The feature-length documentary Under the Red Sea was lovingly assembled by oceanographer Dr. Hans Haas. The film poses several intriguing questions regarded the methods by which various forms of sea life communicate with one another. As narrator Les Tremayne comments on the action, the audience sees the effect that human-engendered sounds have on barracuda, groupers and the like. Perhaps at the insistence of the film's distributor, RKO Radio Pictures, several minutes of screen time are devoted to the underwater activities of curvaceous female-diver Lottie Berl. The less-attractive male members of the expedition include Gerald Weidler, Leo Rohrer, Edward Wawrowetz and Alfonso Hocchauser.