As local algae poisonings subside, rehabilitated sea lions get ‘a second chance of survival’

After five weeks recovering at SeaWorld’s rescue center from the effects of a toxic algae bloom, a sea lion seemed to be feeling fin-tastic as she was released back into the wild Thursday — a welcome success as San Diego emerges from a recent rash of pinniped poisonings.

The poisoning was a result of an algae bloom along the California coast that produces domoic acid, so toxic it damages the brain and heart of infected marine mammals.

Although the blooms are a natural phenomenon and seasonal poisoning outbreaks are common along the coast, California was hit especially hard this year, resulting in a surge of sick animals washing ashore.

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Sick, disoriented and aggressive sea lions are washing ashore. Here’s why, and here’s how San Diegans can help

Local experts are asking beachgoers to keep a safe distance and report strandings, amid a bloom of toxic algae that produces a neurotoxin that damages some marine mammals’ brains.

July 2, 2023

The neurotoxin was first found in waters off Santa Barbara and Ventura counties in early June, resulting in reports of sea lions and dolphins dying off by the hundreds.

As it trickled down the coast, SeaWorld’s rescue team — the southernmost in the West Coast Stranding Network — began seeing an uptick of rescue calls off of San Diego.

“We did gear up for a pretty busy season, and we were pretty fortunate that we didn’t have as many sea lions as the other facilities did,” said Steven Dunning, a senior zoological specialist at SeaWorld San Diego.

The sea lion released Thursday, about 4 or 5 years old, was among 18 cases of suspected domoic acid poisoning, involving 17 sea lions and one dolphin, that SeaWorld has responded to since May.

Domoic acid travels up the food chain — from the plankton that eat the algae to squid and shellfish to the larger marine mammals that then eat them. Top predators ingest the most toxins and get the sickest, resulting in neurological symptoms that can range from abnormal behavior and unusual aggression towards humans to seizures and even death.

Kim Peterson, a rescue curator at SeaWorld San Diego, said this particular sea lion was in rough shape when they found her on June 30. She was seizing, lethargic, dehydrated and completely unresponsive for days.

On board SeaWorld’s 36-foot boat, Second Chance, off the coast of San Diego on Thursday, Aug. 3, 2023, a recent rescued sea lion, known as ZC2338 is taken out to be released in open water.

(Nelvin C. Cepeda/The San Diego Union-Tribune)

Treatment plans are made on a case by case basis. Each animal is treated with a range of medications and fluids to flush out the toxins.

“Our veterinary team will administer different types of medications to help the healing process of the brain,” Dunning explained. “Then over time, we hope that a combination of a proper diet, medication fluids will help heal her enough, put weight on her, that eventually you get her to the point where you can return her.”

They also will overfeed the animals, as part of their aggression comes from hunger, Dunning added.

After spending the last few weeks getting the toxin completely flushed out of her system, she’s made a full recovery.

On Thursday morning, Dunning and TG Plein, an associate zoological specialist at SeaWorld San Diego, loaded the sea lion — along with two yearlings — onto a rescue boat aptly named “Second Chance.”

Although animals are typically released near where they are found, Dunning says they take special precautions with sea lions that recovered from acid poisoning, as they could still be aggressive toward humans.

“We try to give them a chance to just sort of explore the area, get their bearings,” he added.

After traveling about five miles off the coast of Point Loma, the sea lions were released, eagerly jumping one by one from the boat back into the open ocean. They dove down and circled the boat before swimming off together.

“It’s nice to be able to get another healthy animal out there and hopefully give them a second chance of survival,” Dunning said.

Two more sea lions being treated for suspected domoic acid poisoning are expected to be released next week.

On board SeaWorld’s 36-foot boat, Second Chance, off the coast of San Diego on Thursday, Aug. 3, 2023, senior zoological specialist, Steve Dunning (l) and TG Plein (r) release a sea lion, known as ZC2338.

(Nelvin C. Cepeda/The San Diego Union-Tribune)

Not all are so lucky.

When the animals are poisoned, the acid begins to destroy the brain until they no longer know basic survival functions, such as how to evade predators and find food.

If an animal isn’t rescued and does not receive critical care soon enough, Dunning says they can suffer irreversible brain damage, which many do not survive.

The more affected fish an animal consumes, the greater impact it can have on their bodies — which is why pregnant animals eating for two have been hit so hard, Dunning added.

Back at the center, one 6-week-old pup is getting stronger after her mother died from the toxin.

“The mom didn’t survive, but her pup is actually doing really well — getting healthy, eating, putting on weight,” Dunning said.

Pups will stay at the rescue center for about a year — about as long as they’d typically stay with their mother — as zoologists slowly wean them from bottle formula to eating fish to teaching them how to hunt on their own.

Although the bloom has since dissipated, SeaWorld is still seeing its effects. On Thursday, as the three sea lions were released, another was rescued from Mission Beach with symptoms.

Experts say the scope of this year’s poisonings were on a scale they have not seen before. Peterson, the rescue curator, called it one of the worst blooms she’s seen at SeaWorld San Diego.

Harmful algae blooms are typically a result of upwelling, a process that brings cold, nutrient-rich water from the deep ocean to the warm surface and stimulates algae growth, explained Clarissa Anderson, a biological oceanographer and harmful algae bloom expert at the Scripps Institution of Oceanography at UC San Diego.

Anderson is executive director of the Southern California Coastal Ocean Observing System, which is responsible for monitoring harmful algae. It uses data from samples collected weekly at nine university-run or municipal pier stations from San Diego to Humboldt counties to help predict when and where toxic blooms will occur.

But algae blooms are not the only oceanic phenomenon that result in increased strandings, Dunning pointed out.

This year’s El Niño season is also expected to increase the number of rescues SeaWorld must perform, as it will result in a change in the water temperature, pushing fish into deeper water and making it harder for top predators to find enough food, Dunning said.

Thus far this year, SeaWorld San Diego has rescued 51 sea lions, 14 northern elephant seals, six fur seals, three sea turtles, one dolphin and one harbor seal.

Those who see an animal in need of help can contact its rescue team at 1-800-541-SEAL (7325) or SWC.Rescue@seaworld.com.