Pair of Rehabbed Otters to Carry New Biological Transmitters

A pair of otters that were nursed back to health from near death will serve as the ambassadors for a new tracking technology that will record their biological information over the course of their lives.

The new tags, known as a Life History Transmitters developed by Markus Horning, were surgically inserted in female otters Langley and Sprout during a recent procedure at Sausalito’s Marine Mammal Center, where the animals were paired up.

When released later this month, the tags’ sensors will record information like light, temperature and the chemistry of the abdomen. The data will help researchers understand more about how and when the animals reproduce and the cause of their deaths. The only catch is, the data won’t be available until the animals die and the tag is released through decomposition and the data uploaded to a satellite.

“With all these different data that’s collected with the tag,” said Shawn Johnson, the center’s Director of Veterinary Science,” we can make a lot of inferences about the whole life of the otter.”

Veterinarians at Marine Mammal Center implanted the Life History Transmitter along with a standard radio tag which will provide short range information of the animals’ travels.

“These tags will give us information about the end of the animal’s life,” Johnson said, “and the radio tag will give us information about the beginning of their life.”

Langley was discovered on the Central Coast near San Luis Obispo — she was found onshore clinging to her mother who was suffering from a fatal shark bite. Veterinarians at the Marine Mammal Center nursed her back to health.

Sprout was found in the Monterey Bay thin, emaciated and suffering the effects of Domoic Acid poisoning, a naturally occurring bio-toxin that impacts sea creatures. Veterinarians with the Monterey Bay Aquarium nursed her back to health and eventually sent her to the Marine Mammal Center.

“We had a great conversation with each other,” said Dr. Cara Field of the Marine Mammal Center, “and decided the two of them would be good companions and brought them together here in Sausalito.”

Researchers estimate there are only about 3,000 sea otters left in California, although their numbers have greatly rebounded from the days when they were hunted. But experts say their further recovery has been stymied by another creature of the sea — sharks.

“Right now it’s the shark bites that’s preventing them from expanding their range,” Johnson said.

The population of otters is dispersed around the Central Coast and in the Monterey Bay. Beyond that, researchers said they seem to travel to places where it’s difficult to study their lives. The hope is the new tags will shed more light on their trajectory, and could potentially even help determine the cause of their deaths — such as in the case of a sudden death by shark bite.

“The ability to put a tag like this that stays with the otter, causes no harm, yet collects data throughout the animal’s life span,” said veterinarian Michael Murray of the Monterey Bay Aquarium, “is a wonderful way to understand more of what happens in other parts of sea otter range. “

The new Life History Transmitter has been previously tested, but this is the first time it’s being used on otters to be released in the wild. Researchers plan to release the pair later this month in the Monterey Bay.

“They’re both females that can really have a benefit to the population,” Johnson said, “and we want to make sure they’re thriving.”

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