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The Graeffe's sea cucumber breeds by releasing *** or eggs,
collectively known as "gametes", into the water.
It waits until the conditions such as current and water temperature are right,
then rises up off the substrate into the current
to give it's gametes the best chance of a successful fertilization
with those of an unknown mate.
This phenomenon of broadcast spawning
is not unique to sea cucumbers;
it is common among many reef creatures.
Here, a pizza anemone releases its gametes at night.
Over a breeding period that last some weeks
oysters release their gametes into the water.
Only a tiny fraction of the eggs become fertilized
and an equally small number of the resulting larvae survive to adulthood,
so the oysters release literally litres of gametes
to ensure the species' survival.
One of the most intelligent and fascinating creatures found around the reefs of the Andaman Sea
is the pharaoh cuttlefish,
seen here snatching prey with its long feeding tentacle.
Many a time cuttlefishes are found in courtship in shallow water.
Cuttlefishes copulate face to face,
using their ten tentacles to embrace.
The male cuttlefish passes spermatophores into a pouch beneath the female's mouth.
He may first use a jet of water to flush out the spermatophores of any previous mates.
The couple are so engrossed in the mating process
that they seem oblivious to all around them
and they allow divers to approach very closely.
After copulation the female seeks a suitable crevice in the rocks or coral,
and she passes her eggs over the *** and into it.
If fertilization was successful
the eggs will hatch around 19 days later.
The failure rate is high however,
and sometimes the cuttlefish's aim is not too accurate!
The male is extremely protective over his female mates after copulation.
He will attempt to warn competitive males away
with a striped coloration and by raising his median tentacles.
But occasionally a confrontation is inevitable.
The bigfin reef squid's mating process is similar to that of the cuttlefish.
Here we get a rare glimpse of a male escorting a female
as she deposits her eggs.
The squid can change color rapidly
to communicate and to display emotion.
At Western Rocky Island this male day octopus
is doing everything it can to appear strong
by standing tall and using skin texture and color.