Kermadec Islands_ New Zealand’s Volcanic Ocean Oasis _ FD Ocean

North-east of New Zealand, a ridge of underwater volcanoes extends 1,400 kilometres into the Pacific Ocean. Only the Kermadec Islands on this ridge are visible above sea level. Each is the summit of an emerging volcano, and this arc of islands is the northernmost reach of New Zealand's bigger Blue Backyard. The open ocean between New Zealand and the Pacific Islands is like a desert, devoid of the nutrients necessary for life to thrive. But the Kermadec Islands are an oasis in this desert. An upwelling of nutrient-rich waters from the deep trench located near the island arc continuously delivers just enough food to support this diverse neighbourhood. But in spring every year, there's an event that will affect the lives of all the weird and wonderful residents of this magical place. This is when an enormous male groper will change his spots for stripes as he competes for a mate. A gang of marauders seek to devour their neighbour's offspring, no matter how well the nests are hidden. Parents on the island's vantage points will do whatever it takes to nurture their demanding offspring, while another parent, passing through the Kermadecs, will face a mother's worst nightmare on her epic migration. It's October in the Kermadec Islands, and the spring bloom is underway. Every year at this time, when the cold water transporting nutrients up from below hits the warming surface water, there's a bloom in the plankton, which is the foundation of the food chain. Suddenly, populations of all the residents also explode. Bluefish, huge schools of Mau Mau, Trevally, and Galapagos sharks. The water teams with a multitude of marine animals, all primed to exploit this significant event the best way they know how. Raoul Island is the largest in the Kermadecs group, and its dense Pohutukawa forests tell an ancient story of how life found its way here. Tiny seeds, blown on the wind, established themselves on bare volcanic rock, and grew to live in sync with the ancestors of our Tui, also likely to have blown here in storms. Seabirds would also have been among the first to discover these barren rocks. One of the most unique and charismatic of these seabirds is the Tasman booby. The species was apparently named booby after a slang word meaning stupid, because the fearless birds often landed on board sailing ships and were eaten by sailors. Dark facial skin gives them a masked appearance. They have colorful legs and feet, and a wingspan which can be up to two meters. In sync with the nutrient-rich spring bloom, November is peak time for booby courtship. Boobies mate for life, which can be 20 years, so decisions can't be made lightly, and the first choice may not always be successful. Booby courtship requires the males to demonstrate nest building to attract attention. He's really just moving a few sticks around, but this female is taking notice. When boobies feel they're in with a chance, they signal by sky pointing. Once paired up, they move on to beak clashing and preening in unison. When all the courting formalities are done, the culmination is relatively subdued. Both will incubate the one or two eggs that will be produced, and both mates' efforts will also be critical in parenting the precious chicks when they hatch. The Kermadec Islands are also home to New Zealand's largest population of a particularly intriguing fish, the spotted black grouper. Heavy-lipped, shifty-eyed, and around two meters long, weighing 70 kilos, the adult males can be as big as a human being. Contrary to its name, the grouper is neither always black nor always spotted. At will, all can change the color and patterning of their skin from dark to a mottled white with black stripes. This striking transformation can help avoid detection, and it's also a signifier of mood. This dark-colored male is in a state of low arousal, but that is about to change. With the arrival of the spring bloom, the priority for all the males is to find a mate. With an entourage of juvenile trevally, this big guy spies a target. She signals interest by a swift color change, as does he, but it seems she's not yet ready to mate. There's another species that the Kermadec Islands play host to, at this time every year. During spring, around a thousand humpback whales pass by on their migration south. They've come from the Pacific Islands, where they breed, and are heading to their summer feeding grounds in the cold waters of Antarctica. Despite the plankton bloom, this female humpback with her calf in tow will not snack here or at any time during her months-long trip south. Weighing as much as 40 tons, she has enough energy stored in her blubber to fuel her for 9,000-kilometer journey. Her calf, however, is just a few months old, and even though its mother slows down to compensate, it's often a struggle for the young whale to keep up. The calf must also surface to breathe far more frequently than its mother. As the calf swims up for air this time, mum helps