NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: contaminants, biology, bioaccumulation, food web

Objective(s): To identify and quantify the physical, chemical and ecological processes that affect contaminant transfer in Arctic aquatic food webs in response to observed and predicted climate variability & change in the Husky Lakes watershed; and to provide people and regulators of Inuvik and Tuktoyaktuk with tools to effectively monitor selected highly valued components of their environment.nitoring of locally relevant sites.

Project Description: The long term goals of this research are: 1. to identify and quantify the physical, chemical and ecological processes that affect contaminant transfer in Arctic aquatic food webs in response to observed and predicted climate variability & change in the Husky Lakes Watershed (HLW); and 2. to provide people and regulators of Inuvik and Tuktoyaktuk with tools to effectively monitor selected highly valued components of their environment. The short term goals (2 years) of this research are: 1. collecting baseline information on HLW’s cryosphere, food web, and contaminants, and their interactions; and 2. explore existing Traditional Knowledge (TK) on subsistence fishing. The specific objectives of this research are to: 1. characterize the lake-ice conditions and associated lake productivity and aquatic food webs along a hydroclimatic/salinity gradient within the Husky Lakes Watershed (HLW); 2. using MYLAKE (Saloranta and Andersen 2007) as the physically-based modeling platform, develop and validate a process-based hydro-ecological food-web sub-component coupling changes in hydro-climatology and ice conditions to water column productivity and food webs; 3. use the characterized food webs to explain uptake of Hg including isotopes as tracer/marker through a comparison of: i) spatial comparison of Hg bioaccumulation in food webs; ii) Hg stable isotope ratios in biota along a salinity gradient in the HLW and with lakes outside the HLW; 4. review of existing and new documentation of Traditional Knowledge (TK) on historical and present ice and climate conditions and fish biology and subsistence fisheries; and 3. combine both knowledge bases to help develop future strategic monitoring of locally relevant sites. All sampling will be guided by standardized protocols for lake sampling such as those available from CIMP, however minor amendments will be made when needed to achieve project specific goals. The research team will conduct complete aquatic food web sampling at all selected lakes to characterize trophic structure. The sampling is described below. Methods will be adapted seasonally, for example, gill nets will be set in open water (September) or under ice (with community members). Once samples are obtained, they are preserved (frozen) and shipped to several laboratories for chemical analysis (contaminants and stable isotopes). Aquatic macro-invertebrates / benthos will be sampled using Ponar samplers and kick-sweep method (a maximum of 10-15 g wet weight of each species will be collected per lake). Zooplankton (>250µm) will be sampled using zooplankton nets (about 10 g wet weight of bulk zooplankton per lake). Possibly, phytoplankton samples (<250µm) will be taken from each site by scraping small rocks. Sub-samples/tissue samples of all species collected will be taken and preserved for trophic analysis (stable isotopes C, N and S), species identification (biodiversity work), and contaminants. Dissolved oxygen and temperature profiles in the lake water columns will be obtained on site using YSI probes from an inflatable boat equipped with an electric motor. Limnological parameters and water chemistry will be characterized using standard methods for collections (water samples - about 4 L per lake) and analysis at EC laboratories (NLet). The research team plans to join community members and learn their way of fishing at the study lakes, where possible. Some samples of fish muscle (~20 grams) will be taken from fish caught be community members, if they agree. Obtaining samples this way will reduce the number of fishes we needed to catch for this study. Fish sampling will include all species present in each lake using angling/jigging, gill nets (60m long multimesh gill nets and mesh sizes 36-42 mm will be used; sets of 1-3 hours with hourly checking of the nets), minnow traps, seine-nets, and electro-fishing (NOTE: this method will be used very limited; nearshore habitat only, for small fish species and young-of-year that would be missed otherwise; will only be used when conditions allow safe and effective use; this method will only be used on gravel shorelines). A range of sizes (ages) of each species will be collected. This is necessary to characterize the food web including dietary preferences of fish at several life stages. All fish collected will be killed for subsequent tissue analysis. Fish work will be licensed by DFO (License to fish for scientific purposes). The research team will collect 20 to 50 specimens from each present fish species at each lake (and at 5 sites in the Husky Lakes). In the unexpected event of collection of a specimen not listed in the list, three specimens will be collected, preserved for ID, and handed to the Department of Fisheries and Oceans (DFO) and Fisheries Joint Management Committee (FJMC) for their records. Northern organizations will be co-leads of this project (ARI - confirmed and Tuk HTC - invitation pending), with the long term goal being those (or other) local organizations to take over and leading long term monitoring in the proposed study area and of valued ecosystem components therein. The research team aims to hold 25 Traditional Knowledge interviews and compensate the participants. The researchers will be presenting the project at schools/college in Inuvik and Tuktoyaktuk. The research team hopes to recruit future project team members/co-leads from the ENRTP college course. They will hold workshops and presentations that will be open to the public in conjunction with the field work. The southern members of the field crew will be open minded to listen to and learn about concerns the community members involved in the project may have. Communication with Northern partners is a key component during the field trips and throughout the project duration. Results from this proposed study would be presented to local communities in person (and/or through interviews in print media or radio) and at national and international meetings of the respective sub-disciplines, e.g., Mercury2011, AGU 2012, SETAC, IPY 2012 Montreal. Results will be published high impact peer-reviewed journals, in adequate reports, and media (local radio etc). The research team is thinking of partnering with the Environment and Natural Resources Training Program (ENRTP) and this program either via field trips to the lakes or via teaching efforts by project members. The researchers will continue to communicate the research plans and progress before and after fieldwork to all Northern partners. The fieldwork for this study will be conducted from April 5, 2012 to December 20, 2012.