Freshwater Fisheries in Canada: Historical and Contemporary Perspectives on the Resources and Their Management

Chapter 17: Winter as a Defining Season for Canadian Fishes

Bailey C. McMeans, Peter A. Cott, Thomas A. Johnston, Paul J. Blanchfield, Matthew M. Guzzo, and Richard A. Cunjak


Many would say winter defines Canada as a nation. Canada is a frozen country in winter (Figure 1) and depending on latitude and altitude, ice cover can last over half the year. Cold water temperatures, variable ice, and flow regimes, reduced habitat suitability, light limitations, hypoxia, and low levels of productivity are just some of the demanding conditions characteristic of winter in freshwaters (Shuter et al. 2012). As far back as Hubbs and Trautman (1935), fisheries professionals in Canada have considered winter to be a critical period in the life of freshwater fishes. Winter is generally recognized as a period of higher mortality, particularly for younger age-classes (Hurst 2007), and research exploring winter as a critical period for freshwater fishes has increased as of late (e.g., Blanchfield et al. 2009; Suski and Ridgway 2009a, 2009b; Helland et al. 2011; McMeans et al. 2020). Although we have progressed in our recognition that interesting and important ecological processes occur under ice and influence fish, much more needs to be done. This is especially true as the pace of natural resource exploration and development increases in colder regions of Canada (Cott et al. 2015) and as climate change further complicates our understanding of environmental relationships and sensitivities among freshwater fish species and populations (Christiansen et al. 2013). The goal of this chapter is to explore the following questions: