Fireworm Spectacular

Sitting on a dock in Isla Morada, watching the stars come out as dusk turned into night, when suddenly a bright green luminescence appeared in the water. At first I thought it must be a glowing jellyfish. Then more appeared, and looking more closely I saw each was a brightly glowing wriggling worm, a couple of inches long, creating around it a luminescent pool about a foot across. They were there for a minute then vanished. Altogether forty or so must have suddenly appeared, and just as suddenly disappeared. Within minutes the show was over.

Subsequent research revealed I had just seen the mating ritual of the bearded fireworm. It happens on the third quarter of the moon in Spring, fifty-six minutes after sunset. The females come out of the mud, swim up to the surface and put on this spectacle, attracting the males up to them.

But how come such exact timing, I wondered? At first I must I thought be triggered by the degree of darkness reached 56 minutes after sunset, on a day when there is no full moon. But a day or two after the full moon, the sky would be that dark. Why did it not happen till the third quarter – and this was exactly on the third quarter, seven days after the full moon.

I was left in wonder. One of those fascinating ways life on Earth is linked to the cycles of the moon – and so precisely.

And my own timing was perfect too. Had I not stayed on the dock till it got dark, I would not have seen them. Had it been en another day, I would not have seen them. Perhaps this is the only time in my life I will be privileged to witness this magic luminescent dance. But I shall be eternally grateful for having done so. (Or maybe I will return on the third quarter of the April full moon next year.)

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