Entosphenus tridentatus is a fairly large representative of the Cyclostomata superclass. Its range is from the Bering Sea to the Northern California coast. It is also found off the coast of Asia, the Commander Islands and the island of Hokkaido. Like all lampreys it has a scaleless, cylindrical body from head to dorsal fin that flattens slightly at the tail. The mouth is round and the maxillary plate has three teeth. Lamprey can be caught with a variety of fishing equipment.