Canadians and Americans share a priceless resource: the Great Lakes basin ecosystem, linked downstream with the St. Lawrence River. Spanning two provinces and eight states, the Great Lakes-St. Lawrence region is an important part of our physical and cultural heritage. We depend on our Great Lakes for drinking water, recreation, transportation, power and economic opportunities. Yet, the demands of a large population in this region have taken their toll over time, and the impacts of industrialization, climate change, invasive species and toxic contaminants, among other pressures, are evident in the environment.
The Great Lakes Water Quality Agreement, signed in 1972, commits Canada and the United States to restore and maintain the chemical, physical and biological integrity of the Great Lakes ecosystem. Environment Canada, the U. S. Environmental Protection Agency and their many Great Lakes partners work together to evaluate the current condition of the lakes and the progress towards the goals established under the Agreement. This process involves the development and assessment of key indicators for issues such as invasive species, human health, contamination, and degradation and loss of aquatic and terrestrial habitats. It is challenging to simplify the complex nature and condition of the Great Lakes ecosystem; however reporting on indicators is a way to take complex information and make it more understandable. These indicators are discussed at the triennial State of the Lakes Ecosystem Conference (SOLEC), and are evaluated in the State of the Great Lakes reports.
How is the Health of the Great Lakes Measured?
State of the Great Lakes Reporting presents the compilation of scientific analysis and interpretation of data that tells us how the Great Lakes are doing. Through this binational process, 63 ecosystem indicators are assessed every three years, and overall assessments are done for the following indicator categories: Human Health, Contamination, Biotic Communities, Coastal Zones, Aquatic Habitats, Invasive Species, Resource Utilization, Land Use-Land Cover and Climate Change.
How Healthy are the Great Lakes?
It is challenging to simplify the complex nature and condition of the Great Lakes ecosystem. In 2009, the overall status of the Great Lakes ecosystem was assessed as mixed. A few indicators or areas were considered good, most were mixed and a few were listed as poor. The trends of the Great Lakes ecosystem components varied as some were improving and some were deteriorating. Efforts are needed to improve the state of the Great Lakes, so that it meets ecosystem objectives or can otherwise be considered in an acceptable condition.
Let’s take a look at some highlights from the State of the Great Lakes 2009 report.
- Can we drink the water?
- Can we swim at the beach?
- Can we eat the fish?
- Are we making progress to improve air quality?
- What is the state of coastal wetlands?
- Why are non-native species a problem in the Great Lakes and how are they getting here?
- What is the state of top predator fish in the Great Lakes?
Ten health-related parameters are used to assess treated drinking water quality in the Great Lakes region. The parameters include chemical and bacterial contaminants as well as treatment success. Although drinking water treatment facilities generally do not completely eliminate all contaminants, according to these parameters the Great Lakes provide residents with some of the finest drinking water sources found anywhere in the world. Based on those parameters, water treatment plants in both Canada and the United States are using successful treatment technologies.
Most Great Lakes beaches are safe for swimming most of the time. Some beaches, however, are at times unfit for swimming because of high levels of bacteria in the water particularly in areas around cities and areas of intensive agriculture. Based on 2007 data from over 1600 beaches along the U.S. and Canadian coastlines of the Great Lakes, an average of 67 percent of beaches were open more than 95% of the time. Work to keep human and animal wastes out of the waters is continuing, and improvements in the monitoring of beaches are providing people with more timely and detailed information about beach conditions.
Contaminant levels in Great Lakes fish have declined significantly from their historic peaks. More fish from most areas of the Great Lakes are safe to eat. However, a significant proportion of fish are still contaminated enough that they should only be eaten in limited amounts or not at all. A decrease in the concentration of contaminants in sport fish can be attributed to the elimination of the use of a number of toxic chemicals in the environment. Although declines in polychlorinated biphenyl (PCB) concentrations have been observed in lake trout, concentrations still exceed consumption limits so it is important to continue monitoring. Some new chemicals of concern have been detected in fish and are now being monitored.
Air quality seems to be improving on a regional scale, but localized problem areas still exist. Contaminants in air, such as nitrogen oxides and ground-level ozone, can be used to infer possible impacts of air quality on human health and the environment in the Great Lakes basin.
