The Pacific lamprey (Entosphenus tridentatus) is an eel-like fish that lacks jaws and paired fins. Their mouth is round and can have 3 large teeth which help them attach to fish and other organisms, getting nutrients from their blood. In their larval stage, lampreys are called ammocoetes. During this stage they burrow into the silt and feed by filtering their food from the water. Instead of having gills like most fish, lampreys have breathing holes along their bodies. Their long slender bodies can reach up to 31 inches. Their coloration in freshwater is mostly brown and can be greenish grey in the ocean.
In the past you could find lampreys common along the West Coast of the United States. Throughout the years, the population of these unique organisms has declined. Some of the common threats to the Pacific lamprey are:
- Water diversion, which obstructs upstream migration
- Chemical spills
- Temperature change, which can cause deformation and death of eggs and ammocoetes
- Ocean water quality can decrease the number of fishes, which in turn means fewer hosts for adult lampreys
- Non native species predation
- Human use for harvesting to use as a bait fish.
The U.S. Fish and Wildlife Services have created the Pacific Lamprey Conservation Initiative to help improve the status of this species by implementing research and conservation actions.