Distribution of Trematodes Cryptokotyle (Trematoda, Heterophyidae), in Fish of the Family Gobiidae in the Estuary Waters and the Black Sea in Southern Ukraine

Abstract

Abstract The article describes occurrence and distribution of Cryptocotyle trematodes in fish in the waters of the Dnipro-Buh estuary and the Black Sea in Mykolaiv and Odesa Region. Study was conducted in 2015-2016. Two trematode species were found in natural waters of these regions: Cryptocotyle cancavum Crepli, 1825 and Cryptocotyle jejuna Nicoll, 1907. Th e latter species has not been previously registered in this region in southern Ukraine. Varying intensity of infection with Cryptocotyle metacercariae was observed in fish of Gobiidae family: Mesogobius batrachocephalus Pallas, 1814, Neogobius melanostomum Pallas, 1814, N. fluviatialis Pallas, 1814. Th e most affected species was N. melanostomum, with the prevalence of infection 59.2 %. Less infected were N. fluviatialis and M. batrachocephalus, with the prevalence of infection 30.4 % and 17 % respectively. The intensity of infection was the highest in N. melanostomum - 211 metacercariae per fish, followed by N. fluviatialis and M. batrachocephalu - 124 and 89 metacercariae respectively. Cryptocotyle was the most prevalent in the Dnipro-Buh estuary (cape Adzhigol, Mykolaiv Region) and much less prevalent in the waters of the Black Sea in Mykolaiv and Odesa Regions. Mean prevalence of infection was 31.4 %.