title: Impact of the cestode Triaenophorus nodulosus on the exotic Lepomis gibbosus and the autochthonous Perca fluviatilis.
abstract: The effects of plerocercoids of the cestode Triaenophorus nodulosus infecting the livers of native Eurasian perch Perca fluviatilis and non-native pumpkinseed Lepomis gibbosus was investigated in 17 sites along the Moselle watershed. With a single exception, infected individuals were not observed in the main channel whether or not northern pike Esox lucius, a final host, was present. In ponds where the pike was present, the prevalence of T. nodulosus averaged 86% in Eurasian perch and 15% in pumpkinseed. The parasite was not present at all in ponds when pike were absent. Parasite load, hepatosomatic index (HSI), gonadosomatic index (GSI) and body condition index (CI) were compared between hosts in one site where parasite prevalence and fish abundance was highest. HSI in infected perch was significantly higher than in uninfected perch, whereas no differences in HSI were detected between infected and uninfected pumpkinseed. While perch were more frequently infected and had a greater average parasite load than pumpkinseed, there were no significant differences in either indicator between the two species. Furthermore, no significant differences in GSI or CI were observed between infected and uninfected fish in either species, by either gender or maturity stage. We hypothesize that pumpkinseed is more resistant to the parasite or less likely to feed upon infected copepods than perch.
authors.affiliation: Université de Lorraine,Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC),CNRS UMR 7360,Campus Bridoux,Rue du Général Delestraint,F-57070 Metz,France.
authors.forename: G
authors.initials: G
authors.lastname: Masson
authors.affiliation: Department of Agroecology and Environment,ISARA Lyon (member of university of Lyon),23 rue Jean Baldassini,69364 Lyon,France.
authors.forename: M
authors.initials: M
authors.lastname: Vanacker
authors.affiliation: Environmental and Resource Studies Program and Department of Biology,Trent University,Peterborough,Ontario K9J 7B8,Canada.
authors.forename: M G
authors.initials: MG
authors.lastname: Fox
authors.affiliation: Ecole Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES),1 Quai Koch,BP 61039,67070 Strasbourg,France.
authors.forename: J-N
authors.identifier: http://orcid.org/0000-0002-1935-7689
authors.initials: JN
authors.lastname: Beisel
mesh_terms: D000818:Animals; D002589:Cestoda / Q000502:physiology*; D002590:Cestode Infections / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D005393:Fish Diseases / Q000453:epidemiology / Q000469:parasitology*; D005399:Fishes; D005602:France / Q000453:epidemiology; D058507:Host Specificity; D058865:Introduced Species; D045483:Rivers
keywords: Moselle River