Catostomus commersoniiBlack mullet(Also: Brook sucker; Carp; Coarse scaled sucker; Common sucker)

Geographic Range

White suckers (Catostomus commersonii) are a highly ubiquitous species. Their range is over 2.5 million square kilometers, stretching from east of the Mackenzie River to Labrador in Canada, and into 40 states in the Eastern and Midwestern United States. White suckers are also an introduced species in the Colorado River drainage basin. ("Catostomus commersonii", 2013; Page and Burr, 2011)


White suckers occupy a wide range of habitats including streams, rivers, and lakes but are usually found in small creeks with cold, clear water and small or medium-sized rivers. White suckers are also highly tolerant of polluted, murky, and anoxic waters, as well as a wide array of stream gradients. They do not require dense vegetation and prefer temperatures between 11.8 and 20.6 degrees Celsius. Lethal pH for white suckers ranges from 3.0 to 3.8. (Becker, 1983; "White Sucker Catostomus commersonii", 2013; "Catostomus commersonii", 2013; Page and Burr, 2011; Zimmerman, 2012)

  • Aquatic Biomes
  • benthic
  • rivers and streams

Physical Description

White suckers have a long, round body and grow to an average length of 241 mm and a maximum weight of about 2.5 kg. They have olive brown to black coloration on their back and a lighter colored, or white belly, with dusky or clear fins. Breeding males gain gold coloration on their backs and red (or less commonly cream or black) stripes across their sides. They have a toothless, sucking subterminal mouth with no barbels. The mouth region is additionally characterized by thick pappilose lips, with a lower lip that is about twice as thick as the upper lip. White suckers have fewer lateral line scales (between 55 and 58) and a shorter snout than their close relatives, longnose suckers. Young white suckers have dark blotches on their backs and sides. (Becker, 1983; "White Sucker Catostomus commersonii", 2013; "Catostomus commersonii", 2013; Page and Burr, 2011; "White Sucker, Catostomus commersonii (pictured) Longnose Sucker, Catostomus catostomus", 2013; Zimmerman, 2012)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • sexes shaped differently
  • Range mass
    2.5 (high) kg
    5.51 (high) lb
  • Average mass
    0.4 kg
    0.88 lb
  • Average length
    241 mm
    9.49 in


Embryonic development of white suckers is faster in warmer temperatures. Organs begin developing on the same day as fertilization, indicated by the formation of a head region. Soon afterwards, the embryo becomes mobile, develops its circulatory system, and increases in length. Their larvae hatch after about 5 to 7 days and are 21 to 25 mm in length, with slanted mouths and short intestines. When white suckers are less than 51 mm in length, they tend to feed in shallow water, 15 to 20 cm deep and along lake shores. In some populations, white suckers are mature by the time they are 2 years old, however, on average, suckers are mature by age 3. In other populations, males mature at a faster rate (2 years old) than females (3 years old) but all are mature by age 4. (Becker, 1983; Long and Ballard, 1976; McElman and Balon, 1980)


After migrating upstream to a spawning area with quick running water and a gravely substrate, female white suckers settle to the bottom. Males, who arrived earlier, crowd around her until just two males find a place on either side of her. The three fish then rapidly vibrate together, releasing sperm and eggs. After this brief (1.5 seconds) spawning act, the female continues upstream to find two more male mates. Presumably, the two males may also seek a new mate. Males do not compete for females and typically ignore each other. (Becker, 1983)

White sucker spawning and upstream breeding runs last for six weeks in the spring, or early summer in more northern regions. Upstream breeding runs usually occur at night and spawning typically lasts from April to early May. This is timed to occur shortly after ice melts from a spawning area, the duration of spawning may be related to the water temperature. Male white suckers reach the spawning area earlier than females and outnumber them. White suckers do not build nests or defend a territory. The spawning area usually has quick running water and a gravely substrate, but spawning can sometimes occur in lakes if conditions allow. Males may show "head trembling" behavior (vibrating their heads rapidly from side to side for a short time) towards a nearby female who has come to rest at the bottom of a rapid. Head trembling may also be directed at other males in the spawning area, although males do not fight for access to mates. Along with head trembling, male white suckers also spread their pectoral fins, extend their dorsal fin, and protrude their jaw. (Becker, 1983; Long and Ballard, 1976; "Catostomus commersonii", 2013; Zimmerman, 2012)

