- 22 hours ago
Kingdom of the Coelacanth
Category
🐳
AnimalsTranscript
00:00Neptune, Neptune control.
00:04Go ahead, control.
00:06Summer 2024.
00:08Neptune 2 are all stopped if you choose to move upslope to 180 and follow transects to the north.
00:20Roger.
00:23An expedition is setting off in search of a little-known fish that lives in the deep sea.
00:38It's fossilized skeletons had been found in rocks that are 400 million years old
00:44and suggest that these fish could be the ancestors of all backboned animals, including ourselves.
00:58But their fossils disappear at the same time as those of the dinosaurs, 66 million years ago.
01:06Then, in 1938, a trawler, fishing off the coast of South Africa, made an astonishing catch.
01:15It was undoubtedly the same kind of fish as Seelacanth, but an hour or so earlier, it had been alive.
01:23It was a sensation, a true living fossil.
01:29But little was known about how and where it lived.
01:35Now, a special expedition in a state-of-the-art research ship is setting off to try and discover more
01:41about this living fossil.
01:43It's ready for the water.
01:49And they hit lucky.
01:51What's that?
01:52Oh, that's Seelacanth.
01:53Okay, Seelacanth.
01:55What's that? Is that Seelacanth?
01:56Oh, yeah, yeah.
01:58What have you found?
01:59Seelacanth.
02:00There was a whole group of these ancient fish.
02:07Oh, but look.
02:08Look how they're all moving.
02:10So crazy.
02:11And look at the white tummy.
02:16They even witnessed, for the first time, what appears to be its mating behavior.
02:25And the video recordings they made shed light on how primitive fish like the Seelacanth may have used their fins
02:32to walk on land.
02:36It's just gorgeous.
02:37And when we look at creatures like this, we see the evolutionary history we share with fish.
02:45Join us on a journey to discover more about this mysterious survivor from the very ancient past.
03:05The island of Sulawesi in Indonesia.
03:13It straddles the equator.
03:20And the waters around it contain some of the richest coral reefs in the world.
03:31This is Ocean Explorer, a vessel specially equipped for deep-sea research.
03:39The team has special permission from the Indonesian government to spend two weeks looking for living Seelacanths.
03:50The Seelacanth is called Rajalaut in Indonesia, which means king of the sea.
03:59They have a pair of powerful deep-sea submersibles.
04:04Each has a transparent dome that will give it almost 360-degree visibility.
04:15And they are fitted with an 8K deep-ocean camera system specially developed for this trip.
04:24The ultra-sensitive cameras are able to record clear pictures even in the darkest depths.
04:32They will also use a large unmanned ROV, a remotely operated vehicle.
04:51These are the lead scientists on the expedition.
05:08Dr. Masamitsu Iwata has been carrying out research on Seelacanths for over 20 years.
05:22Having worked and dived in the Indonesian waters for over 20 years,
05:27Iwata knows these seas very well.
05:32Dr. Masamitsu Iwata is about to see them all.
05:33I'm Kerry.
05:35Lovely to be here.
05:36From South Africa.
05:37Good.
05:37Yeah.
05:38Very good.
05:39Dr. Kerry Sink first became fascinated by Seelacanths when she was a child.
05:48To really see the seascape and the terrain is going to be an incredible experience.
05:55And I think what would be amazing is to see a coelacanth eyeball to eyeball.
06:04The team are planning to explore the waters of the northern shores of Sulawesi.
06:13The area is renowned for its active volcanoes and frequent eruptions have created numerous
06:19caves and cavities on the sea floor.
06:24An earlier survey found a steep underwater cliff here, which the team are keen to investigate
06:31further.
06:35As the sun rises, they're ready for their first dive.
06:43Both subs will be used so they can cover as much ground as possible.
06:51Just feet on there, yup, okay.
06:55Welcome.
07:19The submersible Neptune with Iwata on board is the first to be launched.
07:36Then they launch the Saturn submersible, Nadir, with Kerry on board.
07:52So, Neptune is venting now.
07:55Roger, we'll stop venting now.
07:57Have a good day.
