You’ve probably caught one without even knowing it. Lake Erie’s waters harbor ten invasive fish species that have fundamentally altered the Great Lakes ecosystem since the 1990s.
These non-native invaders arrived primarily through ballast water discharge and man-made canals, establishing thriving populations that now compete with native species, disrupt food chains, and impact the fishing experience you know and love.
Understanding these species isn’t just about fish identification—it’s about recognizing the ongoing transformation of Lake Erie’s aquatic environment and making informed decisions on the water.
Round Goby
Pro Tip: Round gobies are often mistaken for native sculpins, but you can easily distinguish them by their fused pelvic fins—sculpins have two separate pelvic fins.
The round goby (Neogobius melanostomus) stands as Lake Erie’s most successful invasive fish, having exploded in population since its introduction in the mid-1990s. These aggressive bottom-dwellers arrived via ballast water from the Black and Caspian Sea regions and quickly established themselves as the dominant small bottom-feeding fish throughout the lake.
These brownish-gray fish with dark splotching typically measure 4-6 inches, though some individuals reach up to 10 inches. During spawning season from April through September, males develop striking black coloration with yellowish spots. Their most distinctive feature is the characteristic “puffy cheeks” that give them a chipmunk-like appearance, along with their trademark fused pelvic fins that form a suction cup.
Round gobies have become so numerous that they now comprise up to 90% of the diet for endangered Lake Erie water snakes, actually helping this native species recover from near-extinction. However, their impact on the ecosystem remains largely negative. They compete aggressively with native fish species like sculpins, darters, and logperch for food and habitat, while also consuming the eggs and fry of these same native species.
Important Note: While round gobies consume invasive zebra mussels, they also serve as a pathway for toxin bioaccumulation, concentrating PCBs and other contaminants that then move up the food chain to predator fish like walleye and bass.
Their success stems from their adaptability and voracious appetite. Round gobies can alter their diet based on available food sources, feeding primarily on zebra mussels but also consuming aquatic insects, fish eggs, and small fish. This dietary flexibility, combined with their ability to reproduce multiple times per year and guard their nests aggressively, has made them nearly unstoppable invaders.
Sea Lamprey
The sea lamprey (Petromyzon marinus) represents one of Lake Erie’s most destructive invasive species and the target of the world’s longest-running vertebrate invasive species control program. These primitive, eel-like parasites entered the Great Lakes through the Welland Canal in the 1830s and have been devastating fish populations ever since.
Key Insight: A single sea lamprey can destroy an average of 39 pounds of fish during its parasitic lifetime, with only one in seven fish surviving a lamprey attack.
These jawless fish feature a distinctive circular, suction-cup mouth filled with rows of sharp, horn-shaped teeth surrounding a rasping tongue. Unlike bony fish, sea lampreys have cartilage skeletons and breathe through seven pairs of gill openings behind their heads. Adults typically reach 12-20 inches in length and can live up to seven years.
The sea lamprey life cycle makes them particularly destructive. After spending 3-7 years as filter-feeding larvae buried in stream sediments, they transform into parasitic adults that attach to large fish like lake trout, salmon, and walleye. Using their rasping tongue, they bore through scales and skin to feed on blood and bodily fluids, often killing their hosts through blood loss or secondary infections.
Prior to control efforts beginning in the 1950s, sea lampreys contributed to the collapse of the Great Lakes commercial fishery. Lake trout harvests dropped from 15 million pounds annually to just 300,000 pounds by the 1960s. Today, the Great Lakes Fishery Commission coordinates an intensive control program using lampricides (selective pesticides), barriers, and traps that has reduced sea lamprey populations by approximately 90%.
Current Management: The primary control method involves applying TFM lampricide to streams containing larval sea lampreys. This $16 million annual program has been instrumental in protecting $4.5 billion worth of Great Lakes fisheries.
Alewife
The alewife (Alosa pseudoharengus) entered Lake Erie in 1931 and quickly became one of the most abundant fish species in the Great Lakes system. These small, silver-sided fish native to the Atlantic Ocean arrived through man-made canals and found ideal conditions in Lake Erie’s nutrient-rich waters.
