All about Pacific lamprey

• Lamprey are a jawless fish — the most primitive and ancient fish known. Fossil lamprey date to the Devonian era, 360 million years ago — almost 200 million years before there were dinosaurs.

• Lamprey have no scales, and no bones. Their skeletons are made of cartilage.

• Lamprey are a true fish, and are unrelated to actual eels. The Pacific lamprey is one of 38 species of lamprey worldwide. It is anadromous, hatching from eggs laid in freshwater, migrating to the ocean, and returning to freshwater streams again to spawn.

• They migrate mostly at night, and are very efficient swimmers that can swim for at least 24 hours without resting, moving at about 1 mile-per-hour.

• Pacific lamprey eggs hatch into larvae or “ammocoetes” which live in stream-bank sediments for about five years, filter-feeding on diatoms and other microorganisms. They metamorphose into fish-like juvenile lamprey or “macropthalmia” with a primitive sucking disk before beginning their migration to the sea. Pacific lampreys remain in the ocean for up to eight years before returning to fresh water streams to spawn.