Based on the dates of collection of spawning individuals in the original description, the spawning period probably occurs between mid-April and August in Oregon, while in California spawning probably occurs between the end of April and the beginning of May (Ref. 5, pp.
Pacific lampreys begin their life cycle as an ammocoete or larvae, usually within a freshwater stream.

As prey, lamprey is important to many species of fish, birds, and mammals, including humans. The Pacific lamprey is also known as the three-tooth lamprey and tridentate lamprey Description. It is a member of the Petromyzontidae family. Pacific Northwest National Laboratory (PNNL) conducted a study in 2002 to ascertain the effects of the modified extended-length submerged bar screens (ESBS) on juvenile Pacific lamprey at John Day Dam. Close, David, ''Pacific Lamprey Research and Restoration Project'', Project No. The first consisted of in situ video observations of lamprey

North American Journal of Fisheries Management: Vol. In this case, designers of monitoring plans would be interested in the sample size needed to document the presence (or quantify the abundance) of individuals in this life stage. Pacific lampreys are distinguished from other Alaska lampreys by three large teeth on the supraoral bar and three sharp points on each of the central lateral tooth plates.

Sea lamprey have two separated fins on their back (dorsal fins) and suction disk mouth filled with small sharp, rasping teeth and a file-like tongue. Adults nonparasitic. RANGE: The range of the Pacific lamprey within the North Pacific extends from the Bering Sea coasts of Asia and Alaska, southward to the Yuhuntun River, Hokkaido, northern Japan and southward to Punta Canoas, central Baja California and Mexico. Due to their unique life history, the Pacific lamprey is an important component to the ecosystem both as a predator and prey. This length has meaning specific to Pacific lamprey monitoring because it is the approximate length at which larvae are likely to begin metamorphosis (Schultz et al. 562 Pacific lamprey were captured during this period. The Pacific lamprey (Entosphenus tridentatus) is an anadromous parasitic lamprey from the Pacific Coast of North America and Asia.
Average Pacific lamprey length was observed to be proportional with increasing distance traveled upstream, and the relatively short-bodied fish used in translocations were significantly shorter than all three samples of upstream fated fish. The sea lamprey is a jawless parasite that feeds on the body fluids of fish.

Freshwater; creeks and rivers. The project focused on three tasks. Radio tags were surgically implanted into the body cavity of 100 Pacific lamprey.