NWT RESEARCH DATABASE

Regions: Sahtu Settlement Area

Tags: aquatic ecosystems, biology, environmental monitoring, habitat assessment, benthic invertebrates, fisheries assessment

Objective(s): The objective of the project is to characterize biophysical conditions in Bosworth Creek in the area surrounding the lower Bosworth Creek bridge, both upstream and downstream from the location of a former weir.

Project Description: WorleyParsons, on behalf of Imperial Oil, is planning to initiate a benthic invertebrate and fisheries assessment program for the portions of Bosworth Creek adjacent to the Imperial Oil operations in Norman Wells, NWT. The objective of the project is to characterize biophysical conditions in Bosworth Creek in the area surrounding the lower Bosworth Creek Bridge; both upstream and downstream from the location of a former weir. The weir was installed in the creek at the lower Bosworth Bridge in the 1960s, and was subsequently removed in 2005. The proposed program will provide an assessment of current creek conditions with respect to benthic and fisheries components, and supplement qualitative baseline data collected over the past 3 years by Sahtu Renewable Resources. Imperial Oil's Bosworth Creek monitoring program will consist of 1) benthic invertebrate sampling; 2) fish sampling; and 3) fish habitat assessment. The fisheries tasks will be undertaken in the spring and fall of each year, whereas the benthic sampling will be conducted annually. The benthic invertebrate and fisheries assessments will be undertaken to collect the following: - The composition, distribution, relative abundance, movements and general life history parameters of existing fish populations; - An assessment of fish habitat suitability (spawning, rearing, feeding, migration, overwintering), particularly critical and sensitive habitats; - An evaluation of seasonal use of available fish habitat; and, - A description of benthic invertebrate community composition, abundance and distribution in the study area. Benthic Invertebrate Sampling Benthic invertebrate samples will be collected at 3 to 4 locations on Bosworth Creek. The sampling stations will be located upstream of, at, and downstream of the original weir location (i.e., lower Bosworth Creek bridge). Three benthic invertebrate samples will be collected at each sampling station using a Hess cylinder. Samples will be preserved, sorted and identified. Benthic sampling will be conducted in general accordance with the Canadian Aquatic Biomonitoring Network (CABIN) program methods where appropriate, to allow for collaborative data sharing. Fish Inventory Inventories of fish populations will be conducted during the spring and fall open water seasons. The primary sampling techniques will include backpack electrofishing and minnow trapping. Many measurements will be collected on all fish captured, including species identification, life history stage, gender, length, weight, and fish condition. Efforts will be made during all of the fish sampling work to minimize mortalities by regularly checking sampling gear and the use of proper handling techniques. Fish Habitat Assessment The stream habitat assessments will be conducted to assess the habitat features of Bosworth Creek. This assessment will examine individual channel habitat units (e.g. parts of a creek: riffle, run, pool) in combination with water depth, velocity and substrate characteristics to provide a rating for each of these channel units in relation to various fish life history stages (i.e., spawning, rearing, adult summer, migration and overwintering). As the project will build on work previously conducted by others (Sahtu Renewable Resources Board, Mackenzie Mountain School, Department of Fisheries and Oceans, Environment Canada, INAC, etc.) there is intent to share information collected with those parties/organizations. We will provide a written or oral project updates / summary in 2010. The fieldwork for this study will be conducted from October 9, 2009 to October 30, 2009.