Coming up next on Jonathan Bird's Blue World,
Jonathan travels to an uninhabited island in Indonesia to find thousands of sea snakes! Hi, I'm Jonathan Bird and welcome to my world! Some of the world’s richest coral reefs
thrive in Indonesia. Located in the middle of the so-called coral
triangle, the diversity of species and colors of Indonesian reefs absolutely amazes me every
time I get the chance to dive here. This time however, it’s not the reefs I
have come to film, but a remote and uninhabited island whose waters are reputed to teem with
thousands of sea snakes! The island, known as Manuk, is an active volcano
a hundred kilometers from the nearest inhabited island, smack dab in the middle of the Indonesian
archipelago. Getting there is no easy task. I have chartered the Seahorse, a traditional
Indonesian Pinisi built for divers, for a special itinerary to reach Manuk Island. Divemaster Jandri meets me at the marina in
Sorong. It took me 2 full days of flying just to get
to Sorong from the United States! He takes me out to the Seahorse, my home away
from home for the next two weeks. This expedition will take 14 divers 1200 miles
across the Banda Sea, from Sorong to Alor, stopping to dive along the way at many islands,
the most important of which of course is Manuk. I board the Seahorse, and once everyone else
has arrived, we pull anchor and head for the open sea, in search of some serious underwater
adventures! The next morning, we reach our first dive
site (so and so island) in Raja Ampat. I can hardly wait to hit the water and get
a look at the spectacular reefs. Raja Ampat is the most biologically diverse
area in Indonesia, and therefore, the world! As I roll into the water and get my camera,
the first thing I see is a wonderfully healthy shallow hard coral reef! Nearby are sea fans sheltering tiny fish. Along the drop off, larger schools of fish
hunt, swirling around the reef. In the deep blue, a school of Spadefish regard
me without fear as I swim among them. Back at the reef, a camouflaged fish lies
on the sand between the coral heads. It’s a crocodilefish, an ambush predator
waiting for prey to come close. Even its eye has camouflage! Later in the day, I suit up once again for
another mind-blowing experience. This is a dive on a tiny seamount, a coral
pillar that would be a small island if only it were a tad taller. This underwater tower is the home of the largest
school of butterflyfish I have ever seen. They hover here, in the strong current, apparently
feeding on something that the current brings to them. They don’t seem to mind my presence at all. It’s a mesmerizing experience to dive within
the school, enveloped on all sides by colorful fish. Exhausted by swimming in the current, I relax
and drift away from the seamount. I float gently towards the surface, where
I make a short safety stop for decompression. Finally I head back to the Seahorse, my first
day of diving done. A beautiful day leads to a beautiful sunset,
and I can’t wait to see what tomorrow brings! For five days, the pilot of the Seahorse advances
us across Indonesia from island to island, with wonderful diving every day. But my mind is focused on one particular spot. And today, at last we have arrived: Manuk
Island. The island is aptly named: Manuk means “bird”
in several Indonesian dialects. And birds it has! Manuk is completely uninhabited and there
are a few reasons why. First of all, it’s kind of steep. But more importantly, it’s an active volcano! There are steam and sulfur vents all over
the island. Standing downwind, you can smell the distinct
odor of brimstone. But the question is—are there any sea snakes
here? I depart for the first dive with my fingers
crossed that I will see tons of sea snakes… …So, let’s go check it out! When I get down to the reef, I see a wonderfully
healthy ecosystem, with beautiful coral, abundant fish and crystal clear water. You couldn’t ask for a nicer place to do
a dive. The walls drop off steeply into deep water. The reef looks perfectly healthy except for
this: an underwater volcanic vent! Toxic gases and heat are coming out of the
sea floor here. Coral can’t grow too close to this vent. The water is murky and the rocks are stained
yellow. Whatever I’m swimming in right now is probably
not good for me or my camera! Up in shallow water, volcanic bubbles are
percolating out of the sea floor. Nothing will grow on these rocks either. The volcanic nature of Manuk Island is everywhere. Yet, among the volcanic bubbles swims a sea
snake! It is apparently unaffected by the water quality. It swims casually by flapping its flattened,
paddle-like section of tail. I follow it down onto the reef, mesmerized
by its swimming. Sea snakes are among the most venomous animals
on Earth. They use this venom to hunt, and fortunately,
attacks on people are extremely rare. Soon I start to see other sea snakes, and
I realize that more and more have been appearing. Were they here before and I didn’t see them,
or did they come out from someplace? Clearly, some were sleeping. This one is taking a nap in plain view on
the reef. I guess they don’t really have to worry
about predators. I watch this one sleep for a little while,
and start to wonder if it’s even alive. So I give it a little tickle. I wouldn’t do this with a land snake, but
sea snakes are very easy-going, almost mellow and rarely aggressive. The snake just moves a couple of feet away
and goes back to sleep. Pretty soon I notice that as the snakes are
waking up, they are coming over to check me out. Are they curious? They investigate my fins and gear. They swim closely around me. I know they are not aggressive, so I just
try to stay still and not frighten them. Look, they are so mellow I can hold one. Notice how it flicks its tongue. Like land snakes, this is how a sea snake
“smells” but at the same time, the tongue flicking helps get rid of excess salt from
glands in its mouth. Because sea snakes are reptiles just like
land snakes, they have lungs and need to breathe air just like people. So a sea snake must head to the surface every
once in a while for a breath. Sea snakes have a huge lung that takes up
nearly the entire length of their bodies so they can hold a big breath that will last
a while. Each time a sea snake surfaces, it usually
spends a minute or two resting and breathing, before gulping in that last big breath and
diving back down to the reef. A breath can last 1-2 hours depending on the
species, but most sea snakes breathe more often than that unless they are sleeping. They can also absorb a little bit of oxygen
from the water directly through their skin, which helps them extend their dives. As I ascend from my last dive of the day,
I’m really excited about all the sea snakes I saw! Wow, that dive was snaketacular! I’ve seen sea snakes before, but never that
many. The next morning I’m up at sunrise, and
heading out to the reef for an early morning dive. Early morning is when the sea snakes hunt,
and I’m hoping to witness the reef alive with sea snakes on the prowl! Underwater, the light levels are still low,
and I’m heading out to a deep seamount where I saw a lot of sea snakes yesterday. This should be a good place to find some sea
snakes hunting. When a sea snake hunts, it takes advantage
of having a small head and a thin body to go from hole to hole in the reef, poking its
head inside. It hopes to corner a fish or invertebrate
that’s hiding in the hole. Once the hunting starts, more sea snakes start
coming in to the reef to join the hunt. On this seamount more than a hundred feet
from the surface, dozens of sea snakes are gathering to prowl the reef for food. Sometimes, they appear to work together to
make sure nothing escapes. My time is limited at such a deep site, and
all too soon, I must head for shallower water. There are more sea snakes in the shallows. Sure, I have seen sea snakes before, but why
are there so many here at Manuk Island? Is it the remoteness of the place, far from
people? Is it a lack of some other predator? For now, nobody is quite sure. But there is no doubt about it, Manuk might
be named after the Birds but to me it will always be the island of the snakes.
