The Big Blue - Ocean Stories from Down Under | Episode 3 | Free Documentary Nature

[Music] [Music] [Music] the poor Knights Islands rise off the coast of New Zealand's Northland nearly 2,000 hectares of world-renowned Marine Wonderland and protected Island sanctuaries aangi to the South tafiti Rahi to the North and the many craggy Pinnacles around them isolated protected [Music] forbidding the poor Knights Islands have no beaches or so it seems there are beaches here white sandy and entirely underwater the poor Knights Marine reserve is one of the world's most pristine underwater environments The Towering architecture of its wreaths provides habitats for light lovers bottom dwellers and everything in between all the residents

know their place but order can break down in an instant a devoted father can lose everything when hungry neighbors raid his nest of eggs a female will change sex if she has to and nothing is what it seems It's Dawn and a sand dagger's rest wakes from his secret sleeping place his bold colors identify him clearly as a male but he began Life as a she ressers are a family of fish which are almost all born female and most remain female all their lives but each carries inside her the potential to become male the boldly

striped male can grow to around 45 cm while the Fe females like this one with her juvenile are smaller in muted brown and white the juveniles display a gold stripe and black tail dot for several months until they become adults together they form the male's herum and their morning is spent foraging on the ocean floor the sand daggers live on small Inver vertebrate animals found on the Sandy seabed and among the algae growing on the reef they suck food in and spit sand out fishing has been banned in the poor Knights Marine reserve since the

1990s and yet this female sandager r with an injured mouth may have survived being hooked by a poacher or attacked by by a predator nearby a stingray unwittingly provides cover for one of the poor Knight's most cunning Ambush Hunters the powerful Kingfish attempts to hide beneath some of its unsuspecting neighbors as it stalks prey waiting until the very last second to strike the reef is full of camouflaged [Music] Predators each with one thing on their mind it's summer here and the population has swelled with exotic visitors which come here to breed and feed the sea

surrounding the poor Knights is a couple of degrees warmer than Mainland Waters here warm Waters from the East Oakland current mixed with colder Southern Seas attracting a dazzling diversity of marine creatures rarely found in one place from cold water loving species like these blo mocki to the Exotic colorful subtropical [Music] visitors and this New Zealand native the blue Mau they congregate in the poor Knights archers by the thousands feeding on the Abundant Zoo Plankton as father and mate this male Sander's r supervises as Haram closely even controlling the female's food intake so they don't get

big enough to threaten his authority his neighbor the demelle has an entirely different approach to Family [Music] Life less than half the size of the sand daggers demel range from almost black to pale blue but almost always display their distinctive white dorsal dots two on each side like the sand daggers this male demelle has a family to protect only they are not born yet clinging to this rock invisible amongst the furry brown algae are hundreds of demelle eggs in just a week they will hatch but only if the male maintains his vigil there are plenty

of fish in this neighborhood who will happily help themselves to a meal of Juicy defenseless demelle eggs between the sand daggers and the demel there's an uneasy coexistence in just a moment these tolerant neighbors can turn on each other and social order can break down [Music] entirely as recently as 18,000 years ago a mere blink in geological time the poor Knights Islands were part of the New Zealand Mainland since the last ice age the sea has risen 120 M and now the poor Knights are isolated 22 km off the coast the islands are the disintegrating

remains of a once huge volcano asleep now for 10 million [Music] years as it slipped the pounding sea did their work eating away at the rock until all that is left of the once Mighty volcano are the inhospitable craggy tours of tafiti Rahi and aangi the islands Interiors are thick with Native forests [Music] deep below another kind of forest [Music] thrives Lush lasonia kelp sargassum and sea lettus are both food and shelter for many marine [Music] animals for the black angelish it's also a [Music] garden in his handsome all black outfit with white lips and

single white ear dot this fastidious vegetarian doesn't just guard his chosen food source he cultivates it this male nibbles just enough algae to feed himself leaving a neatly groomed lawn ready for a female to lay her eggs on if he's lucky enough to find a mate while a black angel fish can grow to 28 CM just a couple of rocks away his neighbor is a quarter of his size the crested blenny is a cleaner fish it's a dangerous world out there when you're no bigger than a finger so the blenny finds himself a cozy hole

