NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: water quality, climate change, fish

Objective(s): To obtain baseline data for fish communities in Gwich’in Settlement Area lakes and use these data to predict future changes in fish communities caused by climate change.

Project Description: The purpose of this project is to obtain baseline data for fish communities in Gwich’in Settlement Area (GSA) lakes and use these data to predict future changes in fish communities caused by climate change. Specific objectives are to: 1) develop a baseline data set for fish populations, fish habitat, water quality, and water temperature for small and medium sized lakes within the Mackenzie Delta region; 2) develop fish habitat models to identify habitat suitability for coldwater fishes in the region; 3) forecast how the distribution of coldwater fish will change under climate change scenarios; 4) assess the likelihood of expansion of coolwater fishes, such as walleye, into GSA lakes. 5) evaluate the potential impact of invasions by coolwater fishes for burbot, lake trout, and grayling The research team will sample 40 lakes along the Dempster Highway between Fort McPherson and Inuvik. The selection of lakes along highways will allow for access by motor vehicle rather than by helicopter. Water bodies larger than two hectares located adjacent to the highway will be identified with satellite imagery and assigned a number. The research team will then use a random number generator to select lakes for sampling. To obtain fish community data, the research team will set gill nets following the Broad Scale Fish Community Monitoring Protocol (BSFCMP). The team will use both large and small gill nets set for 16-22 hours in each lake during August. Nets will be distributed among the depth layers of each lake, and the effort will be distributed equally over the area of each lake. This project will represent an opportunity to determine if the guidelines can be directly adhered to for lakes in the Gwich’in region. Students and crew members who will assist for netting and sampling will be trained and tested in identifying common species found in the Northwest Territories. When a specimen cannot be identified in the field, crew members will be instructed to collect a voucher specimen for examination back at York University in Dr. Sharma’s laboratory. Water quality data and lake morphometric measurements will also be collected from each lake. These data will be necessary for building statistical models used to predict future changes in fish distributions. These data will include: lake bathymetry, water turbidity, secchi depth, water chemistry, pH, dissolved oxygen, temperature, and chlorophyll-a. Using the fish community data and water quality data collected, in addition to climatic data from online climate databases, the team will develop species distribution and thermal habitat availability models to predict the distribution and availability of suitable habitat for coldwater and coolwater fishes. Following validation of empirical models, the team will forecast the distribution and suitable habitat for coldwater and coolwater fishes in 2050 and 2070 using climate scenarios and downscaled climate projections that have been generated by the Northwest Territories Department of Environment and Natural Resources. Using these projections, the research team will identify in which lakes coldwater populations may be lost and in which lakes coolwater fish populations may invade, under varying scenarios of climatic change. In such cases, these lakes will be categorized as lakes that may need to be more actively monitored to ensure subsistence fishing for the local communities. Further, in lakes where walleye should invade, the team will develop empirical models to understand the interactions of invading walleye with native fishes using established statistical methods. Lakes at highest risk of invasion of coolwater fishes and loss of coldwater fishes will be recommended for further monitoring and management plans. Community members and aboriginal organizations have been involved in the design of this project and will continue to be involved in carrying out fieldwork and interpreting results. During each summer field season, D. Gray, S. Sharma, or one of their graduate students, will attend a local Hunters and Trappers Committee meeting or a Renewable Resource Committee meeting in Inuvik or Fort McPherson. This will be scheduled in advance of summer field work to ensure that there is time available in the meetings to speak about the project. During the first field season, the team will discuss the selection of lakes, and in subsequent years the team will update the committees on the progress and seek further guidance. Local community members will be directly involved in carrying out the work and helping to interpret the results. We will have two local guides with boats during each summer to assist with fieldwork and fish identification. The research team will ensure that the results from this project are communicated to Northwest Territories Cumulative Impacts Management Program (NWT CIMP), community members, and decision-makers. NWT CIMP will obtain annual reports on the progress, copies of manuscripts submitted for publication, datasets for fish and environmental characteristics, and a final report. For community members, the team will arrange meetings each summer with local renewable resource councils and/or hunters and trappers committees. The research team will present the work at Water Stewardship Strategies Workshops, and will describe this work in a Northwest Territories Environmental Research Bulletin. To communicate with decision-makers, the research team will publish the results in refereed journals, speak regularly with members of the Gwich’in Renewable Resources Board, attend professional meetings, and make the data freely available on the Northwest Territories Discovery Portal. The fieldwork for this study will be conducted from August 13, 2017 to September 1, 2017.