Adult Sturgeon Spawning in the Upper Sacramento River 2015-2016

(Upper Sacramento River, Shasta, Tehama and Glenn counties)

Species / Location

Sturgeon are a very slow-growing fish that live a long time (70+ years) and spawn periodically--not annually. Sacramento River mainstem supports a run of anadromous green sturgeon (Acipenser medirostris) listed as Threatened under the Endangered Species Act (ESA). Anadromous white sturgeon (Acipenser transmontanus) are also present in this part of the mainstem and they are a very important recreational fish. “Anadromous,” means that these fish spawn and rear in fresh water for 1-2 years, then the young fish migrates to the bay and ocean where they reach adulthood before returning to their natal streams to spawn.

Monitoring and Research

Based on historical work undertaken by the Department monitoring and Research of sturgeon has been conducted sporadically by U. S. Fish and Wildlife, U.S. Bureau of Reclamation, California Department of Water Resources, California Department of Fish and Wildlife, as well as U. C. Davis. Results from past surveys indicated overall adult spawning population numbers has decreased considerably since the early 1970s. Since the start of the current drought in 2012, researchers have been concerned over reduce number of spawners and lack of understanding of habitat utilization. This current monitoring/research effort has been assessing the status and trends in adult green sturgeon populations and determine environmental characteristics of spawning habitat providing information to aid in real time resource management decisions. This information has been used by NOAA and others to formulate recovery plans and make decisions that aid the recovery. Once funded, implementation of the California Coastal Monitoring Plan would add to localized monitoring efforts and provide more resolution to sturgeon population status and trends statewide.

Need for Program

On January 17, 2014, Governor Brown issued a proclamation declaring a state of emergency due to prolonged drought conditions. That declaration was then redoubled on April 25, 2014. These Proclamations direct the Department to take specific actions related to evaluating and managing the changing impacts of drought on threatened and endangered species and species of special concern, as well as to conduct specific monitoring actions described in the State and Federal Water Project Drought Operations Plan.

Drought impacts local sturgeon populations through high water temperature, low water levels and decreased water quality. This research continues to improve the Department’s ability to predict needs and impacts to sturgeon.

Future Efforts

Sturgeons typically enter Sacramento River to spawn between February and March, and seem to target deeper holes with fast flowing water and coble sediment. They are monitored using a Dual Frequency Identification Sonar (DIDSON) and an underwater high-speed camera along with a specialized GPS tracking system. These tools identify, count, track, and observe behavior of individual fish. Environmental metrics associated with active spawning sites are collected to aid in the determination of preferred locations and times. With this information fisheries biologist can advise natural resources managers on potential impacts to sturgeon and the habitats that support them. The methods and information developed here will be refined and adapted to apply to sturgeon populations outside of the Sacramento River watershed. This science-based research project was well vetted throughout the sturgeon research community. Due to the project’s success and the usefulness of the information, additional funding from NOAA will keep this work going for another year.

Ultimately, the vision is to build a cooperative and collaborative management and research group to address all green and white sturgeon issues to develop sustainable populations. The Department has taken a step towards this with the formation of the Director’s Sturgeon Working Group to focus efforts and improve communications with others. Monitoring and research provided by this project is the start of this long-term vision for sustainable sturgeon populations in California for the benefit of the public.

green sturgeon at bottom of river
Green Sturgeon (Acipenser medirostris) in natural habitat. CDFG photo by Mike Healey.

white sturgeon at bottom of river
White Sturgeon (Acipenser transmontanus) in natural habitat. CDFG photo by Mike Healey.