Temporal stability of polymorphic Arctic charr parasite communities reflect sustained divergent trophic niches

Polymorphic Arctic charr Salvelinus alpinus populations frequently display distinct differences in habitat use, diet and parasite communities. Changes to the relative species densities and composition of the wider fish community have the potential to alter the habitat-niche of sympatric Arctic charr populations. This study evaluated the temporal stability of the parasite community, diet and stable isotopes (δ13C, δ15N) of three sympatric Arctic charr morphs (piscivore, benthivore and planktivore) from Loch Rannoch, Scotland, in relation to changes to the fish community. All Arctic charr morphs displayed distinct differences parasite communities, diet and stable isotope signatures over time, despite the establishment of four new trophically transmitted parasite taxa, and increased fish and zooplankton consumption by the piscivorous and planktivore morphs respectively. Native parasite prevalence also increased in all Arctic charr morphs. Overall, Loch Rannoch polymorphic Arctic charr morp...