A single female can produces between 20,000 and 50,000 eggs, about 2 to 3 mm in diameter, which are usually fertilized by two males who float on either side of her during the spawning act. All three fish vibrate together rapidly for about 1.5 seconds while the female releases her eggs and the males release their sperm. The female then swims upstream where she may mate with two more males. Due to this, a single female's eggs may be scattered in clumps over a large area. The sticky eggs sink to the bottom of the spawning area and become attached to gravel and other bottom material. After incubating for 5 to 7 days, the larvae hatch and remain in the area for 1 to 2 weeks. Their fry then migrate downstream about 1 month after spawning first occurred. Depending on the location, white suckers become sexually mature in 3 to 8 years, with males maturing faster than females. Adult white suckers suffer low spawning mortality rates, between 16 and 20 percent. (Becker, 1983; Long and Ballard, 1976; "Catostomus commersonii", 2013; Zimmerman, 2012)

  • Breeding interval
    White suckers breed once a year.
  • Breeding season
    White suckers breed in the spring, usually from April to early May.
  • Range number of offspring
    20000 to 50000
  • Range time to hatching
    5 to 7 days
  • Range age at sexual or reproductive maturity (female)
    3 to 8 years
  • Range age at sexual or reproductive maturity (male)
    3 to 8 years

There is no parental investment in white suckers.

  • Parental Investment
  • no parental involvement


White suckers have a maximum life expectancy of about 17 years. ("White Sucker, Catostomus commersonii (pictured) Longnose Sucker, Catostomus catostomus", 2013)

  • Range lifespan
    Status: wild
    17 (high) years


Young white suckers less than a year old form schools of several hundred fish. Adult and juvenile white suckers feed day and night but are more active at night when they move into shallower water. White suckers tend to coordinate their movement so they are inshore during the evening and offshore by morning. In stream habitats, large white suckers can be found in deep pools. White suckers are also excellent dispersers, particularly after spawning. In one such case, an individual white sucker ended up 56 km away from the area it was tagged 5 years previously. (Becker, 1983)

Home Range

White suckers are not known to maintain a specific home range.

Communication and Perception

During spawning, male white suckers may show "head trembling" behavior, vibrating their heads rapidly from side to side towards a nearby female, who rests at the bottom of a spawning area, or to other males in the spawning area. Males, however, do not compete with each other for access to mates. Along with head trembling, male white suckers may also spread their pectoral fins, extend their dorsal fin, and protrude their jaw. (Becker, 1983)

Food Habits

White sucker fry passively feed on Protozoa, diatoms, small crustaceans, and midge larvae carried to them by currents. As white suckers mature, their mouthparts move to their underside, allowing them to bottom-feed. As adults, they feed additionally on fish, fish eggs, plants, mollusks, insects, rotifers, chironomid larvae, mayflies, and algae. However, their feeding pattern is nonrandom. Adult white suckers feed primarily on zooplankton and benthic invertebrates with mild seasonal variation, but they may also specialize in one or the other as a form of resource partitioning, or selectively feed on the largest individuals if resources are abundant. (Becker, 1983; Saint-Jacques, et al., 2000; Zimmerman, 2012)

  • Animal Foods
  • fish
  • eggs
  • insects
  • mollusks
  • aquatic or marine worms
  • aquatic crustaceans
  • other marine invertebrates
  • zooplankton


White suckers are an important food source for several species of fish and land animals. Muskellunges commonly feed on white suckers during foraging. They are also fed on by bass, burbot, brook trout, sea lamprey, walleye, and northern pike. The latter two primarily feed on eggs and small white suckers up to about 203 mm long. Small white suckers are also eaten by bald eagles, herons, loons, and ospreys. Bears and other animals will feed on white suckers during spawning periods. (Becker, 1983)

