaš and the channels Čonakut and Novi kanal. Out of 198 sampled fish, 20 were infected with a third stage larvae parasite belonging to the genus Contracaecum Railliet & Henry, 1912 resulting in a prevalence of 10,1 %. No other parasite taxa were found in infected fish. Abundance and total biomass of nematode larvae positively correlated with fish biomass. Intensity of infection was highly variable, with numbers of nematodes per fish ranging from a minimum of 2, to a maximum of 952 (aver. 180). No difference in Fulton’s condition factor and length-weight relationship between infected and uninfected fish was observed. Good general condition of infected Prussian carp indicates a high tolerance towards Contracaecum sp. infection, as well as a minimal negative effect of parasites on the host