Experts from The Marine Mammal Center demonstrate their innovative rescue techniques in Mexico, helping save a sea lion mother and her dependent pup.
March 3, 2016
Imagine having to leave a helpless entangled California sea lion to suffer because there’s nothing you can do for her. The sea lion’s injuries are the result of human impacts, making the desire to help even stronger, yet because she’s a wild animal in a difficult location, she’s inaccessible to the trained professionals who might be able to help.
That very feeling of helplessness led experts at The Marine Mammal Center to develop innovative rescue techniques that allow them to remove entanglements, mostly gillnets, from wild marine mammals without risking human lives in the process.
Our rescue team uses a special combination of drugs that allow the animal to sleep while retaining her breathing reflex. Although the animal being rescued is sedated enough to not be a danger to the rescue team, she will automatically rise to the surface to take a breath whenever she needs one. This drug combination is also unique because it can be easily reversed, which helps speed up the recovery process.
The sedatives are delivered remotely via a specialized dart that also includes an acoustic tracking device. The dart was designed especially for this purpose by Dr. Shawn Johnson, Director of Veterinary Science, and Dr. Greg Frankfurter, a former Koret Foundation Veterinary Intern at the Center.
Dr. Frankfurter then worked closely with a team of designers from Autodesk who volunteered their time to help modify and improve the dart design using a 3D printer.
The dart’s acoustic tracking device allows the rescue team to keep track of the animal in the water until it is fully sedated, a process that takes about 10 minutes. A series of “pings” from the device are detected via hydrophone, and our team follows the sound until they are able to spot the animal.
Once the animal is fully sedated, our veterinary experts are able to remove the entanglement, reverse the sedation and release her back to the wild. More than 20 sea lions have been rescued along the California coast using this acoustic tracking method since its development in 2014.
“Now that we have developed this technology and honed our skills in its use, we want to share it widely in order to ensure entangled marine mammals throughout the world are able to get the care they need,” says Dr. Johnson.
One area of the globe facing similar rescue challenges is the California sea lion rookery on Los Islotes, part of the protected Espiritu Santo Archipelago in Mexico’s Sea of Cortez. The number of entangled sea lions in the area is fairly large given the size of the rookery, but the rocky terrain makes rescues difficult.
Mexican filmmaker and environmentalist Eréndira Valle learned this firsthand when she was in the area filming and saw many sea lions entangled in fishing line and nets, moving her to take action.
Valle consulted government agencies, marine science universities, and even started a petition to help, but it wasn’t until she met Dr. Daniela Barcenas, a like-minded conservation veterinarian, that her mission gained some traction. The two women began working together to give the entangled sea lions at Los Islotes a second chance at life.
Dr. Barcenas was selected to be one of three veterinarians taking part in The Marine Mammal Center’s International Veterinary In-Residence program last year. She trained at our headquarters in Sausalito for three months and joined our rescue team on several remote darting missions along the coast of California.
Meanwhile, Dr. Barcenas and Valle collaborated with Sophie Guarasci, a veterinary technician at the Center, on a plan to bring our rescue experts to Los Islotes. As word spread about the upcoming workshop, interest in the project snowballed.
Local organizations and businesses stepped up to provide mission-critical boats, equipment and personnel. And more than two dozen participants from local government agencies, universities and scientific institutions signed up to take part in the training.
“It’s very exciting to see so many people so excited about this project here in Mexico—all the different government agencies, veterinarians, universities,” Guarasci says. “I think it’s great to see such collaboration—everybody working together all trying to accomplish the same thing, which is to help these animals.”
When our rescue team landed in Cabo San Lucas, Mexico, with the dart gun and sedatives in tow, they were in for some troubling news: the “suspicious” equipment was being held indefinitely at international customs and heavy winds were in the forecast.
Disheartened, but still determined, the team took a boat out to the rookery at Los Islotes the following day to scout for entangled animals. The situation was worse than anyone had expected—the team quickly spotted seven sea lions, including one adult female, visibly suffering from entanglements in gillnets and derelict fishing gear.
With the darting equipment still stuck in customs, there was nothing they could do but return to shore to prepare for the next day’s planned classroom lectures.
Early the next morning, the team found out that the port might be closed for the next several days due to extreme wind conditions. Thinking quickly on their feet, they accepted a generous offer from the La Paz Whale Museum to make their ocean expedition yacht, the Narwhal, a floating classroom while they awaited updates from the port authority.
When our rescue team got the news that the wind storm was going to hold off for one more day, they knew they had a narrow window of opportunity to act. Luckily, by then Valle had received the darting equipment from customs. And with the help of the Cortez Club, a local diving and ecotourism company, she was on her way from Cabo San Lucas, a two-and-a-half hour drive and a one hour boat ride away.
With the throttle down, the Narwhal headed for Los Islotes. During the journey, Guarasci and Dr. Barcenas began their presentation to officials from Mexico’s federal environmental agencies: PROFEPA, the environmental enforcement office, CONANP, which manages natural protected areas, and SEMAR, the Mexican Navy Secretariat.
Once at the island, the group split into two smaller boats and searched the rookery for entangled sea lions. Even with 30 people on the search team, this time they were only able to spot two entangled animals and one was huddled too close to other sea lions, making it too risky to dart.
The other entanglement victim was the same adult female sea lion that had been spotted the day before. The team named her Calafia, for a mythical warrior queen thought to rule over a kingdom of a women living on the Island of California.
Calafia was lying in a perfect position, alone on top of an isolated rock formation exposing her left shoulder like a bull’s-eye for the acoustic dart. As soon as Dr. Johnson darted Calafia, she dove into the water and swam away, unaware that the team was tracking her every move with the hydrophone and following her in their boat.
After about 10 minutes, Calafia was completely sedated. But thanks to the unique drug combination used to sedate her, she was still coming to the surface to breathe spontaneously, making it possible for the team to pull her aboard the small boat and transport her to the deck of the Narwhal.
help disentangle sea lions in Mexico's Sea of Cortez.
The group of 30 Mexican officials watched as Dr. Johnson and his team examined Calafia’s wounds. The entanglement around her neck, which turned out to be monofilament line from a gillnet, was so deep and had been there so long that her skin had started to grow over it.
After administering additional anesthesia to ensure Calafia was fully asleep, Dr. Johnson removed the monofilament line and treated her wounds. Then he reversed her anesthesia and Calafia woke up and quickly made her way back to sea—she was finally free!
After the successful rescue and with dusk setting in, the Narwhal headed back home. As predicted, the winds were heavy enough to keep the Narwhal docked for the next two days. The group returned to attempt another mission, but the persistent winds made the risk too high.
On a final sweep of the rookery, the team returned to the same rock where they had darted Calafia just days before. They found her lying in the same spot with just a scar around her neck and blue flipper tags. To everyone’s astonishment, a small sea lion pup was nursing beside her. Calafia was a mother!
Although the rescue team had to leave behind seven entangled animals that day, everyone onboard the Narwhal can take pride in knowing they’ve made a difference for Calafia, her pup and many others. The success of the workshop and disentanglement demonstration led Mexican officials to adopt this remote sedation technique as standard practice because it is safer for the animals and for the humans involved.
“Just as rescuing Calafia from her entanglement also helped save her pup from being an orphan, we are hopeful that this cross-border collaboration will create a ripple effect resulting in many more lives saved,” Dr. Johnson says. “This is just the first of many disentanglement efforts to come.”
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