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Michigan

Meet the 17 invasive fish Michigan residents should know about

Northern snakehead can walk from one body of water to another

Kayla Clarke, Senior Web Producer

Tags: Invasive Michigan
There are 17 species of invasive fish that Michigan is monitoring. (Michigan.gov)

There are 17 species of invasive fish that Michigan officials are monitoring.

Six of the species have established populations in Michigan or in the Great Lakes. Those species are the Eurasian ruffe, round goby, rudd, sea lamprey, tench, and tubenose goby. Two of the species have been detected in Michigan or the Great Lakes. Those species are the grass carp and the Japanese/oriental weatherfish.

Nine of the species on Michigan’s list of invasive fish have not been detected in the state or in the Great Lakes. Those species are bitterling, bighead carp, black carp, silver carp, ide, northern snakehead, stone moroko, wels catfish, and zander.

Bitterling

Bitterling (George Chernilevsky)

Bitterling have not been detected in Michigan. They are found in marshes, lakes, ponds, muddy/sandy pools, and backwaters of rivers. They eat small larvae of insects and plant material.

They need freshwater mussels to reproduce. Female bitterling lay their eggs between the gills of bivalves, once the eggs are fertilized, they hatch inside the live mussel. The fish rids the bivalve of parasites, which is beneficial.

These fish are small. They have a grey-green back with silvery white sides and belly. They have a metallic streak on the hind end of the sides. Their fins are pale orange and have gray shading. The mouth is oblique, inferior, or just terminal. The lower jaw is never longer than the upper jaw.

Bighead carp

The bighead carp is a large, narrow fish with eyes that project downward. (U.S. Fish and Wildlife Service)

Bighead carp have not been detected in Michigan. Bighead carp eat plankton, which is a primary food for many fish that are native to Michigan -- including walleye, yellow perch, and lake whitefish. Bighead carp eat up to 40% of their weight per day. Females can produce up to one million eggs.

Officials said if bighead carp make it to the Great Lakes, they will populate nearshore areas and large rivers -- which could reduce sport and commercial fishing. These fish live in a wide range of temperatures. They have been found in at least 18 states surrounding the Ohio and Mississippi River basins.

These fish can grow up to five feet long and weigh up to 90 pounds. They have a large head with a toothless, downturned mouth. The eyes sit below the mouth. Adult bighead carp are dark grey with dark blotches. The keel is between the anal and pelvic fins.

Black carp

Black Carp (U.S. Geological Survey Columbia Environmental Research Center)

Black carp have not been detected in Michigan. They live in large rivers and lakes but require large rivers to reproduce. They can grow up to 6 feet long and weigh up to 150 pounds. They have elongated, laterally compressed bodies, blackish-bluish gray to almost white bellies, and pointed heads with a flattened front portion.

These fish consume up to 20% of their body weight per day. They eat mollusks and snails. If they become established in the Great Lakes, they could threaten Michigan’s native mussel populations. They would also compete with native mollusk-eating fish including freshwater drum, redhorse species, and lake sturgeon.

Grass carp

Grass carp (2013 State of Michigan)

Grass carp have been detected in the Great Lakes. These fish can grow longer than 5 feet and weigh more than 80 pounds. Their eyes sit even with the mouth, they have large scales that appear crosshatched, and their dorsal fins are shorter than a goldfish or common carp.

They eat plants and consume up to 90 pounds of food a day. They only digest half of the food and expel the rest, which can contribute to algal blooms. Grass carp are known to destroy weed beds that are used by native fish for spawning.

They like to live in quiet, shallow waters. When temperatures decrease, the fish move to deeper waters. Grass carp are tolerant to low levels of salinity, so they occasionally enter brackish water.

Silver carp

This silver carp was caught about nine miles from Lake Michigan on June 22, 2017. (Illinois Department of Natural Resources via AP)

Silver carp have not been detected in Michigan. These fish can grow longer than three feet and weigh up to 60 pounds. They have light, silver bodies with a white body. Their eyes sit below a toothless mouth. The keel extends from the anal fin forward past the pelvic fin base.