08:02Have a good day.
08:07We're really, really happy.
08:20Go ahead and check it out.
08:25We'll win the prize.
08:25Have a good day.
08:25All right.
08:27We'll go ahead and check it out.
08:27Go ahead and check it out.
08:28Leaving the creatures of the shallows behind, they head for deeper water.
08:34They're now at a depth of 200 meters.
08:38Deeper than this, it's pitch black.
08:44Control, control, this is Neptune.
08:46Depth 2 to 4 meters.
08:53They now plan to search an area roughly half a kilometer long.
09:01But in this darkness, that is not an easy thing to do.
09:25They're searching for bright spots that could be reflections from Masi Lekanth's eyes.
09:42There are two bright specks in the darkness.
09:53It's a carpet shark, sitting motionless on the sea floor, waiting for prey.
10:06Meanwhile, Kerry's sub is scouring a different section of the cliff face.
10:18What is it?
10:20Jelly nose. Jelly noises. The crazy ones.
10:25It's a jelly nose. A rare kind of deep sea fish that, until recently, had never been seen alive.
10:37Its long ray-like fins are thought to be sensors that allow the fish to feel its way around in
10:45the darkness.
10:59I've never seen one before.
11:07Thresher sharks, Mark.
11:09Oh, oh, oh, oh, shark.
11:11Dark. Yeah, thresher.
11:14It's a thresher shark, with a distinctive long tail fin.
11:19It's at least three meters long.
11:27I'll slowly come up towards him.
11:30I'll just see how he reacts, okay?
11:32Yeah. Yeah.
11:36They appear to have entered the shark's territory.
11:39And it's slowly circling the submersible.
11:49I am.
11:54Two smaller fish have sought shelter underneath the sub.
12:04They don't seem in the least fazed by such a strange contraption, and appear to be using it as a
12:10place to hide from the shark.
12:19But suddenly, there's a problem.
12:24See, it's different. See, it's shimmering.
12:30A strong underwater current has stirred up the sea floor, and the particles of sediment are obscuring the view.
12:41It's no longer safe to continue.
12:43They must return to the surface.
12:58The area is known for its strong and unpredictable ocean currents, which can make underwater exploration very dangerous.
13:07The team have to be prepared for setbacks like this, but it's frustrating when their time down here is so
13:14limited.
13:27So why are scientists so fascinated by the coelacanth?
13:33It seems that these primitive fish may have solved a long-standing evolutionary mystery.
13:42Coelacanths first appeared more than 400 million years ago, long before the dinosaurs, and they thrived in oceans around the
13:51world.
13:53It was thought that they became extinct at the same time as the dinosaurs, 66 million years ago.
14:09Then, in 1938, fishermen pulled up from the depths of the Indian Ocean, a specimen of this ancient fish that
14:18was alive.
14:21Its discovery stunned the scientific world.
14:24The coelacanth was not extinct after all.
14:31Since those first discoveries, scientists around the world have been searching the deep sea for a living coelacanth.
14:43Then, in 1997, there was another surprising discovery.
14:49A coelacanth was caught far from Africa in Asian waters.
14:54The discovery reawoke interest in this strange fish.
15:09Three days into the expedition, and the team have decided to try a new strategy.
15:19The target depth is around 160.
15:26They have decided to concentrate their search to depths of around 160 meters, which are rich in underwater caves, and
15:35where water currents are relatively stable.
15:45Today is the day we're going to find the fresh.
15:56Fifty minutes into the search, and Iwata notices some interesting looking rocks.
16:08Clumps of them stand on the otherwise even sea floor.
16:31Clumps of them stand on the otherwise even sea floor.
16:35Clumps of them stand on the above.
16:36Clumps of them stand on the above.
16:38Oh, it's here, is it?
16:39Shilakanth.
16:39What's that?
16:40Ah, that's Shilakanth?
16:42Yeah, maybe, maybe.
16:46A closer look reveals a creature hiding in the cracks.
16:54What's that?
16:55Is that Shilakanth?
16:56Yeah, maybe, maybe.
16:59Yeah, maybe.
