Comparison of eDNA sampling strategies for detection of the myxozoan parasite Tetracapsuloides bryosalmonae and two salmonid fish hosts

Abstract

New molecular techniques have replaced and complemented traditional methodologies, which are applied to determine species composition and richness, as well as some other components of biodiversity based on species composition. This master’s thesis evaluates two different environmental DNA (eDNA) sampling methods for the monitoring and early detection of Salvelinus alpinus, Salmo trutta, and the myxozoan parasite Tetracapsuloides bryosalmonae in Lake Norsjø, Norway. This study compared two sampling methods for water collection: ten 1 liter bottles and one 10 liter container to evaluate their eDNA detection sensitivity. Both methods successfully detected the two fishes, and the 10 liter container allowed for increased reproducibility and detection of eDNA. Nevertheless, the parasite was not detected, a result that is possibly explained by the fact that Low water temperature affects parasite DNA emission. The results highlight the need for researchers to use appropriate sampling methods, consider environmental conditions such as levels of suspended particles and temperature, filter characteristics, and limitations of molecular techniques during eDNA study design to accurately infer species distributions using such new technology.