They feed on plankton, which is a primary food for many native fish -- including walleye, yellow perch, and lake whitefish. They consume up to 40% of their body weight per day. Each female silver carp can produce up to one million eggs.

Silver carp will leap high out of water when disturbed by boat motors. Boaters have been injured by these fish. If they get into the Great Lakes, these fish could reduce sport and commercial fishing opportunities, officials said.

Eurasian ruffe

Eurasian Ruffe (U.S. Geological Survey/Bugwood.org)

The Eurasian ruffe is established in Michigan. They can be identified by their olive-brown back side and yellow-white belly. They have fused dorsal fins with no notch and dark spots on membranes between the rays of the fin. They have a small, downturned mouth.

These fish are bottom-dwelling fish that inhabit fresh and brackish waters. They mainly eat aquatic insects, but they occasionally eat the eggs of other fish. They have a well-developed sensory system that helps them feed at night. They have few natural predators.

Ide

Ide (Michigan)

Ide have not been detected in Michigan. These fish can reach about three feet long and have “chunky” bodies with an arched back and belly. They have small, bluntly pointed heads and a forked caudal fin. They can be silver or golden in color.

They live in clean, clear pools of medium to large ponds, lakes, and rivers. They tend to eat larval and adult insects, snails, and other invertebrates. Larger ide may also eat small fish.

Michigan officials believe ide could become more of a problem than common carp if they establish a population in the state.

Japanese/oriental weatherfish

Japanese/Oriental Weatherfish (Pamela Woods)

The Japanese or oriental weatherfish have been detected in Michigan. They have eel-like bodies that are brown with greenish-grey-brown marbled markings on the dorsal side and a pale, silver color on the ventral side. They have small, narrow mouths, with thick and fleshy lips and six barbels. They may reach up to a foot long, but are usually smaller. The female is often longer than the male.

They eat small benthic invertebrates and detritus. They are competition for aquatic insects and that can put native fish populations at risk. They are often found in shallow, low-gradient waters with muddy or silty substrates. They can live in waters with poor oxygen and through long droughts by burrowing into soft substrates. Their intestines act as an accessory respiratory organ.

Northern snakehead

Northern Snakehead (Photo courtesy of U.S. Geological Survey, Bugwood.org.)

The northern snakehead has not been detected in Michigan. These fish live in many different habitats. They can breathe out of water anywhere from three to seven days. They can use their pectoral fins to move from one body of water to another -- they move slowly and are usually not successful.

Their body length can reach up to 33 inches. The color is generally tan with dark brown mottling. They have sharp teeth, an extended anal fin, and the pelvic fin is up near the gills and pectoral fins.

They are a concern because they do not have any natural predators. They can out-compete native fish species for food.

Round goby

Invasive Round Goby (2010 State of Michigan)

The round goby has an established population in the Great Lakes. They are freshwater fish, but prefer brackish water. They perch on rocks and other substrates in shallow areas of water. They eat zebra mussels, some native snails, aquatic insects, other males’ eggs and smaller fish.

They can grow up to a foot long. The young fish are usually solid slate gray in color, older fish are blotched with black and brown. They have a black spot on the rear of the first dorsal fin. They have a fused pelvic fin.

They are a local concern because they eat a lot and are aggressive, which means they can dominate other native species. They also have a well-developed sensory system that helps them feed at night.

Rudd

Rudd (U.S. Geological Survey, Bugwood.org)

Rudd have an established population in Michigan. They can adapt to most environments, but they prefer stagnant and slow-flowing water. Their diet usually consists of fish in the early spring and shifts to mostly vegetation in the summer and fall.

They have a deep and stocky body with a green-brown back, brassy yellow sides, and a near-white belly. They can reach around a foot and a half long. The pectoral, pelvic, and anal fins are bright red-orange. The dorsal and tail fins are red-brown. The tail fin is forked and the lower lip is protruding. There is a red spot on the iris of the eye.

They are a local concern because the impact they have on the environment is mostly unknown. Its ability to shift what it eats gives it an advantage over other species. The rudd could also increase nutrients in the water due to how poorly it processes plant material.