17:01A closer look reveals a creature hiding in the cracks.
17:02it's their first glimpse of a live coelacanth.
17:06Unlike the dead specimens,
17:09the living coelacanth is a steely blue colour with light flecks.
17:16I can get us a little closer,
17:19but if we just do a bit of filming here,
17:21so we don't scare it off, right?
17:27It's a coelacanth.
17:28Understood. Market location.
17:31Silacanth.
17:32Yeah.
17:32They've got them.
17:33Yeah.
17:34Control, control.
17:35This is Neptune.
17:37Confirm that the silacanth is over.
17:39Wait for it.
17:43After half an hour,
17:45the silacanth emerges,
17:47giving them a better view.
17:49It's over a metre long.
18:11The other team have found yet another coelacanth.
18:16Great.
18:17That is pretty spectacular.
18:26This is the first time that anyone has recorded such a high-quality 8K image of a coelacanth in its
18:35natural habitat.
18:44Its large eyes are adaptations to the poor light down here.
18:52The fish are extremely sensitive and can see quite well even in darkness.
19:13Most animal species continue to evolve in some way over time,
19:18but astonishingly, the coelacanth has remained almost unchanged for over 400 million years.
19:32It has scales that shimmer in the light,
19:35a characteristic that doesn't fossilize.
19:43Its fleshy fins are far more versatile than those of most fish.
19:51They move in a coordinated way, keeping its large body steady.
20:10One of its oddest features is its tail fin.
20:13Like that of fossil silacanths, it has a little tuft at the end,
20:19which it can move independently.
20:23What function this could have still baffles scientists today.
20:28Perhaps it acts as a small rudder and helps the fish to make tight turns.
20:35Or maybe it's an electrosensor that helps it navigate in the eternal darkness.
20:41Much about this ancient creature is still a mystery.
20:49It's a mystery.
21:05Congratulations!
21:08So cool!
21:09Yay!
21:10We found it!
21:13We found it!
21:14Mr Kczyćquin who survived surveil our economy in the world.
21:15Which can survive at great depths still remains largely unknown,
21:18despite efforts of scientists across the world.
21:24Deep-sea exploration is not only challenging but costly.
21:28So every day is precious.
21:31Change is put!
21:33To maximize their chances of observing war behavior,
21:37the team have decided to deploy all of their equipment simultaneously.
21:42We are launching number two before we are recovering number one.
21:49Yes. That was the request, yes. All this and all up?
21:52Yes. Okay. Okay. Thank you.
21:59The aim is to carry out continuous observations for 72 hours.
22:06It's an ambitious plan and requires the crew to run the subs in shifts day and night.
22:15This is a first even for the crew of Ocean Explorer.
22:23The scientists are now sure that coelacanths stay dormant throughout the day.
22:30They suspect that the fish is nocturnal,
22:32so they start their daily shift in the early evening.
22:43Control, control. This is Neptune. I have cave in sight.
22:49This coelacanth is still in exactly the same spot as it was when they found it the previous day.
23:04They know perfectly well that the coelacanth, to sustain its massive body, must come out to feed sometime.
23:19But it doesn't move, even at night, as the team proves by speeding up their video recording.
23:27It remains in exactly the same spot.
23:32At midnight, the second sub with carry-on board sets off.
23:36At midnight, the second sub with carry-on board sets off.
23:44She now takes over from Iwata in keeping watch.
24:03But even after ten hours, the coelacanth has still not shifted and shows no sign of wanting to look for
24:11food.
24:18Finally, at eight in the morning, the team decide to bring out the unmanned ROV.
24:24The next sub with carry-on board sets off.
24:26The next sub with carry-on board sets off.
24:31Carry is exhausted.
24:35They've now been watching the coelacanth continuously for 24 hours.
24:41But it still has shown no sign of moving.
24:47Perhaps the sub's lights are making it nervous.
24:53So they switch to infrared lights that are virtually undetectable by any fish.
25:00Okay, darkness.
25:01Darkness.
25:07And still the coelacanth does not move.
