Via ODFW: The Pacific Lamprey is an old, old fish—one that dates back 500 million years, and while biologists will be the first to tell you what they don’t know about the prehistoric fish, what they do know is fascinating.
An Oregon native, the Pacific lamprey, is long and eel-like. It is classified as a fish but has no jaws or fins. Its disk-shaped mouth is dominated by three large and many smaller teeth, and its life history is jam-packed with more intriguing events than a soap opera.
Pacific Lamprey life stages
It hatches from an egg in two to three weeks as larvae, called ammocoete. For the next three to seven—yes seven!—years, it lives burrowed in the muck of stream and river beds. During one summer, the ammocoete goes through a slow metamorphosis and becomes a juvenile lamprey, developing eyes and a mouth. On winter flows, it migrates to the ocean, becoming an adult. Once in the ocean, and after years of feeding on algae, it cuts its new teeth by becoming parasitic to larger fish. After a couple of years, it leaves the ocean and returns to freshwater. Then, there is nest building, courtship, spawning and death. What’s not to find fascinating?
Pacific lamprey populations are in serious decline. A new effort to rebuild Pacific Lamprey stocks is underway, but creating them through hatchery means is proving difficult. An article details the project here.