Lake Michigan, a vast freshwater expanse, supports diverse aquatic life. Its varied habitats, including deep, cold waters, rocky shorelines, and sandy bottoms, create an environment suitable for numerous fish species. This complex ecosystem provides essential breeding, feeding, and sheltering grounds for its inhabitants.
Native Fish Species
Lake Michigan is home to several indigenous fish species. The Lake Trout, a significant native predator, inhabits the colder, deeper parts of the lake. Lake Whitefish and Cisco (Lake Herring) are important native species in the lake’s food web. Yellow Perch are common native species found in various habitats.
Suckers, like the Longnose Sucker, contribute to the benthic community, feeding on bottom-dwelling organisms. Burbot, a freshwater cod-like fish, are also native, known for their elongated bodies and single barbel. Smaller native fish, including Darters and Sculpins, occupy specific niches near the lakebed or in tributary streams.
Introduced and Invasive Species
Lake Michigan’s fish community has been altered by non-native species, some introduced for sport fishing and others accidentally. Chinook Salmon (King Salmon) and Coho Salmon (Silver Salmon) were introduced from the Pacific Northwest in the 1960s to create a sport fishery and control invasive Alewife. Steelhead, a migratory Rainbow Trout, arrived in the late 1800s. These Pacific salmonids primarily prey on Alewife and Smelt, supporting a popular recreational fishery.
More problematic non-native species include the invasive Round Goby, Alewife, and Sea Lamprey. Round Gobies, from the Black and Caspian Seas, arrived via ship ballast water in the 1990s. They compete with native fish for food, consume game species’ eggs, and displace smaller native fish.
Alewives, a herring species, entered through canals and proliferated rapidly, causing massive die-offs. They negatively impact native fish by consuming early life stages and contributing to thiamine deficiency in predators like Lake Trout. Sea Lampreys, parasitic fish from the Atlantic Ocean, also entered through shipping canals, decimating native fish populations, particularly Lake Trout, by feeding on their blood.
Other invaders, such as Zebra and Quagga Mussels, transported by ballast water, filter vast amounts of water, altering the food web by reducing plankton availability.
Conservation and Management
Various agencies collaborate to manage and protect Lake Michigan’s fish populations. State Departments of Natural Resources (DNRs), federal agencies, and tribal entities monitor fish stocks and regulate sport and commercial fishing. Stocking programs maintain introduced sport fish populations, like salmon and steelhead, which rely on hatchery production due to limited natural reproduction in the lake’s tributaries.
Controlling invasive species is a major management effort. The Great Lakes Fishery Commission coordinates a broad program to reduce Sea Lamprey populations, mainly through lampricides in spawning streams, barriers, and traps. These efforts have successfully reduced sea lamprey numbers by over 90% in most areas. Research continues on new control methods, including pheromones. Habitat restoration and water quality improvement initiatives also contribute to the lake’s overall fish community health.