- 2 days ago
Scientists and local communities are working together to protect endangered sea turtles and their nesting grounds in the Western Pacific Ocean.
Hawksbill turtles and leatherbacks swim across thousands of miles of ocean during their lifetimes. But little is known about where they go, complicating efforts to save them. The Nature Conservancy (TNC) and local communities in the Solomon Islands are working to discover the secrets to their migration—and saving them from extinction.
Hawksbill turtles and leatherbacks swim across thousands of miles of ocean during their lifetimes. But little is known about where they go, complicating efforts to save them. The Nature Conservancy (TNC) and local communities in the Solomon Islands are working to discover the secrets to their migration—and saving them from extinction.
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AnimalsTranscript
00:15The Moon, the Earth, and the Earth's largest feature, the Pacific Ocean.
00:25It's vast, a third of the whole planet.
00:30Larger than all the land put together.
00:35For us, this ocean is unknown.
00:39Alien.
00:43Imagine what it must be like to call it home.
00:52A sea turtle.
00:56She's an ancient traveler.
00:58She will cross this whole, vast ocean to lay her eggs.
01:07On the way are lightning-fast fish and leviathans.
01:21She'll encounter the ocean's most intelligent predators and terrified prey.
01:33There are mountain summits, over dark depths, and beyond sparkling coral reefs.
01:51Most of life on Earth is here, but it is changing, shifting, like the ocean currents themselves.
02:09In telling her story, we'll see some of the dramas she'll face along the way.
02:25A little backwater, off the west coast of Mexico.
02:32The loggerhead turtle has made her home here.
02:41It's a quiet, safe spot, with plenty of shellfish to eat, enough even to share.
02:57Thirty-five years ago, she hatched on a beach on the other side of the Pacific.
03:02She drifted all the way across.
03:10Now, suddenly, she has an urge to lay her eggs where she was born.
03:18Scientists satellite tracked a loggerhead from Mexico.
03:22They discovered details of a 9,000-mile route, longer than any other migration, on land or
03:29in the sea.
03:30A perilous journey.
03:42Spanish explorers named this ocean Pacifica.
03:46Peaceful.
03:47They must have been lucky with the weather.
03:49It must have been.
04:17It's been a very special for us.
04:29She has faced typhoons before. She knows what to do.
04:42She holds her breath and keeps below for about six hours at a time.
04:50The only ones in trouble are us. Time to leave.
05:11For the animals, a storm is wonderful. It stirs up the water. It will bring life.
05:25The Pacific is probably the only place on Earth where there can now be a million square miles with no
05:32people.
05:40Blown a little off course, she reaches the doldrums off Central America.
05:46She is reorientating herself. She has pads on her flippers for walking the way her ancestors once did on land,
05:55before dinosaurs.
06:07Turtles have been part of the Pacific since the ocean was young. They are the oldest sea creatures that still
06:13have to breathe air.
06:23Winds and currents sweep up the chaos of the storm into long lines of debris.
06:31Not just flotsam. Everything is gathered up, including turtles.
06:38This is a green turtle. The loggerhead will encounter many of them on her journey.
06:47They all go along the lines of debris and edges of currents. They are busy highways.
06:56Here in the doldrums, famous for its becalmed sailors, the ocean sweepings stretch visibly for hundreds of miles.
07:10Nutrients churned up by the storm feed clouds of microscopic plants, phytoplankton, minuscule green worlds.
07:22A teaspoon of ocean contains thousands of eggs and larvae, like seeds waiting for spring.
07:33Tiny animals magically appear. Jellies, mycids, krill.
07:46Clouds of plankton make up, worldwide, half of life on earth.
08:03It feeds the ocean.
08:10Fish appear as if from nowhere.
08:19The schools gather around anything for protection.
08:25Even this disconcerted turtle.
08:42The only other place for fish to hide is behind each other.
08:46Looking for them are the most intelligent predators in the ocean.
08:51If they hang outside.
08:53Can they appear in the ocean from the ocean?
