Commander Melville is a pink whale who rescues the Muppets from being lost at sea in the 1980 graphic novel Muppets at Sea. The Muppets' cruise ship, the Queen Mabel, sinks when Beauregard pulls a plug belowdecks and lets on water. The Muppets are just managing to stay afloat when Coleridge the Albatross arrives with his old friend, Commander Melville.
Melville has found Gonzo, who was last seen sailing an old pot off into the sunset dressed as a pirate. Gonzo and the rest of the Muppet gang pile on to Melville's back and sail off into the sunset, to safety.
At the end of the book, Kermit reveals that Commander Melville refused Gonzo's offer to join his act, but Coleridge took Gonzo up on it.
The source of Melville's naval rank is unknown.