Data from: Seasonal dietary shifts enhance parasite transmission to lake salmonids during ice cover ...

• Main Authors: Prati, Sebastian, Henriksen, Eirik H., Knudsen, Rune, Amundsen, Per‐Arne
• Format: Dataset
• Language: English
• Published: Dryad 2020
• Subjects: Arctic; Norway; Arctic charr; Northern Norway; Salvelinus alpinus; Subarctic
• Online Access: https://dx.doi.org/10.5061/dryad.r2280gb8w; https://datadryad.org/stash/dataset/doi:10.5061/dryad.r2280gb8w

Changes in abiotic and biotic factors between seasons in subarctic lake systems are often profound, potentially affecting the community structure and population dynamics of parasites over the annual cycle. However, few winter studies exist and interactions between fish hosts and their parasites are typically confined to snapshot studies restricted to the summer season whereas host-parasite dynamics during the ice-covered period rarely have been explored. The present study addresses seasonal patterns in the infections of intestinal parasites and their association with the diet of sympatric living Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in Lake Takvatn, a subarctic lake in northern Norway. In total, 354 Arctic charr and 203 brown trout were sampled from the littoral habitat between June 2017 and May 2018. Six trophically transmitted intestinal parasite taxa were identified and quantified, and their seasonal variations were contrasted with dietary information from both stomachs and ... : Fish sampling and processing In total 354 Arctic charr and 203 brown trout were sampled from the littoral habitat (<15 m depth) between June 2017 and May 2018 using multi-meshed gillnets with panels of eight different mesh sizes from 10 to 45 mm, knot to knot (Table 1). The sampling was carried out monthly during the ice-free season (June to November) and every second month during the ice-covered period (December to May). During the ice-covered period, gill nets were pulled out and retrieved through holes in the ice by means of submerged ropes. The ropes were positioned in the lake in December when the ice thickness was still modest. The nets were left in the lake overnight for approximately 12 hours during the ice-free period and approximately 16 hours during the ice-covered period. In the field, fork length in mm, weight, sex and gonad maturation of all fish were recorded. Stomachs were opened and the fullness degree was determined on a scale from 0 to 100%. Prey types were identified and their ...