A chance discovery by a college student reveals that Atlantic salmon are reproducing in the Great Lakes --- at least in the St. Mary’s River, which connects Superior and Huron.
“We were conducting research for my sturgeon thesis when we found the Atlantic salmon fry,” said StefanTucker, a Lake Superior State University graduate. “It was very exciting to everyone who was a part of my research to imagine what we had just stumbled upon.
“While sorting through my samples at the lab with Roger (Greil), we began to ID the salmonids and Roger had a suspicion that they were Atlantics,” he added. “We caught wild Atlantics in our next two sampling events, so we wanted to confirm our ID and we sent a few to Dr. Gerald Smith at University of Michigan, who confirmed the identification.
Atlantic salmon (Salmo salar) are native to Lake Ontario, but their populations severely declined by the late 1800s, according to Tucker’s abstract. During the early to mid-1900s, Atlantic salmon were stocked throughout the Great Lakes in effort to reestablish them into Lake Ontario and introduce the species into the upper Great Lakes. However, these efforts had minimal success.
In 1987, LSSU, in cooperation with MDNR Fisheries, began stocking Atlantic salmon in the St. Mary’s River. While the effort has resulted in a very successful recreational fishery, along with an excellent educational experience for students, it appeared that Atlantics were still not reproducing naturally even though they would return to the river spawning grounds every year. Biologists wondered if competition from other salmonids spawning in the St. Mary’s in greater numbers – including chinook and pink salmon – was keeping Atlantics from thriving.
While this is the first documentation of natural reproduction of Atlantic salmon in the upper Great Lakes, Tucker’s study concludes that “the extent of natural reproduction and mechanisms influencing reproductive success are unclear and warrant further attention.”