I’ve had a lot of fun writing for the Monterey Bay Aquarium, so I thought I’d highlight some of the stories here on my own blog. This article was originally published on the Monterey Bay Aquarium blog. That’s me at left in the photo.
“One, two, three…” With that pronouncement, Karl Mayer of the Sea Otter Research and Conservation program opens the door of a small dog kennel. A 45-pound southern sea otter, known only as 451, paws the air inquisitively, eyes the broad expanse of Elkhorn Slough, and executes a perfect dive into his new life.
Like many of SORAC’s otters, 451 started life in a cataclysm. He was abandoned on a Santa Cruz county beach in October 2008, then brought to the Monterey Bay Aquarium at two weeks of age and seven pounds. There, for nine months, he was coddled, cared for, and occasionally chastised by an exhibit otter named Toola, serving as a surrogate mother.
As we watch, Otter 451 surfaces about 200 feet to starboard, floats on his back, and considers his circumstance. Given the fact that 451 spent the first nine months of his life in an 18-foot enclosure at the Monterey Bay Aquarium’s SORAC facility, it’s only natural that this small estuary, while less than a mile across, seems as vast as the Pacific.
To date the program has successfully released 12 surrogate-reared otters into the wild—five males and seven females. So far, three of the surviving females have produced offspring of their own.
Considered extinct in the 1920s, southern sea otters (Enhydra lutris nereis) were placed on the endangered species list in 1977. Despite decades of federal and state protection, they’re still at a fraction of their historic numbers. In a worrisome trend, a spring 2009 census indicated there were 2,654 sea otters along the Central Coast, a four percent decline from the previous year.
SORAC, a program of the Monterey Bay Aquarium, has been trying to understand and conserve sea otters for more than 20 years. Since 2005, Karl and his staff have been raising and releasing stranded pups through the surrogate program. The goal is to evaluate surrogate-rearing by studying behavior and survival of pups after release. The hope is that these pups assimilate into the wild population, survive to maturity and produce offspring of their own.
Ultimately, it’s all about conserving the sea otter population. ”In order for this effort to be considered successful, we have to demonstrate that surrogate-reared pups not only survive, but contribute to the wild population,” says Karl.
For the SORAC team, a call can come in at any time. Typically, a beachgoer will find an abandoned pup and bring it to the attention of State Parks, the Marine Mammal Center in Sausalito, or any number of other agencies. “But ultimately,” says Karl, “they come to us. We coordinate all the sea otter stranding responses.”
A pup may have been abandoned for any number of reasons—the mother may be ill, or the two may just have been inadvertently separated. “Our first step,” says Karl, “is to try and re-unite the pup and its mother.” Typically, this involves getting the pup to “vocalize,” for instance, by gently pinching its foot. Hopefully, the mother will recognize the call of its offspring and the two will be successfully re-united.
This occurs only about 20 percent of the time, according to Karl. But if it doesn’t, and the pup is otherwise healthy, SORAC may have just gained another candidate for its surrogate program.
“Anyone seen an otter?” says Karl, at the helm of our small Zodiac. A beeper is going off insistently, receiving a signal from a transmitter in 451’s abdomen, but the otter is nowhere to be seen. Karl scans the muddy banks with binoculars for a few seconds and suddenly declares, “There he is.” Otter 451 is exploring the pickleweed, aimlessly.
Karl and his staff have a lot invested in this otter. For months, they have been watching its behavior behind the scenes at the Aquarium, on video camera, sometimes up to 20 hours a day.
Each pup is placed with one of three surrogate mothers at the Aquarium, who share food, groom and protect the young otters as if they were their own. During this time, SORAC staff take special care to minimize human contact, wearing ponchos and welding masks to disguise the human form. This ensures that the young otters don’t develop an affection for their caregivers—or vice versa. “We need to create a buffer,” says Karl. “These animals are so charismatic, it’s easy to become attached to them.”
After about six months, the young otter undergoes surgery to have the transmitter implanted, in anticipation of release. It also gets colored flipper tags, a transponder tag and a general health check from the Aquarium’s veterinarian. It’s placed back with its surrogate mother for a few weeks to recuperate. If all goes well, a surrogate-reared pup will be released into the Slough at seven or eight months of age.
Karl and his staff are hoping that otter 451 has the skills necessary to survive in the wild. Now, out here in the Slough, they’re about to find out.
Karl Mayer of the Sea Otter Research and Conservation program (SORAC) is scanning the bay, looking for a recently released southern sea otter, known only as 451. The otter was abandoned on a Santa Cruz county beach in October 2008, then brought to the Monterey Bay Aquarium to be reared by an exhibit otter named Toola, serving as a surrogate mother.
Out here in the bay, work can be long stretches of boredom punctuated by moments of excitement each time the receiver goes off. Our Zodiac sports a crude, duct-taped pole with what looks like a television antenna on the top. Karl periodically scans the dial for otters with active transmitters. Otters are his life, and he doesn’t need notes to convey the life history of each one. “That’s 339,” he says of one of the beeps. “The first surrogate-reared pup to have offspring of her own.”
