Great Lakes
Thunder Bay National Marine Sanctuary wreck, William P. Rend. via NOAA

Great Lakes - Shipwreck Life: How Fish and Other Aquatic Species Utilize Great Lakes Shipwrecks

All that remained of the schooner was a bit of its hull – a tightly-packed row of wooden planks stretching 40 feet across the bottom of Lake Huron.

Sunbeams easily penetrated the 20 feet of clear lake water above the wreck. The site appeared lifeless.

There were no schools of emerald shiners, black-striped minnows or yellow perch in sight. The wooden planks were not covered with algae nor encrusted with zebra or quagga mussels. So, the sudden appearance of a bass approaching at warp speed took the diver completely by surprise.

A 3-foot smallmouth bass was using the wreckage as a nest site, and the aggressive male was undeterred by the diver’s larger size. It attacked at full speed, making direct contact with the diver’s underwater camera.

Only when the diver slowly backed away did the smallmouth retreat to its nest at the far end of the wreckage having successfully deterred another visitor to the site.

That’s just one example of the kind of interaction divers can have with the underwater wildlife around Great Lakes shipwrecks.

Shipmates

Together, the five Great Lakes contain upwards of 6,000 shipwrecks. These vessels are scattered across the entire Great Lakes from the Thousand Islands on the eastern end of Lake Ontario to Duluth on the western end of Lake Superior.

“Wrecks create little ecosystems because you’ve got all these little nooks and crannies,” said Mike Thomas. “The structure supports arthropods and isopods at the bottom of the food chain. Those species attract small fish and the big fish come in to eat the little fish.”

Thomas recently retired after 30 years as a Michigan Department of Natural Resources research biologist, so he’s very familiar with the habits of Great Lakes fish.

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