ProjetL'ADN environnemental utilisé comme révélateur des conséquences des méthodes de pêche sur la productivité des poissons des écosystèmes lacustres
Recent technological advances have led to a renewed interest in the application of genetic tools to monitor abundance in populations of conservation concern. Environmental DNA (eDNA) is emerging as a powerful new tool through which population abundance might be quantified. Our research will examine if eDNA can be used to estimate census size in socioeconomically important natural fish populations experiencing human harvesting pressures. We will use whole lake experiments involving brook trout populations in Canadian national parks located in the Rocky Mountains. Brook trout are not native to this region and remediation efforts by Parks Canada target such populations for removal. This represents a unique opportunity to test how experimentally simulated harvesting regimes impact harvested populations as well as their broader ecological communities. As part of a NSERC strategic project grant we will conduct a large-scale harvest experiment based on experimentally-controlled depletions across a series of nine brook trout populations over three years. We will annually quantify the census size of each population using traditional methods and then subject five populations to simulated size-selective overharvesting regimes. We will collect eDNA samples every year from each lake pre- and post-harvest. Using quantitative PCR techniques we will quantify the amount of brook trout DNA present in each sample and, by relating that information to our census size estimates and environmental data, determine whether it is possible to use eDNA to reliably infer changes in each population’s total abundance as a result of human harvesting activities. The opportunities to conduct such tests in an empirically controlled manner are rare; this experiment therefore represents a valuable opportunity to empirically evaluate the efficacy of eDNA as a non-invasive fisheries monitoring tool.