Occurrence of gyrodactylids on wild Atlantic salmon, Salmo salar L., in Danish rivers

• Published in: Journal of fish diseases Vol. 31; no. 2; pp. 127 - 134
• Main Authors: von Gersdorff Jørgensen, L, Heinecke, R.D, Kania, P, Buchmann, K
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.02.2008; Blackwell Publishing Ltd
• Subjects: Animals; Denmark; Denmark - epidemiology; DNA, Ribosomal Spacer - genetics; Fish Diseases - epidemiology; Fish Diseases - parasitology; gyrodactylids; Gyrodactylus; internal transcribed spacer; internal transcribed spacers; Mutation; Polymerase Chain Reaction - veterinary; Polymorphism, Restriction Fragment Length; Population Density; Prevalence; Rivers; Salmo salar; Salmo salar - parasitology; Trematoda - classification; Trematoda - isolation & purification; Trematode Infections - epidemiology; Trematode Infections - veterinary; Denmark
• ISSN: 0140-7775; 1365-2761
• DOI: 10.1111/j.1365-2761.2007.00875.x

Three hundred and one parr of wild salmon, Salmo salar L., from three river systems in Denmark were examined in December 2005 and August 2006 for gyrodactylid infections. The species determination was done by morphological analyses of the opisthaptoral hard parts and molecular analyses of the internal transcribed spacer (ITS) region using PCR restriction fragment length polymorphism (RFLP) and sequencing. Five species of the genus Gyrodactylus were found: Gyrodactylus derjavini, Gyrodactylus teuchis, Gyrodactylus truttae, Gyrodactylus arcuatus and Gyrodactylus salaris. The parasite species G. derjavini dominated over G. teuchis and G. truttae and only one specimen of G. arcuatus and one specimen of G. salaris were recovered. This specimen of G. salaris had the same mutation in the ITS-region as a previously described non-pathogenic Danish G. salaris variant. The prevalence of gyrodactylids on the salmon ranged from 0% to 100% but the mean abundance never exceeded 12.8.