Monterey Bay Aquarium: Study shows benefits of sea otter surrogacy program

The Monterey Bay Aquarium said in a blog post Monday that a new study shows that the aquarium’s surrogate program is helping to increase the otter population at Elkhorn Slough.

The aquarium pairs female otters in captivity with orphaned otter pups to help them learn life skills, like how to groom themselves and forage. The hope was that when the pups were released in Elkhorn Slough, they would be able to live on their own.

A new study from Oryx shows that pups raised by surrogates are surviving as well as those raised in the wild and that they’ve boosted the otter population at Elkhorn Slough, which the aquarium said is helping to restore the estuary ecosystem.

Between 2002 and 2016, the aquarium has released 37 surrogate-reared pups in that area, and scientists said the surrogate-raised otters and their offspring now make up more than half of Elkhorn Slough’s otter population growth.

“The success of those individuals wound up having both population-level and ecosystem-level impacts,” said Karl Mayer, sea otter field response coordinator at the aquarium and lead author of the new study. “This lays the groundwork for a new discussion around returning sea otters to more of their historical range.”

Part of why the aquarium believes the program is successful is that as opposed to wild-released otters, surrogate-reared pups do not have an established home range, so they do not try to return to it and instead adopt Elkhorn Slough as their territory.

Because of the surrogate-reared otters’ lack of home range and survival rates similar to their wild counterparts, the aquarium said introducing otters elsewhere may be worth investigating. Historically, other estuaries on the California coast supported otter populations and the aquarium said they could benefit from their return.