25:18At 7am the following day, 39 hours later, it finally does something.
25:38The coelacanth, at last, is on the move.
25:41We're supposed to follow there.
25:43Yeah.
25:45Do we follow?
25:46Yeah.
25:46Well, of course I don't.
25:47I don't know.
25:48Okay.
25:53It swims slowly, but in a way that our scientists have not seen before.
26:09It propels itself forward by moving its fins rhythmically from left to right.
26:19The two fins appear to provide forward propulsion.
26:40Ahead is a vertical cliff face.
27:03The coelacanth makes its way purposefully along the steep cliff.
27:14So this is a good.
27:16Then, it comes to an overhang in the rocks.
27:37She's near?
27:38Yeah, she's near.
27:39That's perfect.
27:41Yeah, we want to leave her somewhere where she can maybe stay.
27:45We don't want her going.
27:47Mark the last waypoint.
27:51Big Mama's new hits.
27:55Death one, six, zero.
27:58The fish has disappeared into the crevice.
28:07Oh, God, yeah.
28:14The place where the coelacanthus chosen to hide is one the scientists had not expected.
28:20It's a large overhang in the cliff, effectively an underwater cave.
28:29Tracking the fish's movements has led them to a new hideout.
28:33This is a real reward for the 72-hour vigil.
28:44Then Terry spots something else.
28:48Oh, I think I see another one.
28:50What?
28:50On the left.
28:55Oh, three.
28:57Oh, there.
28:57There you go.
28:58Is it?
29:05There appear to be more coelacanths hiding in the cave.
29:09It's an extraordinary sight.
29:14One, two, three, four, five, six, seven, eight.
29:19Eight.
29:20Eight.
29:21Eight.
29:22Eight.
29:22Eight.
29:23What is happening?
29:26There are definitely eight individuals and the team are astounded.
29:32What could be the reason for such a gathering?
29:45Spawning aggregation.
29:49It's hard to know why these coelacanths have assembled in such a tight space,
29:54but they seem to be resting peacefully side by side.
30:06Suddenly, the thresher shark reappears.
30:18The coelacanths retreat further into the crevice.
30:32The arched overhang provides good cover,
30:36allowing even a large fish like a coelacanth to hide unnoticed.
30:45The cave also provides protection from ocean currents,
30:49so there is little danger of being swept away.
30:58It's a fortress in the kingdom of the coelacanths.
31:21To help them get a better view beneath the ledge,
31:24the crew use another piece of equipment.
31:34It's a tiny underwater camera that they maneuver into position
31:39and attach to the rock face.
31:42Despite its small size,
31:45it gives a surprisingly detailed image.
31:51They can just distinguish a coelacanth huddling underneath the ledge.
32:03Within minutes, swarms of tiny fish appear.
32:08They're lantern fish attracted by the camera's bright light.
32:22Once the swarm has dissipated,
32:24the coelacanth comes into view again.
32:32And then...
32:37Slowed down, we can see what happened.
32:40Faster than the blink of an eye,
32:43it lunges for a passing morsel of food.
32:51This is very different from the slow-moving languid creature
32:55the team had seen until now.
33:00The footage clearly shows the coelacanth
33:02feeding in a manner only known to be used by prehistoric fish,
33:07until now.
33:09Recent research has shown that this way of feeding
33:13is only possible because of the unique shape of their skull.
33:18It is in fact split into two halves,
33:21which are connected by a special hinged joint.
33:27This allows the fish to widen its mouth to more than 30 degrees,
33:33enabling it to bite with the force needed
33:35to feed on hard, scaly animals
33:38or to swallow particularly large prey.
33:45Many ancient sea creatures once had this kind of a hinged joint,
33:49but the coelacanth is the only known living fish
33:53to still possess one.
33:57So at last, we're starting to unravel some of the mysteries
34:01that surround this ancient creature.
34:04It uses its fleshy fins to propel itself slowly through the water
34:10and into narrow crevices.
34:12But when necessary, it can move surprisingly quickly.
34:20And the unique joint in its skull allows it to open its mouth wider
34:26than most modern-day fish are able to do.
