How to Dive in the Dark


Lighting up the details of the reef at night with your underwater light reveals everything in a full spectrum of vibrant colour that you would never see during the day.

Nocturnal wildlife

Many creatures on the reef are nocturnal. They include predators, such as whitetip reef sharks and moray eels, that hunt at night. Crinoids, such as basketstars and featherstars, creep from their daytime hiding places to feed on the plankton. It’s at this time that the coral polyps come to life, protruding out from the hard coral, waving their arms.

Strangely, many of the more easily frightened animals seem unaware of divers at night, and they will be mesmerised by your diving light. Other creatures take advantage of this fact to make their hunting easy.

Some of the animals commonly encountered at night include rays feeding, hawksbill and green turtles browsing, goatfish probing for their supper in the sand, and crabs and lobsters parading out in the open. It’s also during the night that the octopus stalks its prey of shellfish.

Some animals are considered particularly special quarries for night divers. These include the flashlight fish in the Indo-Pacific and the rosy-lipped batfish of the Galapagos and Cocos islands. Spanish dancers – sluglike invertebrates found everywhere in the tropics – are also wonderful to see at night.

Night diving

A loss of spatial awareness is the greatest challenge to the newly certified night diver. Without a visual check on where you are, you need to rely on your instruments to tell you how deep you are and in which direction you should be going. Many diving computers have their own integral lighting to help you read them in the dark.

It is essential to control your buoyancy unless you are diving over a sea floor of a fixed depth. When it’s dark, it’s easy to go deeper than you intend if there is no fixed visual reference and you omit to continually check your depth gauge or computer.

A reliable light is essential, and so is a backup light ready for use should it be needed. There is a huge range of lights with a variety of features to choose from, but the most important thing is to have one that functions. Backup lights are vital, as all diving lights can fail by flooding, running out of power or simply by blowing a bulb.

Always start a dive with a fully charged light and enter the water with it already working. If you don’t want the light shining, block out the light rather than switch it off. This is because the lightbulb is most likely to fail during the current surge when it is switched on, and you don’t want this to happen while you are underwater in the dark.

When signaling, shine your light on the signal you are making with your hand. If you wave your light so that it flashes across the field of vision of another diver, it will attract their attention.

Experienced dive guides believe that when divers are bobbing on the waves after a dive, they can only deliver one or two signals reliably. The signals they suggest using are a steady light, which means ‘come and pick me up when you can’, and a frantically waved light, which means you have an emergency situation. A submersible strobe beacon is useful in an emergency because it emits a bright flash of light repeatedly over a very long period of time, clearly marking a position that can be seen from all angles.

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About the Author: Cody Riffel is a regular contributor to MegaHowTo. She likes to write on variety of topics, whatever interests her. She also likes to share what she learns over the Internet and her day-to-day life.

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