Cumulative Impact Monitoring Program 2011/12 Project description summary
Project name: Biological monitoring and assessment of fish populations, with a focus on lake trout biology in Great Bear Lake
Program theme: (landscape change, cumulative impacts, thresholds) Cumulative impacts
Project keywords and valued components: Great Bear Lake, fish, Lake trout, biological monitoring, traditional ecological knowledge
Project team/partners: Louise Chavarie, Colin Gallagher, Deborah Simmons, William M. Tonn
Status: In development / Pending funding / In Progress / Completed In progress Location: If research is localized please include lats and longs. Please attach shapefile or GoogleEarth image, if available. If the study is regional, please use a bounding box if possible.
Sahtu Settlement Region, Great Bear Lake (66°N, 121°W), Community of Deline (65° 11′ 12″ N, 123° 25′ 18″ W)
Smith Arm study area
Great Bear Lake
Deline Tagging area Community of Deline
Brief project description:
Objectives/goals of the project 1) Develop time series information to monitor changes and track the status of lake trout and other species in Great Bear Lake through: a) collection of biological data for analysis of size and age structure, fecundity (egg number per female), growth and mortality of lake trout populations in each arm of GBL (Smith Arm only in 2011-12) b) collection of species composition information and if sufficient data are available, size structure and other biological characteristics of other species among arms of the lake (Smith Arm only in 2011-12).
2) Develop an understanding of variation, habitat use and food web relationships among lake trout in Great Bear Lake by integrating western scientific methods and traditional ecological knowledge.
Methodology and sampling techniques used To address objective 1: Fish were captured in the Smith Arm area of Great Bear Lake using randomly set gillnets (paired 140 mm subsistence, and 38-140 mm multi-mesh research nets). Data on numbers and species of fish together with location (position), date, net depth, water temperature and quality (pH, total conductivity, total dissolved solids), and other environmental conditions were recorded for each net set. Larger trophy sized trout and other fish species were measured, fin clipped for age determination, and released if they were in good condition. All remaining retained fish were sampled for biological information such as fork length, round weight, ovary weight, sex, and maturity stage, aging structures (otoliths and fins), stomach contents, and muscle tissue for stable isotope analyses. Digital images of each fish were taken for use in morphological analysis and, in some cases, species identifications. Following sampling, all reasonable sized sampled fish were smoked and dried at the camp site using traditional methods and later distributed to residents of Deliné. Ages of each fish were determined by staff at the DFO Ageing Lab (Freshwater Institute) by embedding, sectioning, and reading otoliths using standard protocols for each species. Preserved eggs were measured and counted to determine egg size and fecundity of trout and other species.
To address objective 2: We used a combination of archived and recently collected data and tissue samples conduct address a-c below: a) A combination of classical morphological measures and geometric shape analysis is being to identify and quantify morphological differences among lake trout within Great Bear Lake. Landmarks (as x and y coordinates) were obtained from field collected digital images with the program tpsDIG and used to generate measures of body shape, and fin and body length. Lake trout morphs were identified through cluster analysis based on these measures and variation was further quantified and illustrated through Canonical Variance and Principal Component Analyses. b) The trophic ecology of different lake trout morphotypes in the Great Bear Lake food web is being examined by combining analysis of diets with stable isotopic (SIA) and fatty acid analyses (FAA) to describe the trophic ecology of different lake trout morphotypes in the Great Bear Lake food web. c) We are examining differences in life-history traits (e.g., growth rate, age and size structure, mortality) among lake trout morphotypes to determine whether morphological and trophic characteristics are associated with differences in life-history strategies and population productivity. Data to feed into these analyses are being collected through objective 1. d) We are examining local ecological factors (e.g., habitat characterization, food web composition) in relation to the distribution (location-specific catch rates) of trout with different morphologies and trophic ecologies to better understand the distribution and movements of lake trout among specific habitats. To complement catch-related habitat use information, we conducted tagging during 2010 (Dease Arm) and 2011 (Keith Arm) to obtain detailed information on temperature (°C) and depth (m) (measured every hour for 2 years) of water occupied by trout using LAT 1100 series archival tags (http://www.lotek.com/lat.htm). Tags were retrieved by fisherman and a reward was given for each returned tag. e) We are integrating local knowledge with biological information collection (a-d) through individual and group interviews which were conducted with Déliné community members. We recruited local fishermen and/or former fishing lodge guides and elders fr discussions, followed by individual interviews co-facilitated by a community researcher who was fluent in the local Sahtúot’ine (Great Bear Lake Dené) language. Discussions and interviews included maps and stories, and Dené terminology related to places, names as well as diets of lake trout. A Traditional Knowledge-science workshop was organized at the local school to share information we obtained with students.