out by holding it at the surface. It's a behavior often seen with newborns, and a sign her calf is fatigued. This stopover at the Kermadec Islands is perfect timing for a hungry calf. The calf needs to feed regularly, and drinks nearly 200 liters of mum's thick yogurty milk every day. Rather than suckling, the mother squirts milk into her calf's mouth, using muscles in her mammary glands. With its belly full of milk, it's time to breathe again. This calf will be completely dependent on its mother for around a year. Calves which become separated from their mothers face starvation, or an encounter with other long-distance travelers to the Kermadec Oasis. All around the emerging volcanic islands and rocks which make up the Kermadec Arc, the residents exploit the spring bloom. Each species is driven by instinct to consume as much food as possible during this time when the plankton multiplies. Beneath the reefs surrounding the islands, their volcanic ancestry is apparent, as bubbles escape from small vents in the sea floor. Surrounding the bubble gardens grow the famous Kermadec corals. There are rugs of soft coral known as shagpile, towers of hard corals, gorgonian coral fans, and the leafy coral, where large plates spiral outwards from a central column. It's subtropical here, with the water temperature a lot cooler than in the tropics. So instead of forming huge interconnected reefs, the Kermadec hard corals form islands. These islands provide homes to many of the residents, including those who prefer to keep a low profile, like the cranky-looking scorpionfish, the bizarre sea hare, not a plant but a type of sea slug, and the just plain weird diadema urchin. The terrifying eyeball which appears to be checking for prey is actually its anus. There's another member of the freak show down here, but it doesn't live entirely in harmony with coral. The crown of thorns starfish eats coral. It has a primitive eye on the tip of every arm, and so uses vision and a sense of smell to seek out its victims. When it reaches a coral island, it grasps its prey with spine-covered arms, turns its stomach inside out, and digests living polyps from the coral skeleton. A ghostly white scar is always left on the coral, displaying where it was eaten alive. Just one crown of thorns sea star can devour six meters a year. In high numbers, they wreak havoc on the coral islands. Very few species are unique to the Kermadex. The islands emerged from the ocean as volcanoes just a million years ago. But during that time, the Kermadex scaly fin evolved into a distinct species found nowhere else. These pretty little fish are dedicated gardeners. All adults tend a patch of algae which they regularly mow by nibbling at it. This might seem a relaxed occupation, but the job involves dealing to would-be garden raiders, which come in many shapes and sizes, including grouper, 50 times its size. When a huge school of blue maumau turn up on the edge of the scaly fin's territory, things could turn ugly. Strangely, they fail to disturb its dinner. The reason is scaly fins recognize that these fish don't eat algae. Maumau are plankton feeders, so this time the precious garden is safe. Every year at this time, the residents of the Kermadec islands are treated to an eerily beautiful soundtrack, which resonates throughout the underwater world. It's the song of a male humpback whale. As a mother whale and her calf cruise into the shallows of Raoul Island, the crooner reveals himself. His song is directed at the adult female whom he hopes to woo. Creases on the underside of the calf just above its tail result from being tucked inside the womb and show it's just a few days old, so it's unlikely the female is ready to mate again just yet. But the singing male is playing a long game. By acting as her escort on the migration, he could be first in line to mate with her when she's ready. Northeast of Raoul Island are the Maya's islets, where the 100 or so breeding pairs of Tasman boobies raise their chicks every year. High on a rocky ridge with wraparound ocean views is Booby Point, home to a number of nests. These two boobies, with a daily view of humpback whales frolicking, must have staked their claim early this year. They already have a chick. It's fluffy down indicating it's probably around two weeks old. Both male and female will groom their baby and take turns feeding it for the next eight weeks. Right next door are two other brooding boobies. Who have taken advantage of a rock to divide their nests. On the left is a female who is still incubating a single egg. On the right is a female whose chick has just hatched. It's likely these females mates are currently hunting at sea. So when a random booby arrives, both females are on high alert. Tiny chick mum is so agitated she endangers her newly hatched chick. As the neighbours watch with great interest, both single mothers team up to chase off the intruder. In the commotion, the large fluffy chick demands to be fed. Booby dad responds with some chick