NWT RESEARCH DATABASE

Regions: Gwich'in Settlement Area

Tags: environmental impact, petroleum industry, biology, habitat, pipeline corridor, aquatic invertebrates, fisheries, erosion

Objective(s): This study is designed to investigate fish and benthic invertebrate abundance and species composition at selected stream crossings of the proposed Mackenzie Gas Pipeline and lakes possibly affected by the pipeline.

Project Description: This study is designed to fill science gaps in Environment Canada’s understanding of the structure and functioning of the aquatic environment potentially impacted by various aspects of the Mackenzie Gas Project. While data collected during the Environmental Impact Assessment studies (carried out in conjunction with the proposed construction and operation of the Mackenzie Gas Pipeline) are relatively comprehensive in describing the major physical-chemical features of the aquatic environment, they are lacking in the descriptions of the biological features of these environments, and as a consequence, their sensitivity to various stressors. Accordingly, the aim of this study is to investigate fish and benthic invertebrate abundance and species composition at selected stream crossings of the proposed Mackenzie Gas Pipeline and lakes possibly affected by the pipeline. There are two areas of general concern. The first concern involves the tributaries where the physical habitat will be disrupted for what is believed to be a short period of time due to pipeline construction. Disruptions, in the terms of increased bank erosion, will be easily viewed once the pipeline is constructed and impacts assessed through comparisons of benthic (and forage fish) populations in areas with increased sediment loading with unperturbed areas upstream. The second area of concern is the small ponds and lakes along the pipeline routed and near the drill pads. These waters are more likely to be effected in smaller ways (e.g., increased chemical release in some lakes near development). Approximately seven streams and seven lakes or ponds in the Gwich’in Settlement Area, which will likely be affected by the proposed Mackenzie Gas Pipeline route, will be sampled. For stream sampling, at each sampling location, a quantitative investigation of the fish community will be carried out by closing off a 100 m reach using seine nets and then by electroshocking the reach in three passes. Captured fish will be worked up (species determination, length and weight) and then released. Any fish killed during shocking will be kept for further laboratory analyses (stable isotope, ageing, etc.). A quantitative investigation of the aquatic invertebrate community will also be conducted at each sampling location through collection of three samples using a quantitative net sampler similar to a Surber sampler. Captured invertebrates will be preserved on site. In addition, water sampling will be carried out at each sampling location. Transportation to stream sampling locations will be by helicopter. Investigations at lakes or ponds will consist of the following activities (to be performed at deep sites): 1) water quality (temperature, DO, pH, conductivity, turbidity) measurements using a YSI multiprobe; 2) collection of plankton using a fine-mesh net; 3) collection of a water sample using a Niskin water bottle; and 4) collection of a sediment sample using an Eckman dredge. Near-shore activities will consist of collecting aquatic invertebrates using dip nets, and capturing forage fish using a seine net or by electroshocking. Transportation to lake sampling sites will be by float plane, and subsequently by a portable boat, which will be assembled and used on each lake. No base camps will be set up during the course of the fieldwork. The research team will operate out of Inuvik. The findings of this study will be shared with community organizations through project reports and possible community visits. Fieldwork will be conducted from March 26 to April 6; June 18-25; August 6-27; and September 17-24, 2007 at the following locations: Unnamed Stream (68.40086, 133.30273); Unnamed Stream (68.19537, 133.04619) Unnamed Stream (68.16473, 132.98152); Unnamed Stream (68.09615, 132.82916); Travaillant River (67.90868, 132.19312); Unnamed Stream (67.86168, 132.07565); Unnamed Stream (67.80836, 131.69374); Thunder River (67.53466, 130.84937); Unnamed Lake (67.80840, 131.69377); Caribou Lake (67.98249, 132.93285); Hill Lake (67.97859, 132.55142); Fish Trap Lake (67.94490, 132.22014); Wood Bridge Lake (67.87591, 132.16648); David Lake, (67.82955, 132.14780); Crossing Creek Lake (67.81579, 132.01921); Travaillant Lake (67.69184, 131.78891).