09:11They have enoughised in their darkness than the ocean falls over this…
09:12Here we go.
09:25These are spinners in 100-strong superpods calling to each other, coordinating the hunt
09:32and spinning.
09:55Are they getting their bearings, communicating, shedding parasites or is it just exuberance?
10:03We don't know.
10:06The dolphins have allies, those most mammal-like of big fish, tuna.
10:13Tuna are warm-blooded, powerful and intelligent with a good sense of smell and good eyesight.
10:21When they team up with dolphins to hunt, no other predators can compete.
10:30Turtles, much slower, are just passers-by here.
10:41The fish hear the dolphins and tuna coming and become a whirling tornado.
10:46Fishermen call it a bait ball.
10:53The fish hear the fish.
10:53The fish hear the fish.
11:28In less than an hour, the bait ball is devoured.
11:32Too bad for the slower silky sharks.
11:58On land, packs or prides are never on this scale.
12:08But when one land predator comes to hunt here, it is on an industrial scale.
12:33This yellowfin tuna alone justifies the expense.
12:41Better still is to catch the fish in their thousands and sell them for millions.
12:50The nets around the tuna and dolphin are slowly closed, trapping everything big.
13:07So that the tuna can be called dolphin-friendly, the dolphins are helped out of the nets.
13:16Everything else is hauled up, including huge manta rays and marlin, which are thrown back to die.
13:37There are only a quarter of the turtles there were 50 years ago, when efforts to protect them began.
13:48Ninety percent of the fish are gone from here too.
13:52Our loggerhead turtle is swimming through a poorer world.
14:10Making a big comeback are the most primitive large sea creatures of all.
14:15Twenty foot long, open ocean jellyfish.
14:20They are filling in for the missing fish.
14:23They are filling in for the missing fish.
14:35Lion's mane, common and moon jellies are increasing worldwide too.
14:40For a loggerhead, good news, jellies she can eat.
14:57Jellies and other simple animals don't just drift.
15:00Their daily trips to the depths is the largest mass migration on earth.
15:13Turtles can't follow the jellies down, but they sense the dark landscape miles beneath them.
15:19Their brains contain cells that can detect magnetic fields and map the iron-rich ancient volcanoes below them.
15:34Fish follow the same landmarks.
15:37They mass above the foothills that surround the huge mountain ranges.
15:44These foot-long trevelli jacks are drawn here by food.
15:49Plankton are fed by rich currents forced upwards from below.
15:53It is the first sign that volcanoes are rising up ahead.
16:08She follows the seamounts and valleys that stretch to the west.
16:19Turtles need to sleep, and they can't afford to doze, just drifting on the currents.
16:24Once, whenever she can, she finds a peak for the night.
16:32They are like fish cities along the highway.
16:57Other turtles are here.
17:11Predators and prey live side by side.
17:15A mori eel guards a nursery of young fish.
17:18It would eat them if it could.
17:20Instead, these teeth keep other predators at bay.
17:25Anything dangerous hides baby fish.
17:35Another defense is, just don't look like a fish.
17:43You need to keep a step ahead of anything that might eat you.
17:52White-tipped reef sharks, for instance.
17:58They lounge around and let tiny wrasse clean them.
18:16There are turtles on this seamount.
18:19Some resident, and some passing through.
18:22And sharks do attack turtles.
18:26By day, there is no problem.
18:28As the sea starts to darken, the sharks get restless.
18:51A sea turtle shell offers some protection, but she can't pull in her head or flippers.
18:57They can easily be bitten off.
18:58She can't just hide all night.
19:01She'll need a breath of fresh air at least once.
19:04That means a careful dance around the sharks.
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19:13Do you 45 perox clearmetros
19:13Have engaged in the wolves yet?
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19:33It's you time for us 49 butx avoid.
19:49The shark's main interest is fish, most of which sleep or hide motionless in crevices.
19:56Any movement sends out an electrical signal.