in a rock and lets the world come to it these demel have come to the blenny with a problem they have lice and blennies eat lice with their sharp little teeth and even sharper reflexes the blennies pick parasites off larger [Music] fish it's a win-win situation if the demel seem nervous it's because the blenny occasionally takes a bite of [Music] fish parasite free for now the demel move on to a far greater challenge the Turning tide brings fresh Plankton into their domain but the Dem mels must make a perilous Journey to the surface to get

it it's a highrisk venture for these little fish so they travel in a convoy for safety never straying far from The Reef demel's eyes are close to their mouths which helps them see their food as their flexible lips scoop zo Plankton from the water the rewards of their Journey are great but so are the risks at the surface they have to hold their own with far bigger fish a large predatory Kingfish slips in among the Silvery Snapper and little deazel it's also here to feed but not on Plankton demel are more to its taste although

even greater danger comes from above these deadly Hunters are guts or [Music] takao the serrated Cliffs of the small smaller poor Knights islands make perfect nesting colonies for over 4,000 [Music] ganet with no rivers on the islands to wash silt into the sea the ganet can easily spot their prey in the clear [Music] water they tuck their wings in and hit the water at up to 145 km an hour inflatable air sacks around their necks absorb the impact then deflate once they surface allowing them to swallow their [Music] prey not all demel make the dangerous

migration ation to the surface summer is breeding season and many males already have eggs in their Rock nests to defend but this doesn't stop them enticing new females into their territory when a female is ready to breed her egg duct called an osor extends beneath her body ready to release her eggs but she needs a little encouragement the male demelle nuzzles the female's belly and rubs his body against hers to stimulate her to lay as she flutters her body she is depositing microscopic eggs amongst the algae on the Rock and he Quivers as he inseminates

the eggs [Music] From This Moment On he is committed not to her but to the nest until the eggs hatch in a week's time he begins an exhausting vigil seeing off any fish that come too [Music] close the female on the other hand is free to head off to find another male it's the Summer of Love at the poor Knights and everyone's pairing up few fish actually mate instead they spawn but many perform courtship rituals or show colorful [Music] displays this male pigfish signals his Amorous intentions with dashing white eyeliner and a flashy dorsal dot

they'll fade once he's completed spawning the sand agger's approach to breeding is less colorful spawned in Open Water the eggs are left to take their chances as part of the Plankton soup and Plankton is what everyone around here eats [Music] what family he has the sandaga supervises very carefully this female in Dre brown and white is just one of many in his herum and he's pretty tough on all of them it's not just to keep them in line it's to keep them female all female sand daggers carry the potential to become [Applause] male but he

doesn't want another male in his territory his domineering Behavior keeps the femal stressed and stress stimulates estrogen the hormone that keeps the females female but there's one aspect of life in his little rocky Kingdom that even he cannot control poised in the Pacific like a tuatara ready to pounce the island of tafiti Rahi is a theater of war a feud has been rumbling around the poor Knights for millions of years two ancient natives one Predator one prey New Zealand's largest reptile the Tuatara and the giant WETA the Tuatara family has been around for 250 million

years extinct on the mainland except in captivity Tuatara can only survive on predator-free island sanctuaries they are the poor Knight's top land predator they hunt lizards frogs chicks eggs and giant weter a species that's only been around a mere 190 million years weighing up to 50 g WETA are one of the heaviest insects in the world rats cats and Stokes are kept at Bay by the poor Knights forbidden Cliffs and spires and those 22 km of ocean keeping Tuatara safe but not their [Music] prey 100 M below them another ancient creature [Music] patrols stingrays have

been around for over 140 million years before the dinosaurs died out famous for the poison in their Barb Tails they only use these weapons in self-defense Rays have no bones they're all muscle and cartilage just like their close relatives sharks but they're not great Predators they just eat shellfish fish on the ocean [Music] floor this female short-tailed Stingray is looking for food only she's never going to see it her eyes sit on top of her head to watch for potential Predators above so she finds her food using sensory organs called ampuli of enen zini located

