NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: water quality, biology, fish habitat, community based monitoring, whitefish

Objective(s): To maintain a community-based monitoring program of whitefish in the Peel River watershed, based in the communities of Fort McPherson, Aklavik, and Tsiigehtchic.

Project Description: This licence has been issued for the scientific research application No.5062. The two primary objectives are to: 1) maintain a community-based monitoring program of luk dagaii (broad whitefish, Coregonus nasus; herein referred to as whitefish) in the Peel River watershed, based in the communities of Fort McPherson, Aklavik, and Tsiigehtchic. Specifically, the research team measure fundamental biological characteristics: length, weight, age and spawning status, body condition, and obvious parasite or disease, in addition to determining habitat and watershed use patterns through otolith microchemistry analysis. The team provide ongoing training, equipment, and support for subsistence harvesters who collaborate on the project and who assist to collect biological data on harvested fish. 2) To use data collected in this community-based monitoring program to address two research questions related to ecology and use of whitefish. These questions emerged from existing Indigenous and scientific knowledge of broad whitefish in this system. Specifically, the research questions are: a) What are length, age and spawning condition of broad whitefish captured in the subsistence fishery? How do these compare to baseline data collected on broad whitefish between 1998-2002? How are these characteristics changing over contemporary time? and, b) How do broad whitefish captured in the subsistence fishery use the watershed? What habitats are most important to their survival and productivity? Addressing this objective will also include collecting some additional water samples to identify river habitat use. Sample and data analysis from fish harvested in 2017-2018 is ongoing, but preliminary results reveal high diversity in migration patterns (including confirming previously-known ocean migrations and describing many between-river migrations). These fish that travel across large portions of the watershed are particularly susceptible to the impacts of changing hydrology and erosion, and this highlights the need for ongoing community-based monitoring on this nutritionally and culturally important species. Migratory variation in Mackenzie River system broad whitefish: Insights from otolith strontium distributions. Monitoring spawning populations of migratory coregonids in the Peel River, NT: the Peel River fish study 1998-2002. Fisheries and Oceans Canada, Central and Arctic Region. Broad whitefish Data collected in this community-based monitoring program and other previous research has shown that ocean-migrating broad whitefish use the Peel River as spawning habitat, and that these fish also make extensive migrations between rivers in the lower Mackenzie Delta. As harvester catches are comprised of fish with very different migration patterns and which occupy different sets of habitats, it is likely that the fish will be differently exposed to and impacted by cumulative environmental impacts. Because of this vulnerability and the importance of this species for communities in the region, this project looks to detect any changes to whitefish distribution and population health that may emerge over time. Additionally, this work helps to assess the vulnerability of fish with different migratory strategies. Using data collected across multiple years, the research team will identify the population values for fish size-at-age, body condition, and catch-per-unit-effort, and will describe how these values vary through time. Lower Mackenzie water sampling: only in the first two years of the program, the team have identified that Mackenzie watershed whitefish exhibit varied migrations and rely upon multiple rivers (manuscript in preparation). However, the current ability to identify high-resolution spatial movements is hindered by a lack of spatially-comprehensive elemental "fingerprints" (strontium isotope signatures) across the watershed, which the research team use to match the signatures in the fish to their habitats. In some fish, the team have identified "fingerprints" (strontium signatures) in the otolith that do not match the six locations where there are currently water strontium signatures. The research team seek to remedy this by using additional water samples at primary tributaries and in the Delta, and developing a model that will integrate values between sample locations to create a high-resolution map of signatures (an “isoscape”). This will provide a tool to match fish to specific locations in the watershed, on a scale relevant to local disturbances and subsistence fishing access. Because this isoscape can be applied to analysis of fish otolith from any species, this model will further illuminate which areas of that Mackenzie River watershed are important to organisms and the access to subsistence resources. To measure whitefish length, weight, and spawning conditions and extract otoliths, the research team collaborate with harvesters who assist to sample harvested whitefish. Broad whitefish have been observed in spawning migrations from July-October, with a return migration in October-November after the ice freezes. The sampling takes place during harvest season, beginning in July and continuing through October (or when ice forms). Some under-ice harvest may also take place, if harvesters are able. Harvesters sample 5-10 fish per day, for two consecutive days every other week, and capture fish with 5-inch mesh gillnets to target migrating broad whitefish. Once fish are captured, monitors sample for a suite of biological data: length, weight, photograph, spawning condition, otolith extraction, fin clip, enumerate and identify all fish captured in the set, and collect other tissue samples for contaminant analysis (once per week). On each data collection day, harvesters also note qualitative observations about water conditions (level of sedimentation, amount of debris, and water level). The research team calculate annual and cumulative population means and inter-annual variability in whitefish attributes including body condition, size-at-age, catch per unit effort and migratory patterns. Otoliths are aged and, where relevant, processed using a standard procedure for otolith microchemistry. Additionally, the team intend to process fin clip samples to identify fish nitrogen and carbon isotopic ratios. This identifies fish trophic level and diet, and the habitats in which they feed. Samples will be processed for 10 individuals sampled in early August and 10 sampled in late September at each sample location from 2018 (~80 samples total), the same fish for which otoliths are to be analyzed in 2018. Values from this analysis will be compared across locations and time, and the team will use a mixing-model approach to determine fish diet using published “end member” (prey) values. Deliverables from this project will be communicated to communities and government organizations in three primary formats. In most cases (besides presentations) outputs will be shared with all collaborating and supporting organizations: the Gwich’in Renewable Resources Board (GRRB), the local Gwich’in Renewable Resource Councils (RRCs), the Aklavik Hunters and Trappers Committee (ATHC) and the Government of the Northwest Territories (through the Cumulative Impacts Monitoring Program). Deliverables: 1) Presentations in 2021-2022 to local audiences (via video recordings or calls): a. Present at GRRB annual winter meeting; b. Plain language summary produced and distributed in Aklavik and Fort McPherson; and, c. Anticipated presentations at ArcticNet annual meetings. 2) Documents to share with all organizations listed: a. Produce peer-reviewed publications on: (i) strontium isoscape model and (ii) analysis of additional fish strontium samples to evaluate temporal and spatial trends in migration strategies; b. Produce a plain language summary annually and distribute; and, c. Update current working document on project approach and best practices for standardized fish sampling and distribute annually. 3) Database and summary statistics: a. Summarize metrics that are relevant to population dynamics and the eventual development of a management plan (e.g., size-at-age and catch-per-unit-effort) and share with all organizations annually; and, b. Develop database of raw data on whitefish to be made publicly available 2 years after collection or upon publication, whichever occurs first, through the Mackenzie Data Stream. The fieldwork for this study will be conducted from September 30, 2021 to December 31, 2021.