Buddy's duties include boat checks, running up and down the pier, chasing seagulls and squirrels. — Ray Ewing

Beneath a billowing American flag and light breeze off the harbor, Buddy sat in salute at the U.S. Coast Guard Station Menemsha early Monday morning, chest proudly puffed, ready for his next treat.

The three-year-old golden retriever was sworn in as a seaman recruit by Senior Chief Jason Olsen at a special enlistment ceremony. With the duty crew standing behind him, Buddy became a rank and file member of the Menemsha team.

“Be it known that Buddy, in selfless service to his country in affirming the oath of enlistment in the United States Armed Forces, hereby enlists in the United States Coast Guard in the rank of seaman recruit and rank as such,” Mr. Olsen read from the certificate.

“All right, good job, Buddy,” he added with a pat to the dog’s head.

“Does anyone have an ink pad?” Mr. Olsen asked. Buddy’s pawprint will go on his enlistment certificate.

Station Menemsha’s former mascot, Bridger, died in September 2011 at the age of 12 and was later buried at sea.

Now Buddy will fill the void, Mr. Olsen said. “It seems like the crew is a lot happier. It’s great to come in and have the dog here. He increases morale. People who had dogs or always wanted dogs but weren’t ready for it, having Buddy teaches a level of responsibility.”

Buddy arrived in Menemsha two months ago from North Kingston, R.I.

His responsibilities include daily boat checks, running up and down the pier, chasing seagulls and squirrels, sleeping at the feet of on-duty crew members and greeting visitors. He is trained to stay out of the galley, and sits patiently in the doorway during mess hour.

After a hard day at work, well-deserved rest. — Ray Ewing

Canine mascots are a longstanding Coast Guard tradition; through the years they have served as both companions and search and rescue workers. Buddy is officially designated as a mascot with the U.S. Army veterinary clinic and is eligible for care through the military.

Buddy’s single-stripe rank is marked on his blue collar. He is eligible for advancement by mastering new commands.

For now, his command repertoire includes sit, stay, come and shake (give a paw).

“We’re trying to get him to salute,” Mr. Soscia laughed.

While Buddy has been on board Coast Guard boats, he has yet to go on his first official mission and needs a life preserver, which will be ordered for him.

“We’ll take him out in the spring and see how he does,” said Mr. Olsen.