Lake Huron Canadian Nearshore Assessment, 2021 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 2021, Canada conducted an assessment of the state of nearshore waters in Lake Huron. The assessment classifies the Lake Huron nearshore into Regional Units based on ecosystem type. The 2021 Highlights and Results Reports summarize the findings of cumulative stress across the 23 Regional Units of Lake Huron’s nearshore.

Overall, Lake Huron’s nearshore areas are under low or moderate stress. The South Manitoulin Island Regional Unit is under very low stress. There are no areas assessed as high stress although there are two Areas of Concern within the regional units: the St. Marys River and Spanish Harbour Areas of Concern. The Regional Units assessed as low stress are Cockburn Island, Christian Island, Collingwood to Meaford, Owen Sound, Colpoy’s Bay, Cape Croker to Cabot Head, Fathom Five and Cape Hurd to Chiefs Point. Although Regional Units in southern Georgian Bay are under low stress, there are some issues related to shoreline alteration associated with cottage and recreational development in the Collingwood to Meaford, Owen Sound and Colpoy’s Bay Regional Units. All other Regional Units are under moderate stress. This is largely associated with cottage and recreational development in the Collingwood to Meaford, Owen Sound and Colpoy’s Bay Regional Units.

In the North Channel and eastern Georgian Bay, issues include elevated levels of metals in sediment, advisories against consumption of some fish species, and moderate to poor benthic community quality, which are communities that play a vital role in maintaining sediment and water quality. Four Regional Units (Cabot Head to Burnt Point, Chiefs Point to Point Clark, Point Clark to Goderich and Kettle Point to St. Clair River) are flagged as having concerns for human and ecosystem health due to the presence of cyanobacteria. Small areas of cyanobacteria were detected in some of the larger bays in Georgian Bay and further investigation is required.