Ichthyomyzon castaneusChestnut lamprey

Geographic Range

Chestnut lampreys are native to central North America. Their geographic range stretches as far north as the Hudson Bay in Canada and as far South as the Gulf of Mexico. In the United States, chestnut lampreys are found from Texas to Georgia and from Minnesota to Michigan. In Canada, these lampreys are found from Saskatchewan to Ontario. Their wide range is facilitated by the Mississippi and Missouri River networks, and tends to coincide with the movement of larger host fishes. Research also shows their geographic range increases in a southern fashion during colder months, indicating the migration of the species to warmer waters along with their host fish species. (Becker, 1983; Hall, 1963; Scott and Crossman, 1979; Starrett, et al., 1960)


Chestnut lampreys tend to live in temperate bodies of water such as lakes and rivers. Because of their parasitic nature, they are dependent on the presence of larger host fish and therefore tend to share an environment with larger predators. Chestnut lampreys are active at night, and thus require rocks and river banks that allow them to rest during the day. In order to spawn, chestnut lampreys tend to move to a river or lake that contains a suitable rock bed in which a spawning nest can be constructed. These spawning areas are located upstream of a silt bed, since the ammocoetes need a suitable medium in which to bury themselves in order to subsist until adulthood. (Becker, 1983; Hall, 1963; Renaud, et al., 1996)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Chestnut lampreys are jawless vertebrates from class Agnatha. This species has a cartilaginous skeleton and lacks a true vertebra, even though it is classified as such. They have a long cylindrical body with an approximate adult length of 125 to 250 mm. On average, their body contains 53 myomeres; however, they can range from 51 to 56. Chestnut lampreys tend to have a dark coloration. Most mature adults are brown and black in color, with a cream or beige colored belly. Chestnut lampreys have one large dorsal fin for movement, which often contains a shallow notch in the leading edge. These lampreys have a sucking disk on their mouths that contains rows of bicuspid teeth. The sucking disk has an opening, which when used in conjunction with piston cartilage, allows for suction by which lampreys feed. Chestnut lampreys have a single nostril located between their eyes and seven gill pores located directly behind their eyes. These lampreys also exhibit sexual dimorphism, with males having a urogenital papilla that extends beyond the body, whereas females have a large post-anal fold. (Hall, 1963; Hardisty and Potter, 1971)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range mass
    30 to 40 g
    1.06 to 1.41 oz
  • Range length
    125 to 271 mm
    4.92 to 10.67 in


Chestnut lampreys follow the general development patterns of parasitic-based lamprey species. This species has two life stages, larval and adult. The larval phase continues for an average period of 5 to 7 years. After hatching, the ammocoetes float downstream and bury themselves in a layer of silt. Over the next few years, they filter feed on diatoms and other microscopic particles found in the sediment. At around 3 to 4 years, these ammocoetes begin to develop their sucking disk. The addition of bicuspid teeth around their mouth opening allows for parasitic feeding and is necessary for the transition to adulthood. Through metamorphosis into the adult phase, lampreys enter a higher trophic level compared to ammocoetes. Adults are capable of sucking blood and other nutrients from host fish using their sucking disk. Chestnut lampreys average another one to two years in their adult parasitic stage. Once their parasitic cycle is completed, chestnut lampreys spawn and die shortly thereafter. (Hall, 1963)


Chestnut lampreys do not exhibit an advanced mating system. Males spawn with multiple females. After completing the spawning process, both sexes die. Females attract potential mates using pheromones during spawning. (Case, 1970; Hall, 1963)

Spawning occurs in late spring, once the water temperature increases to 10°C (50°F). Once spawning season arrives, chestnut lampreys migrate upstream to smaller tributaries. Adult lampreys build nests using their sucker disks to clear rocks and debris. Once cleared, the female attaches to a rock and the male wraps his tail around hers to allow for egg insemination. Thousands of eggs are released into the nest. The eggs hatch approximately 2 weeks after fertilization, after which they drift downstream and bury into soft sediment until maturity. Adults die shortly after spawning due to degeneration of the digestive system. (Case, 1970; Manion and Hanson, 1980)

  • Breeding interval
    Chestnut lampreys breed once in their lifetime.
  • Breeding season
    These lampreys breed from late spring to summer.
  • Average number of offspring
  • Range age at sexual or reproductive maturity (female)
    5 to 7 years
  • Range age at sexual or reproductive maturity (male)
    5 to 7 years

Since adults die shortly after spawning, there is little to no parental investment other than the prezygotic investment of preparing the nest. (Case, 1970; Manion and Hanson, 1980)

  • Parental Investment
  • no parental involvement


Chestnut lampreys live in a larval state for 5 to 7 years, during which they develop the ability to feed parasitically off of larger host fish. Upon maturity, lampreys feed for a period of one to two years. Once the time comes to spawn, lampreys migrate to a suitable area, spawn, and die shortly afterwards. The total lifespan of chestnut lampreys is approximately 6 to 9 years. (Becker, 1983; Hall, 1963)