around her mouth they detect electrical charges emanating from creatures in the sand she vacuums up great mouthfuls of seabed grinding up the good stuff with her teeth and blowing the rest out through her gills every summer large numbers of rays migrate to the poor knights from the open ocean and gather in its towering underwater arches to [Music] breed sometimes they exhibit a behavior rarely seen anywhere else in the [Music] [Applause] world longtailed and short-tailed stingrays hover between the archers one stacked above another riding the current flowing through these narrow passes this Behavior might be connected

with mating but for now it's a mystery these animals are keeping [Music] Undercover a pink female pigfish checks out a tiny yellow clown T but possibly knows not to get too close like the Stingrays it too has a venomous Secret Weapon It's a Kind of puffer fish which have a poisonous gland inside them few fish eat a clown T and live to do it again the PO Knight's Reef abounds in gorgeous urchins anemones sponges and [Music] corals they may look like plants but they're all animals in that they eat and even have mouths although some

of the prettiest may turn out to be an animal of a different sort a scorpion fish can mimic a coral encrusted Rock in the blink of an [Music] eye these nudie branks are [Music] animals these two are even mating nudie branks are soft bodied mollusks and are highly toxic in the visual language of the sea bright colors spell po poison and warn other animals to stay [Music] away in among the garden-like colonies of sponges and corals the demel lay their precious [Music] eggs for the guarding male keeping his embryonic young alive means keeping them fresh

every few minutes he fans them with his petral fins which re oxygenates the [Music] water the much larger Black Angelfish chooses a smooth vertical face for his nest this one has found an excellent Niche but its secluded location is no deter to prying [Music] neighbors his white ear dot signals his defensiveness he turns it on when guarding off when cting in every direction devoted fathers are trying to protect their [Music] young the demelle and the the Black Angelfish have this in common if either male takes his eye off as young even for a moment hungry

neighbors will Mob the nest and a whole generation becomes [Music] lunch [Music] the poor Knights islands are forever [Music] changing the forces of Tide wind and salt smash these Cliffs relentlessly sculpting them into dramatic arches and caves and sending great slabs of rock plunging into the ocean here on the seafloor each Fallen Boulder hosts a miniature ecosystem home to colonies of algae and neones and demelle eggs the devoted demelle dads continue their demanding vigil while unattached demel are free to forage for food The Nest bound fathers have to get spy on whatever planktonic scraps float

past he must keep the nest site free of obstacles and never drop his guard as egg predation is common the more aggressively he defends his patch the more likely his young will make it to hatching but with so many hungry neighbors around there's only so much one fish can do it only takes a second as he chases off one Intruder for another to sneak in and sniff out his eggs then others get the same idea a female Sander's R starts to eat his eggs then more of her Haram join in within seconds there's a feeding

frenzy and most of the culprits are other demel a sandager male pushes in and two usually vegetarian black angel fish are part of the carnivorous throng somewhere in there is the father of all the disappearing eggs helplessly trying to repel the mob it's an exercise in futility after all that work clearing the space attracting a mate guarding and air rating the eggs and going without food there's nothing for it but to stop start all over [Music] again as night falls over the poor Knight Islands the Tuatara is in his element its eyes have cells adapted

for day and night vision making it an invincible Night Hunter the giant wetter heads for the the trees but Tuatara can climb trees [Music] too while the adults hunt the juveniles shelter in Burrows by day they swap places it's safer that way as two Atara adults are known to cannibalize their young this young Tuatara is not long hatched from its egg its gender was determined by temperature before it hatched eggs kept warmer produce male offspring cooler temperatures produce females so global warming threatens the two atara's very existence as the day draws to an end beneath

the ocean surface the daytime species either hide or adopt camouflage colors for the night the sandager RASS seek Refuge while their neighbors the goatfish sweep the floor for a final meal their lurid pink will dwindle to mtled Sandy tones the marble fish hunkers down in a crev and the fluorescent pink Mau tones it down a little turning blotchy to blend in with the reef The blennies Retreat into their [Music] holes and the demel snooze in a cave with a sleepy [Music] pory the most secretive sleepers of all are the sand dgar for a long time

