Search

Freshwater environments cover only a tiny fraction of the planet's surface, yet they are biodiversity hotspots and support almost half of the global fish diversity, including globally and locally endangered species. In the UK, three species of national conservation value namely, Arctic charr (Salvelinus alpinus L.), European whitefish (Coregonus lavaretus L.) and vendace (Coregonus albula L.), are threatened throughout their limited distribution range by a number of human-driven environmental changes. To combat a further loss of these priority conservation fish, non-invasive, sensitive and reliable monitoring tools are required to assess their status and guide appropriate conservation measures. Advances in the field of environmental DNA (eDNA) have shown the potential of this tool to detect low-abundant species, however the actual application of eDNA methods (e.g. targeted and metabarcoding) for rare species monitoring has been mostly limited to the collection of presence/absence information. The scope of this thesis is to explore novel aspects of eDNA metabarcoding including the ability to estimate fish biomass/abundance, determine fish spawning and assess distribution and abundance of priority conservation fish across a variety of UK lentic systems. This thesis provides evidence that eDNA metabarcoding accurately reflects absolute fish biomass and abundance in high fish density ponds, and quantitative estimates are repeatable between different methods of DNA capture. This thesis demonstrates that eDNA metabarcoding determines location, timing and effort of Arctic charr spawning and can be as sensitive as quantitative PCR. Lastly, eDNA metabarcoding provides accurate information of Arctic charr, vendace and European whitefish distribution and abundance in UK lentic systems including sites of special conservation interest. The fish community information obtained from eDNA metabarcoding is, therefore, beneficial to predict future changes in distribution and abundance of priority conservation fish as well as to design appropriate management actions, and can enormously contribute to more efficient monitoring programmes in UK lentic systems.