Lakehead University Student Maps Thunder Bay Harbour Fish Habitats
Posted on: October 31, 2018
Left: Michelle Willows kayaks into shallow water to collect data on fish habitats where larger vessels cannot travel. Right: Vegetation was sometimes extensive and visible from the surface. Credit: Michelle Willows.

Thunder Bay Harbour was listed as an Area of Concern (AOC) requiring a Remedial Action Plan, or cleanup plan, in 1987. This is due to years of industrial activity, waste disposal, pollution and channelization, degraded water quality and disrupted natural aquatic and nearshore habitats. When originally listed as an AOC, ten of the fourteen beneficial use indicators, defined by the Great Lakes Water Quality Agreement, were labelled as impaired in Thunder Bay Harbour. Extensive remediation efforts have been implemented since this time and five of the ten beneficial uses are being evaluated for re-designation to “not-impaired” status while one has already been re-designated. Four beneficial uses remain to be restored, including Fish and Wildlife habitat.

RAP Infosuperior: Thunder Bay Harbour Area of Concern

We recently spoke with Lakehead University masters student Michelle Willows who completed field mapping research this summer in Thunder Bay Harbour with the purpose of quantifying and characterizing existing fish habitat in the Thunder Bay Harbour and Area of Concern. In addition to quantifying habitat, Willows collected data to examine environmental characteristics including aquatic macrophyte abundance, water quality, substrate structure, bathymetry and the surrounding geography of the Thunder Bay Harbour near shore environment.

Michelle says the results were often unexpected with more habitat in places that she expected to remain barren or surprisingly little underwater habitat where onshore habitat was abundant and vibrantly populated. According to Michelle, her “final product will include high-resolution maps depicting environmental characteristics and comparing them over a large scale”. She states that “the data will assist in delineating the level of habitat fragmentation, the ratio of hardened shoreline from prolonged industrial activity, indicate areas with adequate vegetation and evaluate current habitat.”


Top: Infrared image depicting plants and substrate (red). Bottom Left: Down scan. Bottom Right: Side scan.These images depict an abundance of submerged macrophytes along the inner break-wall at North Harbour. Credit: Michelle Willows.

A multi-method approach was employed by Michelle Willows using broad-scale surveys to define the physical structure of the Thunder Bay waterfront and sonar scans to illuminate the lake bottom and underwater vegetation. Scuba surveys were completed in areas that were too shallow for sonar vessels in order to complete the data. Michelle was able to observe the state of habitat in the Thunder Bay Harbour through many lenses as she paddled through certain areas, dove in others and collected sonar to show where the lake bottom was murky, vegetated, or barren.

There is currently no official habitat status for the Thunder Bay Harbour but Michelle Willows’s research will contribute to our understanding of how effective remediation efforts have been in improving habitat.  When completed, Michelle’s work can be referred to when new remediation concepts are developed for future habitat improvement on the North Shore of Lake Superior. Michelle is supervised by Dr. Rob Stewart of Lakehead University’s Department of Geography and the Environment.

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