In response to a need for scientific information that could be used to delist Beneficial Use Impairment 14 (Loss of fish and wildlife habitat) in the St. Clair River and Detroit River International Areas of Concern in Michigan, this paper summarizes a large scale geographic mapping investigation designed to integrate data on two variables that many riverine fish respond to in selecting where to spawn in these waters (water flow velocity and water depth) with available maps of the Huron Erie Corridor. Our objectives were to locate and map these two physical components of fish habitat in the St. Clair and Detroit Rivers and Lake St. Clair using a geographic information system (GIS) and identify where, theoretically, fish spawning habitat could be remediated in these rivers. Target fish species to which this model applies include walleye (Sander vitreus), lake whitefish (Coregonus clupeaformis) and lake sturgeon (Acipenser fulvescens). Our analysis revealed areas in each river that possessed suitable water velocity and depth for fish spawning and therefore could theoretically be remediated by the addition of rock-rubble spawning substrate like that used at two previously remediated sites in the Detroit River: Belle Isle and Fighting Island. Results of this analysis revealed that only 2.7% of the total area of the HEC possesses the necessary combination of water depth and high flow velocity to be indicated as potential spawning habitat.

Map Information

A Google Earth KMZ file of the following two map layers is available for download here. For browser compatibility, the KMZ file is itself in a ZIP file.

The first map represents the final modeled fish spawning habitat rankings with the dredged, maintained shipping channel areas removed from consideration. All areas shown reflect potentially suitable fish spawning habitat, with higher rankings reflecting faster flow velocities and areas of greater depth. Modeled ranking values range from 12 to 18. These rankings are meant to be used as a guide for targeting field sites for assessment of existing substrates and current use by spawning fish.

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	Ranking 12		Ranking 13		Ranking 14		Ranking 15
	Ranking 16		Ranking 17		Ranking 18

The second map represents the spatial distribution of the reclassified flow velocity values. These areas are shown in their entirety to illustrate the extent of flow velocity categories regardless of whether they fall within a dredged, maintained shipping channel. Category 1 represents flow velocities from 0 to 0.5 m/s. Category 2 represents flow velocities from 0.5 to 0.75 m/s. Category 3 represents flow velocities over 0.75 m/s.

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	Category 1		Category 2		Category 3

Contact Information:

Rose Ellison – U.S. Environmental Protection Agency – [email protected]

David Bennion – USGS Great Lakes Science Center – [email protected]

The HEC once provided spawning habitat for numerous sport and commercial fishes including lake whitefish, lake sturgeon, walleye, and white bass.  Changes to the physical habitat coupled with effects of exotic species and exploitation of fish stocks have impaired the ability of the system to produce and support sustainable fish stocks. The HEC Initiative partners are conducting interdisciplinary studies of fish populations and habitat in the HEC to provide information essential to managing the restoration of fish habitat and populations in the HEC.