Great Lakes Open Water

The open waters of the Great Lakes can be thought of as having nearshore and offshore habitat.

Nearshore habitat begins at the outermost edge of coastal wetlands and extends to 80 meters deep. These ecological communities support many fish species, among them lake whitefish, yellow perch, walleye, and various species of panfish.

Offshore waters, generally 80 meters or deeper, support fish species such as lake herring, deepwater sculpin, lake trout, burbot, and deepwater cisco.

Overall, nearshore habitats are warmer and more productive than offshore habitats and often support a large prey base of plankton species. In the Great Lakes, fish are the dominant open water predator.

Different ecological zones occur in Great Lakes open water. Scientists refer to the nearshore area as the littoral zone, which supports many aquatic plant species. The benthic, or bottom, zone supports a variety of aquatic organisms, some of which burrow in the sediment, and provide food for other species.

open water

Great Lakes islands also contribute significantly to the biodiversity of open water habitats. Their isolated location provides a number of waterbirds with secure, undisturbed nesting sites.