Species: Lampetra ayresii

F - 20,000-200,000 square km (about 8000-80,000 square miles) - F - The river lamprey occurs as widely scattered, isolated populations (Moyle et al. 1995, Moyle 2002) along the Pacific Slope, from the Sacramento-San Joaquin drainage, California, to Tee Harbor near Juneau, Alaska (Lee et al. 1980, Page and Burr 2011). <br><br>In California, this species has been recorded from the lower Sacramento and San Joaquin rivers (especially the Stanislaus and Tuolumne rivers); the Napa River, Sonoma Creek, and Alameda Creek (tributaries to San Francisco Bay); in Salmon Creek and in tributaries to the lower Russian River (Sonoma County, where the species appears to be a regular spawner); a single adult female was captured at Cape Horn Dam in the Eel River; this species has not been adequately surveyed in most California streams (Moyle 2002).<br><br>In Oregon, river lampreys have been found in sites 182 km apart in the Columbia and Yaquina rivers (Moyle 2002). According to the Center for Biodiversity, the species has not been documented in the Columbia River or anywhere in Oregon since 1980.<br><br>Detailed distribution records are not available for Washington, but the species probably occurs in major coastal drainages (Wydoski and Whitney 2003). <br><br>In British Columbia, in the center of their range, river lampreys have been reported from the Strait of Georgia and Fraser River (Beamish and Neville 1995). A landlocked population exists in Morrison Creek, Vancouver Island, British Columbia (Renaud 1997).<br><br>In southeastern Alaska, the species has been recorded north of Juneau at Tee Harbor-Lynn canal area, Douglas Island, Taku River, and in Portland Canal (Mecklenburg et al. 2002). Probably it occurs coastally in areas south of Juneau.