The Vernalis Adaptive Management Plan (VAMP) is one of the most intensive fishery studies ever conducted in California’s Sacramento-San Joaquin Delta. This large-scale, collaborative, multi-agency study investigated how juvenile salmon survival may be affected by changes in environmental variables, such as river flow, water exports, and operation of fish barriers. Beginning in 2008 and continuing through 2011, FISHBIO was selected to coordinate the efforts of more than 30 individuals representing at least six federal, state, and private organizations. Our staff trained project personnel, acquired necessary supplies and equipment, and developed and implemented standard operating procedures to implant acoustic transmitters in thousands of salmon smolts each spring.

In 2011, the team trained and lead by FISHBIO for VAMP also acoustically tagged salmon and steelhead for three other studies being conducted in the San Joaquin Delta. These studies were designed to evaluate the behavior of juvenile salmon and steelhead encountering agricultural barriers and fish barriers, to estimate juvenile steelhead survival, and to compare steelhead survival to juvenile salmon survival. These studies overlapped with VAMP in technical approach, geographic scope, and timing, which facilitated the involvement of the FISHBIO-lead tagging team.

As part of the VAMP investigations, FISHBIO also deployed and maintained fixed-station acoustic detection arrays, designed and implemented a mobile tracking strategy, and processed and analyzed acoustic tracking data. Mobile tracking helped identify “hotspots” of mortality where tags implanted in smolts had become immobile. Overall, the VAMP study found that salmon smolt survival through the San Joaquin Delta can be as low as 2 percent, survival has consistently been less than 12 percent, and predation appears to have a far greater impact on salmon smolt survival than flow. In response to these findings, FISHBIO conducted complementary studies including tagging and tracking of predatory fishes, DIDSON surveys, and review of DIDSON footage collected by other researchers.
View the 2011VAMP Report

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