Winter ice on the St. Lawrence River is like a giant blanket protecting fragile shores and resting fish, plants, and animals. When a vessel tears through this blanket the disturbance to the water below erodes sensitive wetlands and coastal habitat. The resulting open water on the river can disrupt the migration and feeding of bird species, as well as the movement of large mammals. Additionally, ice breaking facilitates commercial vessel operation in ice conditions. Emergency response is more difficult in ice conditions than in open water, which can significantly slow response and worsen impacts from hazardous material spills.¹ On the Seaway, the opening and closing dates for both the Montreal–Lake Ontario section and the Welland Canal are flexible, taking into account ice conditions, the demand for service, and maintenance requirements. But how these factors are evaluated in decision-making is a mystery.

More broadly, ice breaking across the region also raises questions associated with climate change. Scientists predict increased evaporation will be the primary cause of water loss in the Great Lakes, and know that ice cover is the ecosystem’s most effective defence against evaporation in the winter.² But whether ice-breaking accelerates spring ice break up and reduces the lakes natural protection against evaporation is not known. Understanding and addressing this issue is pertinent to both protecting the resource and the shipping industry itself. Otherwise, the industry may be accelerating the very problems they are facing.

 Notes:

¹     Save The River Policy Statement on Opening of the St. Lawrence Seaway Shipping Season, March 2007

²     Confronting Climate Change in the Great Lakes Region, by George W. Kling et al, Union of Concerned Scientists 2003.