The Distribution and Conservation Status of the White Colour Morph of Faxonius propinquus (Northern Clearwater Crayfish) in Lake Simcoe, Ontario, Canada

The white morph of Faxonius propinquus was first identified and described by Dunham and Jordan. They subsequently documented the presence and geographic distribution of other species in Lake Simcoe, including two additional colour morphs of F. propinquus (Dunham et al. 1979). Since then, no further research has been conducted on these populations, even though the lake has now been invaded by the introduced rusty crayfish (Faxonius rusticus). The present study documents the decline and most recent distribution of the F. propinquus colour morphs and the other native species, Faxonius virilis, which also appears to display several unusual colour morphs in Lake Simcoe. The decline of the various colour morphs of F. propinquus, as well as the impact of the F. rusticus expansion in the lake, were assessed through surveys from 2015 to 2018. The significance of the results is discussed with respect to the conservation status and the future management of native crayfishes in Lake Simcoe.