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The Minnesota DNR lists northern brook lamprey as a species of special concern. In order to keep game fish populations high and parasitic sea lamprey populations low, a lampricide treatment is put into streams and rivers where many lamprey, including non-parasitic northern brook lamprey, reside. This lampricide, among other poisons and pollutants, is adversely affecting population size. There is not currently a direct management/conservation plan in place for this species.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
This species is prey for many larger fish throughout its life. While eggs and ammocoetes are particularly vulnerable, adults may be consumed as well. Known predators include rainbow trout, rock bass and brown trout.
Known Predators:
Northern brook lamprey appear very similar throughout their life cycle. This species has a continuous dorsal fin that may or may not be divided by a small notch and is connected to a round, short caudal fin. Individuals are grayish brown dorsally with a pale median line down the back and a lighter ventral side, with the posterior end darker in color (almost black). There are a few differences between ammocoetes and adults: ammocoetes have neither eyes nor a sucking disk mouth (they have a hooded mouth instead). Adults have eyes and disk-shaped mouths with small, poorly developed teeth. Once adults are of breeding age it is possible to differentiate between the sexes (males have a urogenital papilla and females have an enlarged post-anal fold).
Average mass: 2.2 g.
Average length: 16 cm.
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: female larger
Northern brook lamprey typically live for 5-8 years in the wild, dying within a few days of reaching sexual maturity and completing mating. There is no data available regarding captive lifespan.
Average lifespan
Status: wild: 7 years.
Typical lifespan
Status: wild: 5 to 8 years.
The habitat of northern brook lamprey varies throughout the life cycle. Adults are generally found in areas of rapidly flowing water above a very coarse bed, spawning and then laying eggs in crevices beneath rocks and boulders. Ammocoetes (larvae) are generally found in the the calmer waters of brook, stream and river side channels where there is fine sediment or organic debris in which to burrow.
Range depth: 0.7 (low) m.
Habitat Regions: temperate ; freshwater
Aquatic Biomes: rivers and streams
Northern brook lamprey are found in many areas of the midwestern and northeastern United States, including the Mississippi River drainage in Wisconsin, northeastern Illinois, and northern Indiana, and in parts of Canada. They are also found in a Lake Erie tributary in New York and certain tributaries of the St. Lawrence River in Quebec, Canada.
Biogeographic Regions: nearctic (Native )
Northern brook lamprey only feed as ammocoetes. During this time, they feed mainly on organic detrius, diatoms, desmids, protozoans, algae and pollen.
Plant Foods: pollen; algae
Other Foods: detritus ; microbes
Foraging Behavior: filter-feeding
Primary Diet: herbivore (Algivore); detritivore
Although morthern brook lamprey often share habitat with mayfly nymphs and small mussels, there is little evidence that there is any competition amongst these species. Unlike many lamprey species, this species is non-parasitic. There is currently no research available regarding parasites of northern brook lamprey.
Although there is little known positive impact of northern brook lamprey on humans, fishermen do occasionally use this species as bait
There are no known adverse effects of northern brook lamprey on humans.
Northern brook lamprey have two developmental stages: ammocoete (larval) and adult. Larvae hatch approximately 2 weeks after egg fertilization and drift downstream before burrowing into the substrate. Once settled in burrows, larvae feed on suspended algae, bacteria and other detrius for 5-6 years until they metamorphose into non-feeding juveniles, typically in the fall. The transformation process lasts for 2-3 months. Juveniles spend 4-6 months drifting until spring, when spawning occurs and they become sexually mature adults. Adults die shortly after spawning.
Development - Life Cycle: metamorphosis
Although ammocoetes are blind, adult Northern brook lamprey have small eyes. This species also has a lateral line through which the fish may sense vibrations.
Communication Channels: tactile ; chemical
Perception Channels: visual ; tactile ; vibrations ; chemical
During mating, 3-7 northern brook lamprey will build a nest together and spawn in groups of 10-30. Once eggs are fertilized and laid they are often covered with the substrate surrounding the nest.
Mating System: polygynandrous (promiscuous)
Northern brook lamprey spawn in the spring at approximately 6 years of age, just after reaching sexual maturity. Females lay thousands of eggs, possibly due to high mortality rates during the early stages of the species' life cycle. Eggs hatch 2-4 weeks after fertilization.
Spawning is initiated when water temperatures are between 13 and 20.5°C. Males begin nest building by moving stones and gravel to create a small dip in the substrate within shallow, pool-riffle, high-gradient stretches of streams.
