DAO 32:137-143 (1998)  -  doi:10.3354/dao032137

Distribution and prevalence of Anguillicola crassus (Nematoda) in eels Anguilla anguilla of the rivers Rhine and Naab, Germany

Jürgen Würtz1,*, Klaus Knopf2, Horst Taraschewski2

1Institut für Zoologie und Limnologie, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
2Zoologisches Institut/Ökologie, Universität Karlsruhe, Kaiserstraße 12, D-76128 Karlsruhe, Germany

Over a period of 2 yr eels were collected at several sites along the river Rhine as well as from adjacent waters and examined for Anguillicola crassus in the swimbladder. Additionally eels were collected once from a site on the river Naab (Danube system). All eels were searched for both juvenile and adult stages of A. crassus, revealing prevalences of 80% in eels from the river Rhine and 39% in eels from the river Naab. The mean intensities were 5.6 and 7.7, respectively. With respect to the prevalence and mean intensity of infection, no significant differences were observed between the different sampling sites in the Rhine system. Neither the prevalence nor the intensity showed significant seasonal patterns. Further, no correlation between the condition factor of the eels and intensity of infection with A. crassus could be found. Of all eels examined, 28% showed pathological alterations of the swimbladder.

Anguillicola crassus · Anguilla anguilla · Swimbladder · Distribution · Prevalence

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