Scientists have implanted the salmon smolts with acoustical tags as part of the multi-agency research.
"The project goal is to figure out what is killing the young salmon during their journey and solve those problems," state Department of Fish and Game spokesman Harry Morse told Recordnet.
"It's a mystery that must be solved."
He said 1,000 smolts have been implanted with transmitters at the Merced Hatchery as part of the Vernalis Adaptive Management Plan in the San Joaquin River Agreement, the news agency said.
The transmitters are programmed by the US Geological Service. The US Fish and Wildlife Service and two private consulting firms are providing technical assistance to the project.
"Tracking is done in the river and south Delta with acoustic receiver buoys," Morse said. "Buoys have been anchored in key locations throughout the river system and water diversion pathways to track the salmon."
"The results of this study and other evaluations being conducted in the San Joaquin River basin will determine stream flows that are needed to overcome all the impediments to adequate salmon and steelhead production in this river system," Fish and Game biologist Tim Heyne told Recordnet.
Research into Salmon Deaths Mystery
US - The Californian Department of Fish and Game have launched a study into why so many king salmon smolts die each year while out-migrating through the south Delta and San Joaquin River.