Ichthyomyzon gagei
Southern brook lamprey

The southern brook lamprey has a narrow geographic range in North America, living only in the Mississippi River basin, Tennessee River drainage and Gulf of Mexico drainages. It inhabits freshwater temperate waters, mainly small streams during the larval stage and larger streams during the adult stage. Shallow water is preferred and the river bottom must be gravel and smaller rocks for the lamprey to attach and spawn. ("Ichthyomyzon gagei", 2011; "Mississippi River Resource Page", 2011)

Adult southern brook lamprey 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, but the southern brook lamprey typically stays in the smaller rivers and tributaries. ("Ichthyomyzon gagei", 2011; "Mississippi River Resource Page", 2011)

The southern brook lamprey has 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 the northern brook lamprey. Adult Ichthyomyzon gagei 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)

Ichthyomyzon gagei spends the majority of it's life as an ammocoete larva that buries itself in sandy river bottoms and feeds 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 3-4 years. The transformation stage into an adult occurs over a 2-3 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)

Males and females of Icthyomyzon gagei 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 2-3 weeks after fertilization and grow into the larval form and stay that way for 3-4 years. For 2-3 months in the late summer or early fall the larvae metamorphose into adults. Females may carry and release anywhere from 1000-2000 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)

The spawning Icthyomyzon gagei build nests for the eggs, but the adults die after spawning. ("Ichthyomyzon gagei", 2011; Mettee, et al., 2008)

The southern brook lamprey needs ideal conditions for its different phases of life to survive, so it is hard to manage in captivity. In the wild, once fertilized, the eggs hatch anywhere from 2-3 weeks and they remain in the larval phase for 3-4 years. Once they metamorphose into the adult phase they spawn very fast because they only survive 2-26 days. (Beamish and Thomas, 1984; Hassan-Williams and Bonner, 2007; Mettee, et al., 2008; Rainer, 2010)

Once in the adult form, the southern brook lamprey has only a few days to reproduce and create a nest for their offspring. The spawning is conducted in large groups of around 20-40 and the adults may work together to build nests. (Cochran and Pettinelli, 1987; Cochran, 1987; Mettee, et al., 2008)

The adult form is the only mobile form. After metamorphosis adults develop the abilty 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)

The southern brook lamprey is non-parasitic. 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)

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. ("Ichthyomyzon gagei", 2011; Hammerson, 2010)

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

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. The southern brook lamprey is sold in bait shops to catch pike, perch and chub. (Hassan-Williams and Bonner, 2007; Rainer, 2010)

There are no known negative economic effects for humans by this species.

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