The Big Blue Ocean Exploration

Starving sea lion pups stranding in alarming numbers on Southern California beaches

Diminished supply of forage fish believed responsible

sealionsPMMC

Young sea lions being cared for at the Pacific Marine Mammal Center in Laguna Beach, California. Credit for all images and video: PMMC

Starving young sea lions are coming ashore in unprecedented numbers on Southern California beaches, presumably because of a diminished supply of forage fish.

Rescue and rehabilitation facilities are at capacity with undernourished animals and have been flooded with calls from beachgoers who are encountering the mammals on the sand and, in some cases, even on sidewalks and roads.

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According to CBS News, about 100 sea lions are rescued on California beaches annually. More than 700 have been rescued so far this year. Most have been recently-weaned juveniles.

“They’re very sick,” said Keith Matassa of the Pacific Marine Mammal Center in Laguna Beach in Orange County.

That facility, one of a handful from Santa Barbara to San Diego, has rescued more than 130 sea lions, which is a record for the first three months of a calendar year.

“A normal sea lion at this age—8 to 9 months old—should be around 60, 70 pounds,” Matassa said. “We’re seeing them come into our center at 20 to 25 pounds, and they really look like walking skeletons.”

(On the bright side, some of the animals are being released healthy. Below is a video showing two yearlings and an adult sea lion released back into the wild earlier this month by the PMMC.)

SeaWorld’s San Diego-based rescue unit has brought in more than 170 animals so far this year, compared to 113 for all of 2012.

“It boils down to these pups are not getting enough food to survive on their own,” Dave Koontz, a spokesman for the facility, told the San Diego Union-Tribune. “After they are weaned from their mothers, the food is not there or [is] at a depth they can’t reach.”

sealion2Sea lions prey largely on smaller bait fish such as anchovies and sardines. Mysteriously, these fish have been in short supply, perhaps causing adult sea lions to wean their pups prematurely.

Scientists are studying ocean currents and other environmental conditions in an attempt to determine why the bait fish is so scarce.

Sarah Wilkin of NOAA Fisheries said that nearly all of the rescued sea lions were born last summer, and that generally the pup strandings peak is May or June of the following year.

Wilkin could not say that this is a record year for pup strandings, because record-keeping has only become reliable over the last five years, thanks to an increase in rehab centers and the information their staffs provide.

But, Wilkins added, “This is definitely off the charts for the past five years.”

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