Current Status: Not Impaired
Based on the available scientific evidence, the Degradation of Fish and Wildlife Populations BUI was officially redesignated to “Not Impaired” in 2024.
This redesignation reflects that:
- The delisting criterion requiring fish community health to be comparable to suitable reference sites through two consecutive studies has been achieved.
- Wildlife assessments found no evidence of population impairment linked to local environmental conditions.
- Required remedial and monitoring actions identified through the Remedial Action Plan have been completed or addressed.
The redesignation does not mean that monitoring stops. Ongoing stewardship, habitat restoration, and environmental protection efforts continue throughout the watershed. However, it does mean that fish and wildlife populations within the Canadian portion of the St. Marys River now perform similarly to those found in comparable healthy Great Lakes ecosystems.
Why This BUI Was Listed
When the St. Marys River was first identified as an Area of Concern, there were concerns that fish and wildlife populations were being negatively affected by decades of environmental stress.
Historical industrial activity, shoreline development, pollution, invasive species, and habitat alterations had the potential to impact the health and diversity of native fish and wildlife populations. There was also limited information available about wildlife populations, making it difficult to determine whether environmental conditions were affecting their abundance and reproductive success.
Because of these concerns, the Degradation of Fish and Wildlife Populations Beneficial Use Impairment (BUI) was designated as impaired.
What Has Changed
Over the past two decades, extensive monitoring and scientific studies have been completed to better understand the health of fish and wildlife populations throughout the St. Marys River.
Fish community assessments conducted by Fisheries and Oceans Canada used an Index of Biotic Integrity (IBI) approach, which evaluates factors such as species diversity, abundance, age structure, reproductive success, and overall ecosystem health. Results from two consecutive studies found that fish communities within the St. Marys River were comparable to those found in healthy reference locations.
Researchers concluded that the river continues to support a native fish community that is diverse, complex, and healthy.
Wildlife studies also showed positive results. Surveys of common terns, black terns, herring gulls, and other indicator species found no evidence that wildlife populations within the Area of Concern were performing differently than populations outside the Area of Concern. Studies also found no evidence that local contamination was affecting reproduction or population health.
As a result, the scientific evidence demonstrates that fish and wildlife populations in the St. Marys River are functioning similarly to those found in healthy Great Lakes ecosystems.
Status on the Canadian Side
On the Canadian side of the St. Marys River Area of Concern, fish and wildlife populations have been thoroughly assessed through multiple monitoring programs and scientific studies.
These assessments found that:
- Fish community health is comparable to suitable reference sites.
- Native fish populations remain diverse and self-sustaining.
- Common tern and black tern populations continue to breed successfully within the Area of Concern.
- Wildlife reproductive success is similar to populations outside the Area of Concern.
- No evidence was found that local contamination is impairing fish or wildlife populations.
- The monitoring and assessment actions identified in the Remedial Action Plan have been completed.
Together, these findings indicate that environmental conditions now support healthy fish and wildlife communities throughout the St. Marys River.