Salmon are indeed present in Lake Michigan, supporting a popular sport fishery. These fish are not native to the Great Lakes ecosystem; they were established through intentional stocking programs decades ago. These programs aimed to address ecological imbalances and create new recreational opportunities.
Types of Salmon
Lake Michigan hosts several salmon species, including some trout commonly called salmon due to their similar life cycles and recreational value. Chinook salmon, often called King salmon, are the largest and most sought-after species, identifiable by their silvery body with black spots. Coho salmon, or Silver salmon, are popular for their excellent taste, especially in early spring. Steelhead, migratory rainbow trout, also populate Lake Michigan and can spawn multiple times, unlike true salmon. Less common Atlantic salmon are also present through stocking programs.
How Salmon Came to Lake Michigan
Salmon were introduced to Lake Michigan in response to a significant ecological problem in the mid-20th century. By the 1950s and 1960s, invasive alewife populations exploded, causing massive die-offs that littered shorelines. Alewives, small fish native to the Atlantic Ocean, thrived due to the decline of native predators like lake trout, impacted by overfishing and sea lamprey predation.
To control alewife numbers and establish a new sport fishery, Michigan began stocking Coho salmon in 1966. Chinook salmon followed in 1967. These Pacific salmon successfully preyed on alewives, reducing their populations and transforming the lake’s ecosystem.
Eating Salmon from Lake Michigan
Eating salmon from Lake Michigan requires attention to health advisories from state public health departments, such as the Michigan Department of Health and Human Services (MDHHS). Advisories are based on contaminant levels that can accumulate in fish tissue. Polychlorinated biphenyls (PCBs) and mercury are primary contaminants of concern, although per- and polyfluoroalkyl substances (PFAS) and dioxins/furans are also monitored. While contaminant levels in Great Lakes fish have generally declined since the 1970s, some recent data indicate a leveling off or even an increase in certain species. MDHHS regularly updates its “Eat Safe Fish Guides” with specific consumption recommendations, often expressed as a “MI serving” based on body weight.
These guidelines are not laws but help individuals make informed choices about how much and which types of fish to safely consume. For instance, some advisories recommend limiting consumption to one serving per month for certain species or even issuing “Do Not Eat” warnings for particular areas. To minimize contaminant exposure, it is often advised to trim away fat and skin before cooking, as some chemicals accumulate in these areas. Varying the types of fish consumed and consulting the latest local advisories helps ensure safety.
Salmon’s Role and Management in the Ecosystem
Salmon are top predators in the Lake Michigan ecosystem, primarily consuming prey fish like alewives. This helps regulate alewife populations, which were once a nuisance. The long-term balance between salmon and their prey is managed by agencies like the Michigan Department of Natural Resources (MDNR) and the U.S. Fish and Wildlife Service (USFWS). Management includes ongoing stocking, though Chinook salmon levels have been reduced recently to align with declining alewife populations and prevent an overabundance of predators.
Monitoring fish health, assessing prey fish abundance, and setting fishing regulations are part of this comprehensive strategy. Researchers use predator-prey ratio analyses to evaluate salmon populations and food sources, guiding stocking and harvest limits. Despite stocking, a substantial portion of Lake Michigan Chinook salmon are now wild-spawned, highlighting successful natural reproduction in some areas. These efforts aim to maintain a sustainable and diverse fishery while adapting to dynamic changes within the ecosystem.