Spatial and long-term trends in persistent organic contaminants and metals in lake trout and burbot from the Northwest Territories

Regions: Sahtu Settlement Area, South Slave Region

Tags: contaminants, traditional food, fisheries assessment, mercury, organic contaminants

Principal Investigator: Evans, Marlene S (39)
Licence Number: 14185
Organization: Environment Canada
Licenced Year(s): 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004
Issued: Jun 26, 2007
Project Team: Derek Muir (Environment Canada), Jonathan Keating (Environment Canada), Monica Krieger (Lutsel K'e Dene First Nation), Dolphus Tutcho (Deline RRC), Ed Reeves (Deline RRC), Shawn Buckley (Hay River), Tom Unka (Akaitcho Territory Government)

Objective(s): This study is designed to find out whether contaminant levels are changing in lake trout and burbot in the Northwest Territories. The researchers hope to collect lake trout from Great Slave Lake (Lutsel K'e and Hay River) and Lac Ste. Therese, and burbot from Great Slave Lake (Fort Resolution). In addition, they hope to collect northern pike (and possibly walleye) from Lac Ste. Therese and Birch Lake.

Project Description: This study is designed to find out whether contaminant levels are changing in lake trout and burbot in the Northwest Territories. The researchers hope to collect lake trout from Great Slave Lake (Lutsel K'e and Hay River) and Lac Ste. Therese, and burbot from Great Slave Lake (Fort Resolution). In addition, they hope to collect northern pike (and possibly walleye) from Lac Ste. Therese and Birch Lake.
Their study has a focus on Great Slave Lake. They have been looking at lake trout in two regions of Great Slave Lake since 1993 and propose to continue this research monitoring in 2007.
The researchers are looking at lake trout in the West Basin because it receives contaminants from the Slave River and the air, because fish grow faster, and because of its importance in the commercial and domestic fisheries. They are looking at lake trout from the East Arm because this region of the lake receives most of its contaminants from the air, because the fish grow slow, and as a consequence, are not harvested commercially as in the West Basin. Lake trout would be collected at Lutsel K’e (East Arm) and from the commercial fisheries at Hay River (West Basin) as in past years.
The researchers also propose to continue their monitoring of contaminant levels in burbot liver from Fort Resolution. Lake trout are uncommon at Fort Resolution and so burbot is a good fish to monitor for this community. They have been looking at burbot at Fort Resolution since 1993. The NCP also calls for 1-2 additional lakes to be sampled on a five year period in the Northwest Territories with a focus on lake trout and mercury. The researchers propose to sample Great Bear Lake and Lac Ste. Therese in 2007. Mercury levels were measured in Great Bear Lake lake trout in 1978, 1979, and 2001 and in Lac Ste. Therese in 1980, 1992, 1993, and 2001. Great Bear Lake is very important to the community of Deline who live on the lake shoreline and fish it regularly. Lac Ste. Therese was used by Deline until the late 1990s when very high mercury levels were reported in the lake trout, walleye, and pike living in this lake. They want to find out if mercury levels have changed. With Sahtu Renewable Resources Board funding, they will examine mercury levels in northern pike collected from Lac Ste. Therese and Birch Lake.
The following activities are planned for this project:
-20 burbot will be collected from the West Basin of Great Slave Lake by community members from Fort Resolution during their normal subsistence fishing activities.
-20 lake trout will be collected from the West Basin of Great Slave Lake by the Hay River commercial fishery.
-20 lake trout will be collected from the East Arm of Great Slave Lake by community members from Lutsel K’e during their normal subsistence fishing activities.
-20 lake trout and 20 northern pike (and possibly 20 walleye) will be collected from Lac Ste. Therese by community members from Deline during their normal subsistence fishing activities.
-20 northern pike (and possibly 20 walleye) will be collected from Birch Lake by community members from Deline during their normal subsistence fishing activities.
-All fish will be captured using gill nets or by angling.

The results of this study will be communicated to individuals and communities in the NWT through reports and possible community visits.

Fieldwork will be conducted from June 26 to December 31, 2007 on the Great Slave Lake near Lutsel K’e (East Arm), Fort Resolution (West Basin) and Hay River (West Basin), and on the Great Bear Lake (Keith Arm), Lac Ste. Therese and Birch Lake near Deline.