May 16, 2009
Lights, sound push baby salmon past pumps
Biologists say they're using sound, bright lights and bubbles to keep baby salmon from being sucked into pumps on California's San Joaquin River.
The pumps divert water from the southern Sacramento-San Joaquin River Delta for use on farmland and for drinking water for 25 million Californians, the San Francisco Chronicle reported Saturday.
The $1 million project is the latest attempt to save baby salmon en route to the sea and also could aid threatened delta smelt, said Jerry Johns, deputy director of the state Department of Water Resources.
The system began operating a month ago when more than 900 tagged juvenile chinook salmon were released about 15 miles from the pumps, Johns said.
As the fish encountered strobe lights, a curtain of bubbles and a hum in varying frequencies, 79 percent of them turned away from the pumps and remained on course for the open sea, Johns said.