Author: Beatrix Beisner, Professor, Aquatic ecology; Co-Director, Groupe de recherche interuniversitaire en limnologie (GRIL), Université du Québec à Montréal (UQAM)

As a lake researcher, I have in recent years had quite a few people ask me whether jellyfish really do live in lakes. Some people think they are seeing things, or that their friends or family are. I’ve even heard of marital spats over the issue! So, are jellyfish present in Canadian freshwater lakes or not? Yes, jellyfish do exist in lakes here in Canada. These organisms are related to saltwater jellyfish (Cnidaria), only much smaller. The reasons why more people are suddenly becoming aware of these creatures is simply due to their growing numbers — numbers that are on…