Islands in the ice stream: were spawning habitats for native salmonids in the Great Lakes created by paleo‐ice streams?

Abstract

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 comparing the locations of spawning habitat for these species in the main basin of Lake Huron with surficial substrates and the hypothesized locations of fast‐flowing Late Wisconsinan paleo‐ice streams, we hypothesize that much of the spawning habitat for these species in Lake Huron is the result of deposition and erosion by paleo‐ice streams. This hypothesis may represent a new framework for the identification and protection of spawning habitat for these native species, some of which are currently rare or extirpated in some of the Great Lakes. We further suggest that paleo‐ice streams may have been responsible for the creation of native salmonid spawning habitat elsewhere in the Great Lakes and in other glaciated landscapes.

Fine‐scale acoustic telemetry reveals unexpected lake trout,Salvelinus namaycush, spawning habitats in northern Lake Huron, North America

“…We suggest that differences in habitat quality at our study site may vary over small spatial scales and may depend on currents. The lakebed south of Drummond Island is a drumlin field that may support high‐quality spawning habitat due to relief created by glacially derived bedforms that provide surfaces where currents may penetrate the substrates (Riley et al., , ). Therefore, future research on lake trout spawning habitat should investigate the role that lake currents play in fine‐scale habitat selection.…”

Reliance on lakes by salmon, trout and charr (Oncorhynchus,SalmoandSalvelinus): An evaluation of spawning habitats, rearing strategies and trophic polymorphisms

“…Sufficient flow may be provided to shoreline-spawning sites by groundwater upwelling from natural springs (Blanchfield & Ridgway, 2005), groundwater from a proximate tributary penetrating through the lakeshore (Wilson, 2014) or the gravity-driven pull of water at the transition from the lake to its outlet (Couturier, Clarke, & Sutterlin, 1986). Less commonly, wind-driven currents may generate adequate flow for successful spawning near mainland or island shorelines (Callaghan, Blanchfield, & Cott, 2016;Leonetti, 1997), or on deep reefs or bedforms (Riley et al, 2017) (Figure 1). Areas of appropriate substrate may be determined by hydraulic processes and topography, as spawning sites must receive enough wave action or current to prevent accumulation of fine particles but not so much that eggs become dislodged or physically shocked (Ellen Marsden et al, 1995;Eshenroder, Bronte, & Peck, 1995;Low, Igoe, Davenport, & Harrison, 2011).…”

“…Lake trout broadcast spawn over a wide range of depths and substrates in lakes throughout their range in North America. In the Great Lakes, they most commonly spawn at shallow inshore sites near the mainland and islands (including algae beds), or at deep offshore sites over reefs and bedforms created by paleo-glacial activity (Ellen Marsden et al, 1995;Kelso, MacCallum, & Thibodeau, 1995;Krueger & Ihssen, 1995;Riley et al, 2014Riley et al, , 2017. Stream spawning by lake trout also occurs in select tributaries of lakes Nipigon and Superior (Dymond, 1926;Loftus, 1958).…”

A Hemimysis‐driven novel ecosystem at a modified rubble‐mound breakwater: An Engineering With Nature® Demonstration Project

“…Natural rocky habitats include glacially polished and/or cracked bedrock, glacial grooves in such bedrock typically infilled with cobble, talus slopes, and glacial deposits (Janssen et al, 2005). Glacial deposits such as drumlins can have much interstitial space (Riley et al, 2014(Riley et al, , 2017, so drumlins may be the closest analog to boulder breakwaters. Rocks of the size of Milwaukee Harbor's breakwater boulders can be found but scattered and not abutting, so they do not form caves.…”