The Marine Mammal Center’s record-breaking patient load in 2014 included an influx of emaciated young sea lions. (Sarah van Schagen/The Marine Mammal Center)
The Marine Mammal Center’s record-breaking patient load in 2014 included an influx of emaciated young sea lions. (Sarah van Schagen/The Marine Mammal Center)

Last year a record number of sea lions washed up on Central and Northern California beaches, according to The Marine Mammal Center, the organization that treats wounded wild marine animals.

Usually the center near Sausalito treats fewer than 20 sea lion pups a year, but in 2014 that spiked to 245. Older sea lions also stranded themselves in record numbers last year, 449 up from 176 in 2013. A neurotoxin found in algal blooms affected 34 percent of the adults.

The sea lions were sighted all the way from San Luis Obispo to Mendocino. When rescuers responded to calls, said Shawn Johnson, Director of Veterinary Science, the emaciated pups looked extremely undernourished.

“It’s very sad,” Johnson said. “Imagine starving to death and not eating for many weeks, where your skin is just hanging off you.”

Why Do Pups Get Stranded?

Strandings happen when sea lion moms abandon their pups before they are ready to feed on their own. Scientists are unsure precisely what is causing these events.

Blarney McCresty, an adult male California sea lion, was treated for domoic acid toxicity during his rehabilitation at The Marine Mammal Center.
Blarney McCresty, an adult male California sea lion, was treated for domoic acid toxicity during his rehabilitation at The Marine Mammal Center. (The Marine Mammal Center)

One possibility is rising ocean temperatures. Fish live in specific temperature ranges and warmer water could change their habitat, which means sea lion moms swim father afield to find the same amount of nutrients.

Scientists do know that when the adults are unable to provide for the pups they abandon them. If the infants are younger than 10 months, they don’t know how to fend for themselves and wind up on beaches throughout the state.

Each year the center is able to save about 50 percent of the pups that are rescued, by nourishing them back to health with a slurry of ground-up fish.

The center is working with biologists from the National Marine Mammal Laboratory to study the health of sea lion populations on the Channel Islands, where the animals breed. They’re hoping to help predict future strandings.

“We’re bracing for another very big year in 2015,” Johnson said. “The biologists observing sea lions at the Channel Islands say the pups are underweight so we’ll likely have another busy spring.”

Sea Lions Have Brain Damage, Experience Seizures

California sea lions Atlas, Orbit and Caelum return to the ocean at Chimney Rock in Point Reyes after receiving care at The Marine Mammal Center.  (Conner Jay/ The Marine Mammal Center)
California sea lions Atlas, Orbit and Caelum return to the ocean at Chimney Rock in Point Reyes after receiving care at The Marine Mammal Center. (Conner Jay/ The Marine Mammal Center)

Since 1998, scientists have discovered sea lions with a neurotoxin that causes memory loss and seizures. Domoic acid is created by certain types of algae and passed up the food chain from fish to the animals that eat them.

Once ingested, the toxin enters the bloodstream, traveling to the brain where it starts causing brain damage. Scientists performing memory tests on the animals also found that the animals lost memory function.

If treated immediately, some of the sea lions survive but once the toxin accumulates the animals often experience multiple seizures and die.

This year, four sea lions have been admitted to The Marine Mammal Center that have domoic acid. Because these harmful algal blooms can be toxic to humans as well, the center alerts the health department when several animals are discovered with the toxin.

“When it comes to domoic acid, they literally are the canaries in the ocean or coal mine,” Johnson said. “We do what we can but some of these sea lions might not have enough memory to survive out in the wild.”

Sick Sea Lions Wash Up on California Beaches 20 January,2015Lindsey Hoshaw

  • robert gamaza

    It’s sad to see whats happening to these poor animals. First they’re stranded, then also their food is poisoning them and causing memory loss and seizures. Stuff like this doesn’t happen naturally and due to bio-accumulation this higher up the food chain animals experience it at a much more rapid pace due to the amount of the poisoned fish they consume. Things like this that start at the bottom of the food chain just make everything worse and worse. It’s also crazy seeing the spike in stranded sea lions go from about 20 per year to 245! Now that’s extreme. I’d say this is a serious problem seeing that spike number and i believe we should help resolve it anyway possible.

Author

Lindsey Hoshaw

Lindsey Hoshaw is an interactive producer for KQED Science. Before joining KQED, Lindsey was a science correspondent for The New York Times, The Boston Globe, Forbes and Scientific American. On Twitter @lindseyhoshaw

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