Monitoring and Evaluation of the Potential Impacts of the Red Bluff Diversion Dam on Green Sturgeon
Introduction:
Information on the temporal and spatial distribution of Federally-listed adult Southern Distinct Population Segment (SDPS) of green sturgeon within the Sacramento River upstream and downstream of the Red Bluff Diversion Dam (RBDD) is needed for assessing potential impacts of the dam and the continuing survival of this species. Through the use of acoustic telemetry we hope to increase our knowledge of adult green sturgeon use of holding and spawning habitats within the upper Sacramento River between Keswick Dam and Hamilton City. Through a collaborative multi-agency effort with UC-Davis and USFWS, adult green sturgeon will be implanted with ultrasonic transmitters and released each year during the spring months of 2008-2010. Movements of the adults, as well as other adults previously tagged by other researchers, will be monitored using a mobile tracking receiver and stationary monitors established by Reclamation and the Central Valley Fish Tracking Consortium. Monitors will be strategically placed downstream and upstream of the RBDD in order to better define the movements of adult green sturgeon in the vicinity of the RBDD and thus providing better information needed to make well-informed management decisions on the operation of the dam.
Objective:
The project has three specific technical objectives:
- Determine green sturgeon holding and spawning habitats upstream and downstream of the RBDD.
- Obtain better information regarding the timing of pre-spawning and post-spawning migration.
- Document the temporal and spatial occurrences of the species upstream and downstream; and in the vicinity of the RBDD.
Methods:
Adult green sturgeon will be captured during the months of March, April, May, and June using either a braided line gill net or by hook, line and sinker. Each adult green sturgeon will be internally implanted with a Vemco V16-6L transmitter having a 90 second pulse with a battery life of approximately ten years. A sterilized 12 mm, 134.2 kHz, full duplex, passive integrated transponder (PIT) tag will be inserted under the bony plate just anterior of the left side of the neck line. A uniquely colored FT-4 spaghetti tag with a stainless steel wire core will also be inserted at the posterior base of the dorsal fin. Each spaghetti tag will have an identification number, agency identification, and contact information and will be color coded for individuals captured and released upstream and downstream of the RBDD, respectively. Manual tracking of the sturgeons will be conducted weekly until all tagged green sturgeon have moved downstream of Hamilton City.
Progress:
In 2008, green sturgeon were captured, tagged and released downstream of the RBDD. Monitoring of movements of these individuals has been ongoing utilizing both the manual tracking receiver and the stationary array of monitors. Reclamation hs purchased and strategically deployed four monitors in the vicinity of the RBDD, with two more monitors planned for deployment by mid-September, 2008. All stationary monitors have had tag detections of one or more of the ten adults tagged this year, as well as other previously tagged green sturgeon.