Sea lamprey

Sea Lamprey (Credit: Wikimedia Commons)
  • Names: Petromyzon marinus
  • Status: Established in Michigan
  • Learn more: Michigan.gov

Adult sea lamprey feed on the body fluids of other fish, usually killing them. Larval lamprey burrow into sediment and live for up to 10 years as filter feeders.

They are found in all five of the Great Lakes and some tributaries in Illinois, Indiana, Michigan, Minnesota, New York, Pennsylvania, and Wisconsin. Sea lamprey have a high reproductive potential and a lack of predators. An established population of sea lamprey has had a “devastating effect on the state’s fishery.”

Sea lamprey have an eel-like body, two close dorsal fins, seven gill openings, and a large, round, mouth with sharp, curved teeth and a rasping tongue.

Stone moroko

Stone Moroko (Seotaro)

These fish live in well-vegetated ponds, small lakes, and small channels. They eat small insects, plant material, fish, fish eggs, and planktonic crustaceans. They have not been detected in Michigan, but are a concern because they would compete with farmed fish species for food. These fish could also act as a vector for infectious fish diseases and contribute to eutrophic conditions.

They have a yellowish-green to silver body color and grow to about eight centimeters long. They have a superior and transverse mouth, pale yellow fins, and the dorsal fin has a darker stripe. Young individuals have a dark stripe along the side.

Tench

Tench (U.S. Geological Survey, Bugwood.org)

These fish are freshwater members of the carp family and live in lakes with weedy or muddy bottoms. They eat insect larvae and mollusks. They are able to survive in waters with low-oxygen. Officials do not know if these fish contribute to the degradation of the water quality or if they are just able to live where native species cannot.

They have thick-set bodies ranging in color from deep olive to pale golden tan. Their eyes are bright red/orange in color. They have a small barbell at both corners of the mouth. These fish can be found in Michigan. Officials said it is difficult to identify the impact they have because they are often lumped together with other species in the family.

Tubenose goby

Tubenose Goby (Copyright 2010 State of Michigan)

These fish have established populations in Michigan. They were introduced to the Great Lakes basin and inhabit Lake Superior, Lake Erie, and Lake Huron. They also can be found in Lake St. Clair and the St. Clair River.

They eat benthic invertebrates, such as amphipods. Their dietary requirements put them in competition with native darter populations in the Great Lakes. It is believed these fish got to the Great Lakes via ballast water introduction.

Native look-alikes and how you can tell them apart from tubenose goby:

  • Spoonhead Sculpin: pelvic fins not fused, all fins lightly speckled except for clear pelvic fins, scaleless body.
  • Slimy Sculpin: pelvic fins not fused, scaleless body.
  • Mottled Sculpin: pelvic fins not fused, dark spots all over first dorsal fin, scaleless body.
  • Deepwater Sculpin: pelvic fins not fused, scaleless body.

Wels catfish

Wels Catfish (Bernard Dupont via USGS)

Wels catfish live in lowland rivers, backwaters, and well-vegetated lakes. They occasionally enter brackish water in the Black and Baltic seas.

They have not been detected in Michigan, but they are a concern because of their voracious predatory habits. They are nocturnal and eat fish and other vertebrates. They pose a threat to native vertebrates and can reduce water quality.

They can grow up to 10 feet long and live 80 years. They have very large mouths with three pairs of barbels, one pair on the upper jaw and two on the lower jaw. They have brown backs and sides and a nearly-white belly.

Zander

Zander (U.S. Geological Survey, Bugwood.org)

Zander live in eutrophic lakes, brackish coastal lakes/estuaries, and large turbid rivers. They feed on gregarious fishes in pelagic waters. They have not been detected in Michigan.

They have an established population in Spiritwood Lake in North Dakota. Michigan is concerned because if Zander are introduced they could lead to a crash in some fish communities. There is also a concern for hybridization with walleye.

These fish have a slender body, a grey-green back, a white belly, and dark transverse rings. They have two dorsal fins, a pointed head, and many small teeth, and a few large teeth. It is not a hybrid of a pike and perch.

Find more coverage here on invasive species Michigan officials are monitoring.

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About the Author
Kayla Clarke headshot

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.

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