20:29Refreshed by a breath of night air, the turtle looks for a place where she can sleep unmolested.
20:36A cave is good, usually.
20:44Sometimes turtles hiding from sharks get lost in cave systems.
20:48They can't get to the surface, and they drown.
21:16The turtle can breathe in peace.
21:30If it has been a really hard night, a turtle might briefly rest, seeing in another gang of night hunters,
21:37hammerhead sharks.
21:47Hammerheads are no threat to turtles.
21:50They're just here to be looked after.
22:02The black and yellow barber fish and angelfish clean the shark's teeth from the night's hunt.
22:09The hammerheads are up from the depths chasing squid, sweeping through the dark with the electrical sensors in their heads.
22:16Now they relax, roll over, and let the barber fish do their job.
22:21When they're underfooted.
22:38When they're in the middle of the night, they are fine.
22:38If they are other than the maneuvers…
22:38The black and yellow deer shark.
22:38They're out there, there is no neighbors.
22:39The ocean is lost in the middle of the night.
22:40It's part of the night as the middle of the night.
22:40The club is on the night out of the night.
22:40The storm The lake is evacuated by the night.
22:41The water is gone, and it's not too late.
22:43The water is not discussed before the night.
22:44The water is whilst sounds of anything like it is not different.
22:46The human of the smoke's handman's blood.
22:51Hammerheads in their thousands rest together.
22:54Many will soon head for Hawaii, 2,000 miles away, to give birth.
23:02The Pacific has few really long-haul travellers.
23:06Turtles aren't normally considered in the same league as albatrosses or humpback whales.
23:12Except for loggerheads.
23:15She beats them all.
23:30Leaving the seamounts behind, she crosses into deep, open water.
23:35Next stop, Hawaii.
23:40All across the Pacific, she'll pass green turtles on the way to feed or nest, having their own difficulties along
23:48the way.
23:52This green shell is badly cracked.
23:55Whatever attacked her, her shell saved her life.
24:00It's easy to think of a turtle shell as some prehistoric relic, a defence against monsters long gone.
24:06In fact, the ocean is still dangerous.
24:09The largest predator ever is alive today.
24:16It is the sperm whale, with teeth twice the size of Tyrannosaurus rex fangs.
24:31A sperm whale could crush a turtle shell.
24:33But what it wants is a mile down.
24:38Squid.
24:47The deeper you go, the larger squid get.
24:56These are humbled squid.
24:58Six feet long.
25:00They are aggressive and very dangerous.
25:03Six feet long.
25:30The sperm whale is aavoast of the fat.
25:32can go further down and get the giant squid 50 feet long and with eyes like
25:37dinner plates. They're mainly known to science by the great scars they leave on
25:43sperm whales.
25:50There's good reason to be built like a quarter-ton tank.
25:56Her armor comes at a price. She's slow. All the other long-distance travelers are
26:02sleek and fast. In a weightless world some of the fastest are also the biggest.
26:22Most of what's said about a blue whale refers to its size. A tongue heavier than
26:27an elephant, veins wide enough for a human to swim down. But they are very fast.
26:33Few boats can keep up. They mainly have to be studied from the air. The turtle seems
26:39from a slower bygone age.
26:47A blue whale burns up energy. Over a thousand calories a minute. So do its
26:53relatives, thin and say whales. They zip around the Pacific. The record is 2,500
27:01miles in 10 days.
27:11A loggerhead is slow and cold-blooded. She can travel 9,000 miles. She just chugs on.
27:24But like a tractor on a motorway, this isn't always safe.
27:33The ocean's buccaneers are looking for bait balls.
27:46Slow-moving objects are a magnet for frightened fish.
27:55Better to keep out of the way.
28:19All that's left is a shower of scales. They ought to be topped with a food chain, but they're not.
28:29This is longlining. And the main targets are marlin, swordfish and tuna.
28:38Eighty miles of lions, with baited hooks every few yards, are reeled out one day and reeled in the next.
28:45Lots of wildlife is caught. Only swordfish and tuna are kept.
