Progress on restoring the river is measured by 14 beneficial use impairments, or BUIs. A beneficial use is the ability of all living organisms (including humans) to use the Great Lakes without adverse effects. As of June 2020, the Detroit River Canadian Area of Concern (AOC) has 7 impaired beneficial uses, 6 unimpaired, and 1 requiring further assessment. The projects and research described here provide the scientific evidence to determine when a BUI is no longer impaired.
Scientists from the University of Windsor’s Great Lakes Institute for Environmental Research (GLIER), Environment and Climate Change Canada, the Canadian Wildlife Service, Ministry of the Environment, and the Ministry of Natural Resources continue to study the condition of the Detroit River as part of the DRCC’s delisting strategy—including sediment & water quality, wetland condition, fish populations and contaminants in fish just to name a few! For more information, please visit our Annual Review (yearly reports) and DRCC Publications pages.
Mapping our Progress
GLIER has created the Delist Areas of Concern (AOC) Metadata and Mapping System tool for the DRCC. The goal of this web-based database is to consolidate Detroit River research in one place to help better understand the overall health of the river. Researchers, government agencies, and the public will be able to browse this online library containing geospatial data (i.e., data associated with a geographic location) and non-geospatial data (e.g., reports, presentations, photographs, databases, etc.) related to scientific research and monitoring of the rivers.
Restrictions on Fish Consumption
When contaminant levels, like mercury and PCBs, are unsafe in fish, consumption advisories may recommend that people limit or avoid eating certain species of fish caught in certain places. In 2015/16, GLIER and researchers from the University of Michigan built on their previous work in applying a new eco-sleuthing technique, known as mercury isotope analysis, to “fingerprint” sediment mercury sources. Their recent study showed that high concentration mercury hotspots in U.S. and Canadian waters could be distinguished based on these “fingerprints”. Additional sediment and invertebrates samples were collected in the Detroit River in 2015 and mercury isotope analysis was completed. In the future, these distinct mercury “fingerprints” could be used to assess what sources of mercury are getting into fish in different regions of the river.
Additionally, GLIER has been synthesizing and analyzing geospatial data in order to develop new probabilistic models for the purpose of assessing the Restrictions on Fish Consumption BUI. A geodatabase was developed to populate, store, query, share, and view BUI related data. The data will be analyzed and used to generate synthesized models via artificial intelligence approaches.
The DRCC launched a fish consumption survey in 2019 to collect data on what people catch and eat from the Detroit River. So far, majority of anglers captured in the survey eat fish from the river (4 oz to 8 oz each meal about 1 to 4 times per month, on average). Most anglers prefer to pan fry, grill or bake the fish they catch and the most common fish consumed from the Detroit River according to the survey are walleye, yellow perch, white perch, and large and smallmouth bass. The fish consumption survey will be incorporated into the assessment of the Restrictions on Fish and Wildlife Consumption BUI. Do you fish the Detroit River? If so, take the fish consumption survey here.
It is expected that all available data for this BUI will be assessed in 2020/21, with an assessment report indicating the status of the BUI completed by March 2021.
Degradation of Benthos
The environmental quality Detroit River is reflected by the kinds of insects living in the river bottom sediment. In 2016, researchers reviewed sediment chemistry and benthos data collected from extensive sampling events. They found that the benthic community in the Detroit River is typical of what a connecting river environment would support. There are no toxic effects to the benthos from the sediment and the benthic community is similar to upstream sites in the river. This work shows that the river has improved over time and good progress has been made through the numerous cleanup projects completed to date. The DRCC has officially requested the re-designation of the Degradation of Benthos Beneficial Use Impairment (BUI) to “not-impaired.”
Phytoplankton and Zooplankton
Phytoplankton (tiny plants) and zooplankton (weak-swimming microscopic animals) are key components of aquatic ecosystems, forming the base of most aquatic food webs. Environment and Climate Change Canada analyzed 65 archived plankton samples collected in different surveys areas. In 2015, zooplankton samples were taken at various sites along the Detroit River.
Additionally, from July to November 2019, scientists from the Department of Fisheries and Oceans Canada sampled 8 sites in the Detroit River to assess phytoplankton and zooplankton community composition in the water column to inform the Degradation of Phytoplankton and Zooplankton Populations BUI. The scientists examined the type, biomass, and productivity of zooplankton, phytoplankton, and microbes within the river. Researchers are in the process of interpreting the additional data collected and will prepare a report in the spring of 2020 summarizing their findings including any changes in the abundance and diversity of the zooplankton and phytoplankton communities.
Bird or animal deformities or other reproductive problems
Due to their long life span, much of which is spent in or around water, snapping turtles provide excellent insight into environmental health. Locally, researchers monitor turtle nests to ensure turtles are hatching normally and to ensure mercury and polychlorinated biphenyls (PCBs) are not accumulating in eggs. In 2014 and 2015, there was no significant difference in hatching success or deformities between samples from the Detroit River area and samples collected at Long Point. Furthermore, PCB levels in eggs have been decreasing over time.
Tree Swallow Monitoring
Tree swallows feed on insects that emerge from the bottom of the river, where they may be exposed to
toxic chemicals. When the birds eat the insects, they can accumulate these toxins. Environment Canada and Climate Change researchers have erected 25 nest boxes at four locations along the river. These boxes will be monitored 2-3 times per week during the nesting season. Data will be collected on reproductive success (clutch size, hatching success, fledging success, weight at fledging) and contaminants in eggs including PCBs, mercury, and polybrominated diphenyl ethers (PBDEs).
Environment and Climate Change Canada’s wildlife toxicologists have completed three years of field work for reproductive health assessments on tree swallows for the Bird and Animals Deformities BUI. By collecting and analyzing the eggs and plasma of these Tree Swallows, researchers can determine if contaminants are adversely affecting reproduction. The final year of monitoring has been completed and a draft assessment report is anticipated in 2021.
In 2015, a partnership between the Michigan Department of Natural Resources, the U.S. Geological Survey and the Ontario Ministry of Natural Resources and Forestry was developed in order to conduct a full creel survey of the Detroit River. This survey will help the DRCC to assess the Degradation of Fish and Wildlife Populations Beneficial Use Impairment (BUI). A creel, or angler survey, is a tool fisheries managers use to gather information on fish populations. Individual anglers are interviewed to gather information about the number of hours they fished, what species they’re targeting, the size of the fish they caught, and whether they released or harvested the fish. This creel survey provides a snapshot of the recreational fishery measuring the effort, catch, and harvest of fish from the Detroit River.
Anglers put in over 600,000 hours on the river with the majority of recreational fisheries catch and effort at 54% and occurred during April and May in 2015. Anglers caught and harvested over 500,000 White Bass (more than any other species). Walleye is the preferred fish sought out of the Detroit River with 73% targeted and 87% harvested (around 150,000 fish). There were 192,000 Yellow Perch caught, mostly in September (68% at a rate of 4.13 perch per angler hour). Over 100,000 Smallmouth Bass were caught in 2015. Either in May (22%) during the Michigan catch and release season or in September (30%). Of all the Smallmouth Bass caught, 97% were released. Anglers in the Detroit River caught over 4,000 Muskellunge. Most muskies were caught in the spring (April to June); however, it does appear that catches do occur throughout the year. Similar to the Lake St Clair Muskie fishery, 99-100% of all Muskie caught were released.