In the United States portion of the Great Lakes basin, concentrations of nitrogen oxides and ground-level ozone are decreasing. These successes are attributed to improvements in urban areas. In the Canadian portion of the basin, concentrations of nitrogen oxides have also decreased as a result of improvements in urban areas. Although ozone levels remain a concern, there has been an overall decreasing trend in peak ozone concentrations. This decrease is partly due to weather conditions being less conducive for ozone production, and the reductions of nitrogen oxide emissions in Ontario and in the United States.
Great Lakes coastal wetlands are a considerable ecological, biological, economic and aesthetic resource. They are an important habitat for many species of plants, fish and wildlife. Coastal wetlands also have important functions. For example, they help to reduce damage from floods and erosion, and remove excess nutrients from surface waters.
Great Lakes coastal wetlands are in peril as indicated by the decrease of coastal wetland area, declining wetland-dependent bird and amphibian populations and deteriorating plant community health. An estimated 50% of the original Great Lakes wetlands have been lost basin-wide. The inventory on the remaining Great Lakes coastal wetlands is in the initial stages of implementation. Great Lakes coastal wetlands are degrading because of the impacts of water level stabilization, sedimentation, contaminant and nutrient inputs, climate change, non-native species invasions and intensive industrial, agricultural and residential development.
Basinwide surveys have detected both positive and negative population trends in coastal wetland amphibians; however, the negative population trends have been significantly higher than the positive trends. Declines in various populations of toads and frogs have been recorded throughout wetlands in the Great Lakes region. Contaminant concentrations in snapping turtle eggs have shown declines, however contaminant levels in the fish they consume still exceed the environmental quality guidelines. Overall, the surveys indicate that contamination is present throughout the coastal wetland aquatic food web.
The introduction and spread of non-native species are having significant impacts on the ecology and economy of the Great Lakes region. Non-native species, now totaling 185 aquatic and at least 157 terrestrial species, continue to be discovered in the Great Lakes basin. Examples of non-native species that have negatively impacted the ecosystem include: zebra mussels, sea lamprey, purple loosestrife, and the emerald ash borer. Economic costs of mitigation can be significant. Sea lamprey controls cost Canadian and U.S. governments over $20 million USD per year, in an effort to protect the entire Great Lakes fishery, which is valued at up to $4.5 billion USD annually and supports more than 80,000 jobs.
The presence of invasive species can be linked to many current ecosystem challenges including the decline in the lower food web’s Diporeia populations, fish and waterfowl diseases, and excessive algal growth. Shipping, canals, online purchase of aquatic plants, and the aquarium and fish-bait industries are pathways of introduction and spread of non-native invasive species. The Great Lakes ecosystem has been and will continue to be extremely vulnerable to introductions of new invasive species because the region is a significant receptor of global trade and travel.
The top of the Great Lakes aquatic food web is comprised of native fish, such as lake trout and walleye, and non-native fish such as coho and chinook salmon. Since these fish have a significant role in the ecology and economy of the region, their populations are monitored and maintained in part through stocking programs. Habitat alteration, invasive non-native species, changing food supply, fish harvesting and contaminants exert negative pressures on these fish.
Lake Superior is currently the only lake where natural reproduction of lake trout has been re-established and maintained. In Lake Huron, self-sustaining populations occur at a few locations in Georgian Bay in Canada. In the U.S. waters of Lake Huron there are widespread but low levels of natural reproduction. Natural reproduction has been occurring in Lake Ontario and Lake Michigan at very low levels. To improve survival in Lake Erie, a deepwater strain of Lake Superior lake trout is being introduced and is also being considered for Lake Ontario. These fish may be better suited to survive in offshore habitats not colonized by traditional strains.
For More Information
- State of the Great Lakes Reporting
A process for assessing and reporting on the state of the Great Lakes ecosystem based on a suite of ecosystem health indicators.
- Facts and Information
Great Lakes information on a number of topics, as well as Quickfacts, Publications, Data and Science, and Maps.
- Great Lakes Publications
Documents and reports about the Great Lakes available from Environment Canada.
- Lakewide Management Plans (LaMPs)
Binational action plans for cooperatively restoring and protecting the ecosystem of individual Great Lakes.
- Great Lakes Areas of Concern
Locations in the Great Lakes basin that have experienced environmental degradation, and have Remedial Action Plans in place to guide restoration and protection efforts.
Binational.net is a collaboration between the United States Environmental Protection Agency and Environment Canada, to provide a single window for information on joint Great Lakes programs.
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