An adult harbor seal who was nursed back to health has been released back into the ocean.

The seal, named Phil by those who cared for him, was found stranded in a Delaware bog in April. He was suffering from an eye infection, dehydration and other ailments. He was rescued by a team from the Merr Institute.

Phil’s doctors said that he made great progress in his recovery.

“This is a joyful day for us, and we’re so grateful to the National Aquarium for helping us get to this point,” says Merr Institute executive director Suzanne Thurman.

Thurman says that the seal is eating on his own, and tests show he is in good health to be out on his own. He was released Tuesday morning from the Gateway National Recreation Area at Sandy Hook.