Today’s post comes from Laura McClintock, Senior Naturalist at Sibbald Point Provincial Park.
The sun shines, glistening on the ice. It’s winter on Lake Simcoe.
From the shore, it appears that the lake is “asleep” during the winter months, with no movement visible. However, that’s just what’s on the surface. The reality below is quite different.
Winter for the aquatic species of Lake Simcoe is necessary and mysterious. Let’s dive in.
A little about Lake Simcoe
Lake Simcoe is located 70 km north of Toronto and is the fourth largest lake located entirely in Ontario.
At the time of first European contact, the lake was named Ouentironk (oo-ent’-er-onk) of the Wyandot people, meaning beautiful water.
Sir John Graves Simcoe, first lieutenant-governor of Upper Canada, later named the lake after his father, Captain John Simcoe, in 1793.
The beautiful waters of Lake Simcoe are home to over 50 species of fish. A variety of invertebrates and aquatic plants also depend on the lake’s complex ecosystem.
In the summer months, Lake Simcoe is filled with farmers, sunbathers and boaters. As temperatures drop in fall, seasonal changes are felt above and below the lake’s surface.
Autumn sales volume
Throughout the year, Lake Simcoe experiences different water temperatures and densities, depending on depth.
Cold water is denser than warm water, causing it to “sink” to the bottom of the lake. Warm water remains on the surface.
As the seasons change, the air temperature decreases, which in turn also reduces the (warmer) surface water temperature. What happens to this water when it cools? In the fall months, the lake experiences a phenomenon called fall rotation.
This is when the cooling water from the top descends and the wind stirs the bottom water of the lake toward the surface.
For a short period, all the water is approximately the same temperature (about 4 degrees). Water temperature is related to the amount of oxygen the water can contain. The colder the water, the more oxygen can be dissolved.
Once the turnover is complete, the surface water will be colder and freeze. The water temperature under the ice will range between 0 and 4 degrees.
The oxygen in this cold water will be all the oxygen available to lake life during the winter. After fall renewal, dissolved oxygen levels will dictate where different aquatic species spend the winter.
Life at different depths.
The shallow parts of Lake Simcoe are where there is the least amount of oxygen. As a result, animals that winter here often slow down to conserve oxygen and energy.
Midland painted turtle
Painted turtles and snapping turtles will burrow into the muddy bottom of shallows and slow their breathing and heart rate. This process is called brumation. Slowing down during the winter months, turtles rely more on the shelter of the lake bottom than on actively using oxygen.
On the other hand, cold water species, such as lake trout, need access to deeper water. Lake trout have begun to reproduce naturally in Lake Simcoe over the last twenty years and depend on the oxygen-rich environments deep in the lake.
A yellow perch caught in Lake Simcoe
In winter they usually find themselves between 25 and 37 m below the surface, where they feed on aquatic invertebrates, crustaceans and other fish.
One of the most common fish species in Lake Simcoe is the yellow perch. Yellow perch feed on invertebrates and a variety of fish eggs and babies.
Yellow perch are primarily a shallow water fish and remain in the 2 to 9 m depth range at the beginning of winter. As winter progresses and dissolved oxygen is depleted, yellow perch will move to deeper, oxygen-rich areas.
Maintain a healthy lake
Cold waters and frozen lakes are essential for the survival of aquatic species, especially cold-water fish species.
These cold-water species require higher levels of dissolved oxygen than warm-water species and struggle to survive the winter when oxygen levels are low.
Dissolved oxygen levels in the lake are dictated not only by temperature, but also by human activity.
Phosphorus is a natural and essential element in the lake. However, when phosphorus levels become too high, they can become a factor in depleting oxygen levels, affecting fish and other life forms.
Our habits can have positive impacts on these issues, such as reducing water use, choosing phosphorus-free fertilizers, and using phosphate-free soaps both at home and when visiting parks.
Are you planning your visit?
Located on the south shore of Lake Simcoe, Sibbald Point Provincial Park is a popular ice fishing hotspot.
The park remains open year-round for day use and permits are required at all times.
When planning your visit, reserve your daily vehicle permit in advance.
If you’re trying ice fishing, it’s always important to fish responsibly!
Follow all fishing regulations and handle your bait responsibly.