Range fluctuations in Pacific Lamprey along the arid Pacific Coast of southern California

Authors: Stewart Reid, Damon Goodman

Year: 2017 (xlix)

Abstract

Long-term monitoring, surveys and incidental observations of Pacific Lamprey, Entosphenus tridentatus, established a declining trend in all populations south of Big Sur, with the apparent disappearance of Pacific Lamprey from all southern streams by 2016 Factors for the disappearance of lampreys may include long-term drought, urbanization, water management, oceanic conditions and passage barriers A passage improvement project in San Luis Obispo Creek mitigated the barrier in 2013 No lampreys were found in monitoring surveys from 2011-2016 However, in 2017 Pacific Lamprey were once again spawning in the middle of town Additional scattered observations of adult lampreys occurred in other southern California drainages in 2017 These observations provide insight into natural range fluctuations and the possible changes that may be seen with environmental shifts over time