Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes 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 can 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 and may be especially important along the southern edge of the range of the species. 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.
Bibliographical noteFunding Information:
Funding was provided by the Great Lakes Restoration Initiative administered by the U.S. Environmental Protection Agency through a project awarded to the Great Lakes Fishery Commission. We thank C. Holbrook, E. Larson, J. Van Effen, L. Lesmeister, M. Lancewicz, Z. Holmes, D. Operhall, J. Osga, S. Meihls, C. Wright, B. Lamoreux, S. Seegert, S. Farha, B. Maitland, K. Smith, and R. Darnton for their technical assistance in conducting the acoustic telemetry study. Thanks also to R. Reining, A. Handziak, D. Pine, and P. Barbeaux for their assistance in procuring lake trout. We thank L. Mohr, R. Eshenroder, and B. Lantry for their comments on an earlier draft of this manuscript. The use of trade names or commercial products does not imply endorsement by the U. S. Government. This is Contribution 1841 of the USGS Great Lakes Science Center and Contribution 1 of the Society for Trout and Glacier Research (STAGR) (GL - 00E23010-3).
- Glacial bedforms
- Lake Huron
- Lake trout
- Spawning habitat