In 2022, Carleton University biologist, Grégory Bulté arrived at Opinicon Lake for his first day of field work for the season. Bulté has been studying and tracking northern map turtles since 2003, returning every spring to the lake.
As he went to retrieve his camera from the hibernation site, he spotted a dead turtle. He paddled towards it and then noticed another. Sightings of turtles with crushed shells and missing limbs continued. In his wetsuit, he swam the shoreline to pick up the carcasses, counting 142 in total —10 per cent of the total population.
Northern map turtle, Opinicon Lake © Lisa Richardson
This was the first time Bulté had witnessed a mass mortality like this. His research points to river otters accessing the hibernating turtles through holes in the ice.
It is uncertain how the holes in the ice formed. Climate change, human-made openings, and shifting ecosystems may be potential causes.
“We don’t have direct evidence that any cause led to this particular event. However, we thought it was important to publish this study, because what it did show, is that map turtles hibernate in such a way that it makes them vulnerable to fatality if something goes wrong,” said Bulté.
Ice protects turtles from predation. While there are no de-icing bubblers, which push bubbles into the water to stop it freezing around docks, next to the hibernation site at Opinicon Lake, Bulté has seen an increasing trend in their overall use.
“We are worried that without any regulation or knowledge of where map turtles spend their winters, we could decimate a population rapidly if these tools are put in close proximity,” said Bulté.
Since 2022, Bulté has not witnessed another mass mortality event. He is currently working alongside a statistician to analyze data from 2022 to 2026 to better understand how the population has been affected.
He believes that humans need to learn how to cohabitate better with wildlife.
“If we cannot keep them in their environment, what does that say about everything else we do to the environment?”
Opinicon Lake, Ontario Nature Annual Gathering 2012 © Noah Cole
Ontario Nature’s Acting Conservation Science and Stewardship Director, Jenna Quinn emphasized that turtle species are at risk and cannot afford additional threats.
“It is important that we always move with nuance and understand that every action we take has a consequence,” said Quinn.
Work is being conducted to conserve the ecosystems that inhabit the turtles.
Ontario Nature’s Reptile and Amphibian Atlas (ORAA) is one tool that is currently being used to inform ongoing conservation work. It documents current knowledge of the distribution of reptiles and amphibians in the province, increasing public awareness and appreciation of these species.
Additionally, the Rideau Canal is a part of Preserving Legacies, a global organization dedicated to safeguarding heritage places and practices by advancing climate adaptation solutions that strengthen community resilience.
The canal is currently in its second phase of the project, which involves the creation of a comprehensive Risk Assessment that will be shared with the community.