Dr Samuel Jamison (George Rowe) is an American marine biologist who is lured south of the border to Mexico when he is contacted by an elderly scientist, Ernst Steinhauer (John Mylong). He shows him a large and priceless pearl that he claims has been found in the waters off the island of Tiburon, and there is the promise of more where that came from. Intrigued, Samuel agrees to investigate, yet when he arrives at Steinhauer's home he finds not a trace of him - except his broken monocle. Undeterred but suspecting foul play, Samuel journeys to the island where he makes a remarkable discovery...
The Mermaids of Tiburon was one of the few films written, produced and directed by underwater photography expert John Lamb, and he liked the idea so much he returned to add to his footage twice, renaming the film The Aqua Sex and putting less of the finned mermaids in it and more of the topless women, a strong hint of the direction into hardcore pornography he was about to follow. The first incarnation of this film, on the other hand, was as wholesome as it was possible to be, the presence of seasoned and highly idiosyncratic heavy Timothy Carey as the villain notwithstanding.
On television, Lamb was best known for supplying the underwater footage for Voyage to the Bottom of the Sea, and that's pretty much what is on offer here: lots and lots of undersea camerawork. There is a nod towards a thriller plot when Samuel is followed to the island by Carey's unscrupulous pearl seeker Sangster, accompanied by a verging-on-the-stereotypical Mexican Pepe (Jose Gonzales-Gonzales) who owns the boat, but for the most part what you see is a big slab of fish, seaweed, and a collection of models wearing fishtails.
This is because there are genuine (or as genuine as it's possible to get in a low budget flick) mermaids in the waters around the island, where we are told hardly anyone ever ventures. While he's on the lookout for pearls, Samuel sees what he thinks are large fish but on strapping on his scuba gear and going for a swim he realises what he is seeing are the mermaids. They never speak to him, and you may well be marvelling at the length of time the ladies in the title roles can hold their breath, but this merely bolsters the oddly dreamlike presentation.
I don't know if Lamb was a fan of Jacques Cousteau, but his efforts here were reminiscent of one of the Frenchman's famed documentaries if Cousteau had ever discovered mermaids, that is. There's hardly any dialogue, just a plentiful amount of narration as if this were some kind of nature exploration movie, and it's only when Sangster begins chucking dynamite around and feeding Pepe to a rubber shark that anything resembling tension arises. It's as if Lamb wanted to make a recording of his self-created mermaids yet felt a duty to put the framework of a real story around it, but although it's always good to see Carey, this works best in the long sequences of the cast under the sea. Eccentric it may be, but it has a certain charm. Music by Richard LaSalle.