(Belated post from Turks & Caicos)
Tied to a dive ball just of the Ananyara Resort on the west coast of Caicos. (As you can see the resort looks like the dogs bollocks, but is more expensive).
Pete is grilling some Brazilian chorizo (smuggled by your correspondent at great personal risk), when he suddenly sees green lights all around the boat. They are wriggling green lights, which occasionally have bright pin prick lights spiral around them in ever deceasing circles until contact and, aaah, lights out (youtube link)….. The whole thing takes about ten seconds. At first Pete thinks it’s flashbacks from his high school years. But, no!
It turns out that this is the mating display of the marine worm Odontosyllis enopla. During the 2 – 4 days after the full moon, exactly 55 – 57 minutes after sunset, the female worms rise to the surface and start glowing: [article translated from the Italian also article here]. The males (also glowing) are attracted to the light and approach the female in ever decreasing circles until they get there and release their sperm.
As an aside, the diving off this mooring ball was spectacular. The ball is in 35 ft of water. Swim 100 yards away from shore and it gradually slopes to 50ft before you hit a wall that drops to ~1000ft (according to the chart). Lots of healthy coral, sharks, turtles, and large grouper all pretty much indifferent to our presence