Galapagos: Realm of Giant Sharks Page #6

---

coming here for a specific reason,

but it's got to be something important

enough that we see literally

hundreds of whale sharks

in an area like the

Darwin Arch during the season.

And we don't see

whale sharks anywhere else

in the Galapagos Archipelago,

so they're coming to Darwin's Arch

for a specific reason.

I still think that

the Whale Sharks are

coming here for birthing.

One thing that just

about all the females,

the big female whale

sharks have in common

is that they're pregnant, they

seem to be in an advanced

stage of pregnancy, and so

we think that they are probably

birthing down at depth.

Alex Hearn:
There's a steady trickle

of sharks coming through.

Why aren't they all coming at once,

you know? Are they coming

when they're ready to come perhaps?

I suspect that there's an internal

clock that's telling them it's time

to move up to Darwin, and then,

out to wherever it is that

they're giving birth.

Narrator:
If not in the deep

channels surrounding

Darwin Island, then perhaps these

females are giving birth out in the

Galapagos rift zone to the north.

This region took shape

millions of years ago,

when titanic sections of the Earth's

crust began pulling apart.

The undersea terrain is lined

with ridges and sea-mounts,

and hydrothermal vents that attract

a variety of deep ocean creatures.

The nooks and crannies of the ocean

bottom could offer

could offer myriad safe havens for

infant whale sharks to grow.

Where and when the females give birth

is just one of the mysteries of

whale shark reproduction.

A single pregnant female

captured by fishermen in Taiwan

offered some remarkable clues.

Scientists moved in quickly to

dissect the shark.

They found that she was

carrying 300 offspring.

They represented all

stages of development,

from tiny embryos to

pups ready to be born.

That's not all - Genetic tests

showed that each of

the offspring was fathered

by the same male.

The female had been able

to maximize an encounter with this

male, by storing up his semen,

then using it over time

to fertilize her eggs.

This may be an adaptation to lives spent

traveling alone over long distances.

One of the longest documented

whale shark journeys, was made by

a mature female named Rio Lady.

She was tagged off Mexico's Yucatan

Peninsula in the year 2007

by researchers from Florida's Mote

Marine Lab and Mexico's Domino Project.

They watched as she headed over

to the coast of Cuba,

then turned south into the Caribbean.

Past Jamaica, she turned and swam

straight for the Atlantic Ocean.

Moving out to the middle of the

Atlantic, Rio Lady crossed the equator.

That's where her tag

Rate this script:0.0 / 0 votes