“…This phenomenon appears to be in accordance with the environmental matching hypothesis, stating that the impacts of an invader decrease with environmental conditions that diverge from its physiological optimum (Ricciardi et al 2013, Iacarella andRicciardi 2015). Our study joins a growing body of literature exploring environmental factors that promote invasion refugia within invaded freshwater ecosystems (Grabowski et al 2009, Kestrup and Ricciardi 2009, Priddis et al 2009, Iacarella and Ricciardi 2015, Latzka et al 2016, Astorg et al 2020, Boddy et al 2020, Boddy and McIntosh 2021. More specifically, we aimed to address environmental determinants of invasion hotspots and refugia of an invasive benthic fish, the round goby (Neogobius melanostomus), in a large and complex river system, the St Lawrence River, which drains the North American Great Lakes.…”