Using Acoustic Tag Technology to Augment the Salmonid Tracking Study and Address Specific Issues of Interest Related to Endangered Species Act Permitting for Sand Mining and Maintenance Dredging within the San Francisco Bay-Delta Estuary
Introduction:
The dredging and sand mining communities active within the San Francisco Bay estuary are participating in part of a three-year study of the migration of late-fall run juvenile Chinook salmon passing downstream through the Sacramento River, Delta, and San Francisco Bay. This study focuses on Suisun Bay and the Carquinez Strait region of the estuary, which was identified as the primary area of concern for sand mining activity.
Objective:
The objective of this investigation is to augment the acoustic tag monitoring network to include tag detectors designed to monitor the migration rate of juvenile Chinook salmon passing through Suisun Bay and the Carquinez Strait. Specifically to:
- Determine the migration rate (residence time) for juvenile Chinook salmon within Suisun Bay between Antioch and Carquinez Strait. The migration rate and duration of residence for juvenile Chinook salmon within Suisun Bay and the Carquinez Strait determines, in part, their vulnerability to entrainment into the hydraulic suction head and their potential exposure to the overflow plume. The more rapid the migration rate through the area of Suisun Bay where sand mining occurs the lower the probability that adverse impacts associated with sand mining would occur.
- Determine the migration of juvenile Chinook salmon from the lower Sacramento River through Montezuma Slough. To the extent that juvenile Chinook salmon migrate through Montezuma Slough they would be bypassed around the primary areas within Suisun Bay where sand mining activity occurs, and thereby would avoid the potential for adverse affects
- Determine the migration of juvenile Chinook salmon from the lower Sacramento River through Montezuma Slough. To the extent that juvenile Chinook salmon migrate through Montezuma Slough they would be bypassed around the primary areas within Suisun Bay where sand mining activity occurs, and thereby would avoid the potential for adverse affects
Methods:
The basic experimental design includes the deployment of four Vemco VR-2 continuously monitoring acoustic tag detectors within the main Suisun Bay channel near Chipps Island. Two units were deployed in the channel near Chipps Island on the north side of the channel and two units were deployed on the south side of the channel. One additional detector was placed in Montezuma Slough. The results of tag monitoring will be used to estimate the transit time (days) for each of the juvenile Chinook salmon released upstream by NMFS that successfully migrates through Suisun Bay. Transit time for passage of each detected fish would be correlated with net Delta outflow and other environmental parameters.
Progress:
We have deployed all monitors at Chipps Island and in Montezuma Slough. The Monitors are being interrogated every two weeks. Tag detection files have been regularly submitted to the salmonid tracking group for inclusion in the database and towards making them available on the web page.