Ostracods in Bonaire – a sexy dance while diving. A few days after the full moon an astounding phenomena happens underwater in Bonaire that is akin to an underwater firework display by tiny creatures called Ostracods!
Our friends on Ad Astra had been talking about this amazing display for weeks and so after the full moon they decided to plan another day out on their big boat, Ad Astra. Our friends from Element joined us for a total of 10 people (7 divers). We headed over to Klein Bonaire to a site called Sharon’s Serenity. The plan was to dive the site during day light hours, then go back and do a second dive at night to try to witness the mating of the Ostracods.
The first dive was pretty amazing. Matt and I headed out first and explored 23 meters below the surface to find a wide array of sea life. We saw a small school of Hawaiian Black Triggerfish also called Black Durgon which are actually dark blue with a tad bit of green if you get up close and personal (which they wouldn’t let us). The white strip is actually silver, but it appears to glow as they swim by.
As we were waiting for the other divers, we explored a huge coral that had a large cave or protected area (perfect for lion fish and/or lobsters) so I peered in and to my surprise there were 4 HUGE lion fish – probably 15-18″ in length hovering upside down! I was so darn impressed and in awe of these stunning creatures that I almost forgot they are destroying the reefs. I showed Matt and a few of the others the find and eventually swam back to the boat. Matt and I had a good long dive, over 60 minutes at this site.
We got back on Ad Astra and enjoyed some light snacks and shared stories of what we saw below. Just after sunset, we put our gear on again and jumped back in the water. Since the current had picked up a bit, we decided to head to the bow of the boat toward the mooring. A few of us were armed with flash lights so as we waited for full darkness as we explored the shallows and found several eels and lots of fire worms which are pretty spectacular at night but hurt immensely if you touch them.
We had a strong current and in an effort to minimize our movement and use less air, we decided to hold on to the mooring line to wait for the Ostracod show to begin. We had already turned off our lamps and were truly just hanging out in 6.5 meters of water in the darkness. We did have the moonlight and once your eyes adjusted you could see so it wasn’t total blackness.
The Ostracods (or Seed Shrimp), are tiny creatures (only a few millimeters long) live in shallow water for mating. They belong to the Crustacea family (shrimp, lobsters, and crabs) and produce a blue glow to attract a partner.
There are many creatures that can glow, especially marine life at greater depths. This phenomena is called bioluminescence. The glow is produced to attract a partner for mating or for signaling alarm to others. Other sea life that glow underwater are (specific types of) octopus, jellyfish, worms, plankton and deep sea fish.
Cypridinid ostracods are one of the type of Ostracods that can be found around Bonaire, the ones that produce the magnificent bioluminescence show around full moon. On land male fireflies attract mates by producing light patterns with bioluminescence, the same goes for Cypridinid ostracods underwater.
The magical mating show happens two to five days after the full moon. The glow and glitter explosion will take place 45 minutes after the sun has set and before the moon fully rises – and if and only if the Ostracods have NOT been disturbed by any light (dive torch, street light, lights from buildings, etc).
While we were waiting for the Ostracods to start mating we experienced a pretty cool display of bioluminescence ourselves. We started to wave and clap our hands underwater and were gifted with a dramatic display of something that looks like green fairy dust from Tinkerbell. This came from much smaller (microscopic) animals, a type of plankton, called Dinoflagellates. Dinoflagellates are found around the whole world and mostly seen around the new moon phase.
After the Dinoflagellates showed up, we slowly saw more and more tiny dots lighting up in the reef, for just a split second. After a few more minutes the dots became strings. The single Ostracods were swimming in a vertical line towards the surface while flashing and signaling the females. The line of bioluminescence was about 50 cm long sometimes and stayed visible for a few seconds. Nature can be just astounding! The closer we got to the soft coral, the more we saw, surrounding us – it was truly magical and a bit romantic. Maybe because Matt was holding my hand, but also because we knew we were enjoying a once in a lifetime experience.
We did not bring the GoPro down as we don’t have the proper equipment to shoot at night below the water, but thanks to Google you can find plenty of images online (see below). Famed photographer Elliot Lowndes who filmef this National Geographic documentary, you can see a different species lighting up the nighttime Caribbean. This is ont the same species who were in Bonaire, but it gives you an idea of what it is like during this mating ritual. Check out this video, especially :30-:53 for highlights
Above the water, you get a beautiful show as well – we did NOT see anything this spectacular, but we did see vibrant green ostracods floating on the surface of the sea.