NWT RESEARCH DATABASE

Regions: Sahtu Settlement Area, Dehcho Region, South Slave Region

Tags: contaminants, mercury, burbot, lake trout

Objective(s): To continue to investigate whether contaminant (mercury, other metals, persistent organic contaminants) levels are changing in fish in the Northwest Territories with a focus on Great Slave Lake.

Project Description: This licence has been issued for the scientific research application No.5350. The purpose of this study is to continue to investigate whether contaminant (mercury, other metals, persistent organic contaminants) levels are changing in fish in the Northwest Territories with a focus on Great Slave Lake. The research team plan to arrange collections of lake trout from the Hay River area and Lutsel K’e areas; burbot from the Lutsel K’e and Fort Resolution areas; and northern pike from the Fort Resolution area of Great Slave Lake. The team also plan to conduct a reassessment of mercury concentrations in lake trout (and other species) from Kelly Lake as requested by GNWT Health and supported by Tulita and Norman Wells, both of whom use this lake. Fish will be collected by local organizations. All Great Slave Lake fish will be collected by community members. Collected fish will be frozen and then shipped to Environment and Climate Change Canada-Saskatoon, where they will be processed and sampled. Kelly Lake fish may be processed in the field. Determinations will be made of length, weight, sex, liver weight, gonad weight, stomach contents, and muscle moisture content. Any abnormalities (internal or external) will be noted. Muscle, liver, stomach, and otolith samples will be collected from each fish. Otoliths will be sent to a private contractor for the determination of fish age. Tissue samples will be submitted to Environment and Climate Change Canada laboratories in Saskatoon and Burlington for stable isotope (muscle) and contaminant analyses (metals in lake trout and burbot muscle; organic contaminants in lake trout muscle and burbot liver). These data are proving to be very valuable in investigating why contaminant levels are or are not changing in fish over time. The research team plan to collect: 20 burbot and 20 northern pike will be collected from the Fort Resolution area of Great Slave by the community; 20 lake trout will be collected from the Hay River area of Great Slave Lake by a commercial fisherman; 20 lake trout and 20 burbot will be collected from the Lutsel K’e area of Great Slave Lake by the community; and up to 20 lake trout, 20 northern pike 20 inconnu and 15 lake whitefish will be collected from Kelly Lake with sampling organized by the Sahtu Renewables Resources Board with probable assistance from Renewable Resource officers with GNWT. The research team maintain regular contact with community members by telephone and email from Northern Contaminants Program (NCP) proposal submission, NCP report submission, obtaining fish for analyses, and discussing results. Copies of the proposal and annual report are provided to the community organizations. The team also have developed simple posters of the mercury results which have been well received. Zoom meetings have become more frequent in support of this and related studies. A fall visit is planned to discuss results to date. There are similar exchanges of information with Tulita and Norman Wells of their wish to measure mercury concentrations in Kelly Lake fish and as part of our related Cumulative Impact Monitoring Program project investigating fish health and polycyclic aromatic hydrocarbon concentrations relative to natural oil seeps and Imperial Oil at Norman Wells. A fall visit in planned. The fieldwork for this study will be conducted from August 22, 2022 to December 31, 2022