Arctic lamprey
The Arctic lamprey is a unique species of fish that resembles an eel and thrives in the cold waters of the Arctic region in the northern hemisphere. This species can exhibit different lifestyles; some are parasitic and migratory, attaching to other fish to feed on their bodily fluids, while others are non-parasitic and non-migratory, primarily feeding on invertebrates in freshwater environments. Notably, Arctic lampreys have distinctive gill holes behind their eyes and undergo a notable life cycle that includes a larval stage where they are blind and toothless, known as ammocoetes. These young lampreys filter food from the water until they mature and metamorphose into adults, developing teeth and, for some, the ability to migrate to the sea. Adult Arctic lampreys can reach up to two feet in length, displaying dark brown to blue-black skin on their backs and lighter colors on their bellies. The lifespan of Arctic lampreys is still uncertain, although parasitic individuals are thought to live longer than their non-parasitic counterparts. This species is one of nearly 40 lamprey species worldwide, and its adaptability to extreme environments makes it a fascinating subject for study in marine biology.
Arctic lamprey
This species of fish survives quite well in the frigid waters of the Arctic in the northern hemisphere. Arctic lampreys may be either parasitic and migratory or non-parasitic and non-migratory.
Kingdom: Animalia
Phylum: Chordata
Class: Agnatha or Cephalaspidomorphi
Order: Petromyzontiformes
Family: Petromyzontidae
Genus: Lampetra
Species: Japonica
Among the nearly 40 lamprey species worldwide, the arctic species is perhaps one of the more unusual species. Even though it shares many features with other lampreys, it distinguishes itself by where it lives and its eating habits. Within some lamprey species, the lampreys grow up in freshwater and then live in the ocean as adults. These lampreys are also parasitic feeders on other fish. Other lamprey species spend their entire lives in freshwater and feed on invertebrates, or creatures without backbones. It appears that arctic lampreys may live like those in either of these two groups. What determines these differences between lampreys is not clear.
Like all other lamprey species, young arctic lampreys hatch from eggs which females have laid and which the males then fertilize. This is called spawning, and it occurs in shallow rivers and lakes where the lampreys hollow out nests among the gravel on the bottom. After spawning, the adults die. When the young worm-like lampreys, called ammocoetes or prides, hatch, they burrow into the mud or sand. At this stage in their lives they do not have all the features of the adults. The ammocoetes are blind and do not have teeth. They filter tiny organisms and invertebrates, or creatures without backbones, from the water or bottom with mucus-coated hairs in their mouths. Although they grow, they still do not become adults until at least a few years later. After this time, they metamorphose, or change into the adult form. Their eyes come to the skin surface and open, and teeth appear on the round discs on their heads. At this point in their lives, some arctic lampreys swim downstream to the sea and are parasitic feeders for up to two years. The others stop feeding and then spawn, dying soon afterward.
Adult parasitic lampreys may grow to be two feet (60 centimeters) long, while the non-parasitic ones reach seven inches (18 centimeters) in length. The adult lampreys have dark brown to blue-black skin on their backs and yellow to light brown skin on their bellies. Their dorsal, or back, fins are light tan to gray, and they have dark spots on their caudal, or tail, fins.
The life span of the arctic lampreys is not known for certain, but it is likely two years longer for parasitic lampreys than for non-parasitic lampreys.