Much like swimming in the dark, night scuba diving can either appeal to you or perhaps creep you out, or maybe a little bit of both. I find that scuba diving at night is very different from having zero or no visibility, because at night your light can penetrate the darkness, but in no-viz, your light does nothing but reflect particles back at you.

Some of our dive club members flatly state “No Thanks!” when the idea of a night dive is brought up. Others cannot wait to experience it, at least once. I find that they are fun but diving at night also means getting back pretty late afterwards, sometimes de-gearing at night with mosquitos liking the salt water all over you, as well as having to still clean your gear and hang it to dry before all is said and done.

Diving group gets its gear together at the Somes Sound night dive as the sun sets. Charles H. Lagerbom

There is also a bit more preparation for night diving than day diving. Lights are always handy to have for scuba, but a night dive definitely requires a good-sized bright light and a back-up one as well. So, testing your lights for battery power and its o-rings for water-proof-ness, are high on the to-do list, as you prepare your gear for a night dive.

My night dive light is a Princeton Tec Sector 5 LED light that puts out 550 lumens in a pistol-style grip. The number of lumens basically means brightness or light output. The four C-sized batteries need to be loaded and tested and the o-rings checked nothing more frustrating than to have your light go out on you during the dive or have it flooded by having bad o-rings.

The Tech Sector 5 is decent-sized and can get heavy, so there is a lanyard for it to attach to my wrist. The lanyard also helps as lights can easily be dropped. I was searching for a mooring in the Penobscot at Winterport and had switched my light from one hand to the other. Before I could attach the lanyard, it slipped out of my hand and was gone. One second there and then ‘poof!’ it was on its way to the bottom, not to be found.

The comforting cone of light helps during a night dive, but it does narrow one’s focus. Charles H. Lagerbom

For night dives, I also attach a Princeton Amp 1 onto my tank knob behind me. It puts out a constant 45 lumen spot beam, just enough light so that I can be spotted by anyone following. Other divers use light or glow sticks, one diver had a strobe light attached to his rig. That made it wicked easy to keep track of each other, kind of like following an airplane.

Depending on the dive site, divers sometimes set up two lights in a line perpendicular to the shore (usually one of a different color) at their entry/exit point. This is so that if you surface out a way from shore, you can hopefully see the two lights and then swim to where they align and from there follow them into the entry/exit point.

We did a night dive at Somes Sound in Acadia and the two shore lights worked like a charm. I surfaced with my buddy pretty far out. It was my first night dive and I was nervous about being out on the ocean in the dark, so it was pretty reassuring to see those two lights and know all I needed to do was line them up for my exit point.

Somes Sound that night was also alive and active! And that brings up the big draw for night diving: the profusion of marine life. That night, I never saw so many lobsters in my life! Hundreds were crawling all over the place, way more alive and way friskier then when I see them during the day. They were trying to elbow each other out of the way as they fought to get into the lobster traps.

Another cool thing during our Acadia dive was when we gathered together at a depth of about 20 fsw (feet of seawater) and everyone doused their lights. At first it was a little disorienting, but then the instructor moved his arm and I saw a bunch of mini explosions of light.

They were tiny specs of bioluminescence, made up of tiny plankton which light up in a blue-ish color. This plankton bioluminescence results from a light-producing chemical reaction, called chemiluminescence. Scientists still are not sure why many creatures have it.

It is thought that coral uses bioluminescence to protect itself from UV sun radiation while some make use of it to communicate. Others use it as a predatory tool, as a warning, as an attraction, for a mimicry effect or even as camouflage.

Charles Darwin, writing in his journal aboard the Beagle, bound for the Galapagos Islands and his theories on evolution, encountered the sea’s bioluminescence and noted “the vessel drove before her bows two billows of liquid phosphorus, and in her wake, she was followed by a milky train.”

At Beauchamp Point in Rockport, where we have done quite a few night dives, there is a point in our regular circuit that we do where one can experience a “freefall” through the darkness. There is a series of ledges that in daylight are easy to navigate around or over. But at night, you come over them and then you are suspended in…well…nothing, you are in total darkness in the water column.

You might be able to feel yourself slowly descending, but there is no visual reference cue or anything to confirm it. Your beam of light just points out as a bright white cone into nothingness. It is an eerie yet exhilarating experience. Your light finally picks up the outline of the bottom as you approach it, and your senses start registering parameters again. Pretty cool!

One other visual affect that can be a little unnerving in night diving is that darn cone of light. At first, it is comforting as you swing it around and point it at something, just so your eyes can register a shape or an object.

But the cone itself becomes the main thing you focus upon and seems to hide anything and everything just outside of it. You get the distinct impression that there is something hovering, maybe just off your shoulder, just out of the light. When you swing the light there, of course nothing is there, but the feeling still lingers in your imagination.

My goal with night dives was to see and video some Longfin Inshore Squid (Loligo pealli). I have yet to see one, but on one night dive we did come upon on a clump of their squid egg clusters. At first, I thought it was a large anemone. This particular cluster was huge, I learned later that each capsule can hold up to 200 squid eggs!

Pictured are Longfin Inshore Squid egg casings. Charles H. Lagerbom

We were about twenty feet down at Beauchamp Point one night and my light flashed on a fish sitting on the bottom. It was decent sized, reddish in color with two long whiskers off the head. The fish’s whiskers were actually elongated feeler-like rays of its pelvic fins. These rays act as chemoreceptors which help it feed at night by sensing its food. It was a Spotted Hake (Urophycis regia).

I expected it to swim off as I neared it, trying to get a good image of it with my GoPro. But the fish just sat there looking at me, even as I edged closer and closer to it, eventually close enough for me to start thinking “wow, you won’t last too long in the ocean if you let things like me get this close to you!”

A Spotted Hake is feeding at night at Beauchamp Point. Charles H. Lagerbom

Why didn’t it bolt away when I came up to it? Mentioning it afterwards to the other divers that night, they suggested that maybe this explains the phrase “numb as a hake!” Hmmm, I hadn’t thought of that.

Charles Lagerbom teaches AP US History at Belfast Area High School and lives in Northport. He is author of “Whaling in Maine” and “Maine to Cape Horn,” available through