Kathleen MacGregor1, Isabelle Bérubé1, Rafael Estrada1
1Institut Maurice-Lamontagne, Canada
Biological invasions represent one of the major threats to biodiversity and ecosystem health and functioning. The green crab (Carcinus maenas), a hugely successful invader worldwide, has huge and concerning documented impacts on native ecosystems around the world, and currently represents a major threat for fisheries, biodiversity and ecosystem functioning in many regions. In eastern Canada, the green crab is abundant and widespread in Nova Scotia and southern New Brunswick, but has heretofore been largely absent from Quebec due to waters being too cold. The Magdalen Islands, however, had a population that was first detected in 2004, with numbers subsequently increasing from 2008 through 2012. In 2013, numbers fell and by 2015 only a few individuals were detected. Numbers remained low through 2022, but 2023 has seen a significant increase. Cohort analysis indicates that years with longer periods above 10℃ were correlated with population increases while numbers fell when colder winters occurred. Implications of currently increasing temperatures in the waters of Quebec for the establishment and future spread of green crab both on the Magdalen Islands and in the Baie des Chaleurs are discussed with implications for coastal habitats and ecosystems.
Biography
Kathleen MacGregor’s research centers on marine aquatic invasive species and subtidal benthic marine ecosystems. She uses both model invasive species such as the European green crab in North America and the interactions between kelp and sea urchins to address questions of ecosystem functioning and the impacts of changing ocean conditions. She is particularly interested in the interactions between an organism and its environment and the role that behaviour plays in modifying these interactions.