28:55Turtles go for fish if they're just hanging in the water.
29:09Turtles are legally protected. So sometimes, if they're lucky, they're unhooked and thrown back alive.
29:23After six months, she is approaching the Hawaiian islands.
29:31The loggerhead finds land beneath her again.
29:44Most Pacific islands have a definite life cycle. They start as volcanoes.
29:57Then the volcano dies and the island is, inch by inch, eroded down.
30:14Humpback whales follow the loggerhead in.
30:18They come 4,000 miles from the Arctic to breed here.
30:22Mothers with last year's calves arrive first.
30:29Then come the males, splashing and singing.
30:37The mothers will wean their calves and mate.
30:43Finally, the pregnant females.
30:46They've been feeding in the Arctic until the very last minute.
30:51Now, their new calves will suckle and grow in Hawaii's warm bays.
31:01The bays are also important for green turtles, which come here to breed.
31:09Lovemaking in the surf can be exhausting for animals that weigh a quarter of a ton.
31:23The females haul out from time to time, just to rest.
31:28Scientists take the opportunity to paint numbers on them.
31:33And albatross chicks come down to see what kind of improbable things live under a shell.
31:43This is home for these green turtles and albatrosses.
31:47For a loggerhead, it's just a rest stop.
31:51It's seven months since she left Mexico, and she's barely halfway.
32:02Ahead is an ocean peppered with islands.
32:24Ahead is an ocean peppered with islands.
32:38Below the equator, constellations of reefs reach down over an area the size of Europe.
32:46It is like swimming into some exotic kingdom.
33:15Suddenly, everything is delicate, fragile and beautiful.
33:20Purple Queen Antheas, Royal Dottiebacks, Seahorses in Disguises, Flashing Cuttlefish.
33:33.
33:34.
34:06Green turtles go beyond the reef, heading for the white beaches of fine coral sand to lay their eggs.
34:14They may not be the only reptile with their eye on the beach.
34:23The largest reptile in the world is the saltwater crocodile, or salty.
34:31Saltees swim between the islands and have even been seen miles out to sea.
34:40We don't normally think of crocodiles as seaworthy, but they are.
34:51A fully grown croc can easily catch a turtle and is strong enough to break the shell.
35:16When man came to these islands, he hunted both, and crocs nearly to extinction.
35:23At least turtles are safer now from crocodiles.
35:35The loggerhead stays north, swimming past Wake Island and the fringes of the Marshall Chain.
35:46All the beaches she passes would be fine, but no loggerheads nest here.
35:53Maybe they were wiped out somehow.
36:00This loggerhead has lost half a flipper.
36:03She'll grow old here.
36:05Turtles may live to a hundred or more.
36:13She's accumulated passengers over the years, especially barnacles.
36:20Healthy turtles deal with hangers-on by paying a visit to the local coral reef, to a cleaning station.
36:38Green turtles are regular customers here.
36:44A turtle shell is fused from its ribcage and covered in living skin.
36:49She can feel the tickling on her shell.
37:00To encourage the service, a turtle adopts a special posture.
37:09On a reef, as anywhere, there are those who will abuse the hospitality.
37:18Manta rays come to be cleaned by wrasse and surgeonfish.
37:30Surgeonfish are spawning, and the milky blue clouds are their eggs.
37:46Surgeonfish breed with the cycles of the moon.
37:50The mantas can schedule their cleaning appointments to make sure there's a meal afterwards.
38:11The oceans have rhythms like the land.
38:14The most influential rhythm is something the land doesn't have.
38:20Tides.
38:22When the moon is over the Pacific, it pulls the whole huge ocean towards it.
38:37Tides govern the timing of our journey, and the nesting at the end of it.
38:45Many sea animals can detect rising tides with perfect accuracy.
38:52A coral polyp has created miniature moons, each a bag of eggs.
39:00Once a year, on the same night, corals of a single species spawn.
