Ichthyomyzon gageiSouthern brook lamprey

Geographic Range

Southern brook lampreys are found in the Mississippi River basin, the Tennessee River drainage, and Gulf of Mexico drainages. They inhabit freshwater temperate waters, mainly small streams during the larval stage and larger streams during the adult stage. They prefer shallow water and require a river bottom of gravel and smaller rocks to attach and spawn. ("Ichthyomyzon gagei", 2011; "Mississippi River Resource Page", 2011)


Southern brook lampreys tend to live in swift flowing water but can also be found in the slower moving water, which is generally where the ammocoetes live. The Mississippi River basin is 3705 km long and has a large range of depth, width, and speed depending on the location. Southern brook lampreys typically stay in the smaller rivers and tributaries. ("Ichthyomyzon gagei", 2011; "Mississippi River Resource Page", 2011)

  • Aquatic Biomes
  • rivers and streams
  • Range elevation
    0 to 450 m
    0.00 to 1476.38 ft
  • Range depth
    0.9 to 61 m
    2.95 to 200.13 ft

Physical Description

Southern brook lampreys have an eel-like body shape, a dorsal fin divided into two lobes but is not considered two separate fins. The mouth is a sucking disk filled with bicuspid teeth that distinguishes it from northern brook lampreys. Adults are a tannish or green color on their back and lighter yellow or white on the stomach, the fins are also lighter in color. The larval form lacks eyes and instead of an oral disc, the mouth is hood-like. ("Ichthyomyzon gagei", 2011; Hammerson, 2010; Mettee, et al., 2008; Rainer, 2010)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    1.05 to 4.25 g
    0.04 to 0.15 oz
  • Average mass
    2.2 g
    0.08 oz
  • Range length
    10 to 20 cm
    3.94 to 7.87 in
  • Average length
    16 cm
    6.30 in


Southern brook lampreys spend the majority of their lives as ammocoete larva that bury themselves in sandy river bottoms and feed on bacteria and algae floating in the sediment. The larval stage can change depending on the climate and surrounding conditions but generally ranges anywhere from 3 to 4 years. The transformation stage into an adult occurs over a 2 to 3 month period where it migrates to the faster portion of the stream. In the spring, the adult attaches itself to the gravel bottom where it spawns. ("Ichthyomyzon gagei", 2011; Beamish and Thomas, 1984; Cochran and Pettinelli, 1987; Cochran, 1987)


Southern brook lampreys spawn in a group over a time period of less than a week. Five to 20 adults may build a nest of rocks, and several adults are needed complete the nests. (Cochran and Pettinelli, 1987; Mettee, et al., 2008)

Within a few days after spawning, the adults die. The eggs hatch about 2 to 3 weeks after fertilization and grow into the larval form and stay that way for 3 to 4 years. For 2 to 3 months in the late summer or early fall the larvae metamorphose into adults. Females may carry and release anywhere from 1000 to 2000 eggs during the spawning period and the number of eggs fertilized depends on the number of males present. ("Ichthyomyzon gagei", 2011; Beamish and Thomas, 1984; Cochran and Pettinelli, 1987; Hassan-Williams and Bonner, 2007; Rainer, 2010)

  • Breeding interval
    Southern brook lampreys breed once in the spring and then die.
  • Breeding season
    Southern brook lampreys breed in the spring over a time period less than a week.
  • Range number of offspring
    1000 to 2500
  • Average number of offspring
  • Range age at sexual or reproductive maturity (female)
    3 to 4 years
  • Range age at sexual or reproductive maturity (male)
    3 to 4 years

Spawning southern brook lampreys build nests for the eggs, but the adults die after spawning. ("Ichthyomyzon gagei", 2011; Mettee, et al., 2008)

  • Parental Investment
  • pre-hatching/birth
    • provisioning
      • male
      • female
    • protecting
      • male
      • female


Southern brook lampreys need ideal conditions to survive different phases of their life, so they are hard to manage in captivity. In the wild, once fertilized, the eggs hatch in 2 to 3 weeks and the lampreys remain larvae for 3 to 4 years. Once they metamorphose into the adult phase, they spawn very fast because they only survive 2 to 26 days. (Beamish and Thomas, 1984; Hassan-Williams and Bonner, 2007; Mettee, et al., 2008; Rainer, 2010)

  • Typical lifespan
    Status: wild
    1111 to 1507 days


As adults, southern brook lampreys have just a few days to reproduce and build a nest for their offspring. They spawn in large groups of 20 to 40 and the adults may work together to build nests. (Cochran and Pettinelli, 1987; Cochran, 1987; Mettee, et al., 2008)