Adult alewives typically measure 6-8 inches and weigh about 4 ounces. They’re characterized by their compressed, herring-like body shape, large eyes, and a distinctive saw-toothed belly. Their silver sides often display a golden or brassy hue, and they have a single black spot behind their gills.
Common Mistake: Don’t confuse alewives with native emerald shiners—alewives are larger, have a more compressed body shape, and display the characteristic saw-toothed belly edge.
These prolific filter feeders consume massive quantities of zooplankton, directly competing with native fish larvae and juvenile fish for food. Their feeding habits have significantly altered Lake Erie’s food web structure, reducing food availability for native species like yellow perch, lake herring, and bloater chubs.
During their peak abundance in the 1960s and 1970s, alewives would die off in massive numbers, creating serious problems. These die-offs clogged water intake pipes at industrial facilities and power plants, while beaches became covered with rotting fish. The decay process consumed oxygen in the water, further stressing native fish populations.
Alewives have shown remarkable population swings tied to environmental conditions and predator abundance. When lake trout populations collapsed due to sea lamprey predation, alewife numbers exploded. The subsequent stocking of salmon and trout as alewife predators helped control their populations, though they remain an important forage species for many Great Lakes gamefish.
White Perch
White perch (Morone americana) invaded Lake Erie in the 1950s and have since established themselves as significant competitors to native yellow perch. These Atlantic coast natives likely entered through the Welland Canal or Erie Canal systems and found Lake Erie’s conditions highly favorable for reproduction.
These silvery-white fish with faint horizontal stripes typically reach 6-12 inches in length and can weigh up to 2 pounds. White perch have a deeper body profile than yellow perch and lack the distinctive vertical bars that characterize their native cousins. Their dorsal fin has both spiny and soft-rayed sections, and their mouth extends slightly past the eye.
The ecological impact of white perch on Lake Erie has been substantial. Their introduction coincided with a 79% decline in native yellow perch populations, though multiple factors contributed to this collapse. White perch compete directly with yellow perch for food sources, including small fish, insects, and crustaceans, and they occupy similar nearshore habitats.
Important Note: White perch are incredibly prolific spawners, with females capable of producing up to 150,000 eggs annually. This reproductive advantage has allowed them to establish large populations quickly.
White perch also prey heavily on the eggs and larvae of native fish species, including walleye, white bass, and yellow perch. Their feeding behavior during spawning seasons can significantly impact recruitment of native species, contributing to ongoing population imbalances in Lake Erie’s fish community.
From an angler’s perspective, white perch provide decent table fare and fight well for their size, but their abundance often means they dominate catches in areas where anglers are targeting native species. Many charter captains report frustration when white perch interfere with yellow perch fishing, as they’re often caught in similar locations using similar techniques.
Common Carp
Common carp (Cyprinus carpio) were among the earliest invasive fish introduced to Lake Erie, arriving in the late 1800s through intentional stocking programs. Originally from Asia, these hardy fish were initially viewed as desirable additions to North American waters, but their environmental impact has proven problematic.
These olive-brown fish with large scales can grow quite large in Lake Erie’s productive waters, commonly reaching 15-25 inches and 5-15 pounds, with some individuals exceeding 30 pounds. Common carp have distinctive barbels (whiskers) near their mouth, a deeply forked tail, and a long dorsal fin with a serrated spine.
Pro Tip: You can distinguish common carp from native redhorse suckers by the barbels—carp have four barbels while native suckers have none.
The primary concern with common carp involves their feeding behavior and habitat modification. As bottom feeders, they constantly root through sediments searching for aquatic insects, plant matter, and organic debris. This feeding activity suspends sediments, increases water turbidity, and destroys aquatic vegetation beds critical for native fish spawning and juvenile habitat.
Carp also contribute to nutrient loading problems in Lake Erie. Their feeding stirs up phosphorus-rich sediments, contributing to algal bloom conditions that have plagued the lake in recent decades. Additionally, their waste products add nitrogen and phosphorus to the water column, further fueling eutrophication processes.
Despite their ecological impact, common carp have developed a following among specialized anglers who appreciate their fighting ability and the challenge they present. These fish are extremely wary and can provide exciting angling opportunities, particularly for bow hunters and specialized carp anglers using European-style tactics.