discipline. But soon this little family is happily bonding with some symbolic nest building. Sharing sticks and rearranging the nest continues right throughout their breeding season. And the chicks are always quick to mimic their parents. Meanwhile, the two lone females sit and wait. If their mates don't return to their nest soon to take a turn, the tiny chick and the egg could be at risk. With the spring bloom in full effect, the ocean surrounding the Kermadex is alive with fish. And with increased traffic, inevitably territorial skirmishes abound. This two-spot demoiselle, named for his distinctive markings, has more reason than most to patrol his patch. Two days ago he performed a courtship dance and a female chose him as her mate. As they fluttered against one another, she laid microscopic eggs and he fertilized them. Now, if his eggs are to have a chance, he has to chase off his own kind, who are keen to make a meal of them. The attack subsides momentarily. But a marauding gang of bluefish is headed his way. They are primarily algae eaters, but are also opportunistic feeders. An advance party discovers a mass of squid eggs hidden in a clump of algae. And the gang savagely rip it apart, playing pass the parcel as they devour the eggs. When there's nothing left, the shoal moves on. And they're heading in the two-spot demoiselle's direction. In a random stroke of luck, they coast on past his patch. But instead, the bluefish devour all the nests on this rock, leaving other two-spot demoiselle males with no eggs left to guard. It's a challenging time of the year for Kermadec males, as they are driven to pass on their genes. Three amorous male gropers, dorsal fins erect, flushed white with arousal, compete to perform a courtship dance with a female. But she remains jet black, signaling she's not interested. In contrast to the groper's complicated courtship, this bizarre-looking creature is off to the mollusc equivalent of a lovin. The extraordinary sea hare, to use its full name, flies through the water on winged flaps. It's been summoned by a powerful aphrodisiac, released into the water by other sea hares. Multiple sea hares have formed a sort of conga line, except these guys aren't dancing, they're mating. As more arrive at the party, the line degenerates into a gently swaying mound. All the sea hares on the outside of the pile are male. This one's fertilizing the female next to him. And she's fertilizing the sea hare next to her, because she is also a he. These gender-bending sex parties can involve up to 20 hermaphrodites and go on for days. It's little wonder sea hares live it up while they can. They have a lifespan of just a single year. Up above in Rowell Island Bay, the female humpback whale and its newborn calf appear in no hurry to leave the shelter of the islands. The youngster is in a playful mood and tries out some uncoordinated fin slapping. With far larger fins than her infant, it's time mum shows just how it should be done. Play is critical in a calf's upbringing, and imitating adults helps them to learn how to communicate and later to forage. The next lesson is tail lobbing, which is how whales can communicate over huge distances. The female demonstrates, and her calf copies almost exactly. Humpback calves are dependent on their mothers for more than twice as long as similar whale species. This could be because there's much to learn from migrating whales. The lesson ends with a breach, and out of the blue a third whale appears. It's another calf, and strangely it's not with its mother. She may just be out of sight in the depths below, but the calf also may have been abandoned by its mother because it couldn't keep up. For a few hours the lone calf tags along with its new friends, until eventually the female and calf head off into the late afternoon sun, leaving the newcomer on its own once again. Lost and deprived of its mother's milk, this calf is extremely vulnerable. High on booby point, and one Tasman booby parent sits with the big fluffy chick watching the visitors enjoy their bay. The parents take turns hunting at sea, as their chick grows bigger and more demanding every day. On return the mates always greet each other with beak clashing, and then it's time for a communal preen. Knowing that food will be provided soon, the chick vibrates its throat with excitement. Just below the point family, a female booby still sits patiently on a single egg, and there's still no sign of her mate. Her neighbor's chick is growing, with its down just starting to come through. The chick appears desperate for food, but a lone parent cannot leave her chick to hunt. Then a booby lands on the point. The way they avoid each other's glances is not a good sign. This could be an intruder, but then the male makes a move, and finally the female responds with subtle nest building gestures, which signals acceptance of her mate's return. The female wastes no time in making her escape, off to sea to fill her belly with fish and squid. Now it's the