On a recent Thursday, Otto skipped his $12 seafood breakfast to prepare for surgery.
The 8-year-old southern sea otter was poisoned by exposure to toxic algae, likely after eating a batch of crabs. Toxic algae forms in warming ocean waters and produces a neurotoxin called domoic acid. This neurotoxin concentrates as it moves up the food chain, and it can cause seizures in marine animals and humans. During the winter of 2015 to 2016, domoic acid poisoning shut down the commercial crab season for more than four months.
Veterinarian Mike Murray holds a life history tag before it’s embedded in Otto, an 8-year-old sea otter. (Elena Graham/TMMC)
This year, the number of sea otters stranded on California beaches is up considerably, says Mike Harris, a sea otter biologist with the California Department of Fish and Wildlife.
“We’re on pace in 2017 to break some new records for live strandings and carcasses recovered,” he says.
Scientists still know very little about how domoic acid affects sea otters off the California coast. But in Otto’s case, a recent MRI showed damage to the hippocampus, which affects memory and navigation. Otters use these functions to find their way in the open ocean.
That’s why veterinarians at The Marine Mammal Center in Sausalito decided to try a novel surgery on Otto, which would allow them to monitor his location and learn how the domoic acid poisoning affects him over time.
“It’s definitely a unique procedure,” says Shawn Johnson, the center’s Director of Veterinary Science.
To prepare Otto for surgery, veterinarians can’t shave his fur like they would for a cat or dog. Otters rely on their thick coat to stay warm so shaving it would expose them to cold California waters, potentially leading to hypothermia.
“Most surgeons wouldn’t want to do surgery without shaving,” says Johnson, as veterinary technician Marissa Young parts Otto’s fur with an orange plastic comb. “To really tease all those hairs apart to get to the skin, it’s really hard.”
Young carefully parts the hair to expose a thin line of skin, then smooths the fur down with a gel to hold it in place during surgery.
The purpose of the surgery is to tuck two devices into Otto’s abdomen. One, a VHF transmitter, will allow scientists to track Otto’s location at sea. The other tag, shaped like a pill, will track how he fares once he’s back in the wild. This “life history tag” will measure light and temperature from inside the animal’s body.
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