34:32These ancient features have clearly served the coelacanth well
34:36for millions of years.
34:40Recently, scientists have discovered
34:42that coelacanths can live to be a hundred years old.
34:47In the deep, it seems that it's the slow and the steady
34:51that wins the race.
34:58The scientific team are keen to take a closer look at the footage
35:03to solve a particular puzzle.
35:05What?
35:11Oh, beautiful.
35:12Yeah.
35:20Its fins have a thick, fleshy base,
35:24a characteristic feature of an ancient group
35:27called the lobe-finned fish.
35:32The fins of most modern-day fish are connected to the body
35:36in a way that enables them to flap,
35:39but little more.
35:47The coelacanth's fins, however, are much larger
35:50and have a row of bones attached to thick muscles,
35:54which gives the fins much greater strength.
35:58This arrangement is also found in the limbs of most land animals today
36:02and suggests they share a common ancestor.
36:08Scientists have long puzzled
36:10over how animals first hauled themselves out of the water and onto land.
36:16The coelacanth may provide the answer.
36:22Their fleshy fins may have led to limbs with an upper arm,
36:26a forearm and fingers and toes.
36:34and that enabled the first back-boned animals to crawl out onto land.
36:49Once the evidence from the fossil record is compelling,
36:53it can't show us exactly how these ancient creatures moved.
37:00At the University of Chicago,
37:03evolutionary biologist Dr. Neil Shubin has been trying to solve this puzzle for years
37:09and is very excited by the team's discoveries.
37:15It's like it's a fish with arms.
37:17That's what's amazing.
37:18So the way they swim is with movements of an arm.
37:24They're doing this.
37:26It's not just a little paddle.
37:28It has bones inside that can move much like our own arm bones.
37:32Look at that turn around.
37:35A closer look at the footage reveals some important details
37:40of how the coelacanth uses its frontal or pectoral fins.
37:47It appears to rotate each fin as if it were trying to stroke its own head.
38:00Slowed down, we can see the movement more clearly.
38:07By superimposing the bone structure onto the fin,
38:10we can see that the bone bends at each joint,
38:14allowing for this wide range of movement.
38:27Even the Sages themselves are surprised by this revelation.
38:33I haven't seen it like this, no.
38:36I can make guesses, hypotheses,
38:39about how those bones actually moved.
38:43But I don't really have the creature to look at.
38:45I'm inferring it from a skeleton.
38:48But when I see a video like this,
38:50I begin to see a living creature and how those bones are used.
38:55So it allows us to interpret those fossils in whole new ways.
39:01As we study these fish,
39:03we understand something about ourselves.
39:06I find that very powerful and very beautiful.
39:09And when we look at creatures like this,
39:11we see the evolutionary history we share with fish.
39:16theirst of them,
39:17On land, these bony and flexible structures supporting the body
39:22would have then gradually evolved into well-mostly legs.
39:28Over time, those early limbs evolved into many different forms.
39:36Sturdy legs for walking on land, light wing bones for taking to the sky, and dexterous
39:47hands capable of grasping.
39:52They evolved to meet the needs of different habitats, and as a result, life on land became
40:00rich and varied.
40:03The coelacanth's fins led to limbs suited to movement on land, and so paved the way for
40:09all terrestrial life and our own evolutionary history.
40:19Whilst the coelacanth has shed important light on evolutionary questions, we still know
40:25very little about how the species lives.
40:28Dr. Kerry Sink is hoping to answer some of these questions.
40:34One of her main aims is to find out more about the fish's reproductive behaviour.
40:43Coelacanths have white speckles all over their bodies.
40:48Each fish has its own unique pattern and looks slightly different.
40:58Kerry has used these differences to identify individuals.
41:06I want to be paying attention to what's happening from fish to fish, so I've been taking careful
41:15notes about which fish is which and how they might be interacting.
41:18On this expedition, one particular individual has attracted Kerry's interest.
41:28It's the female that she had followed to the group under a ledge.
41:32Kerry recognises it by a unique feature.
41:45Kerry knows it's a female because of its size.
