NWT RESEARCH DATABASE

Tags: physical sciences, aquatic ecosystems, fish habitat, hydrology, limnology, habitat, ecosystem changes, freshwater ecosystem, water level

Objective(s): To study the freshwater ecology, hydrology, and hydraulics of small lakes and streams in the Lac de Gras basin before habitat modification; to monitor the changes in ecosystem productive capacity resulting from habitat modifications designed to increase habitat connectivity and fish passage; and to assess the effectiveness of such habitat modifications through the use of a Before-After-Control-Impact design.

Project Description: The objectives of this research project are: to study the freshwater ecology, hydrology, and hydraulics of small lakes and streams in the Lac de Gras basin before habitat modification; to monitor the changes in ecosystem productive capacity resulting from habitat modifications designed to increase habitat connectivity and fish passage; and to assess the effectiveness of such habitat modifications through the use of a Before-After-Control-Impact design. Water: Stream gauges will be installed to monitor stream flows, while water level recorders will record lake and stream levels as they change over summer due to evaporation. Temperature loggers will be installed in each of the study lakes and streams to determine thermal conditions over the summer. Water quality traits will be measured directly (specific conductance, turbidity, pH) or water samples will be collected and brought back to the lab for later analysis (total phosphorus, total nitrogen, chlorophyll, and total suspended solids). Habitat: Ground surveys will be used to assess stream geomorphology and substrate composition. The research team will document the composition and amount of vegetation cover available for young-of-year (YOY) fish, both in the streams and within 1 m of stream banks, at multiple transects at each stream. Organic matter availability and production will be determined by counting instream woody debris and shrub stems. Organic matter processing rates will be assessed by setting out leaf packs in mesh bags over a 2-3 week period to quantify decomposition rates. Organisms: Various techniques will be used to sample fish and invertebrate populations in the lakes and streams. Adult fish will be sampled with trap and gill nets, and angling, including ice fishing in winter/spring. Fish abundance in streams will be determined by electrofishing in mid-summer. Collected fish will be measured for length and mass and their diet will be quantified. Sweep nets, plankton tows, and Surber samplers will be used to collect invertebrates in lakes and streams. Attached algae will be quantified by rock scrapings. Movements of tagged fish through the newly modified stream channels will be assessed by direct observation and electronically. In 2012, one member of the research team spent 4 days demonstrating and discussing techniques of the fisheries and freshwater research with community elders during Diavik Diamond Mine Inc. (DDMI's) annual Traditional Knowledge camp. This was rewarding for both sides and the research team hopes to do something like that again in 2013. Regular communications (email, teleconference, meetings) will be maintained throughout the project between the University of Alberta (U of A) Research Team on the one hand and DDMI, Golder Associates, and Department of Fisheries and Oceans (DFO) on the other. The research team will summarize activities at an annual DFO-sponsored workshop in Yellowknife. The U of A Research Team will also give a presentation at a meeting of Environmental Monitoring Advisory Board associated with DDMI to discuss the status, results, and subsequent steps to be taken in the study. There will be opportunities for attendees to communicate their ideas and thoughts about the project to the aforementioned parties. Copies of graduate student theses, peer-reviewed articles, and presentations given at conferences could be sent to interested groups and/or individuals. The fieldwork for this study will be conducted from March 1, 2013 to October 31, 2013.