Invasive Species Threatening Michigan’s Fish
Michigan is defined by water. From the vast Great Lakes to the twisting streams cutting through forests and farmland, the state’s identity and its outdoor heritage are intertwined with fishing. Every year, anglers of all types cast lines hoping to connect with native fish like lake trout, walleye, perch, and smallmouth bass. The waters have long offered not just recreation, but livelihoods, traditions, and priceless moments of solitude.
But beneath the surface, a quiet battle has been unfolding. Invasive species — fish, mollusks, and parasites not native to Michigan — have found their way into these ecosystems. Once introduced, often accidentally through global trade and travel, these invaders spread rapidly. Without natural predators to keep them in check, many have disrupted delicate food chains, crowded out native species, and unfortunately reshaped entire aquatic habitats.
For Michigan’s fish, this isn’t a normal progression. It’s survival. And for those who love to fish, whether on a sunlit lake or a shaded river bend, understanding this growing threat is as important as ever.
Impact
Invasive species are organisms introduced to environments where they are not native, often leading to ecological and economic harm. Several invasive aquatic species have established themselves, posing threats to native fish populations and the overall health of aquatic ecosystems.
Sea Lamprey
The sea lamprey, a parasitic fish native to the Atlantic Ocean, entered the Great Lakes in the early 20th century through man-made canals. Lacking natural predators in these new environments, they attach to native fish like lake trout and whitefish, feeding on their blood and bodily fluids. This has led to significant declines in native fish populations, impacting both commercial and recreational fisheries.
Round Goby
Originating from the Black and Caspian Seas, the round goby was introduced to the Great Lakes via ballast water from ships. These small, aggressive fish compete with native species for food and habitat. They also consume the eggs and young of native fish, further threatening their populations.
Asian Carp
Asian carp, including bighead, silver, grass, and black carp, were introduced to the United States for aquaculture purposes but have since spread into the Mississippi River Basin and now threaten to enter the Great Lakes. These fish consume large amounts of plankton, a crucial food source for native fish species, potentially disrupting the food web and leading to declines in native fish populations.
Zebra and Quagga Mussels
These mussels, native to Eastern Europe, have rapidly colonized the Great Lakes since their introduction in the late 20th century. They filter vast amounts of plankton from the water, depriving native species of food. Additionally, their presence alters nutrient cycles and can lead to the proliferation of harmful algal blooms.
Consequences
Introduction and spread of invasive species in Michigan’s waters have led to:
- Declines in Native Fish Populations: Predation, competition, and habitat alteration by invasive species have reduced numbers of native fish like lake trout, walleye, and perch.
- Altered Food Webs: Invasive species can change the availability and types of food resources, impacting the growth and survival of native fish.
- Economic Impacts: The fishing industry, both commercial and recreational, suffers from reduced fish stocks and increased management costs.
Management
Efforts to combat and manage invasive species in Michigan include:
- Monitoring and Early Detection: Regular surveys help identify new invasions early, allowing for prompt management actions.
- Public Education: Informing the public about the risks of transporting invasive species and promoting responsible practices, such as cleaning boats and equipment, can reduce spread.
- Regulation and Policy: Implementing and enforcing laws that restrict the importation and release of non-native species help prevent new introductions.
- Control and Eradication Programs: Targeted efforts, such as the use of lampricides for sea lamprey control, aim to reduce invasive populations.
The Future
Invasive species are not just a distant issue or something limited to headlines. They are here, in Michigan’s waters, impacting the fish we’ve cherished for generations. Left unchecked, their spread threatens to change the way we interact with these lakes and rivers forever. Fishing trips that once meant reliable catches and vibrant ecosystems could turn into quiet days spent wondering where all the fish went.
The good news is that the future isn’t written in stone. Across Michigan, dedicated biologists, resource managers, anglers, and everyday citizens are working to slow the spread and minimize the damage. Staying informed, cleaning equipment, and following regulations are small actions that, when multiplied across thousands of anglers and boaters, can make a huge difference.
Michigan’s waters still hold incredible beauty and potential. By understanding the threats and doing our part, we can help ensure that future generations will have the same chance to wade into these streams and cast a line, hoping for that familiar tug signaling a native fish on the other end.
For more information on invasive species and how to help prevent their spread, visit Michigan.gov/Invasives
Bobby Pulte, Freelance Outdoors Writer | www.bobbypulte.com