With the help of SORAC volunteers, Karl will spend up to 10 hours a day for the next two weeks monitoring his new charge out in the bay. To learn more about their habits, he uses GPS and a small handheld device to record activity every 10 minutes, detailing its location, dives and—hopefully—its feeding habits.
It’s hard to know what a released otter will do.The best scenario is that he will begin foraging and eating immediately, and stay within the safe confines of the bay. At one point Karl excitedly reports that 451 has got something in his grip. But no luck. “It’s just a clam shell,” he says with a hint of disappointment. If 451 doesn’t summon the instinct to forage and start eating, he’ll need to be recaptured. A young otter has about three days to figure out how to find food “before he runs out of gas,” says Karl. This is why close monitoring is so crucial.
Perhaps the worst scenario is when an otter breaks for the open ocean, where food is scarce and recapture is difficult. “If he goes offshore within the first few days of release, we’ll attempt to recapture him,” says Karl. “For an otter that stranded as a young pup, the open ocean is unfamiliar, and the tendency is for newly released juveniles to swim too far offshore to be able to forage successfully.”
It’s also difficult to locate an otter in open water. When all else fails, Karl gets on his cell phone and summons a plane out of the local airport. The plane is equipped with an antenna and receiver and the pilot knows the frequencies of the various otters in the area. With the pilot’s help, Karl can locate the otter, recapture it and hope for more success next time.
Fortunately, otter 451 elects to stay in the bay. However, he’s not feeding, and two days later, Karl decides its time to recapture him.
Recapturing a 45-pound sea otter—even one that is weak with hunger—is no easy task. Once, an otter went deep into the recesses of the estuary and got caught in a narrow channel. Karl dutifully headed off into the pickleweed, knee deep in mud, to recapture the otter. By the time he had him, the tide had grounded his small boat. So Karl and the wayward otter sat in the mud for hours, waiting for the seas to rise. All told, it was a 12-hour day. At these times, sea otter conservation—while eminently worthwhile—seems less than romantic.
The good news is that recaptured otters tend to do much better the second time they are released. With this in mind, Karl and the SORAC staff will spend a few weeks “adding fat reserves” to otter 451. He’s confident that the second time will be the charm. If so, it will be another success story in the long saga of rebuilding the threatened southern sea otter population.
Just two days after being released into Elkhorn Slough, otter 451 is struggling. Confused and hungry, he starts pacing back and forth in narrow channels, looking for food. At one point, he tries to hike overland to get to another part of the Slough.
That’s when Karl Mayer of Sea Otter Research and Conservation (SORAC) decides to go after him.
“He’d lost focus,” says Karl. “He was just burning energy—not successfully foraging.” Out in the Slough, a young otter can become dangerously weak, get into a place where he can’t be captured—or both. “The stress was mounting,” says Karl. “He was acquiring information and knowledge about the area, but he was also losing weight. Timing is critical.”
Decision made, Karl and a volunteer set off in thigh-deep mud, nets in hand, trying not to have their boots sucked off in the murky depths. The trick is to “sneak up on the otter before he realizes what you’re trying to do,” says Karl. Successfully netted, the 45-pound otter struggles all the way back across the mud flats to the boat. “He was not a happy guy,” says Karl. “He was still robust enough to show some energy.”
Back at the Aquarium, it becomes clear that it was a good idea to recapture 451. During his two days in the Slough, he’d lost more than six pounds—or almost 14 percent of his body weight. He couldn’t have gone too much longer without food.
After a brief quarantine period (customary for animals that have been in the wild), 451 is returned to a familiar environment: the Aquarium’s rooftop SORAC facility. The goal is simple: fatten him up for re-release. Turns out, that’s not hard to do. It takes less than a week for 451 to regain the weight he’d lost rummaging around in the Slough.
Before long, it’s time to try again. Otter 451 is taken back out in the Slough and released. Almost immediately, it’s apparent that he has a new mission in life. He’s picking up small crabs and eating them, mingling with other otters, and staying within the confines of the Slough—all good signs.
No one knows for sure why many otters require a second release, but it likely involves an age-old concept: the school of hard knocks. “There’s the experience of having lost weight, and potentially coming close to starvation, that acts as a trigger,” says Karl. “They realize that food is not going to just appear in a big pile like it does in the Aquarium’s holding facility.”
At this point, the team breathes a collective sigh of relief. The first two weeks of a release are the most critical, as pups figure out how to find food and survive in an unfamiliar environment. After that, they tend do well. Among nine surrogate-reared otters surviving the two-week release period, only one has died within the first year – and that was due to “shark trauma.”
From this point, 451 becomes part of the SORAC’s long-term study of surrogate-reared pups in the wild. It’s another success story, and another small step in helping solve the mystery of the threatened southern sea otter.
“We’re glad this guy stayed in the Slough and figured it out,” says Karl.
(© Monterey Bay Aquarium)