39:27The sea water is so thick with plankton and larvae that, with just a pint of it, you could start
39:33a new reef, colonize a new sea mount, or seed a new bait ball.
39:39If you look for hope, you can find it here.
39:44The sea has an almost infinite ability to regenerate.
39:53But it's also extremely fragile.
39:57The white slabs along this reef are coral, dead coral.
40:02Some of the richest places on Earth are dying because of a degree or two rise in temperature.
40:11The seas are also absorbing more carbon dioxide, making the water more acidic.
40:17It's harder to grow your skeleton in acid seas.
40:32Life in the whole Pacific is changing.
40:37Some of the effects reach out like tentacles around the whole world.
40:48The currents that flow between the Pacific and the other oceans are like huge conveyor belts.
40:59As the warmth spreads, weather changes.
41:02More water evaporates.
41:04It changes from ocean to cloud, becomes storms and floods, or makes droughts.
41:11No one knows how bad it will get.
41:17If turtles have any ancestral memory, they know.
41:2155 million years ago, turtles could visit coral reefs off Alaska or swim to the North Pole.
41:31Now they're swimming over the evidence that it can happen again.
41:36The cold, deep Pacific can cool the ocean as it mixes with warm water.
41:41But there's a problem.
41:43Miles down, in the dark, is where the bodies are.
41:52Decomposition produces methane.
41:54Undersea volcanoes do too.
41:56And there are huge seas of it.
41:59Cold water keeps the methane where it is.
42:02But if it warms, even a tiny bit, the methane bubbles up.
42:07It is a greenhouse gas ten times worse than carbon dioxide.
42:14The last time this happened, half of life was wiped out.
42:21What happens here affects the whole planet.
42:39Turtles have survived because they can travel.
42:44The best food and currents have always been changing.
42:49She's heading for the only beach she knows is safe.
42:52The beach that produced her.
42:56She's come a third of the way around the world, and still has a thousand miles to go.
43:06To find a dot of land not seen for decades, turtles need to map magnetic fields,
43:12chart currents and tides, and use the angle of the sun to navigate.
43:19Recent research also suggests that she uses the unique smell of the shore to guide her home.
43:37Green turtles don't travel as far as loggerheads, but a thousand miles isn't unusual.
43:45All female turtles mate a few weeks before they start nesting.
43:51The males are smaller than the females and have long tails.
43:59It's not only male turtles waiting offshore.
44:10Tiger sharks know about turtle beaches too.
44:15Tiger sharks are not only one.
44:20Not many sharks specialise in eating turtles, but sometimes sharks seem to get a taste for it.
44:42the loggerhead has been traveling for a year now and like the loggerhead that scientists
44:47satellite tracked from Mexico she's zigzagging her way home her beach it turns out is in Japan
44:57she's traveled nine thousand one hundred miles in three hundred and seventy days an average of one
45:05mile an hour nobody saw her arrive but it's the same for all turtles
45:23thousands of loggerheads used to haul themselves up this beach now there's only a handful of turtles
45:42she digs a hole a few feet deep and lays about a hundred eggs then she covers them up and
45:52struggles
45:52back towards the Pacific she won't return to Mexico but spend her long adult life around here Japan and
46:20China there are more and bigger storms now a typhoon in the Pacific last year was the most intensive and
46:30longest-lasting on record storms and rising sea levels wash turtle eggs away the scientists following
46:49the first loggerhead they tracked saw it had arrived safely but then saw it caught in a trawl net and
46:58drowned it was an accident it's also a sort of accident that the Pacific is changing no one thought that
47:15our lives
47:16could have such an effect now we must plot a new course
47:32luck has been kinder to our loggerheads babies and two months after being laid most of them hatch
47:45luck has been kinder to our loggerheads babies and two months after being laid most of them hatch
47:46in 35 years time some of the females among them will be off Mexico and wanting to come back here
47:57maybe a few will swim past clouds of plankton and huge whales mantas and dolphins
48:06maybe one of them will make it back safely across this massive ocean the Pacific
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