All sorts of travel documentaries will highlight destinations that “Do Not Sleep”. Many destinations are even defined by their nightlife. The reefs you dive in your local area or on a dive vacation are there 24 hours a day, so why just dive in the daylight? Why not explore the nightlife on a reef instead of waiting around for the nightlife in your resort to gear up. Take your first night dive.
It is common for first-time night divers to be a bit nervous maybe even scare. Anytime we are facing the unknown it can be a little unnerving. Night diving on a reef brings a new dimension to your diving. The personality of a reef changes when the sun goes down. The fish you see during the day finds places to hide and those that sleep during the day come out to play and eat. Because you are using an unfiltered light source at night, you will find that the reef is much more alive with color at night.
It is said that opera is an emotional experience, the first time you see an opera you will be moved by it, some will love it and others will hate it. Whichever reaction you have, it will stay with you forever. I believe that night diving is the same thing. Not very diver enjoys a night dive. When someone has done a night dive and comes away with that view, it is hard to change their mind. I want to stack the deck in favor of enjoying night diving by giving you a few tips to make that first dive better.
The World of Night Diving
- One of the first comments that you will hear about night diving is that you should dive the site in daylight before doing a night dive. Having dived the site in daylight, you will have some familiarity with the site, which will help reduce some of the stress of the dive. Getting ready and starting your night dive, shortly before sunset can really add to the experience. You have the benefit of the light to get your gear ready and can see the light change while underwater.
- Lights serve more than one purpose. Divers doing a night dive should have two dive torches with them on every dive. Generally this is a larger and more powerful dive torch with a smaller secondary light in case the first one fails. When a dive torch fails, the diver simply turns on the secondary and the buddy team ends the dive. Many experienced night divers will add an additional light for a dive team. If one light fails, then the diver can continue with the team backup since he still has two operational lights. A small marker light is attached to the first stage of the regulator to make it easier to locate a diver whose back is turned to you. Small chemical lights are often used, but there are lights designed for the purpose including yoke lights that replaces your normal yoke screw. If you are diving from a boat, it is a general practice for the boat crew to attach a strobe to the anchor line or the hang bar. This makes it easier to locate the boat.
- Properly using a light enhances your experiences. One thing that you should keep in the mind is that you are visiting the night reef. The marine life is at home in the dark or at least the low light levels at night. Your Dive torch is an intrusion into their world. The beam of your light will be brightest in the middle and drops off as it approaches the edge. Do not center marine life in the brightest portion of your beam. For those things that you want to examine, aim your light beam so that it is just inside the edge of the light. This will provide less stress on the subject and lessen the possibility they will disappear into a hole. The primary torch is generally more powerful than the backup torch. At times you might want to consider not using the primary and use the less powerful and more selective backup torch. If you are taking photographs, be selective on your shots as a rapid series of flashes have a tendency to scatter your subjects.
- Do not limit your field of view. Many novice night divers become too centered on what is directly in front of them and forget the rest of the ocean around them. Make it a habit to take time to look around. Do a few 360s on each dive and see what was outside the beam of your light. Remember too that you are in a three-dimensional environment so look up and down as well as around. At least once, try pointing your torch towards the surface. Some marine life will be attracted to the light. That marine life will attract others such as squid and sharks.
- The ocean has its own lights. Here is a new word for you, Bioluminescence. Bioluminescence is the production and emission of light by a living organism. A firefly is an example that you may have seen before on land. We should never turn off a torch during a dive since the highest rate of failure happens when one is turned on, we can, however hold it against our bodies so the light does not escape. When we do and give our eyes a moment to adjust we may see some examples of bioluminescence. Many different types of marine life including jellyfish and squid will glow in the dark. Some of the most common are some plankton and algae species. While most of these are microscopic and you can not see them with your naked eye, the eye can see the flash of light they can produce. The flash of light is a defense mechanism when they are disturbed. If you move your hand through the water when they are present, your hand will look like it is glowing in tiny flashes. Biofluorescenc is another new word for you. It is similar to Bioluminescence but has a different cause. Biofluorescence results from the absorption of electromagnetic radiation in one color by an organism and the reflection is in a different color. Generally, this is not visible by the naked eye, however, by using a blue light and filters on your mask you can see it. Many species of coral and sharks have this trait.
- Night diving is a variation of limited visibility diving. If you are still nervous just recall that a night dive will often have a range of visibility of your torch beam. Many times on a day dive when the visibility turns bad, you will be able to see less than on a night dive.
Night diving is something special, and it is something that every diver should experience.
Have you experience Night Diving? Any tips or experiences you would like to share? Tell us in the comments section below.