If you’ve ever been on a boat at night, and noticed little streaks of light along its’ sides or in its wake as you move through the water, then you have seen bioluminescent marine life in action. Although the creatures that create these magical lights are tiny, the little dinoflagellates are proving just how much energy they are capable of creating, storing, and expending. There are many bioluminescent creatures living in the world’s seas and oceans, from tiny to very large. Here are just a few you might encounter one day.
Caribbean Brittle Stars
In the Caribbean, the brittle star Ophiopsila Riisei, which lives among coral rubble and along the reef crest and fore-reef slopes, glow intensely when left undisturbed, and flash brilliantly if bitten by a predator; shine a light on them, though, and they curl up into little balls. Growing to be as large as 12 inches across, they release a nasty tasting secretion that keeps predators from taking as second bite.
Flashlight Fish
Commonly encountered in the Red Sea, in the many caves they occupy, flashlight fish belong to the family Myctophidae, and are just one of more than 200 similar bioluminescent species. Various flashlight fish live in tropical waters across the world, and are typically less than six inches long. They tend to visit reef environments at night, where they feed on small crustaceans; you’ll see the tiny lights beneath their eyes flashing around you when they are near. They use their little “flashlights” to attract prey, avoid predators, and to communicate with one another.
Pinecone Fish
Pinecone fish can be found in the Pacific and Indian Oceans; these little fish have a bioluminescent spot located at the tip of the bottom lip, which is used to attract prey. While flashlight fish of some species can turn their lights on and off, pinecone fish cannot; they instead tuck their lower lips into their upper lips to prevent their lights from being spotted at inopportune times. Found at depths between 10 and 200 meters, with juveniles preferring much shallower water and adults preferring ledges, caves, and dim reef environments, these fish form nocturnal schools and can put on quite a show. The largest of all pinecone fish is the Pineapple Fish, which grows to be about 12 inches long.
These are just a few of the many bioluminescent creatures you may encounter while diving. For the best chance of encountering these and other fish, ensure you are properly weighted so you can achieve negative buoyancy quickly, and select a sandy-bottomed shallow site where you can relax easily. Cover your dive light to achieve near total darkness, then wait for your eyes to adjust to the dark. Wave a hand in front of your face, and you’ll be able to see the dinoflagellates, looking for all the world like a trail of pixie dust right before your eyes; the best places to see this phenomenon is where concentrations are highest. In areas where barnacles grow along rocks, look for their pale green halos, and in places where sea squirts aggregate, look for their shimmering patterns. Sea pens and sea pansies also glow when irritated, and swarms of female Bermuda fireworms show off in luminescent splendor as they work to attract males. Many jellyfish are bioluminescent, and so are some squid and cuttlefish.
To photograph bioluminescence in action, remember that you must have darkness to operate, and shut off any flashes or external lights. Play with exposure, and be patient. You’ll find that the results can be simply stunning. No matter where you dive, you may get the opportunity to view and photograph some of these creatures; so long as you’re not afraid of the dark.