Rune Knudsen Roar Kristoffersen Armand M. Kuris Kevin D. Lafferty Anna Siwertsson Per-Arne Amundsen Eirik H. Henrickson 2016 <p>The trophic niches of Arctic charr and brown trout differ when the species occur in sympatry. Their trophically transmitted parasites are expected to reflect these differences. Here, we investigate how the infections of <i>Diphyllobothrium dendriticum</i> and <i>D. ditremum</i> differ between charr and trout. These tapeworms use copepods as their first intermediate hosts and fish can become infected as second intermediate hosts by consuming either infected copepods or infected fish. We examined 767 charr and 368 trout for <i>Diphyllobothrium</i> plerocercoids in a subarctic lake. The prevalence of <i>D. ditremum</i> was higher in charr (61.5%) than in trout, (39.5%), but the prevalence of <i>D. dendriticum</i> was higher in trout (31.2%) than in charr (19.3%).<i> Diphyllobothrium</i> spp. intensities were elevated in trout compared to charr, particularly for<i> D. dendriticum</i>. Large fish with massive parasite burdens were responsible for the high <i>Diphyllobothrium</i> spp. loads in trout. We hypothesize that fish prey may be the most important source for the<i> Diphyllobothrium</i> spp. infections in trout, whereas charr predominantly acquire <i>Diphyllobothrium</i> spp. by feeding on copepods. Our findings support previous suggestions that the ability to establish in a second piscine host is greater for <i>D. dendriticum</i> than for <i>D. ditremum</i>.</p> application/pdf 10.1007/s10750-015-2589-2 en Springer Ontogenetic dynamics of infection with <i>Diphyllobothrium</i> spp. cestodes in sympatric Arctic charr <i>Salvelinus alpinus</i> (L.) and brown trout <i>Salmo trutta</i> L. article