Invasive Species in the Great Lakes: What Divers Should Know
Divers in the Great Lakes need to know about invasive species like zebra mussels, round gobies, sea lampreys, and spiny water fleas. Learn what they do, how their spread happens, and how divers can help stop it.
PRESERVING OUR GREAT LAKES AND OCEANS
Invasive Species in the Great Lakes: What Divers Should Know
A System Under Siege
More than 180 non-native species are found in the Great Lakes basin, with about 34 percent considered invasive, meaning they harm ecosystems, economies, or public health. Divers might notice shifts in water clarity, species abundance, or reef structure over time.
Major Invaders Worth Knowing
Sea Lamprey
These parasitic eel-like fish entered the Great Lakes via canals and have decimated native trout and whitefish populations. Each lamprey can kill up to 40 pounds of fish over its lifetime. Control programs using lampricides and barrier structures have reduced their numbers by more than 90 percent.
Zebra & Quagga Mussels
Originating in Eastern Europe, these mussels arrived via ballast water and now dominate nearly all Great Lakes except Superior. They filter massive amounts of plankton, altering food webs and promoting harmful algal blooms. On wrecks and submerged structures, they can burrow and corrode wood or metal, threatening historic dive sites.
Divers should also use caution—sharp shells on docks or entry points have caused injuries.
Round Goby & Spiny Water Flea
Gobies compete aggressively with native bottom-fish for food and shelter and prey on fish eggs. However, they also feed on invasive mussels and have become a food source for lake trout and bass.
Spiny water fleas attack native zooplankton and disrupt food chains from the base up. These tiny invaders also clog fishing gear and boat livewells.
Rusty Crayfish & Invasive Plants
Rusty crayfish outcompete native crayfish, devastate aquatic plants, and consume fish eggs. They are often transported via bait buckets or aquarium releases.
Invasive plants like Eurasian milfoil and Phragmites crowd native vegetation, reduce shoreline biodiversity, and entangle dive gear and boat motors.
How Divers Can Help Prevent Their Spread
Thoroughly Clean, Drain & Dry
Rinse dive gear, wetsuits, tanks, boots, and fins after every waterbody. Drain regulators, jackets, equipment pockets—and even clothing—to avoid transporting hitchhiking species.
Learn to Identify Key Invaders
Teach yourself to spot zebra/quagga mussels, round gobies, lampreys, rusty crayfish, spiny water fleas, and invasive plants. Photograph sightings and report them to tools like Michigan’s MISIN app or the Great Lakes Early Detection Network.
Engage in Citizen Science
Join initiatives such as GLANSIS, the Great Lakes Restoration Initiative, or local BioBlitz events to help collect data on invasive species presence and spread. Your observations can support early intervention and policy decisions.
Advocate for Prevention Measures
Support regulations on ballast water discharge, promote signage at boat launches, and encourage dive centers to train new divers on invasive prevention—especially near key lakes like Erie, Michigan, and Huron.
Practice Responsible Diving
Avoid anchoring or swimming through dense vegetation. Be cautious when moving from one lake to another to prevent transferring organisms or plant fragments.
Happy and safe diving,
The ScubaBlast Team
U.S. Environmental Protection Agency. (2025, May 12). Invasive species in the Great Lakes. Retrieved from https://www.epa.gov/greatlakes/invasive-species-great-lakes-0
Center for Great Lakes and Aquatic Sciences. (n.d.). Invasive species information guide. Retrieved from https://ciglr.seas.umich.edu/project/invasive-species/
Great Lakes Fishery Commission. (2025, June). Sea lamprey control and monitoring updates. Retrieved from accessible official reports
AP News. (2023, Sept 23). Researchers race to document shipwrecks amid quagga mussel destruction. Retrieved from a leading news archive
L. D. Corkum et al. (2017). Ecology of round goby in the Great Lakes. Biological Invasions.
U.S. Geological Survey. (2008). Cercopagis pengoi monitoring data in the Great Lakes. Retrieved from archived EPA data
Michigan Department of Natural Resources. (2025, July). Red swamp crayfish found in Michigan hatchery. Retrieved from local agency report
Michigan Aquatic Invasive Species Field Guide. (2021). Diver Assisted Suction Harvesting (DASH) resource. Retrieved from official state DNR manuals
Great Lakes Aquatic Invasive Species Surveillance Framework. (2025). Best practices for reporting and management. Retrieved from multi-agency PDF guidelines