Grass Carp
Grass carp (Ctenopharyngodon idella), also known as white amur, entered Lake Erie through escapes from aquaculture facilities and intentional introductions for aquatic vegetation control. These large, elongated fish native to eastern Asia can grow to impressive sizes in Lake Erie’s nutrient-rich environment.
Adult grass carp typically reach 25-40 inches and can weigh 15-40 pounds, with some individuals exceeding 50 pounds. They have a torpedo-shaped body with large scales, a blunt head, and a slightly subterminal mouth adapted for grazing vegetation. Their coloration ranges from silver to olive-brown, often with a golden hue.
Key Insight: A single grass carp can consume up to 40% of its body weight daily in aquatic vegetation, making them incredibly effective at altering aquatic plant communities.
The ecological impact of grass carp in Lake Erie stems from their specialized diet of aquatic vegetation. While this might seem beneficial for controlling nuisance plant growth, their feeding can eliminate critical habitat for native fish species. Submerged aquatic vegetation provides spawning areas, nursery habitat, and protective cover for many native fish species.
Grass carp show strong preferences for certain plant species, often completely eliminating preferred plants before moving to less palatable species. This selective feeding can dramatically alter plant community composition in affected areas, potentially favoring invasive plant species that grass carp avoid.
From a management perspective, grass carp present unique challenges because they’re sometimes intentionally stocked in other water bodies for vegetation control. However, their escape into connecting waterways can lead to unintended consequences in sensitive ecosystems like Lake Erie.
Bighead Carp
Bighead carp (Hypophthalmichthys nobilis) represent one of the newest invasive threats to Lake Erie, though established populations have not yet been confirmed in the lake proper. These Asian natives have been found in the lower Great Lakes system and pose a significant risk should they become established in Lake Erie.
These filter-feeding giants can reach truly massive sizes, commonly growing to 30-60 inches and 40-80 pounds, with some individuals exceeding 100 pounds. Bighead carp have a distinctive appearance with an extremely large head (hence the name), small scales, and a mouth that can expand to enormous proportions during feeding.
Important Note: Bighead carp are often confused with silver carp, but bighead carp are larger, have dark blotching on their sides, and don’t exhibit the jumping behavior characteristic of silver carp.
The potential ecological impact of bighead carp in Lake Erie would be catastrophic. These fish consume massive quantities of plankton—the base of the entire aquatic food web. A single large bighead carp can filter thousands of gallons of water daily, removing the microscopic organisms that support everything from small fish to large gamefish.
Their feeding efficiency is remarkable, capable of filtering particles as small as 4 microns from the water column. This would put them in direct competition with all filter-feeding fish, including young game species, native freshwater drum, and gizzard shad. The economic implications for Lake Erie’s $4.5 billion fishery could be severe.
Current prevention efforts focus on early detection and rapid response. Agencies monitor potential entry routes and have established genetic screening programs to detect bighead carp DNA in water samples before populations can establish.
Silver Carp
Silver carp (Hypophthalmichthys molitrix) share many characteristics with bighead carp but are distinguished by their spectacular jumping behavior and slightly different ecological niche. These Asian natives have been detected in lower Great Lakes waters and represent an imminent threat to Lake Erie’s ecosystem.
Silver carp typically reach 20-35 inches and 15-30 pounds, though some individuals exceed 60 pounds. They have a laterally compressed body, small head relative to bighead carp, tiny scales, and upward-angled mouth. Their silver coloration often shows a brassy or golden tint, and they lack the dark blotching characteristic of bighead carp.
Common Mistake: Never assume you’re safe from jumping silver carp in shallow water—these fish can launch themselves 8-10 feet out of the water when startled by boat motors or other disturbances.
The most notorious characteristic of silver carp is their jumping behavior. When startled, they leap clear of the water surface, creating safety hazards for boaters and water sports enthusiasts. Multiple fish jumping simultaneously can create dangerous situations, and their size and speed can cause serious injuries to people in boats.
Ecologically, silver carp share the same devastating potential as bighead carp. They consume enormous quantities of phytoplankton and small zooplankton, directly competing with native fish species at the most fundamental level of the food web. Their presence could reduce food availability for everything from young walleye to adult emerald shiners.
