Recently my buddy and I decided to go for a night dive. It was quite some time ago since we did this. The dive lights were recharged and the photo camera and strobes were prepared. We met at 9 PM at the dive site. Around 9:30 PM we entered the water. Because we hoped to see some coral spawning we decided to go for a long and shallow dive.
What makes night diving different? Of course the absence of natural light makes a big difference, but that is compensated for by taking your own light. And it is the fact that you have your own light source that makes the real difference. You see only the part of the environment that you point your light to. So you are focussed and not easily distracted. And the part that you are shining your light on is seen in vivid color. Because of the closeness of the light source to the object there is hardly any filtering of the light. So you see everything in its real colors. During the day the sun lght is filtered and most of the red is gone. Your brain compensates for that but not completely.
Another big difference is the night life. During the day there is an abundance of fish; at night most of the fish are asleep; and the fishes you see seem "sleep walking"; most of these move slowly. Don't disturb the fish with your lights. They respond by swimming erratically and can swim against rocks or against you. Or they leave their protective cocoons (Parrot Fish) and are a pray for the remainder of the night. Other creatures are more active during the night: The Moray Eels leave their holes and go for a swim in search for something to eat. Large crabs are on the reef eating what is available. Also lobsters can be seen. Check for the small hermit lobsters; their home is nicely camouflaged so they are not so easily seen. Urchins and sea apples go for a walk and can be found on top of the coral. So look closely when diving at night and you will most probably see a lot of creatures that seem missing during the day.
The third difference is the coral itself. During the day what you see is the calcareous housing (exoskeletons) of the coral polyp. During the night the coral polyps come outside to get some food. This looks as if the coral is blooming. Especially Orange Cup Coral is spectacular. During the day you see nothing more than a small dull orange knob; at night there is a bright and rather large orange polyp visible. But also other corals are quite different from their daylight appearance.
For a photographer this gives a lot of opportunities for nice pictures. An external strobe is required for the larger objects but for closeby (macro) photography the internal strobe is also an option. Problem is that you need to find a way to handle all your equipment and stay in control of your dive. You have your hands full with camera and dive light and you also need to control your buoyance and check your gauges regularly. That can be a real hassle the first times that you try. What I found especially practical is mounting a light on top of your camera.
Back to our dive: we did a very relaxed dive for about 90 minutes. We didn't notice any coral spawning but we did see a lot of other things that made this dive worthwile. Certainly something to do more often.
Giant Anemone with a Banded Clinging Crab
Caribbean Reef Octopus
Free swimming Spotted Moray Eel
A Reef Urchin
Long Spined Urchin
A large Channel Clinging Crab
Another Channel Clinging Crab
Polyps of the Great Star Coral
A nice Red Reef Hermit
A Rough Fileclam with white tentacles
A Peacock Flounder
A Long Spined Urchin with a Nimble Spray Crab underneath
