Seahorses
breed frequently in home aquariums. They are prone
to monogamous relationships. The
courtship ritual between seahorses is
a long
arduous process that takes several days. Both seahorses’
colors will intensify
in the course of courtship. Courtship begins with them swimming side by
side while
holding each other’s tails. They will wheel around in unison
as precursor to spawning. This display of affection has become known as
the
“pre-dawn dance.”
Eventually they will enter into the mating dance that will often
continue for
as long as 8 hours. During this time the male seahorse
will pump water into the
egg
pouch on his truck. The egg pouch will expand and open to display its
appealing
emptiness to the female. They will then let go of their anchors and
drift
upward snout to snout often spiraling around each other as they rise.
The
female will then use her ovipositor to insert her eggs into the
male’s brooding
pouch for fertilization. The female's body will grow slimmer
as she releases
her eggs. The male’s body will swell accordingly from the
deposited eggs.
Both
seahorses will then sink
back down to the bottom and the female will swim away. Scientists
believe this
complicated breeding
ritual serves to synchronize the couple for the
deposit
and fertilization of the eggs.
The
fertilized eggs will become enveloped with tissue and embedded in the
brood
pouch. The pouch will regulate oxygen to the eggs and act as an
incubation
chamber. The male’s body will begin producing a hormone
called prolactin. This
hormone is delivered directly into the pouch. Prolactin is the same
hormone
responsible for the production of milk in mammals. Prolactin will
provide
nutrition for the newly hatched seahorses. The incubation period or
pregnancy
will last from 2
to 4 weeks depending
on the species.
The
female will visit the male every morning during the incubation period.
She will hold the male’s tail and they will wheel around
amongst the sea grass
fronds in their natural habitat for several minutes. Then she will
simply swim
away until the next morning rolls around.
Shortly
after the fry hatch the male’s body will undergo a series of
muscular contractions. These contractions will act to expel the newborn
from
his pouch. The average release of young is 100-200 newborns. The number
can be
as low as 5 or 6 or as high as 1,500 depending on the particular
species.
Males
typically expel their young at night.
By morning the male is ready to begin the cycle all over again.
Seahorses
do not care for their young once they are released from the
protection of the brooding pouch. They are simply left to drift away in
ocean
currents. Fewer than 5 out of 1,000 newly born seahorses will survive
to reach
adulthood. As bad as these odds may appear, they are actually one of
the higher
survivability rates among aquatic saltwater species. The fact that the
eggs are
secure in the protective environment of the male’s brooding
pouch until they
hatch is the most significant contributing factor toward their survival
rates.
Most marine species eggs are simply abandoned to be consumed by what
ever fish
comes across them.
