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Common name: Sea lamprey
Scientific name: Petromyzon marinus
Diet (Carnivore, piscivore, sanguivore, eats body fluids, herbivore, algivore, omnivore, detritivore):
Newly hatched larval sea lampreys are freshwater filter-feeders that consume detritus, algae, and other organic material found at river bottoms. Once in a saline environment, sea lampreys develop parasitic abilities, attach themselves to a fish and ingest their blood and skin. Sea lampreys ultimately break down the fish while the fish is still alive. This species is capable of attaching itself to a variety of species of fish and does not seem to have a preference of host species. Once sea lampreys reach sexual maturity, they no longer feed. Parasitic sea lampreys have a detrimental effect on fish within their ecosystem.
Habitat: Sea lampreys are anadromous, so fish born in freshwater (for lampreys usually gravel or rock beds in small, freshwater streams and rivers) who spend most of their lives in saltwater and return to freshwater to spawn. In general, they prefer shallow coastal areas, though they are found at depths between 0.91 and 4.57 m. Sea lampreys thrive in systems where the following are present: 1) waterways lacking obstructions (like dams or waterfalls) with clean sand and gravel areas for spawning; 2) sand beds free of pollutants with a large supply of organic matter for their developing young; and 3) large waterways with a plentiful supply of fish to serve as hosts for their fully developed offspring.
Life stages: There are four stages in the life cycle of sea lampreys, which usually spans 18 months but can last as long as 5 years.
The first of these stages is the spawning phase, which occurs during spring and early summer. From April to June, sea lampreys search freshwater rivers and streams, seeking an ideal location in which to construct a nest and lay their eggs. Once the area is selected, male sea lampreys construct a nest, often moving rocks to create a large indenture or depression in the river or lake bed. A female then lays 30,000 to 100,000 eggs, which the male externally fertilizes. Both male and female adult sea lampreys float away and die soon after spawning. Unique to this phase is the disintegration of the digestive system; adult sea lampreys cannot feed while spawning.
During the second phase, fertilized eggs settle into the sand or gravel and begin to grow. Within a few weeks (3 to 8 weeks), the eggs hatch and the larvae burrow further into the sand or gravel. Larvae filter-feed on algae and other aquatic organic matter. This larval phase can last for more than three years.
In the third phase, known as transformation, larvae metamorphose into adult sea lampreys (by 3 to 5 years of age) . During this phase sea lampreys develop a mouth, teeth and eyes. They also migrate to larger bodies of water, such as oceans.
Sea lampreys remain in this habitat for 12 to 18 months as a mature adult and begin to feed, attaching themselves to fish. This is known as the parasitic phase, during which sexual reproductive organs develop. They can survive up to 5 years in the wild waiting for the opportune time to reproduce. Most lampreys, however, live 1.5 to 5 years in the wild.
Predators: Sea lampreys do not have many known predators, and their most common predators are humans. Sea lampreys are caught in Eurasia and consumed in a variety of dishes.
Conservation Status: Sea lampreys are not protected.
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