Lower American River steelhead spawning surveys (Chinook and lamprey data included), California, 2002 to 2025

Steelhead spawning surveys have been conducted on the Lower American River (LAR) for the years 2002-2005, 2007, and 2009-2025. These surveys in conjunction with annual escapement estimates to Nimbus Fish Hatchery, are used to provide a yearly index of in-river and over all spawning abundance. Reclamation’s mission is to manage, develop and protect water and related resources in an environmentally and economically sound manner in the interest of the American people. In the National Marine Fisheries Service (NMFS) most recent biological opinion (2009), the presence of dams was identified as the most influential stressor to steelhead on the American River because it blocks passage to historic spawning and rearing habitat. Thus, Reclamation is required to monitor the effects of flow regulation by dams on the steelhead life stages present in the river system. Congruently, Reclamation has committed to significant restoration actions including salmonid spawning and rearing habitat rehabilitation on the Lower American River, which also require accurate and robust monitoring. These surveys support the mission and monitoring requirements of Reclamation by collecting the spawning data required to effectively conduct analyses of the effects of regulating Folsom and Nimbus dams on this federally listed species’ critical life stage development and support operational decision making.