Data for: Ectoparasite population dynamics affected by host body size but not host density or water temperature in a 32-year long time series ...

• Main Authors: Henriksen, Eirik, Frainer, Andre, Poulin, Robert, Knudsen, Rune, Per-Arne, Amundsen
• Format: Dataset
• Language: English
• Published: Dryad 2022
• Subjects: host density; gill lice; Salmincola edwardsii; parasite population dynamics; Arctic charr; Salvelinus alpinus; FOS: Biological sciences; Arctic; Copepods
• Online Access: https://dx.doi.org/10.5061/dryad.9w0vt4bk7; https://datadryad.org/stash/dataset/doi:10.5061/dryad.9w0vt4bk7

Host density, host body size, and ambient temperature have all been positively associated with increases in parasite infection. However, the relative importance of these factors in shaping long-term parasite population dynamics in wild host populations is unknown due to the absence of long-term studies. Here, we examine long-term drivers of gill lice (Copepoda) infections in Arctic charr (Salmonidae) over 32 years. We predicted that host density and body size and water temperature would all positively affect parasite population size and population growth rate. Our results show that fish size was the main driver of gill lice infections in Arctic charr. In addition, Arctic charr became infected at smaller sizes and with more parasites in years of higher brown trout population size. Negative intraguild interactions between brown trout and Arctic charr appear to drive smaller Arctic charr to seek refuge in deeper areas of the lake, thus increasing infection risk. There was no effect of host density on the force ... : A total of 6893 Arctic charr were checked macroscopically for S. edwardsii on the gills and branchial cavity shortly after capture, and the total number of adult female copepods were counted. Arctic charr were sampled annually during the ice-free season from 1980 to 2018, except in 1998, but fish sampled from Takvatn prior to 1987 were not checked for S. edwardsii infection. Multimesh gillnets were placed in the littoral (<15 m depth), profundal (25–40 m depth) and pelagic (offshore, >30 m depth) habitats of the lake, and fished overnight for approximately 12 hours. Each fish was wet-weighed (±0.1 g), had its fork length measured (±0.1 cm) and its sex determined. ...