title: The natural history of Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 (Acanthocephala) in a high Arctic lake.
abstract: The acanthocephalan Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 differs from most other species in the genus Echinorhynchus Zoega in Müller, 1776 by infecting mysids (order Mysida) instead of amphipods (order Amphipoda) as intermediate hosts. Here we report on the occurrence of E. bothniensis in mysids (Mysis segerstralei Audzijonytė et Väinölä) and in its fish definitive hosts in a high Arctic lake. Out of 15 907 sampled mysids, 4.8% were infected with a mean intensity of 1.05 worms (range 1-5), although there was notable variation between samples taken in different years and sites. Larger mysids appear more likely to be infected. Of five fish species sampled, charr,Salvelinus alpinus (Linnaeus), and a benthic-feeding whitefish morph, Coregonus lavaretus (Linnaeus), were the most heavily infected (mean abundances of 80 and 15, respectively). The adult parasite population in fish exhibited a female-biased sex ratio (1.78 : 1). Although E. bothniensis is rather unique in infecting mysids, many aspects of its natural history mirror that of other acanthocephalan species.
authors.affiliation: Department of Biological and Environmental Science, University of Jyvaskyla, Finland;
authors.forename: Raija-Liisa
authors.initials: RL
authors.lastname: Aura
authors.affiliation: Department of Biological and Environmental Science, University of Jyvaskyla, Finland.|Marine Science Institute, University of California, Santa Barbara, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Benesh
authors.affiliation: Department of Biological and Environmental Science, University of Jyvaskyla, Finland;
authors.forename: Risto
authors.initials: R
authors.lastname: Palomaki
authors.affiliation: Department of Biological and Environmental Science, University of Jyvaskyla, Finland;
authors.forename: E
authors.initials: E
authors.lastname: Tellervo Valtonen
keywords: Echinorhynchidae; Mysis; body size; intermediate host; sex ratio; thorny-headed worms