There are many lamprey facts that science has at its disposal. For example, here's a fact: an anticoagulant in the lamprey's saliva keeps the wound open for hours or weeks, until the lamprey is satiated or the host fish dies. The lamprey facts also show that King Henry I of England, in a fit of royal gluttony, is said to have died from a "surfeit of lamprey." Other lamprey facts are as follows...
Lampreys live mostly in coastal and fresh waters. Three lamprey species including the Pacific lamprey western brook lamprey and river lamprey are found in the Columbia River Basin. Pacific lamprey populations in the Columbia River Basin have declined and the status of western brook and river lampreys is unknown. The Pacific lamprey ranges from southern California to Alaska. They are found in Washington, Oregon, Idaho, California, Alaska, and British Columbia. They were once abundant in streams in the Columbia River but their distribution has been significantly reduced. Pacific lamprey is a very primitive, eel-like fish. The Pacific lamprey lives in the ocean as adults where they feed on the blood and bodily fluids of marine mammals and fish. Pacific lampreys are anadromous, meaning that they live in both fresh and salt water.
The river lamprey is anadromous and like the Pacific lamprey adults, are parasitic on marine fish. For centuries, river lampreys have been considered a delicacy in Europe. But the unappetizing appearance of the eel-like fish and their unpalatable state when caught on their spawning runs has so far undermined their popularity as a food fish.
The western brook lamprey lives only in freshwater streams. Western brook lampreys are non-parasitic and do not feed as adults.
After about two years in the ocean, lamprey return to fresh water streams to spawn. Upon entering freshwater the adult lampreys stop feeding and spawn or over-winter and spawn the following spring. Lampreys construct nests in small gravel, then spawn, that is, lay their eggs or excrete their semen, and then invariably die. The time between ceasing to feed at sea and spawning can be up to 18 months long-surely one of the most remarkable endurance events in the animal kingdom. Lamprey spawning takes place in riffle areas where the current is swift. The spawning migration from the sea of adult Pacific lamprey usually begins during the period July to September. The nest is slightly larger than the total length of the lampreys. During mating, the female attaches to a rock on the upstream side of the nest and the male attaches to the head of the female, or both attach to the rocks and lie close to each other. Both of them 'vibrate' rapidly for a few seconds when the milt and eggs are released. Eggs are slightly adhesive, and cannot sustain the rapid current. As a result, most eggs are washed into the crevices of the rocks on the downstream side of the nest. Hatching occurs in about 19 days at 15 C. Lampreys begin life as burrowing freshwater larvae (ammocoetes). At this stage, they are toothless, have rudimentary eyes, and feed on microorganisms. This larval stage can last five to seven years and hence was originally thought to be an independent organism. After these five to seven years, they transform into adults in a metamorphosis triggered by unknown factors and emerge as adults averaging 4.5 inches long.
Recent lamprey facts go to show that lamprey are used for scientific research, educational purposes, vitamin oil, and anti-cooagulants. Their spawned out carcasses provide a source of nutrients to the freshwater streams.