Spatial distribution and impact of the gill-parasitic Mazocraes alosae (Herman, 1782) (Monogenea Polyopisthocotylea) on Alosa fallax (Lacépède, 1803) (Clupeidae)

• Published in: Hydrobiologia
• Main Authors: Gérard, Claudia, Hervé, Maxime, Réveillac, Elodie, Acou, Anthony
• Other Authors: Ecosystèmes, biodiversité, évolution Rennes (ECOBIO), Université de Rennes (UR)-Institut Ecologie et Environnement - CNRS Ecologie et Environnement (INEE-CNRS), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, Université européenne de Bretagne - European University of Brittany (UEB), Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN), French Ministry of Ecology and Sustainable Development (‘Programme de connaissances Natura2000 amphihalins en mer’)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Alosa sp; Mazocraes alosae; Gill parasite; Anadromous; Body condition; Microhabitat restriction; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; North East Atlantic
• Online Access: https://univ-rennes.hal.science/hal-01170422; https://doi.org/10.1007/s10750-015-2391-1

International audience Are the distribution of Mazocraes alosae and its impact on the host similar between Alosa alosa and A. fallax according to their resemblances? Parasites were numbered on each gill of shads sampled in North-East Atlantic coastal waters and connected rivers. Their impact on host condition was measured using girth, gonado-somatic ratio, C/N ratio, and Fulton’s K. Prevalence and mean intensity of M. alosae were significantly higher for A. alosa than for A. fallax, including in sympatric conditions. The mean intensity varied among sites whatever fish species; it was higher in coastal–estuarine versus fresh waters only for A. fallax. The distribution of M. alosae was aggregated in the host population whatever species. At the host individual level, some gills (second and third for A. alosa, second for A. fallax) were significantly more inhabited than others, probably in relation with larger water volumes flowing on these gills and mazocraeid sedentary lifestyle. Despite high prevalence and intensity, no negative impact of M. alosae was demonstrated on the host condition whatever the index considered. Our study underlines the major occurrence of M. alosae on shads and the potential use of such benign parasite as biological tag to discriminate closely related host species.