The International Maritime Organization has approved vessel lane changes on approaches to San Francisco Bay and the ports of Los Angeles and Long Beach, and in the Santa Barbara Channel. The changes take effect next year.
Migrating blue, fin and humpback whales are prone to ship strikes since they are often lured to the California shoreline by plentiful krill. All three species are endangered.
In 2010, five whales died in ship accidents in the area outside San Francisco Bay. Under the recently approved lane modifications, three lanes on the approach to the San Francisco Bay will be extended - a move that will limit interaction between whales and cargo ships within the Cordell Bank and Gulf of the Farallones national marine sanctuaries.
In the Santa Barbara Channel, where four blue whales were killed in vessel strikes in 2007, a southbound lane will be shifted a mile north, steering ships away from feeding grounds used by blue and humpback whales. Other lanes will be narrowed.
Similar lane adjustments are in store for the ports of Los Angeles and Long Beach. The twin ports handle more than twice as much shipping container traffic as any other U.S. port.
"This is a win-win situation" for maritime safety and whale protection, William Douros of the National Oceanic and Atmospheric Administration's Office of National Marine Sanctuaries said in a statement.
NOAA helped craft the latest shipping lane changes. The agency said lane changes that went into effect off the coast of Massachusetts five years ago have reduced the risk of whale strikes from ships.