Ecosystem Roles

White suckers serve as a host species for the glochidial stage of the mollusks elktoes and alewife floaters. They prey on Protozoa, diatoms, small crustaceans, midge larvae, chironomid larvae, mayflies, fish, fish eggs, plants, mollusks, insects, rotifers, and algae. Additionally, they are preyed upon by muskellunges, bass, burbot, brook trout, sea lamprey, walleye, northern pike, bald eagles, herons, loons, ospreys, bears, and other animals. White suckers are in competition with yellow perch for benthic invertebrate prey. Removal of white suckers from areas with both species results in higher utilization of benthic invertebrates for food and lower consumption of zooplankton by yellow perch, which in turn increases the growth rate of adults. However, removal of white suckers does not significantly increase the population of yellow perch. (Becker, 1983; Hayes, 1990)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

White suckers are an under-utilized, yet potentially valuable sport fish. They are caught using worms, spears, dip nets, wet flies, and spinning lures. Commercial fisheries catch them using seines, fyke, pound nets, gill nets, and trawls. Their catch is then used as food for both humans and animals, including pets. White suckers are also farmed in ponds and pursued by anglers using spears, hooks, and fishing line. The most important economic value of white suckers lies in their use as food or bait. The bait industry for white suckers was valued at $300,000 in Wisconsin in 1968. White suckers have sweet, white flesh that is not as firm as that of other sport fish. Additionally, white suckers contain large bones between their muscle segments that may render them unappetizing to some. Still, they can be smoked, filleted, or ground into patties to produce tasty dishes. (Becker, 1983; "White Sucker, Catostomus commersonii (pictured) Longnose Sucker, Catostomus catostomus", 2013)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

Although white suckers feed on fish eggs, this does not seen to adversely affect the populations of other fish. (Becker, 1983)

Conservation Status

White suckers are a very robust, common, and wide-ranging species with large population sizes and are therefore designated as a species of least concern according to the IUCN Red List. In a 1958 study focusing on the removal of the species, 12,750 white suckers were removed from a southern Wisconsin stream over a 3-year period. Afterwards, it was estimated that 7,411 suckers still remained in the stream. (Becker, 1983)


Aldo Hernandez (author), University of Michigan-Ann Arbor, Jeff Schaeffer (editor), University of Michigan-Ann Arbor, Leila Siciliano Martina (editor), Animal Diversity Web Staff.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map


Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate


active at dawn and dusk


an animal that mainly eats decomposed plants and/or animals


particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

  1. active during the day, 2. lasting for one day.
external fertilization

fertilization takes place outside the female's body


union of egg and spermatozoan


A substance that provides both nutrients and energy to a living thing.


mainly lives in water that is not salty.


An animal that eats mainly plants or parts of plants.


An animal that eats mainly insects or spiders.


referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


eats mollusks, members of Phylum Mollusca


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


an animal that mainly eats all kinds of things, including plants and animals


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)


an animal that mainly eats fish


an animal that mainly eats plankton


Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)


NatureServe. 2013. "Catostomus commersonii" (On-line). Accessed October 20, 2013 at

Minnesota Department of Natural Resources. 2013. "White Sucker Catostomus commersonii" (On-line). Accessed October 20, 2013 at

State of Michigan. 2013. "White Sucker, Catostomus commersonii (pictured) Longnose Sucker, Catostomus catostomus" (On-line). Accessed October 21, 2013 at,4570,7-153-10364_18958-45693--,00.html.

Becker, G. 1983. Fishes of Wisconsin. Madison, Wisconsin: University of Wisconsin Press. Accessed October 21, 2013 at

Hayes, D. 1990. Competition between white sucker (Catostomus commersonii) and yellow perch (Perca flavescens) : Results of a whole-lake manipulation. Lansing, Michigan: Michigan Dept. of Natural Resources, Fisheries Division.

Long, W., W. Ballard. 1976. Normal Embryonic Stages of the White Sucker, Catostomus commersonii. Copeia, 2: 342-351.

McElman, J., E. Balon. 1980. Early ontogeny of the white sucker, Catostomus commersonii, with steps of saltatory development. Environmental Biology of Fishes, 5: 191-224.

Page, L., B. Burr. 2011. Peterson field guide to freshwater fishes of North America north of Mexico. Boston: Houghton Mifflin Harcourt.

Saint-Jacques, N., H. Harvey, D. Jackson. 2000. Selective foraging in the white sucker (Catostomus commersonii). Canadian Journal of Zoology, 78: 1320-1331.

Zimmerman, B. 2012. Stream Fishes of Ohio. Ohio: Ohio Department of Natural Resources.