Lake Trout in Northern Lake Huron Spawn on Submerged Drumlins

Recent observations of spawning Lake Trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that Lake Trout use drumlins as a primary spawning habitat.  Most salmonines spawn in streams, where they rely on streamflows to sort and clean sediments to create good spawning habitat.  These flows are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for Lake Trout egg incubation, particularly if these bedforms are situated such that lake currents penetrate these sediments.  We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for Lake Trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality Lake Trout spawning habitat at many locations in the Great Lakes.  A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of Lake Trout spawning locations, provide insight into the evolution of unique spawning behaviors by Lake Trout, and aid in Lake Trout restoration in the Great Lakes.