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Gyrodactylus salaris infecting allopatric Arctic charr fry: An experimental study of host survival
THE FISHERIES SOCIETY OF THE BRITISH ISLES, Annual Symposium 2008; Cardiff, 2008-07-21–2008-07-25
Winger, Anja C; Primicerio, Raul; Kristoffersen, Roar; Siikavuopio, Sten Ivar; Knudsen, Rune
Abstract In the present experiment, it was examined if infections with the monogenean ectoparasite Gyrodactylus salaris induce mortality in fry (post yolk-sac stage) of artificially reared Arctic charr (Salvelinus alpinus) from Skibotnelva in northern Norway. About 95 % of the fry exposed to the parasite became infected within the first week post infection, and at the end of the experiment (after 77 days) all fry carried the parasite. The mortality rate was significantly higher in the groups of infected fry than in the uninfected control groups, and when the experiment was terminated, about 30 % of the infected, and only 8 % of the uninfected fish had died. Thus, G. salaris had a pronounced negative effect upon fry survival and caused an additive host mortality. Moreover, the concurrent temporal changes in parasite intensities and aggregation indicated that the parasite-induced host mortality was density dependent.