warning Hi, we've moved to USCANNENBERGMEDIA.COM. Visit us there!

Neon Tommy - Annenberg digital news

Sea Lions Stranding In Record Numbers Illuminate California’s Environmental Challenges

Alexander Wowra |
April 21, 2015 | 6:25 p.m. PDT


Three sea lions currently recovering in a pen at the Califorina Wildlife Center (Alexander Wowra / Neon Tommy)
Three sea lions currently recovering in a pen at the Califorina Wildlife Center (Alexander Wowra / Neon Tommy)
Stark, the little female sea lion pup, continues to fight for survival.

Named after the family that found her on a Malibu beach, the skinny, undernourished animal was taken to the California Wildlife Center, based in Calabasas, Calif., by a team of scientists.

Stark is the smallest member of a group of juvenile sea lions crammed into a recovery pen that is at full capacity. Due to the lack of space, the animals sometimes scratch and bite each other, which can lead to infections requiring treatment.

Despite these harsh conditions, 10-month-old Stark is making an unlikely recovery, said Michael Remski, marine mammal rehabilitation manager at the center.

A record 2,250 starving juvenile sea lions have been stranded in California since the beginning of the year, said Monica DeAngelis, marine mammal biologist at the National Oceanic and Atmospheric Administration, in a phone interview.

The young sea lions are starving as their main food source, sardines, has decreased over the last three years due to uncommonly warm water temperatures, said Nate Mantua, landscape ecology team leader at the NOAA Southwest Fisheries Science Center, also in a phone interview.

At the same time, the population of California sea lions has been growing exponentially since passage of the 1972 Marine Mammal Protection Act. Within the last 15 years, their numbers have approximately doubled to 340,000, said Mantua.

Since food resources are scarce near their breeding grounds, sea lion mothers are forced to make longer foraging trips to feed themselves and their young. “Now, moms often don’t bring back the nutrition the pups need to grow,” Mantua said.

Because they are starving, some of the young leave their mothers long before they usually would, but are often too weak and sick to catch their own food.

SEE ALSO: Promising New Alzheimer’s Research For Disease With Few Treatments

About 750 sea lions are currently being rehabilitated in seven facilities throughout California. All these facilities have operated at full capacity for the last two months, Justin Viezbicke, California stranding response coordinator at the National Marine Fisheries Service, said in a phone interview.

After the scientists and volunteers at the California Wildlife Center find a starving sea lion, they check its vital signs and determine whether the animal needs to be taken to the center.

Then, they need to rehydrate the starving animal because sea lions usually consume water through the food they eat. The staff gives the animal water through a tube that the veterinarian places inside its mouth and plugs into its gullet, said Duane Tom, veterinarian at the center.

The staff has to wait a few days before they start feeding the animal, as anything else than water will overwhelm its digestive system, which has been weakened to the point that it is not used to processing any solid food anymore, said Tom. “Once they are ready, we slowly lead them through a diet of fish mash and electrolytes until we finally introduce them to eating whole fish and giving them medication, if needed,” he said.

The little, brown sea lion Stark was very dehydrated and even started having seizures when she originally arrived at the center.

Her body was not producing enough sugar, which caused her to run low on energy and pass out repeatedly. “That is usually the beginning of the end of them,” said Remski.

Yet the young female pup made it through the first night, and continued to recover.

Stark is in a pen with other sea lions, but does not have to compete with them for food as she would in the wild. Volunteers at the center separate her from bigger, stronger peers during feeding times. She is still skinny, but already tries to swallow entire herring provided by the center’s staff.

Young sea lions are kept in a separate rehabilitation station, where all the weakest animals are given water and food. It contains a few shallow plastic pools, which they can crawl through on their stomachs.

The veterinarian’s goal is to get the animals to a healthy weight, which also strengthens their immune system against diseases.

“Every day, we feed them up to 15 percent of their body weight,” said Julie O’Brian, marine mammal intern at the center.

Once they seem strong and healthy enough, they go from the first rehabilitation station to the second one, where they can swim in a larger, deeper pool.

“When they swim and have gained enough weight, we release them and hope for the best,” Remski said. The staff at the center does not track the animals’ progress once they are back in the wild, but Remski estimated that about half of the animals will survive, given the current low fish stock.

READ MORE: A Flydown Of Parrot Populations In Southern California

The low abundance of sardines and uncommonly warm waters off the California coast are in part associated with the El Niño, a tropical weather phenomenon that can affect the water temperatures in Southern California, said DeAngelis.

Yet, the more dramatic factor causing California’s coastal water temperatures to rise has been a lack of winds off the Southern California and Baja California coasts. “Usually they bring cold, nutrient-rich water,” said Mantua.

Sea lion pup "Stark" eating a herring (Alexander Wowra / Neon Tommy)
Sea lion pup "Stark" eating a herring (Alexander Wowra / Neon Tommy)

Some scientists ascribe the alteration of wind patterns on the West Coast to Arctic melting, which destabilizes the wind pattern called the polar vortex. This can weaken the jet stream and lead to extreme weather where it is not expected, according to a recently published study by Jennifer Francis, research professor at the Rutgers University Institute of Marine and Coastal Sciences.

Another factor is a high-pressure ridge that has caused the ocean to be very calm over the last two winters and created a body of warm water that has been pushing against the West Coast for approximately 18 months. This “warm water blob,” as scientists have called it, led to a higher number of juvenile sea lion die offs over the same time period, said Mantua.

Back in 2013, the number of starving sea lions was so high that NOAA referred to the ensuing die offs as an u

nusual mortality event. In 2014, the fatality rate decreased slightly, but was still alarming, said Remski.

While researchers are uncertain whether this year’s crisis might lower the sea lion population resulting in less competition for food, they worry about long-term effects the warmer waters and the shortage of fish may have on California’s oceanic ecosystem at large.

The sea lions’ struggles are but one indicator of an environmental crisis looming in the waters off the West Coast, according to DeAngelis. “It could be that what we are seeing now trickles down to the life cycles of all the species out there,” she said.

Other signs of changes in the marine ecosystem include frequent sightings of killer whales and even loggerhead turtles in Southern California, which is untypical for the area, said DeAngelis.

Back at the center, Stark continues to look better and could be released back into the wild in approximately two months, according to Tom.

When she joins her peers in the wild, she might face a changing environment that will pose unprecedented challenges to her and other sea lions.

“Maybe this is the new normal. I would suspect that all these anomalies are becoming more common in the future,” DeAngelis said.

Reach Contributor Alexander Wowra here. Check out more from the Science Desk here



Craig Gillespie directed this true story about "the most daring rescue mission in the history of the U.S. Coast Guard.”

Watch USC Annenberg Media's live State of the Union recap and analysis here.