Marine mammal agencies train in sedation by dart to rescue entangled sea lions

NEWPORT BEACH — With whale entanglements on the rise off the Southern California coast, it is no surprise that California sea lions are increasingly being trapped in lines and nets as well.

For the first time ever, five agencies charged with protecting marine mammals from San Diego to Sausalito came together recently to share ideas on how to best aid larger sea lions entangled  in more remote locations off Southern California’s beaches and in local harbors.

Among those plans is a way to sedate — by darting — a sea lion that cannot be captured by net, towel-wrapped or taken away on stretcher.

“We’re trying to encourage our network opportunity to grow outside of Orange County and Los Angeles because we don’t have our remote sedation plan here,” said Justin Viezbicke, California stranding coordinator for the National Oceanic and Atmospheric Administration. “It’s necessary. It provides better safety for us and the animals. Capturing these animals can be very challenging. We see these animals over time and this increases our ability to get them.”

The group training exercise included a day of classroom work at the Marine Mammal Center Los Angeles and two days of field training in Newport Harbor.

 

The collaboration earlier this month included oversight by federal officials, including Viezbicke and Justin Greenman, both on NOAA’s stranding team. Participants included veterinarians and staff from the Pacific Marine Mammal Center, SeaWorld Rescue, Marine Animal Rescue in El Segundo, the Marine Mammal Care Center Los Angeles and The Marine Mammal Center in Sausalito.

Part of the training plan included attempts at freeing three sea lions that were reported entangled in Newport Harbor.

Two of the sea lions had fishing gear cutting into their heads and necks, the other was reported to have puncture injuries, possibly from a dock barrier, said Keith Matassa, who leads animal research at the Pacific Marine Mammal Center and who, with Viezbicke, planned the training and rescue exercise.

“I’ve always believed in collaboration and putting the best minds together for rehabilitation of animals and to deal with chronic life-threatening entanglements,” Matassa said.

Small window of time for success

While remote sedation darting has been done before, there are dangers associated with the procedure. Most sea lions, when hit by darts, will jump into the water. If they are not found quickly they can drown.

A procedure recently introduced by The Marine Mammal Center in Sausalito is intended to prevent such tragedies. Dr. Shawn Johnson, a veterinarian at TMMC and Dave Zahniser, the center’s rescue and response manager, introduced the concept.

The procedure includes a sonic dart attached to a syringe. The needle goes into the animal and injects the drugs, and a pinger emits a signal. A rescue team listens for the signal and as the sea lion moves around, the signal becomes stronger the closer the rescuers get to to its location.

Teams from The Marine Mammal Center routinely use the darting technique to rescue entangled animals found in remote locations between Mendocino and San Luis Obispo and in inland waterways of San Francisco.

“We want to be able to catch and free them before the entanglements cause their death,” Johnson said. “With this technique, the number we’re able to catch has increased.”

Critical to the success of darting sedation is knowing how much sedative to inject into each sea lion. As with humans and anesthesia, the quantity is largely based on weight.

“Determining the weight of sea lions is one of the most difficult processes,” Johnson said. “Having a team of people estimate is important. Getting the weight right means you’re giving the right amount of drug.”

Once a sea lion is darted and then located — often within 10 minutes — the animal is pulled to the side of the rescue boat. Most are taken to the rescue center, treated for their wounds and then released. Some — the heavier ones that are not easily transported — are treated at the side of the boat and are held with a net.

TMMC has rescued 15 sea lions with remote sedation darting this year, Johnson said.

More sea lions reported entangled

Across the stranding network, more reports of entangled sea lions are coming in.

“Most common are monafilament lines across the head and neck,” Johnson said. “These will eventually cut their trachea and will kill them as they grow. We don’t know how long most animals have had the entanglements. Most young animals are curious and they play. Wrap straps and fishing lines get stuck around their necks.”

The Pacific Marine Mammal Center in Laguna Beach has seen a rise in entanglement reports. And marine mammal rescue centers up and down the coast are finding pinnipeds affected by fishing gear, whether it be hooks, nets, or fishing line.

Affected animals include sea lions, elephant seals, harbor seals and Guadelupe fur seals.

In 2017, NOAA reported 55 pinnipeds statewide found caught in gear. In 2018, as of July, 28 had been found stranded with entanglements between San Diego and Sausalito.

The increase in entanglements can be attributed to several factors, said Krysta Higuchi, spokeswoman for PMMC. This includes a shift of food source away from the Channel Islands and closer to shores and harbors, and the habituation of sea lions to humans, as more people hand-feed them in the wild.

There is also trash, fishing line and hooks in their environment.

“It’s a combination of more people looking and reporting,” Viezbicke said. “We’ve also got a large sea lion population with a lot of movement. With more out there, it’s a high likelihood we’ll see more entanglements.”

In April, Viezbicke was out on San Miguel, the most remote of the Channel Islands and the area where sea lions pups are born each June.

“In four days, we disentangled two dozen animals sprinting down the beach with nets,” he said.

Next steps

Back in Newport Harbor, the teams, in three Zodiac boats, scouted the entire harbor over two days. Though they didn’t find the three sea lions that had been reported entangled, they did find one sea lion with a fish hook embedded in its lip.

“It was superficial and we took pictures and analyzed it,” said Laura Palmer, a veterinarian at the Marine Mammal Care Center in Los Angeles who was among the training group. “The decision was made that it wasn’t life threatening and it didn’t warrant the darting procedure. The severity didn’t warrant the response. We talked about picking cases carefully.”

“It  was very productive,” she said of the training. “It’s very important to address this problem. We’re seeing some animals severely entangled but too active to be caught.”