Western River Lamprey – Oregon Conservation Strategy

Western River Lamprey Photo Credit: Mike Hayes, Richard Hays, USGS

Overview

Species Common Name Western River Lamprey
Species Scientific Name Lampetra ayresii
Federal Listing Status Species of Concern
State Listing Status Sensitive

Ecoregions

Coast Range

Oregon’s Coast Range, known for its dramatic scenery, is extremely diverse, with habitats ranging from open sandy dunes to lush forests and from tidepools to headwater streams. It follows the coastline and extends east through coastal forest to the border of the Willamette Valley and Klamath Mountains ecoregions

Columbia Plateau

The Columbia Plateau ecoregion was shaped by cataclysmic floods and large deposits of wind-borne silt and sand earlier in its geological history. It is dominated by a rolling landscape of arid lowlands dissected by several important rivers, and extends from the eastern slopes of the Cascades Mountains, south and east from the Columbia River to the Blue Mountains.

West Cascades

The West Cascades ecoregion extends from east of the Cascade Mountains summit to the foothills of the Willamette, Umpqua, and Rogue Valleys, and spans the entire length of the state of Oregon. It is largely dominated by conifer forests, moving into alpine parklands and dwarf shrubs at higher elevations.

Willamette Valley

The Willamette Valley ecoregion is bounded on the west by the Coast Range and on the east by the Cascade Range. This long mostly level alluvial plain has some scattered areas of low basalt, and contrasts with productive farmland and large urban areas. It has the fastest-growing human population in the state resulting in challenges due to land-use changes.

Nearshore

The Nearshore ecoregion includes a variety of habitats ranging from submerged high-relief rocky reefs to broad expanses of intertidal mudflats in estuaries and hosts a vast array of fish, invertebrates, marine mammals, birds, plants, and micro-organisms. This ecoregion encompasses the area from the outer boundary of Oregon’s Territorial Sea to the supra-tidal zone, and up into the estuaries.

Special needs

In some basins, Western River Lamprey, Western Brook Lamprey, and potentially Pacific Brook Lamprey may function as a species complex that interbreeds. Therefore, access for this anadromous species to the ocean and to the resident Western Brook Lamprey and Pacific Brook Lamprey may be important. May aggregate in high densities. Requires fine gravel beds for spawning. Larvae burrow in fine sediment. Timing of development closely linked to water temperature. Adequate food availability during juvenile stage (marine feeding stage). Migration to ocean may depend on sustained inflow from flooding or snowmelt.

Limiting factors

Habitat access (artificial obstructions), water quantity (reduced flows, flow management), water quality, physical habitat (stream and floodplain degradation), and predation by other species.

Data gaps

Distribution; passage and screening requirements; biology; amount of take; nature and extent of complex, large-scale threats; within-species diversity.

Conservation actions

Education and outreach; improve passage and screening; protect and restore habitat; water conservation; establish Best Management Practices for in-water work; modify non-native angling regulations; pinniped management. See ODFW’s Conservation Plan for Lampreys for strategies.

Key reference or plan

Coastal, Columbia, and Snake Conservation Plan for Lampreys in Oregon

Life History Traits

Strategy Spotlight: Lamprey

Little is known about the basic biology and ecology of lampreys. To address this deficiency, National Marine Fisheries Service biologists analyzed data from two fish assemblage studies that span three decades (1980–1981 and 2001–2012) to provide the first analysis of anadromous western river (Lampetra ayresii) and Pacific (Entosphenus tridentatus) lampreys in the Columbia River estuary: Seasonal abundance, size, and host selection of western river (Lampetra ayresii) and Pacific (Entosphenus tridentatus) lampreys in the Columbia River estuary.

This basic information on western river and Pacific lampreys in the Columbia River estuary adds to the growing body of regional research that should aid conservation efforts for these ancient species. The Oregon Department of Fish and Wildlife has developed a Coastal, Columbia, and Snake Conservation Plan for Lampreys in Oregon that will help guide cooperative efforts to conserve these species.