NWT RESEARCH DATABASE

Tags: biology, food web, fish

Objective(s): To provide baseline information on Lake Trout diversity within the proposed East Arm National Park

Project Description: The research objective is to provide baseline information on Lake Trout diversity within the proposed East Arm National Park The research goals are to sample Lake Trout from each of 3 depth ranges [0-50m, 50-100m, and >100m] at 10 sites in the East Arm, Great Slave Lake; to sample lower food web (i.e., Mysis, zooplankton, benthic invertebrates) from each of 3 depth ranges at two previously sampled sites in the East Arm, Great Slave Lake; to collect habitat data (i.e., depth, temperature, oxygen) from each site sampled; and to collect biological data and tissue samples from n = 25 Lake Trout per site and n = 5 other species per site. Gill nets will only be set on bottom, within specific depth ranges. No nets will extend across two depth ranges. Ranges to be used are 0-50m, 50-100m, and > 100 m. The highest priority will be to sample the two deepest zones on humps or banks. A temperature gauge will be fixed to each net to record temperature every 10min. The total weight of each species will be recorded. A unique number will be assigned to each Lake Trout. A digital image of each Lake Trout will be captured for future body shape analysis. Total body length, body weight in air, body weight in water will be measured on each fish. Gender and maturity will be assessed. A fin clip for future genetic analyses will be collected, otoliths (bones in the head) will be collected for age analysis, the stomach will be collected to assess diet, a dorsal muscle plug will be collected for stable isotope/fatty acid analysis (another way to assess feeding habits over the life of the fish), and heads from each specimen will be preserved to examine differences in dentition (teeth) and gill rakers. In addition to Lake Trout, this same data will be collected from five of each other species captured per net set. Benthic invertebrates will be collected from each site with an eckman dredge or a PONAR grab sampler. Zooplankton and mysis will be collected with a Wisconsin plankton net that will be lowered to the bottom and raised vertically. Water samples at the depth of the net will be collected with a Kemmerer bottle. Water will be filtered through a precombusted GF/C filter to collect a particulate organic matter sample. Temperature, dissolved oxygen, conductivity, and pH will be recorded at the depth of each net set using an YSI650QS meter. Minimum and maximum water depth will be recorded for each sampling event. Once the data and samples have been collected from fish sampled, fillets will be provided to the community of Lutsel K'e. The researchers propose to engage the community of Lutsel K’e in the research by presenting the study design, seeking feedback, and providing research reports and updates on the results to the community. The researchers will also provide a copy of pertinent sampling data to the Lutsel K'e Lands and Resources Department to be incorporated into their database. Data collected will also provide baseline information on Lake Trout diversity within the proposed East Arm National Park. Northern News has agreed to write an article about the research project. Since Northern News is distributed to all of the northern communities, information about the project will be broadly disseminated. In addition, upon arriving in Lutsel K’e the researchers will give a community presentation to describe the study background, rationale, and objectives. A plain-language summary of the project results will be presented to the community upon project completion. The fieldwork for this study will be conducted from July 10, 2010 to September 15, 2010.