Describe how communities and/or partner organizations were or will be involved The Deline Renewable Resource Council (DRRC) was contracted to selected field assistants and pay wages to field technicians; they were also involved in reviewing the study design and in helping develop field sampling plans (i.e., recommending suitable base camp and sampling locations). The Sahtu Renewable Resource Board (SRRB) was involved in reviewing the project and contributed financial support. The Arctic College in Deline provided space for the traditional knowledge workshops and interviews, and Dene students from the Arctic College also assisted with organizing, translation and recording the workshops and interviews. The GNWT Department of Environment and Natural Resources has been assisting with tag returns and providing rewards to local fishermen as well as providing storage space for field gear. The Polar Continental Shelf Project provided air support for travel to and from the Smith Arm field sampling location. The DFO Western Arctic Area Office contributed financial support to the project.
Describe how Traditional Knowledge was or will be involved, if applicable. This project has a specific Traditional Knowledge component (objective 2e above). Interviews and workshops for this component of the project were conducted in December 2011 and February 2012 (see details below). Results from this will be written up as part of a PhD thesis and as a primary publication with proper permissions (validation) from the community. Traditional Knowledge was also used informally to learn about field sampling sites and conditions and determine suitable camping/sampling locations through discussions with the local RRC.
Were the objectives of your project achieved? Yes Objective 1: Between July 28-August 24, 2011, a total of 210 Lake trout, 216 Lake Whitefish, 15 Cisco spp., 13 Round Whitefish and 1 Northern Pike were captured and sampled as described above. Lab- and field- collected data from these samples were analysed to determine composition and catch rates for all species and to estimate the age and length structure, growth rate, sex ratios, physical condition, age-at- maturity, egg-number-per-female (fecundity), reproductive potential, and mortality rates for lake trout in the Smith Arm area of the lake. These data were combined with information from earlier years and other areas of the lake to examine the current and relative status of fish stocks and extend the time series for the Smith Arm area of the lake.
Objective 2: a) Classical morphological measures and geometric shape analyses for approximately 600 lake trout (in different arms of the lake) were utilized to quantify shape variation and identify 4 putative morphs in Great Bear Lake. This work has been written up and will be submitted for primary publication shortly. b) Muscle tissue from 5-10 lake trout/morph/arm as well as representative food items from each arm of Great Bear Lake (n=171) were prepared and analysed for stable isotopes and fatty acids. Stomach contents were also sorted, identified, weighed and counted for 5-10 morphs/arm. Verification of taxonomic identifications, and data analysis and interpretation still need to be completed. c) Life history data on the various lake trout morphs are part of ongoing collections (objective 1) and have been organized in a database. The final analysis of this information relies on the results from objectives 2a and 2b and is therefore still to be completed. d) A total of 110 lake trout were tagged with archival tags in the Deline area. To date 6 of these tags have been returned by fishermen and were on the fish from 2 weeks up to a period of 3 months. Analysis of the logged tag information is pending. e) A Traditional Knowledge workshop to better understand lake trout habitat use and variation was held in Deline in early December 2011. Three group sessions of 6-8 people and 6 individual interviews were conducted over a 2 week period. Interviews were recorded and have been translated and transcribed. Verification and analysis of the information is pending.
Significance of the results (rationale):
What are the key contributions to cumulative effects monitoring in the NWT? The establishment of a baseline and the development of meaningful biological and environmental time series information from our study will provide a valuable tool from which to track and better understand changes in fish populations that are likely to occur with changes in the aquatic environment and/or harvest levels in Great Bear Lake. The detailed scientific research and traditional knowledge on lake trout and cisco diversity, habitat use, and food web relationships will allow us to refine monitoring protocols, develop a deeper understanding of lake trout and cisco ecology, and ultimately better predict and understand potential impacts of harvest and development on these key VC’s.
What is the relevance to decision-makers? Knowledge of how fish populations change with various parameters (including harvest and environmental changes) over the long-term will be of direct use to both co-managers of the fishery and regulators in establishing safe harvest levels and mitigating potential effects of development; our project will thus contribute to effective environmental stewardship of the Great Bear Lake ecosystem. More detailed knowledge of the ecology and habitat use of key VC’s such as lake trout is also important in identifying areas of special importance that may require protection in order to ensure sustainability of populations.
Which decision-makers will likely be impacted by / interested in results? Community of Deline, Local Renewable Resource Council (Deline), Land Claim Board (Sahtu Renewable Resource Board), Sahtu Land Use Planning Board, DFO Fisheries and Aquaculture Management, Aboriginal Affairs and Northern Development Canada
What is the relevance to communities? Fish populations, particularly lake trout, in Great Bear Lake are currently harvested for both subsistence and recreational use and are an important part of the diets of residents of Deline, the only community on the lake. However, very little research has been directed towards monitoring trends in populations and understanding their biology and key habitat requirements. The need for this type of research was identified in the Great Bear Lake Aquatic Ecology Research and Monitoring Plan a component of “The Water Heart: A Management Plan for Great Bear lake and its Watershed (2005)”, developed in part by the community of Deline. The results from our study will add to the existing, albeit limited, trend information for several fish species and help to identify important habitat requirements for lake trout, a key harvested species and important component of the aquatic community in the lake. This information is relevant to the communities in making decisions regarding future harvest, outfitting, and development under changing climatic conditions.
