MASSIVE MORTALITY OF SEA LION PUPS – A MAJOR DISASTER
‘Since 2004, the number of sea lion pups washing up on California coasts has mostly fluctuated between 100 and 150 a year. Scientists noted a worrisome anomaly in 2013, when 1,171 famished pups were stranded on shore – including 309 in January and February. Then, scientists blamed the phenomenon on unseasonably cold waters.
“From a sea lion and biology perspective, we’re learning that the environment is changing every year and the animals are having to adjust,” said Sharon Melin, a Seattle-based NOAA wildlife biologist. “When they can’t, we’re seeing high mortalities.”
The bulk of California sea lion pups are conceived and birthed on four islands, San Miguel, San Nicolas, San Clemente and Santa Barbara, part of the Channel Islands in Los Angeles, Ventura and Santa Barbara counties.
Melin, who has been studying sea lion populations on San Miguel and San Nicolas, said scientists are recording devastating effects from the current warm-water event. In September, the average weight of 3-month-old pups on the two islands was 19 percent less than normal. In February, the average weight of 7-month-old pups was 44 percent less than normal. The pups gained little or no additional weight from October through January.
On San Miguel, where 20,000 sea lions are born each June, Melin said researchers believe “probably close to 10,000 are dead, and we expect more to die over coming months.” She said the mortality rate is similar on San Nicolas.
Scientists say only the pups are in peril because sea lion adults and adolescents can swim long distances to feast on fish in more chilly waters to the north.
Melin and others say current ocean conditions could result in fewer sea lion births next June – and a decline in the overall population if other unusual events occur in coming years. Meanwhile, biologists and veterinarians say other ocean factors, including depleted fish populations, may present an ongoing challenge for the animals.
“There is a complex process happening in our ocean,” said Johnson of The Marine Mammal Center in Sausalito. “The ocean is clearly under stress from the warmer water and, potentially, overfishing. These sea lions are telling us we should be very concerned about the health of our oceans.”
As sea lion pups wash ashore, the public is told not to approach or touch the animals because they may be carrying diseases or parasites, and could bite or lash out in fear. Instead, people are instructed to call hotline numbers for the state’s marine mammal rehabilitation centers and other trained wildlife rescue groups.
Even at The Marine Mammal Center, where most surviving pups will undergo six weeks of rehabilitation before they are capable of returning to the ocean, volunteers are told not to make eye contact, hand-feed them fish or do anything to alter their normal behavior.
“It’s hard because they’re like the golden retrievers of the ocean,” said center spokeswoman Laura Sherr. “Our crews get very attached to them. But we want to bring them back from a state of sickness so they can go back out into the wild.”