During spawning, these lampreys coil together in groups of 3 to 7 individuals before going into the nest. Once in the nest a male attaches to, but does not wrap around, a female (as in some other lamprey species) to complete egg fertilization. Adults then leave the nest and die soon thereafter.
Breeding interval: Northern brook lamprey spawn once during their lifetimes.
Breeding season: Spring
Range number of offspring: 1,115 to 1,979.
Average number of offspring: 1,200.
Range age at sexual or reproductive maturity (female): 5 to 7 years.
Range age at sexual or reproductive maturity (male): 5 to 7 years.
Key Reproductive Features: semelparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
There is no parental investment by adults of this species as they die soon after egg fertilization.
Parental Investment: no parental involvement
The northern brook lamprey (Ichthyomyzon fossor) is a freshwater fish in the family Petromyzontidae. It is closely related to the silver lamprey (I. unicuspis) and may represent an ecotype of a single species with I. unicuspis.[4]
Northern brook lampreys are jawless fishes, also known as cyclostomes. Northern brook lamprey are considered non-parasitic lamprey.[5] They have poorly developed teeth and a round, disc-like, subterminal mouth, called an oral-disc, for suction. Northern brook lampreys have a single dorsal fin that continues along their entire length until it connects with the caudal fin.[6] This dorsal fin can be notched as well. Their coloration is gray-brown dorsally with a light line down the back and an even lighter ventral side. The length of adult northern brook lampreys does not typically exceed 16 cm and the body is attenuate. While the ammocoetes look similar to the adult lampreys the ammocoetes have a hooded mouth instead of an oral-disc and no eyes.[7]
Northern brook lampreys can be found in most of the Midwest and northeast regions of the United States. They inhabit the Mississippi drainage basin in Wisconsin and the Lake Erie tributary in New York.[7] They can be found in parts of Canada as well.
The northern brook lampreys are found in various habitats throughout their lives. Ammocoetes start off their lives burrowed beneath fine sediment or organic matter in quiet waters while the adults live in sand or gravel in swift moving waters.[6] They are typically found in the headwaters of streams that are moderately warm and clean.[5]
As larve (ammocoetes), the northern brook lamprey are filter feeders; feeding primarily on detritus, zooplankton, algae, diatoms, bacteria, pollen and a host of other microorganisms as they remain burrowed in fine substrate in calm waters.[7] The juveniles and adults have non-functional intestines and do not feed; juveniles drift for 4–6 months and the adults spawn and die shortly after spawning.
Spawning occurs around boulders and crevices of large rocks; 3–7 northern brook lamprey will build a nest together and then spawn in groups of 10–30.[7] Once the eggs are fertilized they are often covered and left alone with no parental care given to the young, as the lamprey die soon after. Northern brook lampreys begin spawning at 6 years of age once they have reached sexual maturity. Spawning is triggered by the warming of the water in the spring. Males begin building nests and females lay between 1200[8] and 1524[9] eggs to combat high mortality rates of young.[7]
Once the ammocoetes emerge from the eggs 2 weeks after fertilization, they spend the next 5–6 years feeding on algae and bacteria in burrows. They emerge in the fall as non-feeding juveniles after a 2–3 month metamorphosis and drift for 4–6 months until spawning begins. They then become sexually mature adults, partake in spawning and then die shortly thereafter.[7]
Northern brook lamprey populations are decreasing in the great lakes area and the great lakes drainage basin from lampricides, habitat degradation, and added stressors. A study of Pennsylvania streams found that two of the six species of lampreys normally found breeding in the streams were not there.[10] One of the species not found was the northern brook lamprey. It is speculated that the main reason for population decline is due to the presence of sea lamprey and the lampricides used to be rid of them.[10] In Minnesota, northern brook lampreys are considered a special concern species as they are believed to be declining due to lampricide use and habitat degradation.[6] The lampricide treatments are used in response to the invasive species, sea lampreys, that are currently plaguing the great lake region. The increasing populations of sea lampreys and the increasing use of lampricides in response to sea lampreys has had negative impacts on most populations of lampreys, including the northern brook lamprey.
The northern brook lamprey (Ichthyomyzon fossor) is a freshwater fish in the family Petromyzontidae. It is closely related to the silver lamprey (I. unicuspis) and may represent an ecotype of a single species with I. unicuspis.