Silver carp also reproduce prolifically, with females capable of producing over 2 million eggs annually. They require flowing water for successful reproduction, making tributary rivers particularly vulnerable to invasion. Once established, their population growth can be explosive under favorable conditions.
Rudd
Rudd (Scardinius erythrophthalmus) entered Lake Erie through multiple introduction pathways, including bait bucket releases and aquarium escapes. These European cyprinids have established localized populations in several areas of the lake, particularly in shallow, vegetated nearshore zones.
Adult rudd typically reach 10-16 inches and can weigh 2-4 pounds, though some individuals grow larger. They closely resemble native golden shiners but can be distinguished by their deeper body profile, reddish fins, and slightly upturned mouth. Their scales have a golden to brassy coloration that can appear quite attractive under the right lighting conditions.
Pro Tip: Look for the key identifying feature—rudd have their dorsal fin positioned behind the pelvic fins, while the similar-looking golden shiner has these fins aligned.
The ecological impact of rudd in Lake Erie stems from their varied diet and habitat preferences. Juvenile rudd feed heavily on zooplankton, competing with native fish larvae for food resources. As they mature, they shift to consuming aquatic plants, algae, and small invertebrates, potentially affecting both plant communities and the food web structure.
Rudd particularly favor shallow, weedy areas that serve as critical spawning and nursery habitat for native species like northern pike, largemouth bass, and various panfish species. Their presence in these areas can create competition for both food resources and physical space.
From an angling perspective, rudd can be frustrating bycatch when targeting native species. They readily take baits intended for bluegill, perch, and other panfish, but they’re generally not considered desirable table fare. Their bony structure and muddy flavor make them less appealing than native alternatives.
Eurasian Ruffe
The Eurasian ruffe (Gymnocephalus cernua) completes Lake Erie’s roster of problematic invasive fish species. These small perch relatives arrived via ballast water in the 1980s and have established populations in several areas of the Great Lakes system, including parts of Lake Erie.
Eurasian ruffe are small fish, typically reaching only 3-6 inches in length and weighing less than an ounce. They have a distinctive appearance with a large head, prominent eyes, and spiny dorsal fin that connects to the soft-rayed portion. Their coloration ranges from olive-brown to yellow-brown with dark spotting or mottling.
Key Insight: Despite their small size, Eurasian ruffe are voracious predators capable of consuming fish eggs and larvae at prodigious rates, making them particularly destructive during spawning seasons.
The primary concern with Eurasian ruffe involves their impact on native fish recruitment. These aggressive predators feed heavily on fish eggs and larvae, particularly during spring spawning seasons when native species are most vulnerable. Their feeding activity can significantly reduce recruitment success for walleye, yellow perch, and other commercially important species.
Eurasian ruffe also compete with native darters, sculpins, and juvenile fish for benthic food resources. Their ability to feed actively during low-light conditions and cold water gives them competitive advantages over many native species. They can remain active and continue feeding when native species become less active, allowing them to dominate food resources during critical periods.
These fish reproduce early in the spring and can spawn multiple times per year under favorable conditions. Females produce thousands of sticky eggs that attach to rocks and vegetation in shallow water, and the young develop quickly, reaching reproductive maturity within their first year.
Conclusion
Lake Erie’s invasive fish species represent an ongoing challenge that requires constant vigilance from anglers, managers, and researchers. While some species like round gobies have become integrated into the food web with mixed results, others like the potential arrival of Asian carp species could fundamentally alter the lake’s ecology.
Important Note: Always properly dispose of unused bait, clean your equipment between water bodies, and never transport live fish from one location to another. These simple steps help prevent the spread of invasive species.
Understanding these invasive species helps you become a more informed angler and environmental steward. When you catch an invasive species, you’re witnessing the ongoing transformation of Lake Erie’s ecosystem—a process that continues to unfold with each passing season. Report unusual catches to local fishery managers and consider participating in citizen science programs that track invasive species populations.
The battle against invasive species requires everyone’s participation. Your awareness and responsible fishing practices contribute to larger conservation efforts aimed at protecting Lake Erie’s native fish communities and maintaining the world-class fishery we all depend on for recreation, commerce, and ecological health.
