Rhumb Line

Lake Ontario isn’t alone. All five of the Great Lakes’ surface water temperatures are still above their 1995-2020 averages as of Aug. 21,  according to NOAA Great Lakes CoastWatch. 

According to air temperature predictions made by NOAA Weather Service, above normal air temperatures during the rest of August and September could potentially translate to continued high surface temperatures in the Great Lakes for the rest of summer. 

The most staggering increase of temperatures comes from Lake Ontario, which reached 76.93°F (24.96°C) on July 10. That is 9.72°F (5.4°C) above the average temperature for July 10 from 1995 to 2020 and is the warmest surface water temperature ever recorded on Lake Ontario, according to NOAA CoastWatch data.

The surface water temperature of Lake Ontario continues to remain above average, having hit 73.81°F (23.23°C) on Aug. 20.

These high water temperatures are mainly caused by persistent warm weather along with light winds.  “Climate change is clearly affecting the Great Lakes,” Andrea Vanderwoude, manager of the Great Lakes CoastWatch, reported. “This particular warming is consistent with the larger warming that is occurring.” 

b) A Divide in the Great Lakes – the Nearshore Shunt

With all of the other divisions we see happening around us, do we really need another one??? Alas its happening even in our lakes – a divide between the nearshore waters and offshore waters of each lake. (Offshore waters on the Great Lakes have been defined as waters over 66 ft (20 m) deep.)

Ever encounter sharp mussel shells underwater when you swim or sand that is becoming whiter from crushed shells or bad-smelling masses of algae washing up on the shore – these changes are features of the “nearshore shunt”. Ontario scientists are leaders in identifying and explaining this phenomenon.

Zebra and quagga mussels are invasive species that now dominate Great Lakes nearshore ecosystems. They blanket the bottom of the lakes in vast numbers across much of the Great Lakes. Zebra and quagga mussels are filter feeders that have clarified water in the nearshore areas of the Great Lakes. The increased clarity and filtering traps phosphorus coming into the lakes in the nearshore environments, preventing it from getting into deeper waters as much as it had before the mussel invasion.

The mussels created the divide we see today between nearshore and offshore areas of the Great Lakes — the nearshore areas struggle with excessive blooms of algae, while in the offshore areas there aren’t enough nutrients to support thriving fisheries.

The significance of the nearshore-offshore divide also varies from lake to lake. Lake Erie is the only lake where there are no concerns about low offshore productivity — the focus remains on cutting back on phosphorus to stop alga blooms.

Lake Huron and Lake Michigan, on the other hand, are dealing with the most damage to their fish populations from these low nutrient levels. In these lakes, the fisheries have noticed a decline in the prey fish populations — enough to impact how much predator fish they can stock in the lakes.

“Lake Huron was the earliest lake to show these kinds of trends and changes in the fish community and Lake Michigan is following that path,” said Robert Hecky, a scientist with the International Joint Commission’s Scientific Advisory Board.

Lake Superior’s data suggests that declining nutrients in the offshore could be a problem, but the issue is not as bad as in the other two lakes.

c) Eagle vs Drone

One of our favourite hidden anchorages up north is home to at least one nesting pair of bald eagles. Watching them soar overhead or swoop down for a catch is a breathtaking moment. They are also known to take birds in mid-air, such as gulls. Apparently, that was not enough for one bald eagle.

A bald eagle launched an aerial assault on a drone operated by the Michigan Department of Environment, Great Lakes, and Energy — known ironically in this case as EGLE — ripping off a propeller and sending the aircraft into Lake Michigan.

The attack happened July 21, when the drone was mapping shoreline erosion near Escanaba in Michigan’s Upper Peninsula to document and help communities cope with high water levels.

Environmental quality analyst and drone pilot Hunter King said he had completed about seven minutes of the mapping flight when satellite reception became spotty. King pressed a button to return the $950 drone to him and was viewing his video screen when the drone began to twirl. “It was like a really bad roller coaster ride,” said King, who looked up and saw the eagle flying away, apparently unhurt by its confrontation with technology.

d) Recovering Fish Populations

The variety of fish swimming in Chicago’s rivers have increased in recent decades, which authorities attribute to a decline in pollution, according to a sampling study released Monday by the Metropolitan Water Reclamation District.

The report claims there are nearly 60 different types of fish swimming in the Chicago and Calumet rivers. There were fewer than 10 types of fish in the waterways in the 1980s, according to the Chicago Tribune. Carp is the most frequently found species in the rivers. Among other species netted by district biologists were bluegill, catfish, largemouth bass and yellow perch. Those fish are less tolerant of pollution than carp.

Shedd Aquarium research biologist Austin Happel says the more robust and diverse population of fish is an example of how the fight to cleaning rivers is paying off after decades when they were turned into industrialized sewage canals.

e) Canada – US Government Joint Report:
     STATE OF THE GREAT LAKES

It is impossible to overstate the global importance of the Great Lakes. Many facts are well known. They contain one fifth of the world’s fresh surface water supply and, as home to over 4,000 separate species, are one of the most ecologically diverse ecosystems on Earth. They provide a source of drinking water to tens of millions of Canadians and Americans.

The Great Lakes have always been at the heart of North America’s economy. They are vital to the economies of both Canada and the United States. Our lakes are a job-creation engine. If the Great Lakes Region (Ontario, Québec and the 8 Great Lakes States) were a country, it would be the world’s fourth largest economy in the world (after the United States, China, and Japan – and ahead of Germany, Indian and the UK. It supports manufacturing, transportation, farming, tourism, recreation, energy production and other forms of economic growth. Lake Erie alone supports one of the world’s most valuable freshwater commercial fisheries as well as a popular sport fishery.

The Governments of Canada and the United States have released their 2019 State of the Great Lakes: Highlights Report, which provides an overview of the status and trends of the Great Lakes ecosystem.

Overall, Great Lakes water quality is assessed as "fair and unchanging” The Report notes that, while progress to restore and protect the Great Lakes has occurred, including the reduction of toxic chemicals, challenges cited in the report including invasive species and excess nutrients that contribute to toxic and nuisance algae show that much work needs to be done.

In accordance with the Great Lakes Water Quality Agreement, Canada and the United States, with their many partners, have established a suite of 9 indicators of ecosystem health to assess the state of the Great Lakes. The assessment is made based on indicators such as drinking water, fish consumption, and beach closures. Over 180 government and non-government Great Lakes scientists and other experts worked to assemble available data and prepare the report.

The full report can be found here .

This chart gives a quick snapshot of how the Lakes are fairing with each of the nine criteria.