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Northern brook lamprey

Northern brook lamprey
Ichthyomyzon fossor.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Petromyzontida
Order: Petromyzontiformes
Family: Petromyzontidae
Genus: Ichthyomyzon
Species: I. fossor
Binomial name
Ichthyomyzon fossor
Reighard and Cummins, 1916

The northern brook lamprey (Ichthyomyzon fossor) is freshwater fish in the family Petromyzontidae which consists of the various species of jawless fishes.

Northern brook lampreys are jawless fishes, also known as cyclostomes. Northern brook lamprey are considered non-parasitic lamprey. 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. 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.

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. 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. They are typically found in the headwaters of streams that are moderately warm and clean.

As ammocoetes the northern brook lamprey feed primarily on detritus, algae, diatoms, bacteria, pollen and a host of other microorganisms as they remain burrowed in fine substrate in calm waters. The juveniles and adults do not feed as the 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. 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 thousands of eggs to combat high mortality rates of young. Once the ammocoetes emerge from the eggs 2 weeks after fertilization 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 they die shortly thereafter.


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Wikipedia

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