  • Typical lifespan
    Status: wild
    6 to 9 years


Juvenile lampreys do not exhibit much behavior as they remain burrowed until maturation. The behavior of adult chestnut lampreys is centered on their parasitic nature. Lamprey behavior is focused on locating a potential host, thus they are often found moving in conjunction with large fish. Once a suitable host is found, they feed off of the fish until they are nourished. Chestnut lamprey attachment rarely results in the host's death, as lampreys detach before this occurs. (Hall, 1963; Hardisty and Potter, 1971)

Home Range

Adult chestnut lampreys live within the home range of their host fish. (Hall, 1963)

Communication and Perception

Chestnut lampreys have only been noted to communicate during times of spawning, including pheromone signaling to find mates. Current research on the topic is scant, chestnut lampreys are not known to show any other form of communication. (Manion and Hanson, 1980)

Food Habits

During the larval stage, chestnut lampreys filter feed on diatoms found in the sediment in which they are buried. These diatoms consist of tiny algae particles and protozoa. As adults, chestnut lampreys prey parasitically on a wide variety of larger fish such as carp, trout, pike, suckers, paddlefish, sturgeons, catfish, and sunfish. Feeding season for chestnut lampreys stretches from April to October. The host fish species varies based on location and availability. Lampreys nourish themselves on blood, liquefied skin, and other bodily fluids from their host fish. Although fish do not usually die as a result of the parasitic relationship, it can sometimes cause a secondary infection. Likewise, consecutive or multiple parasitic interactions can result in the death of a host fish. (Becker, 1983; Hardisty and Potter, 1971)

  • Animal Foods
  • fish
  • blood
  • body fluids
  • Plant Foods
  • algae
  • Other Foods
  • microbes


Adult chestnut lampreys have no known predators, however, in their larval stage, chestnut lampreys are preyed upon by burbot and brown trout. (Hall, 1963)

Ecosystem Roles

Chestnut lampreys are parasites and thus have a large effect on the surrounding ecosystem. Lamprey species are responsible for population control and pushing selection against the weaker fish that do not survive after lamprey detachment. (Becker, 1983)

Species Used as Host

Economic Importance for Humans: Positive

Filter feeding ammocoetes can be used as an environmental indicator of water quality. Since chestnut lamprey larvae filter feed in the sediment, smaller than expected populations could potentially indicate pollution in the water or sediment. (Hall, 1963)

Economic Importance for Humans: Negative

Chestnut lampreys can have a negative effect on the fishing industry when populations become too large. Fish that host chestnut lampreys are often left unhealthy and are not suitable for harvest, thus diminishing potential economic gain in some fisheries. Additionally, game fishing revenue may decrease when lamprey populations are high in a given area, as healthy fish are harder to find. (Becker, 1983)

Conservation Status

According to the IUCN redlist, chestnut lampreys have a conservation status of least concern. The population is listed as stable without any major threats currently facing populations. There are no current measures in place to protect the species. (Lanteigne, 1992; Smith and Darwall, 2013)


Timothy Acciaioli (author), University of Michigan-Ann Arbor, Jeff Schaeffer (editor), University of Michigan-Ann Arbor, Lauren Sallan (editor), University of Michigan-Ann Arbor, Leila Siciliano Martina (editor), Animal Diversity Web Staff.



an animal that mainly eats meat


uses smells or other chemicals to communicate


union of egg and spermatozoan


a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.


mainly lives in water that is not salty.


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


makes seasonal movements between breeding and wintering grounds


having the capacity to move from one place to another.


specialized for swimming


active during the night


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


an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death


chemicals released into air or water that are detected by and responded to by other animals of the same species


an animal that mainly eats fish


having more than one female as a mate at one time


an animal that mainly eats blood

seasonal breeding

breeding is confined to a particular season


offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.


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


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).


Becker, G. 1983. Fishes of Wisconsin. Madison, WI: University of Wisconsin Press.

Case, B. 1970. Spawning behavior of the chestnut lamprey Ichthyomyzon castaneus. Journal of the Fisheries Research Board of Canada, 27(10): 1872-1874.

Hall, J. 1963. An ecological study of the chestnut lamprey, Ichthyomyzon castaneus (Girard), in the Manistee River, Michigan. Ann Arbor, MI: University of Michigan.

Hardisty, M., I. Potter. 1971. The Biology of Lampreys. London and New York, NY: Academic Press.

Lanteigne, J. 1992. Status of the chestnut lamprey, Ichthyomyzon castaneus, in Canada. Canadian Field-Naturalist, 106(2): 14-18.

Manion, P., L. Hanson. 1980. Spawning Behavior and Fecundity of Lampreys from the Upper Three Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences, 37(11): 1635-1640.

Renaud, C., S. Ribey, F. Chapleau. 1996. Four records of the chestnut lamprey, Ichthyomyzon castaneus, new to Ontario. Canadian Field-Naturalist, 110: 450-453.

Scott, W., E. Crossman. 1979. Freshwater Fishes of Canada. Fisheries Research Board of Canada, 84: 966.

Smith, K., W. Darwall. 2013. "IUCN Redlist" (On-line). Ichthyomyzon castaneus. Accessed October 30, 2013 at http://www.iucnredlist.org/details/full/202617/0.

Starrett, W., W. Harth, P. Smith. 1960. Parasitic lampreys of the genus Icthyomyzon in the Rivers of Illinois. Copeia, Copeia 1960: 337-346.