Coming up next on Jonathan Bird’s Blue World, Jonathan searches for a rare and elusive reef
fish.
The ocean is full of amazing fish, like this school of surgeonfish feeding on algae on
the reef, colorful anemonefish, or this school of sweepers hiding in the coral for protection.
One of the most beautiful but rarely seen fish is the Mandarinfish, found on coral reefs
of the Pacific.
Hi, I’m Jonathan Bird and welcome to my world!
Mandarinfish are extremely shy and only come out of the reef at dusk to mate.
I’m here in Micronesia on an island called Yap, one of the best places in the world to
find mandarinfish.
And this evening, I am going on a dive to see if I can find a few!
I enter the water right at sunset.
As the light levels get lower on the reef, the daytime fish feed before they must hide
for the night.
A lot of changes take place on the reef at dusk.
Just before the sun sets, I have my best chance of finding a mandarinfish.
In the dim light, I search the reef carefully.
I can’t use a flashlight because it would scare the tiny fish.
Mandarinfish are very shy…they rarely leave the protection offered by the nooks and crannies
in the reef.
There…a small mount of movement catches my eye.
A mandarinfish!
If I didn’t know it where and when to look, I would never find it!
As the sun sinks lower in the sky, the light levels drop, and something magical happens.
The Mandarinfish peeks out to see if the coast is clear.
These reclusive fish only venture from the safety of their coral home to mate, and they
only do it in a narrow window of time at dusk.
A male wanders from female to female, courting each one.
His goal is to spawn as many times as he can, with as many females as possible.
He's not particularly choosy about a partner.
The females size him up—they are a little more selective about a mate than he is.
He's not worried--if one female gets cold fins, another one will jump in at the last
minute.
Then the male and female pair up and begin to make practice runs, rising up off the reef,
cheek to cheek.
At last the pair spawns for real.
Rising well above the reef to keep the eggs from being eaten by the coral, the male and
the female release their spawn at the same time.
The eggs are fertilized in the water column.
Over and over, the male spawns as many times as he can, perhaps as many as ten times in
half an hour.
The fertilized eggs then drift off into open water to develop into tiny baby mandarinfish.
Most will not survive to adulthood.
Once darkness comes, the spawning ends.
The mandarinfish seek protection in the reef, safe for another day.
Well, it’s after sunset and the mandarinfish have finished mating for the night, and gone
back into the reef.
They won’t come back out of the reef until tomorrow night, so for now, it’s time for
me to go to bed.