Western Brook Lamprey

Lampetra richardsonii
Adult western brook lamprey rests on the stream bottom/USFWS Photo

Living Links to the Past 

Something strange lurks in the fresh water streams of Willapa National Wildlife Refuge. Scaleless and cartilaginous (lacking boney jaws, backbone or ribs), lamprey are specialized survivors whose ancestry dates back to 450 million years ago. Lampreys may look like eels, but the resemblance stops there. Lampreys have a circular shaped mouth in place of jaws and they use it to hold onto rocks and prey. Like the famous salmon, most lamprey species are anadromous; meaning they spend their adulthood in the ocean and return to the freshwater stream where they were born to spawn.

Read on to learn how to identify the western brook lamprey. 

Three species of lamprey have been documented in the refuge, including: Pacific lamprey, river lamprey and the western brook lamprey. The western brook lamprey is small compared to its relatives, ranging from 5-7 inches in length. Unlike the Pacific lamprey (up to 30 inches long) and the river lamprey (average of 12 inches long), the western brook lamprey is not a parasite and does not have an ocean-going phase in its lifecycle. Western brook lampreys only have small, non-functional teeth as adults. The other lamprey species found at the refuge use sharp teeth to feed on several species of fish while living in the ocean. Scars from the Pacific lamprey have even been found on whales!

Read on to uncover the quirky lifecycle of the western brook lamprey. 

Forever Young 

Western brook lampreys spend most of their lives as blind teenagers and only live a few, short months as adults; so short that the adults don't eat at all. During the months of April, May and June, adult western brook lampreys seek shallow water with a bottom of coarse gravel and pebbles and a moderate current to build a nest. Males and females pair, then they use their sucker-like mouths to grasp and move sediments creating a depression, or nest, 4-5 inches in diameter in which the female lays her eggs. It is not uncommon for large groups of western brook lamprey to spawn together in a tight cluster. Refuge staff has counted as many as 12 adults together over one nest.

Read on to discover more about the lives of young western brook lamprey. 

A Lot of Lamprey 

As many as 3,700 eggs may be produced by a single female western brook lamprey. These tiny oval eggs are adhesive which helps prevent them from being washed downstream. Eyeless larval lampreys, called ammocoetes, hatch after approximately 10 days. These baby western brook lamprey drift downstream and burrow into the stream sediments of backwater areas or quiet eddies. Ammocoetes are filter feeders, using a hood-like extension of their oral disc to take in and filter mud and water. Through this filtering process they collect and consume microorganisms and detritus (decaying plant and animal matter). As many as 170 ammocoetes per square meter have been documented in coastal streams. Western brook lamprey may stay in this teenage form for up to 5 years before they change into eyed adults and seek mates.

Discover what the refuge is doing to help lampreys.

Learn about the USFWS Pacific Lamprey Conservation Initiative & follow Luna the Lamprey's return from the ocean.

Facts About Western Brook Lamprey

Only live a few months as adults

Adults do not eat

Spawn together in groups of 12 or more 

3,700 eggs may be produced by a single female