Friday, August 23, 2013

Tobago Glow Worms



I have seen many weird things around the world, including cave glow worms and bioluminescence, but of all of them, this tops the list. 

About an hour after sunset, while at anchor, on the night of the full moon, it seemed like the lights of the ocean turned on. At first we thought it was the reflection from the stars above, complete with shooting stars, but no… It was hundreds of small sea worms, each individual glowing with green light. Some seemed to be swimming in figure eights making clouds of light, whereas others (the shooting stars) made blinking beelines for the ones with the clouds. As soon as the two worms met, the lights winked out of existence. And, as suddenly as the miracle had appeared, the lights winked out.

 
These small worms are some species of odontosyllis (I won’t specify because they all look the same to me) and this is a monthly mating activity in the summer months. They live underwater in protected rocky bottoms.  On the night of or after the full moon, females rise to the surface and swim in circles while releasing a bright green bio-luminescent substance.  A female can glow for up to 8 seconds, and can repeat this process up to 33 times over 12 minutes, or until she attracts a mate. (I would suppose they attract a mate pretty quickly, because I’m sure the whole show was at maximum 5 minutes.) When a male sees her, he emits short bursts of light while swimming towards the female. Usually several males are attracted to one female. When they meet, the male and female swim around each other in a narrow circle letting out their sperm and eggs. We learned that it was Christopher Columbus who first noticed this spectacle of the glow worm mating dance in 1492.

Dad found it was hard to get any pictures or video, but the following from the internet captures one or two. You’ll have to imagine this happening all around our home. Dad slowed down the video speed on one section where you can see the male coming in from the lower right.



After doing the research and getting the precise timing after sunset, we were all lined up on the side of the boat waiting the next night and were rewarded with the same spectacle again.

And that is the story of the most amazing light show I’ve seen.

Emily

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