The Great Lakes are the series of interconnected freshwater lakes located in the upper Midwest region along the border region between Canada and the United States. Consisting of Lakes Superior, Michigan, Huron, Erie and Ontario, they form the largest group of freshwater lakes on Earth containing 21% of the world’s freshwater. The total surface area is 244,106 km2 (94,250 square miles). The total volume of water measured at the low water datum is 22,671 km3 (5,439 cubic miles). The Great lakes waters flow east from Lake Superior to Huron and Michigan, southward to Erie and finally northward to Lake Ontario. The Great Lakes waters then drain east via the St. Lawrence River to the Atlantic Ocean.
Lakes Superior is the second largest lake (by area) in the world and Lake Michigan is the largest lake in the world that is entirely within one country. The southern portion of the Great lakes is bordered by the Great Megalopolis that as of 2011 had a population of 59,144,461. The lakes are bordered by the Province of Ontario in Canada and the U. S. states of Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, Pennsylvania, and New York.
The Great Lakes formed at the end of the last ice age as retreating ice sheets carved basins into the land and that filled with meltwater. The lakes are a major highway for transportation, migration, trade and they are home to a large number of aquatic species. Many species have been introduced as a result of trade, and some threaten the region’s biodiversity.
Except for Lake Erie, the lakes tend to be deep and cold. As a result, many coldwater fish species inhabit their waters.
Lake Huron Michigan
Lakes Huron and Michigan have similar surface elevations above sea level and are therefore hydrologically considered to be a single lake made up of two basins. Further references within this website will be as Lake Huron Michigan. The two basins are connected through the Straits of Mackinac that is 8 km (5 miles) wide. Water flows freely through the Strait. The Straits of Mackinac is one of the main connecting waterways within Lake Huron Michigan. The other three important waterways are the St. Clair River, the Chicago River (Chicago Shipping Canal), and the St. Mary’s River. The St. Clair River is a particularly important waterway as it, the Detroit River and Lake St. Clair support the largest remaining population of lake sturgeon. In addition this waterway supports thousands of walleye which travel from the western basin of Lake Erie to feed in southern Lake Huron.
Lake Huron Michigan has a retention time of 22 years. The maximum depth of Lake Huron is 228 m (748 ft) and has an average depth of 59 m (195 ft). It has a surface area of 60,000 sq km (23,000 sq mi.). Lake Michigan has a maximum depth of 282 m (925 ft) and an average depth of 85 m (279 ft). It has a surface area of 58,000 sq km (22,300 sq mi). In biological terms, Lake Huron Michigan is referred to as an oligotrophic lake. An oligotrophic lake is one whose waters are low in productivity and have a high oxygen content.
Like all of the Great Lakes, the ecology (including the fish species composition and food web) of Lake Huron Michigan has undergone drastic changes in the last century. Lake Huron Michigan is home to some 90 fish species. Some of these include lake trout, lake cisco, lake whitefish, bloater and the coolwater species walleye, lake sturgeon, yellow perch, northern pike and smallmouth bass.
The lake originally supported a native deepwater coldwater fish community that was dominated by lake trout, which fed on a number of deepwater ciscoes’ as well as sculpins and other native fish species. The near shore fish community was dominated by the coolwater species walleye.
Several invasive species, including sea lamprey, alewife and rainbow smelt, became abundant in the lake in the 1930’s. The major native top predator, lake trout were virtually extirpated from the lake by 1950 due to a combination of overfishing and the effects of the sea lamprey. Several species of deepwater ciscoes were also extirpated from the lake by the 1960; the only remaining deepwater cisco is the bloater, Coregonus hoyi. Non-native Pacific salmon have been stocked in the lake since the 1960’s, and pure strain lake trout have been stocked in an attempt to rehabilitate the species. The reports suggest moderate natural reproduction of lake trout has been observed.
More recently, Lake Huron Michigan has suffered due to the introduction of a variety of new invasive species, including zebra and quagga mussels, the spiny water flea, and round gobies. Another important impact to several walleye populations in Georgian Bay including that of the Key River was the persistent record setting low water levels that existed between 2000 and 2013. However, the U. S. Saginaw Bay population has thrived possibly as it is a shoal spawning population. And lastly, Asian carp are present in the Chicago shipping canal which is at the doorstep of Lake Michigan. Asian carp is a general term that refers to up to nine carp, Cyprinus, species. Of greatest concern are the Silver carp, Bighead carp, Grass carp, and Black carp as they appear to have the potential to dominate the entire watershed basin of the Great Lakes and interconnecting waterways as a result of their ability to consume a high percentage of the cellular plant material, phytoplankton that is produced in the lakes waters. In 2016, Grass carp and their eggs were found in the Sandusky River of Ohio.
Since 2006, the deepwater demersal fish community of Lake Huron Michigan has been in a state of collapse. A number of drastic changes have been observed in the zooplankton community of the lake. Chinook salmon catches have also been greatly reduced in recent years as a result of the population collapse of their food supply, alewife. In addition, lake whitefish have become less abundant and are in poor condition. These recent changes appear to be attributable to the new exotic species.
The lake’s fish community and food chain remains in a complex flux.
What we are doing
- Supporting the complete closure of the canal linking Chicago and the Mississippi River
- Intervening and encouraging the State of Ohio to eradicate Grass Carp which have appeared in the Sandusky River and Maumee River
- Encouraging our donors and the public to make their concerns about the presence of Grass carp in the Sandusky River and Maumee River and the need for the State of Ohio to take immediate action
- Encouraging the State of Ohio to prohibit the possession and sale of live Grass Carp in the State
- Encouraging the Province of Ontario to take a greater role in dealing with the Asian Carp threat in the Chicago area and the Grass Carp threat in the Ohio rivers and Lake Erie
Facilitate and Support the work of Dr. Pat Chow-Fraser of McMaster University
The work of Dr. Pat Chow-Fraser has included:
- Determining the impact of sustained low, and higher water levels on fish species and the fish community of Georgian Bay
- Determining the impact on wetland plant community during sustained very low and very high water levels
- Determining the distribution of spawning sub-populations of muskellunge in Georgian Bay
- Mapping Blanding’s Turtle habitat in the Georgian Bay Area
- Comparing wetland communities in diked and undiked wetlands in southern Georgian Bay
- Determining impacts of extreme water levels on the quantity of fish habitat in coastal wetlands of Georgian Bay
- Updating changes over thirty years in biological characteristics of degraded muskellunge nursery habitat in southern Georgian Bay
Other areas of interest:
- Investigating the relationship between low water levels and suspected botulism deaths of aquatic birds and Lake Sturgeon.
- Impact of fluctuating water levels upon colonization of Phragmites.