41:49Females are larger than males.
41:53She's keen to follow this female to see if she can discover any evidence of breeding activity.
42:02The sub prepares for another dive.
42:19They have headed to the rock face where they last saw the female coelacanth.
42:30After 30 minutes, the female with the W mark appears.
42:41She is over a metre long.
42:43And because she's larger than the others, Kerry has nicknamed her Big Mama.
42:50And she continues to keep a close watch on her.
42:59Five hours later, the coelacanths begin to do something that the scientists have never
43:04seen before.
43:10Some of the fish begin to hang vertically in the water.
43:17Oh, but look.
43:18Look how they're all moving.
43:20So crazy.
43:23Kerry believes that this may be coelacanth courtship behaviour.
43:30I think we have mating coelacans.
43:40And look at the white tummy.
43:44They don't normally look like that, right?
43:55The coelacanths have turned their undersides white.
43:59Many fish change colour in order to attract a mate, and Kerry suspects that coelacanths may
44:06also do so to appeal to the opposite sex.
44:18The team in the other sub are also witnessing some interesting activity.
44:24One of the coelacanths is heading away from the rest of the group.
44:34It's heading straight for another fish approaching from the other side.
44:53The two fish begin to circle each other.
44:57Perhaps their rival males competing for a female.
45:11Back at Kerry's sub, Big Mama, with her distinctive W mark, is also being approached by a male.
45:23He is clearly smaller than she is.
45:30As he sidles up to her, he appears to rub his head on her underside.
45:38The researchers think that she might also be producing some kind of a pheromone that attracts males.
45:53He continues with this curious mating dance for over three minutes.
46:09This is the first time that anyone has seen coelacanths interacting with one another.
46:16It's an exciting discovery that brings us one step closer to understanding their breeding behaviour.
46:27For Kerry, this is a career highlight.
46:32Just like deep gratitude and something I've wanted for a long, long time, 24 years, I told the coelacanths, thank
46:42you.
46:43Thank you, thank you, thank you.
46:48Big hot first.
46:48So beautiful.
46:50Congratulations, that can be so cool.
46:53He's a
46:53a moment.
46:54Fishy.
46:54I'm so glad you've got this, right?
47:01Although coelacanps have managed to survive for 400 million years,
47:06they now face a new threat.
47:14Oh, what's this?
47:21There is something drifting in the water.
47:25Trash, I guess, maybe?
47:27No, I think so.
47:29The team are shocked to discover plastic waste,
47:32even at these depths.
47:37Throughout the expedition,
47:39they found evidence of human waste products
47:42littering the ocean floor.
47:46So many sunflowers.
47:48Yeah.
47:53The ancient fish now face a deep-sea home
47:57full of our rubbish.
48:00And a dead coelacanth has even been found
48:04with plastic bags in its stomach.
48:12The coelacanth's home is often close to human habitation.
48:20Strong storms and typhoons carry rubbish
48:23deep into areas where the coelacanths live.
48:28And a dead coelacanth's home.
48:32Today, our activities threaten the home of this ancient creature
48:37in all of the world's oceans.
48:49The two-week expedition has come to an end.
48:52And a dead coelacanth?
49:03The coelacanth
49:16I feel the same.
49:19The Cilacanthus is really a very special animal that has this window into the past that has these really unique
49:29features that inspire incredible curiosity.
49:34For me the Cilacanthus is also the ultimate survivor.
49:38And I was just experiencing amazement and awe and gratitude.
49:46The expedition recorded many important aspects of the Cilacanthus life for the first time.
49:53Its discoveries have helped us understand a creature that looks very similar to those that lived 400 million years ago.
50:05Hiding beside underwater cliffs, it now has a slow and energy efficient lifestyle.
50:19And breathes unobtrusively.
50:32As a species, Cilacanths have survived all the environmental upheavals that have transformed the planet.
50:42Watching them has brought to life one of the most crucial episodes in the history of life.
50:49When fish with stout, fleshy limbs emerged onto the land for the first time.
50:54And became the ancestors of all land living backbone animals, including us.
51:02Of course.