March 10, 2014
By Marie Zhuikov
It’s a winter’s night on Lake Michigan. Underwater in the shallows, the eel-like and lowly burbot gather in a brown writhing mass to spawn. With their serpentine bodies and dangly chin barbels, it’s not a pretty picture, but the activity ensures the species’ survival as one of the top predators in the food chain along with lake trout.
Wisconsin Sea Grant scientists have discovered that burbot spawn in deep reefs and also later in the season than previously known. Their findings, recently published in Transactions of the American Fisheries Society, add a fifth spawning behavior to those already identified for burbot.
Burbot, known in Latin as Lota lota from the French word for codfish, are the only species of cod that live entirely in fresh water. Also known as eelpout, lawyer and lingcod, the burbot is prized for its delicate white meat. A popular restaurant on Washington Island off the Door Peninsula, KK Fiske, draws patrons from as far away as Chicago by offering “fresh lawyers” throughout the year prepared fried, boiled, broiled and shish kebabed. However, just as many anglers are put off by the burbot’s eel-like appearance and penchant for wrapping its tail around their arms as they try to unhook it.
For the study, conducted in 2007 and 2008, researchers collected burbot larvae in lakes Superior, Michigan and Huron during spring and summer. While burbot are known to spawn in landlocked lakes and Great Lakes tributaries in winter (January to March), and in rocky shallow waters of the Great Lakes, researchers found burbot larvae at deep reefs in the middle of Lake Michigan and offshore areas of Lake Huron in June through August, signifying that burbot spawn later and deeper than previously understood.
John Janssen, professor of fisheries ecology at the University of Wisconsin-Milwaukee, said the finding was accidental. “We were working on collecting bloater larvae, and we were surprised by the number of burbot we collected on the midlake reef. We were also surprised that we were seeing them in late June. They were really tiny, which means they were just born. This implies there’s a concentration of burbot on those mid-lake reefs.”