NWT RESEARCH DATABASE

Tags: contaminants, mercury, zooplankton, fish, aquatic invertebrates

Objective(s): To determine why fish mercury levels vary among lakes in the Dehcho region.

Project Description: The objectives of this research project are: 1) to determine why fish mercury levels vary among lakes in the Dehcho region; 2) to identify best predictors of fish mercury levels; and, 3) to determine with fish have the lowest levels of mercury and the highest levels of nutrients. The methods for this project include field sampling, laboratory analysis, and data analysis and reporting. The research team collect food web data from each lake, which includes collecting phytoplankton, periphyton, zooplankton, benthic inverts and fish samples. The samples are then analyzed in a laboratory for stable isotopes (to determine food web structure - i.e., who eats who) and levels of total mercury. Each spring, the previous year’s results are reported back during community meetings and the regional Dehcho Aboriginal Aquatics Resource and Ocean Management Program (AAROM) meeting. Collection of the samples involves the assistance of community members with knowledge of the lake and fishery to go out with the researchers and assist in the collection. The collection of samples from the lakes will occur in March and August, for the most part, but this may change depending on logistics and availability of samplers. Dependence on the local fishers is crucial to catching the required amount of fish per each lake. The field sampling is conducted on the land, with local youth, resource monitors, and fishers. Every year, 3-6 local resource monitors and fishers assist in the project, and conduct youth camp activities/capacity-building with 10-20 youth. The research team often sample in collaboration with youth camps (e.g., Kakisa, Ecology camp), and hope to sample in collaboration with Dehcho K'eohdi camps in 2018 (contingent on timing). Communication of the results back to the communities is the most important part of this research. After each field season is completed and samples have been analyzed, the results are reported to the related community (s) in plain language at community meetings. The first community meetings were held in November 2016 (Jean Marie River, Ft Providence, Kakisa), and the second round of meetings occurred in conjunction with the annual AAROM workshop in March 2017. Results were also communicated back to communities during the field season in summer 2017, and during the Northern Contaminants Program results workshop in Yellowknife (September 2017). The next reporting period will occur in early March 2018 (to coincide with Dehcho AAROM workshop). The fieldwork for this study will be conducted from March 1, 2018 to September 30, 2018.