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This BUI will be considered to be ‘not impaired’ when….
Environmental conditions support self-sustaining and healthy communities of indicator fish (e.g., Walleye, Bass, Lake Sturgeon, Brown Bullhead) and wildlife (e.g., black-crowned night heron, Northern leopard frog) species.
The fish portion of this BUI was further divided into subcriteria:
1. Fish communities in coastal wetlands are comparable to those in unimpaired coastal wetlands.
2. The number of adult Lake Sturgeon exceeds 750 individuals.
3. There is no evidence of benthification of fish communities in the Detroit River.
4. Creel and Catch Per Unit Effort (CPUE) surveys for Walleye and Bass indicate angler catch rates and effort are at or above the long-term average.
5. There is evidence of ongoing and/or increased spawning activity for fish species since 2006
What is being done?
Fish Portion:
Results of sub-criterion #1:
- 2022 Detroit River Area of Concern: Fish Populations Assessment Report: The entire weight-of-evidence gathered for this assessment provides strong evidence to support fish populations in the Detroit River are unimpaired. In fact, the findings suggest that the Detroit River supports healthy, diverse, and self-sustaining fish communities, inclusive of ecological sensitive species like Lake Sturgeon and Lake Whitefish, that are comparable or better than neighboring waterbodies and other locations across the Great Lakes.
- Index of Biotic Integrity (IBI) scores from multiple sites within the Area of Concern (AOC) were compared to a non-AOC reference site, the Walpole Island Delta (Midwood et al. 2020). From 2015 to 2017, IBI scores at the study sites were comparable to those of unimpaired fish communities. In addition, wetlands and coastal areas of the Detroit River support high species richness
Results of sub-criterion #2:
- Using mark-and recapture data from 2006 to 2019, the U.S. Fish & Wildlife Service found that the population of Lake Sturgeon in the Detroit River was 6,416 (Chiotti et al. 2023). Most of the population were classified as adults, listed as stable, and show an annual positive trend.
Results of sub-criterion #3:
- Fish assessment data from OMNRF and the Department of Fisheries and Oceans (Currie & Victor 2020) showed that the proportion of benthic fish species (33%) and catch rates of tolerant/invasive species did not change significantly from 1989 to 2018. These values were lower in the Detroit River than in other AOCs with healthy fish populations (Currie & Victor 2020).
Results of sub-criterion #4:
- Creel surveys conducted by OMNRF and the Michigan Department of Natural Resources (MDNR)indicate increased angler catch rates over time. For example, the MDNR found that Walleye catch rates rose to 0.227 fish/angler hr in 2015, compared to 0.171 in 2002–2004, while Smallmouth Bass increased to 0.064 fish/angler hr in 2009 from 0.0 in 2002–2004. Together, creel surveys and angler diaries show an overall increase in Walleye and Smallmouth Bass abundance.
Results of sub-criterion #5:
- Constructed reefs off Fighting Island have promoted spawning by Lake Whitefish and Lake Sturgeon, and egg and larval sampling has confirmed spawning activity of at least 42 species from 17 families in the Detroit River, including Lake Whitefish, Lake Sturgeon, and Walleye. Furthermore, genetic analyses indicate that populations of Lake Sturgeon, Walleye, and Yellow Perch in the AOC are resilient and genetically diverse.
Wildlife Portion:
- 2011 Southern Ontario Bald Eagle Monitoring Program Summary Report: This work aimed to identify and monitor Bald Eagle territories and nests, track movements, assess contaminant levels, and support the care of injured birds. The report found that Bald Eagle populations continue to increase, with new breeding pairs being confirmed and a growing number of young successfully fledging each year.
- 2012 Assessment of wildlife status and trends within the St. Clair River and Detroit River Areas of Concern Using Bird Studies Canada Data: After reviewing available amphibian and bird monitoring datasets, suitable data were selected, mapped, and analyzed to examine trends over time and summarize survey coverage, including where and how frequently monitoring occurred. The review found that marsh bird populations in the AOC are impaired, with species diversity closely linked to the availability of wetland habitat, much of which remains isolated. In contrast, Bald Eagles and migratory waterfowl appeared to be less affected and have shown more stable population trends.
- 2026 – The DRCC is currently supporting two important habitat restoration projects that will help protect and enhance critical wetlands, fish habitat, and wildlife areas in our region. The 1) River Canard Wetland Restoration will strengthen the MMM Hunt Club finger dyke to protect one of the largest remaining wetland complexes on the River Canard and improve habitat for species at risk, fish, reptiles, and migratory birds, and the 2) Fighting Island Wetland Re-Creation will create a sheltered embayment through the construction of six islands, providing new opportunities for aquatic vegetation, fish habitat, and the future establishment of marsh habitat for wildlife.
- Ongoing: Canadian Wildlife Service wetland sampling. Monitoring activities included water quality sampling, surveys of submerged aquatic vegetation, and aquatic macroinvertebrate sampling. Collectively, these monitoring efforts help researchers track ecological conditions over time, identify emerging environmental concerns, and evaluate the effectiveness of habitat management initiatives across the site.
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