Communication and Perception

The adult form is the only mobile form. After metamorphosis, adults develop the ability to swim. Adults also have fully functioning eyes. Sight and touch are the two major forms of communication between species and interactions with the environment. ("Ichthyomyzon gagei", 2011)

Food Habits

Southern brook lampreys are not parasites. The larval forms feed on algae and bacteria floating near their stationary location in gravel or sand. Adult southern brook lampreys do not feed, and rely on stored energy sources to survive a short time. ("Ichthyomyzon gagei", 2011; Hassan-Williams and Bonner, 2007; Mettee, et al., 2008; Rainer, 2010)

  • Plant Foods
  • algae


The larval form burrows into loose gravel or sand so it is hard to find by fish predators. The adult form attaches itself onto rocks in swift moving waters where it is also hard to find because of cryptic coloration. Their known predators include northern pike (Esox lucius), perch (Perca fluviatilis), and European chub (Squalius cephalus). ("Ichthyomyzon gagei", 2011; Hammerson, 2010)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

The larval phase is the only phase that eats and filter feeds on nutrients from algae and bacteria. Southern brook lampreys are not predators. ("Ichthyomyzon gagei", 2011; Mettee, et al., 2008; Rainer, 2010)

Economic Importance for Humans: Positive

Although not a part of the diet for people in the United States, people in countries such as Sweden, Russia and South Korea consume lampreys and some consider it a delicacy. Southern brook lampreys are sold in bait shops to catch pike, perch and chub. (Hassan-Williams and Bonner, 2007; Rainer, 2010)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

There are no known negative economic effects on humans caused by southern brook lampreys.

Conservation Status

IUCN Red List cites southern brook lampreys as a species of least concern throughout the United States.


ryan oldsberg (author), Minnesota State University, Mankato, Robert Sorensen (editor), Minnesota State University, Mankato, Renee Mulcrone (editor), Special Projects, Catherine Kent (editor), Special Projects.



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

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.


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.


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).


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body


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.


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.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.


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.

native range

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


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

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).


uses sight to communicate


2011. "Ichthyomyzon gagei" (On-line). Accessed April 21, 2011 at http://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=AFBAA01040.

2011. "Mississippi River Resource Page" (On-line). Accessed July 11, 2011 at http://www.mississippiriverresource.com/River/RiverFacts.php.

Beamish, F., E. Thomas. 1984. Metamorphosis of the southern brook lamprey, Ichthyomyzon gagei. Copeia, 1984 (2): 502-515. Accessed July 11, 2011 at http://www.jstor.org/stable/1445205.

Cochran, P. 1987. The southern brook lamprey (Ichthyomyzon gagei) in the St. Croix River drainage of Wisconsin and Minnesota. Copeia, 1987/2: 443-446. Accessed July 11, 2011 at http://www.jstor.org/stable/1445782.

Cochran, P., T. Pettinelli. 1987. "Northern and southern brook lampreys in Minnesota" (On-line pdf). Accessed July 11, 2011 at http://files.dnr.state.mn.us/eco/nongame/projects/consgrant_reports/1987/1987_cochran.pdf.

Hammerson, G. 2010. "Ichthyomyzon gagei" (On-line). NatureServe Explorer. Accessed July 11, 2011 at http://www.natureserve.org/explorer/servlet/NatureServe?sourceTemplate=tabular_report.wmt&loadTemplate=species_RptComprehensive.wmt&selectedReport=RptComprehensive.wmt&summaryView=tabular_report.wmt&elKey=102239&paging=home&save=true&startIndex=1&nextStartIndex=1&reset=false&offPageSelectedElKey=102239&offPageSelectedElType=species&offPageYesNo=true&post_processes=&radiobutton=radiobutton&selectedIndexes=102239+gage.

Hassan-Williams, C., T. Bonner. 2007. "Ichthyomyzon gagei" (On-line). Accessed July 11, 2011 at http://www.bio.txstate.edu/~tbonner/txfishes/ichthyomyzon%20gagei.htm.

Mettee, M., P. O'Neil, J. Pierson. 2008. "Southern Brook Lamprey" (On-line). Fishes of Alabama and the Mobile Basin. Accessed July 11, 2011 at http://www.outdooralabama.com/fishing/freshwater/fish/other/lamprey/so/.

Rainer, F. 2010. "Southern brook lamprey" (On-line). Accessed July 11, 2011 at http://www.fishbase.org/summary/speciessummary.php?id=2517.