Islands in the Ice Stream: Were Spawning Habitats for Native Salmonids in the Great Lakes Created By Paleo-Ice Streams?

Lake trout Salvelinus namaycush, lake whitefish Coregonus clupeaformis, and cisco Coregonus artedi are salmonid fishes native to the Laurentian Great Lakes that spawn on rocky substrates in the fall and early winter.  After comparison of the locations of spawning habitat for these species in the main basin of Lake Huron, surficial substrates in the lake, and the locations of fast-flowing paleo-ice streams during the last (Wisconsonian) glaciation, we hypothesize that mechanisms acting within the beds of paleo-ice streams were responsible for the creation of much of the spawning habitat for these species in Lake Huron.  We further suggest that paleo-ice streams may have been responsible for the creation of native salmonid spawning habitat throughout the Great Lakes and elsewhere in glaciated landscapes of the northern hemisphere.  Our hypothesis may represent a new framework for the identification and protection of spawning habitat for these native species at broad scales.