LOS ANGELES, May 26 (Reuters) - A second sea lion rescued from along California's oil-fouled coastline near Santa Barbara has died at SeaWorld San Diego, where veterinarians are still caring for 15 surviving marine mammals brought in for treatment, a spokesman said on Tuesday.
The petroleum-stained pinnipeds are among the earliest apparent wildlife casualties documented from a pipeline rupture that dumped as much as 2,400 barrels (101,000 gallons or 382,327 liters) of crude oil onto the shoreline and into the ocean west of Santa Barbara one week ago.
The spill left an oil slick stretching for more than 9 miles (14.5 km) along the coast and forced the indefinite closure of two popular beaches. The area also has been placed off-limits to fishing and shellfish harvesting.
The stricken region lies at the edge of a national marine sanctuary and underwater preserve that is home to whales, dolphins, sea lions and other marine mammals, along with some 60 species of sea birds and over 500 species of fish.
As of Tuesday, 15 oil-contaminated California sea lions and two elephant seals had been brought to SeaWorld to be cleaned and nursed back to health.
The first arrival, a young sea lion streaked with oil over a third of its body, died late on Friday or early on Saturday after being cleaned, SeaWorld spokesman David Koontz said. A second sea lion died there on Monday, leaving 13 sea lions and two elephant seals still to be rehabilitated and hopefully released.
"Our team is working very, very hard, doing everything they can to give these animals a second chance at life," Koontz said.
Meanwhile, the carcasses of four sea lions and two dolphins have turned up with no visible signs of oil, including a dead dolphin found on Friday in Santa Barbara Harbor, according to officials overseeing the spill response.
Post-mortem exams must still be conducted on all dead animals recovered from the disaster zone, and those that die under care, to determine whether they were spill victims.
The latest official tally of oil-soaked birds indicated that nine pelicans and one western grebe had been discovered alive and five pelicans found dead.
Last week's pipeline rupture resulted in the biggest oil release to hit the ecologically sensitive shoreline northwest of Los Angeles since a 1969 blowout dumped up to 100,000 barrels (4.2 million gallons or 15.9 million liters) of oil into the Santa Barbara Channel.
That much larger spill killed thousands of sea birds and other wildlife and helped spark the modern U.S. environmental movement. (Reporting by Steve Gorman; Editing by Sandra Maler)