What are the key contributions to science/our knowledge base of northern environments Great Bear Lake represents one of the “great” lakes in the world, is the largest lake (by area) entirely within Canada, and one of the largest lakes in the polar climatic region. It is unique among large lakes in that it is characterized by being very deep, highly oligotrophic and having low productivity. Despite the economic and cultural importance of this lake, its ecosystem properties and integrity remain poorly understood, with limited information on harvested fish species. Our study will also extend existing time series information to allow us to better understand changes in the productivity of fish populations in this unique system. Our study will contribute directly to ecological modelling work on Great Bear Lake thus expanding our knowledge of the functioning of this lake and how it compares to other large lakes in terms of resilience to the cumulative effects of climate change, development and harvest. Finally the identification of multiple shallow water morphs of lake trout in Great Bear Lake adds a new dimension to the scientific knowledge base on the origin and maintenance ecological and evolutionary processes related to lake trout diversity and these different morphs likely represent unique components of Canadian biodiversity.
What are the project milestones? (including beginning date and anticipated end-date)
Project start April 2011 Consultation with DRRC July 2011 Gillnetting, environmental sampling, collection of invertebrates and forage fish in Smith Arm late-July to late-August 2011 Trout tagging in Keith Arm (near Déline) Mid-late July 2011 Post field season consultation with DRRC Late August 2011 Lab analysis (diet, SIA, FAA, age reading, fecundity) March 2011 – January 2012 Present at AFS meeting September 2011 Present at NWT Geoscience Forum November 2011 Present at Science in the Changing North and/or the Water Strategy meetings November 2011 TEK interviews, Déline December 2011 Present at SRRB meetings February 2012 Plain language report on 2011-12 activities to SRRB and DRRC February 2012 Report on 2011-12 activities and results to date for CIMP March 2012 Draft manuscript on lake trout morphological variation March 2012 Present at International Polar Year Conference April 2012 Present at International Charr Symposium September 2012 Year 2-6 Activities to occur annually *see below for specific milestones Consultation with DRRC July Gillnetting, environmental sampling, collection of invertebrates and forage fish in each arm of GBL (rotational, 1 arm/year) late-July to late-August Post field season consultation with DRRC Late August Lab analyses (invertebrate ID, abundance and biomass, diet, SIA, FAA, age reading, fecundity) September – January Present at NWT Geoscience Forum, Science in the Changing North and/or the Water Strategy meetings November Present at Canadian Conference for Fisheries Research January Present at SRRB meetings February Plain language report on 2011-12 activities to SRRB and DRRC March Report on 2011-12 activities and results to date for CIMP March Present at other relevant conferences as opportunities arise Specific Milestones Publish Lake trout Morphology Paper Year 2 Draft lake trout trophic ecology paper Years 2-3 Draft lake trout traditional knowledge paper Years 2-3 Draft lake trout life history paper Years 3-4 PhD thesis on detailed lake trout studies Years 3-4 DFO technical report on trends in catch, biological characteristics, and environmental information Years 2-3 and Year 6 Other specific milestones will be dependent on levels of funding received in future years Anticipated end date March 2017 Key deliverables and reporting: Link to needs of NWT
Describe how results of the project were reported or will be reported to communities and other stakeholder groups Presentations on the project and results were reported at the following meetings: - Presentation and Discussion with Deline Renewable Resource Council, Deline, July 2012 - Presentation at American Fisheries Society Annual Meeting, Seattle, September 2011 - Presentation at NWT Geoscience Forum, Yellowknife, November 2011 - Presentation at Water Stewardship Meeting, Yellowknife November 2011 - Presentation at SRRB Annual Meeting, Norman Wells, February 2012 - Presentation to Deline High School Students, Deline, February 2012 - Presentations (poster and oral) at International Polar Year Conference, Montreal, April 2012 Plain Language Reports were also provided to SRRB and DRRC February 2012
Published Papers L. Chavarie, K. Howland, and W. Tonn. (in prep, to be submitted April 2012). An exceptional case of Lake Trout polymorphism: the coexistence of multiple shallow-water forms in Great Bear Lake, Arctic Canada.
Are you willing to be part of GNWT’s ‘ask an expert program’ (Yes / No) * Yes Contact Information Kimberly L. Howland Fisheries and Oceans Canada 501 University Crescent Winnipeg, Manitoba, R3T 2N6 Phone (work): (204)984-4227 Phone (cell): (204)294-1284 Email: [email protected] Fax: (204) 984-2403
* ENR is developing an on-line resource through which the public can ‘ask an expert’. There will be a drop-down box of subject areas and you will be asked to identify the subject area within which you can answer questions. The on-line service will be set-up so that questions posed within this subject area will be automatically sent to you.