A shorter ice season could mean fewer days of winter fishing and safe play on the Whiteway, but how a string of warmer winters might affect the long-term ecology of our lakes and the Columbia River system is more mystifying.
Recent research shows that many parts of the northern hemisphere are experiencing, on average, shorter winters and a shorter duration of ice cover on lakes. The Experimental Lakes Area program of the International Institute for Sustainable Development (IISD) in northwestern Ontario is one organization that is working on figuring out what effects these changes could have on Canadian lake systems over time.
Though there is still much to learn, we do know that lakes undergo biological, physical and ecological processes during ice cover that are uniquely different from other periods of the year. With a changing climate in mind, scientists are making connections between the role of ice in water quantity and aquatic life:
1) Ice cover is linked to evaporation and water levels: The ice acts as a cap, preventing water vapor from escaping into the air and thus reducing evaporation. Less ice and longer periods of exposure may contribute to increased evaporation and lower water levels come springtime.
2) Certain fish species have an advantage under ice: Coldwater fish species such as mountain whitefish, burbot and lake trout all live in Lake Windermere in the winter months and typically thrive under ice with enough oxygen in the water.
Warmer winters could eventually stimulate a northward migration of warmwater fish species, increasing competition for coldwater fish. Ice lends protection from winter storms and disturbances to mountain whitefish eggs deposited in substrate in the fall to develop over winter. Plankton, an important aquatic food source for fish, are also more resilient when protected by a layer of ice.
In other words, the seemingly static ice many of us love to skate, ski and fish on is truly an active and contributing feature of our lake and river ecosystem. Look for our next Watershed Wanderings article in the Columbia Valley Pioneer, which will tune into the rumbling sounds of the frozen lake!
Beneath The Surface is based on the principle that there is often more to know than what is visible from the “surface” of an issue. If there is something that concerns you about the lake and you want to get to the “bottom of it,” call Lake Windermere Ambassadors program co-ordinator Megan Peloso at 250-341-6898 or email info@lakeambassadors.ca and inspire the next column!