male's turn for chick care. All is well this evening on booby point, as the seabirds demonstrate how nutrients from their droppings also add to the plant and bloom. At dusk the predators become more active. Galapagos sharks are prone to cannibalism, so juveniles learn to avoid the adults. Although Galapagos sharks scare even their own kind, not all fish give them a wide berth. This one has attracted a tiny hitchhiker. The juvenile trevally may appear to be pushing its luck, but it's too small to interest a shark. And what better friend could a little fish hope for than one who scares away those who might eat him in one bite? After dark, fish scatter at the spotted black grouper's approach. A scorpionfish scoots across his path, and the hunter begins to move more purposely, keeping a low profile on the seabed. He sneaks up on a rock to see who's hiding. Just when it seems he might go hungry, he corners a bluefish. The swirl of fish scales suggest the hunter did get a bite, but he slips away into the darkness without his prey. While stealth is a common predatory tactic, the lionfish's dorsal fins deliver a venomous sting which causes instant paralysis, and it can use its elegant pectoral fins like a net. Once prey is in range, the lionfish strikes with lightning speed. Scorpionfish use camouflage to hide from their predators. But sharks can locate invisible prey by sensing their electrical field, a highly successful way to hunt. As dawn approaches, the grouper reverts to his more leisurely swimming style. He may have missed his first fish, but this expulsion of grouper poop means he's got a full belly now. Like the Galapagos shark, this grouper has picked up a Cunning little trevally know that groupers with full bellies often belch up the fishy remains of dinner, and the hovering escort gets a free meal. In the waters off Rowell Island, the new light of day reveals a harsh truth. The lone humpback calf didn't make it through the night. Multiple Galapagos sharks have discovered the youngster's body, but they could not have inflicted the massive bite in the calf's flank. It's possible the young whale had already died of starvation, but a lone calf would have been an easy kill for this five meter long great white shark. Its first migration will be its last. The journey and its short life ending among the Kermadec Islands. It's now late December, and the tail end of the rich nutrient upwelling, which triggered a frenzy of feeding and hunting for all the residents of the Kermadec Islands. This booby looks like he may have caught one fish too many. On booby point, the fluffy chick appears bigger than its parents now. Mum seems intent on ensuring her chick eats some greens from the wild spinach which grows all over the mayor's islets. It will be another couple of months before this chick is ready to fly. In the meantime, these parents with their solid partnership will continue to do everything together to ensure the survival of their offspring. Next door on booby point, the egg in the single parent nest has finally hatched. The female tends her chick with all the care she put into her egg, but with no sign of a mate to help provide food, the future for both these birds is uncertain. At the third nest on booby point, what was once a tiny chick is growing rapidly and has an attitude to match. Its constant demands for food and attention provoke a creative parenting response. First, the mother just asks her chick to shut up. When that doesn't work, she begins the old booby trick of symbolic nest building, which works for many situations. Eventually, the chick is distracted and joins in, sort of, but the nest building does the trick. Now the female booby will get some peace. Beneath the surface, life settles back into a pre-bloom rhythm. A school of trevally slide up against a cruising Galapagos shark, cleaning themselves against the shark's sandpaper-like skin. A pair of spotted black grouper take their courtship to the next level, as an unattached male watches. This little scaly fin is still obsessively protecting his garden from pesky two-spot demazels, but the stakes are higher now. Buried in the algae are thousands of minute eggs laid by his mate. A week ago, when this humpback whale mother and calf arrived in the Kermadecs, the youngster was too fatigued to carry on. Now, after a break, both are set to hit the whale trail south to Antarctica once again. Just before they reach open water, a visitor. It's another newborn calf in a frisky mood. The urge to play is contagious and the other calf joins the fun. But again, the newborn's mother is nowhere to be seen. And then, up from the deep, the calf's mother finally arrives. And she's accompanied by a male escort. The opportunity to socialise may well be the reason all these humpback whales choose to stop over at the Kermadec islands. Their paths will diverge as they head south, but it's possible these long-lived giants will meet again next time they pass by this truly unique oasis in our big blue backyard.