Spring 2009 Vernalis Adaptive Management Program field research is underway. The first release group of 136 fish were surgically implanted with HTI acoustic transmitters at the Tracy Fish Facility. After surgery and a short recovery period, fish are transported to the river release site and held another 24 hours. The tagged fish are released in the San Joaquin River upstream from Mossdale and tracked by private, state, and Federal biologists using stationary and mobile tracking techniques. The study is a cooperative effort to evaluate factors that influence juvenile Chinook migration and survival in the San Joaquin River.