My wife and I took a vacation to visit Roatán, Honduras where we got our PADI Open Water Diver certification.
Roatán is not only right next to the second largest reef barrier in the world but also has the Roatán Marine Park who aim to protect Roatán’s natural resources through a variety of efforts. The marine park now shelters the stunning reef along Roatán’s most heavily used stretch of coastline — including West Bay, West End and Sandy Bay — and includes a patrol staff that organizers say has virtually eliminated poaching on the reef. Naturally, we got to learn how to breathe underwater in some of the most amazing conditions.
Best of all, my wife and I were lucky to be in Roatán during a new moon when the night sky was at its darkest. We were told by many divers that one of the best things to do in Roatán was to go night diving, especially when the moon is dark.
As PADI explains in their night diving course, you have to be more aware of certain things. For instance, since its dark, you need to shine a light to yourself when trying to communicate.
We prepared by learning all the nuisances to night diving and going over our dive plan. Then we set out to the ocean around 6:30pm.
We shipped out and was in the water when the last light disappeared beyond the western horizon. We turned our flashlights on and started descending. We followed our leader through the underwater maze of reef, seeing fish we never saw during the day and even seeing an octopus make its way across the ocean floor.
After about 40 minutes of diving, we came to a sandy bottom around 40 ft deep. We landed on our knees and was given the signal to turn off our flashlight.
We were engulfed by total darkness. The only thing that reminded me I was underwater was the current of the water that made me sway back and forth slightly. Then, out of nowhere, the underwater ecosystem came to life.
When we moved our arms and hands, these bio-luminescent micro-organisms were responding and lighting up. Think fireflies (or lighting bugs) that light up when you get close. As another guy puts it, “it was like we were radioactive… every-time we moved we were shooting glowing sand! The bio-luminescence twinkled all around us like stars in the night sky.”
While we were preoccupied with the small wonders, around us in the stillness, the strings started. Like a dangling Christmas light, lighting up in sequence, these string of pearls were all around us. I have never taken acid but I was told this experience was comparable to an acid trip.
When our eyes adjusted to the dark and we were able to see the small shadows of rocks near us, we started to swim through the galaxy of stars. I imagine this is what it would feel like to (safely) fly through a sky of fireworks.
It’s incredibly difficult to explain; even as I’m writing this, I’m finding myself using the backspace much more than I usually do as I can’t find the words to aptly describe the experience.
My dive instructor recommended I not bring the go-pro for the night diving because there would be too much to keep track of with the flashlight and navigating in the dark, not to mention that the video footage wouldn’t be good anyway given the lack of light. True to what he said, I still haven’t been able to find any footage of this phenomenon on YouTube.
Since being back, I looked up to explain what I saw that night. Turns out, what we witnessed was a mating display of these organisms called ostracods. Here is a summary of this paper:
The string of pearls phenomenon is actually the mating display of ostracods. Ostracods are tiny crustaceans, about the size of tomato seeds and they use their bioluminescence to attract mates in the same way that fireflies do. It’s a common phenomenon throughout the Caribbean and is usually best seen about one half hour after sunset or moonset. Male ostracods release their bioluminescent chemicals into the water as a string of dots. It’s a species-specific display – sort of a Morse code. The spacing of the dots in the water is unique to a particular species so females, recognizing the code for their own species, can swim to the end of a string of dots and know that they’ll find an eligible male.
Here is another (more approachable) paper.
If you’re looking for a vacation spot, let me know and I’ll connect you with the dive master who taught me and showed me all the amazing sights underwater!