Diving after dark?
Today Jonathan explains the excitement of night diving!
Welcome to Jonathan Bird’s Blue World!
The ocean is full of interesting and beautiful things to see, from reefs and fish, to sharks
and even whales.
And of course, most of the time we see them during the day.
But they’re still out there at night.
You would think that night diving would be really scary, but believe it or not, once
you get down there, it’s awesome!
Night diving is popular with divers because it is so different from diving during the
day.
Different animals are active, and different behaviors can be seen.
During the day, a reef bustles with activity.
Most of the fish are diurnal—active during the day.
After sunset they hunker down for the night, hiding inside all the tiny holes and cracks
in the reef.
Some, like the parrotfish, sleep out in the open, although the darkness helps keep them
safe.
A different cast of characters emerges on the reef at night: the nocturnal animals.
A sea star is prowling for a meal.
An urchin comes out of the reef on a slow march for food across the sand.
An octopus—every divers’ favorite nocturnal critter—pops its eyes up for a peek.
Then it jets away holding a snack in its arms.
On the
one hand it wants to get back to its den to eat.
But the octopus’s natural curiosity keeps it around for a minute.
Lionfish go on the prowl at night too, hunting sleeping silversides over the sand.
Of course they are cheating a little, using our camera lights to help them find the prey.
Moray eels rest during the day, but at night they use their slender, flexible bodies to
probe into holes in the reef, searching for sleeping fish that think they are safe and
protected.
But sometimes, fish sleep right out in the open.
The moray got lucky.
The fish…not so much.
Another reef, another sleeping fish.
Surrounded by sharks.
Whitetip reef sharks hunt in packs at night.
And they can detect the fish in the reef with their electrosensory systems.
When one shark finally makes a move, all the sharks jump in on the action!
It’s a long, nervous night for any fish hiding in this reef.
Zooplankton rise from the depths at night to feed on phytoplankton in shallow water.
For the animals that eat plankton, the feast begins.
A brain coral extends thousands of sticky tentacles to catch and eat plankton.
A basket star has branching arms that create a plankton-catching net.
But even without eyes, it detects and shrinks from the lights of my camera.
Big swarms of plankton can attract big appetites.
A Manta ray opens its mouth wide to funnel plankton down into strainers on its gills,
doing loops to stay centered around a good spot.
Nighttime is also when the corals spawn, using darkness to protect as many of the eggs as
possible.
This is a rare event.
It only happens a couple nights a year.
But if the corals spawned during the day, the fish on the reef would gobble up all the
eggs.
The whole thing happens fast and the eggs drift away.
Sometimes during a night dive, I wonder….is there a shark out there someplace watching
me?
Well, there’s one way to find out.
A shark night dive!
Chumming for sharks after dark is not everyone’s idea of a good time.
But you never know what might show up.
In this case, a Lemon shark, with a few remoras along for the ride.
A Great Hammerhead overcomes its notoriously shy nature to approach for a snack.
No matter where I dive, there is always something to see at night.
It might seem a little spooky, but once I train my flashlight on something interesting,
I’m no longer worried about being eaten by a mysterious monster in the darkness.
Because even without daylight, the Blue World is a fascinating place.