Yuanyu Cheng
Projet
Preserving the future by learning from the past: Unravelling ecosystem changes in salmon nursery lakesSockeye salmon are of substantial socio-economic and ecological importance to Pacific Rim communities. They serve as a vital food source, hold deep cultural significance for Indigenous people, and contribute to biodiversity and ecosystem stability. However, human disturbances, such as overfishing, climate warming, and increased parasite prevalence from aquaculture, have negatively impacted salmon populations. To protect salmon, we need long-term data to understand their population and environmental changes over time so that the stressors can be detected and quantified. Lake sediment cores are akin to history books written by nature. By extracting genetic material from these sediments, we can gain valuable insights into ecosystem changes and inform effective conservation strategies. In my research, I am extracting DNA from lake sediments to reconstruct ecosystem changes in six sockeye salmon nursery lakes in British Columbia with the goal of answering the following questions: (1) How have salmon abundances fluctuated over the past few centuries? (2) Did fish parasite abundances co-vary with salmon abundances? (3) What changes have co-occurred in sockeye salmon nursery lake food webs? (4) What environmental factors may have contributed to these observed changes? My project will be the first to employ innovative molecular tools for studying salmon ecosystems over hundreds of years. I will share my findings with all potential users, including Fisheries and Oceans Canada (DFO) and Indigenous people, to inform future sockeye salmon management on historical data. Additionally, my optimized molecular method for measuring fish and parasites may be used by DFO at other sites and serve as a cost-effective and minimally-invasive monitoring approach. In the future, such research can be applied across various areas to understand environmental changes and to better conserve our ecosystems.