their resting place was a great unknown at night sand daggers couldn't be found not in caves under rocks or in the kelp they just seemed to [Music] vanish until night divers uncovered their secret [Music] supervised by the male the females and juveniles bury themselves just under the [Music] sand finally when all his Haram are hidden the male Burrows in [Music] two hidden but still vulnerable now the night Predators come out to hunt the fierce but paper thin John Dory flashes its evil eye to make Predators think they're seeing the face of a huge [Music] creature

several species of Mor eel are also night hunters in the poor Knight's neighborhood small filaments in their nostrils detect the vibrations of approaching dinner the largest is the speckled Moray which can live for up to 30 [Music] years it takes little note of this scorpion fish as it heads out in search of more bite-sized [Music] prey the Mosaic Mor has sharp fangs even in the roof of its mouth so it can't entirely close its jaws the Mosaic pattern on its skin continues inside its mouth to confuse prey they can't tell if it's open or closed

the grey Mor lies in weight like the others but also Ventures out to hunt it can detect food buried in the [Music] sand in their hiding place the sand daggers sleep on somehow keeping enough water flowing over their gills so they can breathe just above them on the reef wall the reclusive scorpion fish bides its time this Master of Disguise positions itself and waits for unsuspecting prey to swim by but not all the creatures of the night are out to [Music] kill like most of the poor Knights stingrays mate in summer [Music] too a female

is easy to identify by her flat fanned Tail Fins whereas a male has modified fins called claspers which serve as sexual organs [Music] Stingray courtship is a risky business for the male if the female is not interested she may use that venomous tailb to get her point [Music] across if he does find a willing female he sinks his teeth into her and hangs on tight she may conceive straight away but female rays are also known to sperm bank holding the sperm in their bodies for months until they decide the time is right to conceive far

below the Rays the sandagas are buried and safe so long as no Predator discovers their hiding place but a thin layer of sand offers only so much protection first light pierces the clear waters around the poor Knights islands in the dark below the overhanging reef the sand aggar are still asleep under the sand nothing stirs but a gray Mor eel they have been known to kill and eat sand eggar the creatures of the night now seek the darkness of the caves and the daylight species stir pink Mau take things pretty slowly never burning up much

energy whereas from first light the Black Angelfish seems to be in a state of constant agitation he's got one priority keeping his eggs safe until they hatch The Morning Sun starts to hit the seaf floor but many corners of the reef remain in Shadow the Stingrays slip into the Sandy seabed to rest just as the sand daggers are rising for the day after a night breathing beneath the sand the sand daggers are hungry and need to feed [Music] but something is wrong one of the females has been bitten right through her body it's impossible to

know what did this perhaps it was the grey Mor [Music] eel but the sandagas females have a far bigger problem the male has disappeared whatever is happened to him his Herm is left without a leader for most of the demel today is just another [Music] day undeterred by the destruction of their neighbor Nest they continue to court breed and guard their eggs [Music] by luck and good management some have brought their brood to hatching these minute demel are 3 weeks old and already feeding in Open Water where there's Plankton small enough for their tiny mouths

those which survive to breeding age will be guarding their own nest by the time they're four or 5 years [Music] old and pestering their neighbors the little blennies to attend to those itchy [Music] parasites the Harum of female sandagas Rass get on with their day without their leader but one of the females is already taking over his role in an extraordinary way the minute there's no male the females have no stress without stress promoting estrogen the hormone which keeps them female they start to become male they grow bigger very quickly and although a few females

might begin the process the biggest female has a head start she immediately starts to behave like a dominant male putting the other females under stress again which increases their estrogen and stops them from going any further towards becoming male but this biggest female doesn't just behave like a male she becomes one a radical physical transformation begins her ovaries will turn into testes she will grow 10 cm longer and her muted colors will morph into the bold and brassy uniform of a male in only 2 weeks the transformation will be complete and she now he will

be ready to farther a new generation of Sander's R which will grow breed and establish their own little Kingdoms in this beautiful corner of our big blue [Music] backyard [Music]