Lake Superior Canadian Nearshore Assessment, 2020 Highlights and Results Report

Executive Summary

The Great Lakes nearshore is a key priority for restoration and protection. These waters provide a source of drinking water for most communities within the basin, are the area where most human recreation occurs, and provide a critical ecological link between watersheds and the open waters of the Great Lakes.

While efforts to restore and protect the Great Lakes have been largely successful over the last 50 years, water quality and ecosystem health in many nearshore areas continue to be degraded due to a variety of human-, climate- and invasive species-induced stressors.

The Canada-U.S. Great Lakes Water Quality Agreement includes a commitment to develop an integrated nearshore framework in the Great Lakes that provides an overall assessment of the state of the nearshore waters. Nearshore assessments provide the basis for determining factors and cumulative effects that are causing stress or threatening nearshore areas of high ecological value.

In 2020, Canada conducted an assessment of the state of nearshore waters in Lake Superior. The assessment classifies the Lake Superior nearshore into Regional Units based on ecosystem type. The 2020 Highlights and Results Reports summarize the findings across the nine Regional Units of Lake Superior’s nearshore.

Overall, Lake Superior’s nearshore areas are under low or moderate stress; there are no areas assessed as high stress. The Regional Units assessed as being under moderate stress include Pigeon River to Sleeping Giant (including the Thunder Bay Area of Concern), Black Bay and Chimney Point to Cap Chaillon. Issues in these areas include fish consumption advisories against some fish species; polychlorinated biphenyls (PCBs) in sediment, which are manmade chemicals known to cause harm to human and environmental health; areas of poor benthic invertebrate community health, which are communities that play a vital role in maintaining sediment and water quality; the presence of dams, which impede tributary connectivity; and, beach postings based on elevated of E.coli concentrations. No harmful algae blooms were detected in Canadian nearshore waters of Lake Superior in 2019. Measures of shoreline hardening and treated drinking water are all within thresholds for low stress. At the time of the assessment, there was no available data on Cladophora in Lake Superior.