Host specificity and geographical distribution ofEubothriumin European salmonid fish

Abstract

AbstractThe host specificity and distribution ofEubothrium crassum(Bloch, 1779) andEubothrium salvelini(Schrank, 1790), morphologically fairly similar pseudophyllidean tapeworms parasitizing salmonid fish, were critically assessed on the basis of morphological and genetic evaluation of extensive material collected from different definitive hosts and geographical regions in Europe.Eubothrium crassumoccurs in fish of the generaSalmo, i.e. salmon (S. salar– both freshwater and marine), sea trout (S. trutta trutta), brown trout (S. truttafario), and lake trout (S. truttalacustris), and also in Danubian salmon (Hucho hucho) and vendace (Coregonus albula).Eubothrium salveliniparasitizes Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) in Europe, and also whitefish (Coregonus wartmanni). Rainbow trout (Oncorhynchus mykiss), which is not a native European fish species, was found to be a suitable definitive host for bothEubothriumspecies, which may occur simultaneously in the same fish. Previous records ofE. crassumin Arctic char and brook trout, and those ofE. salveliniin fish of the genusSalmowere most probably misidentifications. Most studies ofEubothriumhave involved salmonids from the northern part of Europe, with few records from southern and south-eastern Europe. This study also confirmed the reliability of the morphology of the apical disc for the discrimination ofE. crassumandE. salvelini.