BIDDEFORD — “Runt,” a harbor seal found this spring, was aptly named. When he was discovered on Islesboro, he was one-month premature.

But now the pup is thriving. He and four other harbor seals that have been going through rehabilitation for several months at the University of New England Marine Animal Rehabilitation Center in Biddeford will be released Thursday at noon at Curtis Cove.

In addition to Runt, “Laffy Taffy,” a female pup found in South Thomaston, “Milk Dud,” a male found on Criehaven Island, “Starburst,” a female found on Mother’s Beach in Kennebunk and “Twix,” another female found on Pleasant Island, will also be sent on their way.

This year’s theme for naming the rescued animals was candy, said Sarah Lucchese, an animal care technician.

But those working at MARC know the animals only by numbers, she said, “to keep ourselves separated.”

On Tuesday, the five to be released were oblivious to their fate. They and the other seals staying at MARC were swimming and playing.

The only hint that something would change were the tests being conducted to make sure no last-minute health problems would endanger them or other wildlife and delay their release.

MARC has been rehabilitating and releasing seals since 2002, said Kristen Patchett, interim MARC coordinator.

The marine animals brought to MARC come from a variety of sources; most stranded in state are rescued by the Marine Mammals of Maine.

This year, MARC has taken in 72 seals, said Patchett. Since April, they’ve taken in 52 harbor seals ”“ the kind that will be released Thursday.

The center has released 27 marine animals, including sea turtles as well as seals, back into the wild since January, she said.

Harbor seals found in April and May are maternally dependent. They have somehow been separated from their mothers and are mostly suffering from dehydration and malnutrition, said Patchett.

After a few months stay at the indoor pools at MARC, many return to health and are released.

Harbor seals found later in the year are weanlings who should be able to survive on their own but often have medical issues, diseases and/or injuries that cause them to become stranded.

Most of these seals are “in really bad shape when they come,” said Patchett, and never return to their natural habitat.

“We have a little more than 50 percent success rate,” she said, “the same expectancy rate as in the wild.”

Harbor seals have a high mortality rate, said Patchett.

When a seal release takes place, she said, “it’s a fun time.”

Many of the releases are open to the public.

The reason to allow public participation is two-fold, said Patchett.

“Part of our mission is to educate,” she said. So “we invite the public to learn about animals” at MARC.

In addition, MARC relies on donations to some degree, said Patchett. “We want to get our name out there for people interested in helping with what we’re doing.”

“I think people enjoy it,” she said about the releases. “It’s an opportunity to see seals up close and personal in a positive way.”

All the seals released by MARC have flipper tags that can be used for tracking the animals. A link to a website to track seals released by MARC and other facilities, as well as more information about Thursday’s seal release, can be found at the MARC website, www.une.edu/marc.

The seal release will take place Thursday at noon at Curtis Cove at Granite Point Beach off Granite Point Road in Biddeford.

Those who find a stranded marine animal in Maine should call the toll-free number of Marine Mammals of Maine at 800-532-9551.

— Staff Writer Dina Mendros can be contacted at 282-1535, ext. 324 or [email protected].