An investigation on helminthic parasites which were determined in some fish species living in Susurluk basin

The aim of this study is to determine seasonal helminth parasites of some endemic (Barbus oligolepis, Cobitis fahirae, Capoeta tinca) and natural (Squalius cii) fish species for Turkey. Among these fish species, B. oligolepis (n:81); S.cii (n:79); C. tinca (n:81); C. fahirae (n:74) Helminth parasites of a total of 315 fish individuals were seasonally investigated between 2020 and 2021. The distribution of these parasite species in fish species was as follows: In B. oligolepis, Dactylogyrus carpathicus, Paradiplozoon homoion, Clinostomum complanatum, in the gills of the host fish, Asymphylodora sp., Caryophyllaeus laticeps, Schyzocotyle acheilognathi, Rhabdochona gnedini and Acanthocephalus sp. were found in the intestines. In S.cii, Dactylogyrus vistulae (22.7%), Paradiplozoon homonion (11.3%), Clinostomum complanatum (11.3%), Rhabdochona denudata (22.7), Caryophyllaoides fennica (7.5%); Dactylogyrus pulcher (6.17%), Paradiplozoon homoion (20%), Allocreadium isoporum (33.3%) and Rhabdochona fourtunatowi (9.8%) in C. tinca; In C. fahirae, Contracaecum sp. (5.4%) species were found. Occurrence and intensities, of parasite species are discussed in detail according to season and length and sex of fish species. This is the first study in which two endemic fish species (Barbus oligolepis, Cobitis fahirae) and one natural fish species (Squalius cii) were investigated in terms of ichthyo-helminthology for Turkey. Fish species are the new host record for helminth parasites. Rhabdochona gnedini is a new record for the helminth fauna of Turkey.In our current study, diet shift of S.cii individuals were also examined. In the food composition of of host fish individuals, Insecta group was recorded at the highest frequency (13.5%), while Cladophora sp. and Melosira varians (Phytoplankton) (18.6%) were found to have the highest frequency. It is observed that S.cii individuals primarily prefer the Diptera (% IRI=67.3%) group, followed by Ephemeroptera (% IRI= 20.8%) and Trichoptera (% IRI= 7.7) groups.