First Records of White River Crayfish (Procambarus acutus) in Canada on Pelee Island, Ontario, with notes on other crayfish species present and their habitats

Abstract Freshwater crayfish rank among the most imperilled groups and play several critical roles in freshwater ecosystems, yet survey efforts remain limited throughout much of Canada and North America. Inadequate survey and monitoring efforts render our ecosystems vulnerable to the introduction and spread of harmful invasive species which can be difficult or impossible to control following establishment. During surveys targeting salamander larvae across Pelee Island, Ontario we incidentally captured crayfish and identified them to species. Three species were detected including two native species known only from collections in the 1960s (Creaserinus fodiens, Faxonius immunis) as well as the non-native White River Crayfish (Procambarus acutus) which has not been documented previously in Canada. Our oldest record of P. acutus is from 2015, and the species currently appears to be widespread and well established on Pelee Island and has also recently been recorded in Six Mile Lake on the Canadian Shield. We provide preliminary data on the aquatic habitats where each species was found on Pelee Island and strongly encourage additional monitoring efforts combined with targeted education efforts to prevent the spread of P. acutus to the Ontario mainland.