
CHICO, California -- On Saturday, April 13, the U.S. Fish and Wildlife Service released a total of 360,000 juvenile fall Chinook salmon on the Sacramento River in a three-year study aimed at increasing their survival on their long journey to the ocean.
The service released 180,000 marked juvenile salmon into the Sacramento River at Scotty's Landing near Chico, 75 miles downstream of where they were born, in the pilot project focusing on increasing the contribution of the Coleman National Fish Hatchery to California's salmon fishery.
Agency staff released the second group of 180,000 upstream at the hatchery to compare their survival to the fish moved downstream. Current practice for the hatchery is to release fish directly into Battle Creek, some 320 miles from the ocean, said John Heil, U.S. Fish and Wildlife Service spokesman, in a statement.
Partners on the study include Golden Gate Salmon Association, NorCal Guides and Sportsmen's Association, Pacific Coast Federation of Fishermen's Associations, UC Davis, and the Bureau of Reclamation.
"The study will test whether moving the salmon's release point to 75 miles downstream from the hatchery on Battle Creek will improve their survival without causing more straying of returning adults," said Heil. "According to studies done between 2007 and 2010, many Coleman salmon are lost in the first 75 miles of travel after release, especially in low water years."
"The fish, moved via tanker truck to the Chico site, were released into an acclimation net pen floating in a side channel of the Sacramento River," said Heil. "The net pen allows the fish to recover from stress and disorientation from the truck ride prior to release into the river. This reduces losses to predation upon release."
Heil said all of the 360,000 fish were marked so that scientists can compare how the two groups survive, harvest, and stray when they return two to four years from now. A subset of both release groups were also fitted with tiny.