Additional interviews with Gary Shannon, supported by some additional research, seems to have led to an answer. Do we finally know who developed the Atari 2600 title Aquaventure back in the summer of 1983?

In Aquaventure you play as a deep sea treasure hunter, desperate for one big score to make your fortune. Your crew believes it has discovered the shipwreck of the notorious pirate Calico Blue, and his lost treasure. We couldn’t find any reference to a real life Calico Blue, but there was a Calico Jack. Learn more.