NWT RESEARCH DATABASE

Tags: aquatic ecosystems, biology, fish habitat, habitat assessment, fisheries assessment, spawning areas

Objective(s): The objective of this research is to identify, measure, and characterize lake trout and northern pike spawning habitat in Nonacho Lake and to confirm the presence of lake trout and northern pike juveniles and adults in potential spawning areas û and to evaluate, quantify and qualify fish habitats in selected locations within the South Slave region.

Project Description: The objective of the first portion of the research is to identify, measure, and characterize lake trout and northern pike spawning habitat in Nonacho Lake and to confirm the presence of lake trout and northern pike juveniles and adults in potential spawning areas. Bathymetric surveys will be conducted at these sites in order to determine the areal extent of habitat loss, and the quality of habitat that will be affected. This will allow for a better assessment of the impacts of water drawdown in Nonacho Lake on key fish species. This research will be done through examining aerial photographs of Nonacho Lake trying to identify potential lake trout and northern pike spawning zones based on water depth, substrate (if visible), vegetation (if visible) and the extent of the littoral zone. Once potential sites are identified, a subsample of sites will be visited in the field to ground truth the aerial photography. Data collection and water depth measurements will occur at appropriate locations. Sampling of fish communities at each site will also occur to help determine if the area is used by juveniles of the target species. Beach seining, gillnetting and electrofishing will be used to capture fish. The objective of the second portion of the research is to evaluate, quantify and qualify fish habitats in selected locations within the South Slave region. In-stream assessments, benthic invertebrate samples and fish use studies will be conducted. The main anticipated species observed include: lake whitefish, round whitefish, northern pike, and longnose sucker while the secondary species may include: lake trout, lake cisco, walleye, burbot, slimy sculpin, lake chub, trout-perch and ninespine stickleback. Fish sampling techniques will include: electroshocking, beach seining from both a boat and by foot and angling. Local knowledge of historical fishing sites, species use and relative densities of fish populations will be incorporated into the reporting phase of the research. Transport for the studies will be provided by small fixed wing aircraft, helicopter, boat, and walking. Fieldwork will be conducted from July 07 to August 31, 2008 at the Nonacho Lake Control Structure, Twin Gorges Forebay, Taltson River, South Valley Spillway (SVS) and Trudel Creek. The Base camp for the work includes the existing Taltson Hydro-plant support facilities and Yellowknife.