Bubbles, Light Show May Save Young Salmon
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SACRAMENTO, Calif. (AP) — Can an irritating blend of bright lights and loud noise deter ocean-bound salmon from deadly waters? The California Department of Water Resources hopes so.
As early as this week, the agency will install an experimental “bubble barrier” in a side channel of the Sacramento River that has become a death trap for Chinook salmon attempting to migrate downstream to San Francisco Bay.
The barrier, a sheet of bubbles enclosing strobe lights and underwater acoustics, is meant to scare young salmon away from Georgiana Slough, near Walnut Grove. Salmon that end up in the slough often succumb to hungry striped bass or other predators, or get sucked into giant irrigation pumps.
The department will track 1,500 salmon to test the success of the barrier, which will be removed by mid-May. Officials said a similar barrier installed at the head of Old River in the south Delta in 2009 and 2010 proved effective in channeling the salmon.
Despite a rebound in 2010, the salmon population has plummeted in recent years, reaching a historic low in 2009. The decline has been attributed to water shortages, as well as climatic conditions that produced little food in the ocean.
State officials have taken numerous steps to revive the population in response to an order from the National Marine Fisheries Service. That includes trucking hatchery-raised salmon around obstacles such as dams and water-export pumps so they have will have a clearer path to the bay.
The current bubble fence will lie more than nine feet below the surface to avoid boats.
(Copyright 2011 by The Associated Press. All Rights Reserved.)