Dispatches from the Kermadecs
Earlier this month, Dr. Rebecca Priestley travelled on the HMNZS Canterbury as part of the Sir Peter Blake Trust's voyage to New Zealand's remote and rarely visited Kermadecs. Rebecca was part of a team of experts selected by Pew Environment Group to travel to this remarkable ocean wilderness.
Pew's Global Ocean Legacy is encouraging the New Zealand government to protect the Kermadec region and its rich biodiversity by creating one of the world's largest, fully protected ocean sanctuaries. Rebecca worked closely with the voyage's scientists – marine biologists, volcanologists and conservation workers – and reported on the team's daily adventures and discoveries.
Content originally posted on the Scientific American's Expedition blog site.
- New Zealand's Remote Ocean Wilderness
- A Serendipitous ‘Event'
- Humping and dumping, Kermadecs style
- Shark fishing with Clinton Duffy
- Dolphin chasing, whale watching and wrestling the Galapagos shark
- Becoming a Raoulie
- Whales on the starboard bow
- Snorkeling around Meyer Islands
- Going Home
New Zealand's Remote Ocean Wilderness
“You can't escape the geology in New Zealand,” said Helen Bostock, a marine geologist on the voyage. “It's in your face whether you like it or not.”
It's true. As we left Auckland this morning we were sailing away from two erupting volcanoes: Tongariro, in the middle of the Taupo Volcanic Zone, had just erupted for the first time in more than 100 years, depositing ash around the central North Island. White Island, a busy little volcano in the middle of the Bay of Plenty, was erupting ash from its Crater Lake.
So where are we heading? We're sailing north along a chain of underwater volcanoes to another active volcano, Raoul Island, about two days sailing from Auckland. Raoul Island – the top 516 meters of a submerged volcano whose slopes extend for thousands of meters beneath the ocean – last erupted in 2006 and we hope it will stay quiet for our visit.
Raoul Island is a pest-free nature reserve, its steep cliffs home to more than six million breeding seabirds. Like all the Kermadec Islands, the waters up to 12 nautical miles around the island are a no-take marine reserve, part of a stunning and pristine marine environment with a unique mix of tropical, sub-tropical and temperate species of fish. This is a rare ecosystem, where large predators rule, untroubled by fishing lines or nets.
On the island, New Zealand's northernmost scientific field base is managed by a small group of Department of Conservation staff and volunteers, and that's partly what this voyage is about.
In any given year, the Island would typically receive about 20 visitors, but this year is a bit special. As well as the annual Department of Conservation staff changeover and resupply, the HMNZS Canterbury – a big, grey beast of a ship that looks as much like a windowless building as an ocean-going vessel – is taking meteorologists, geologists, marine biologists and a large group of students on a Sir Peter Blake Trust Expedition. We'll spend about six days anchored beside the island. The crew and marine specialists will remain on the ship, but 50 of us will go ashore.
Rough seas are forecast. The best thing to avoid seasickness, I'm told, is a lemon and ginger tea and some fresh air. So I'm going up on deck to breath some salty air and keep a lookout for migrating whales.
I'll let you know what we see.
A Serendipitous ‘Event'
I went outside at first light and found the ship in the middle of a heaving grey sea, with nothing but ocean and sky in every direction. Three dark-winged birds – probably petrels – swooped and dived amongst the waves. It might look like a great big nothingness, but there's a lot going on in the ocean beneath us. The birds are diving for fish or small squid. There are whales migrating south as we sail north. There are volcanoes in the depths beneath us, their slopes and geothermal vents home to a rich and often bizarre diversity of flora and fauna.
Then, at midday, our Commanding Officer, Commander Sean Stewart, gave the order to change course. A marine patrol aircraft, flying from Samoa to New Zealand, had spotted “an event” in the ocean north of us. Up to 250 nautical miles long by 30 nautical miles wide, it stood out against the blue-grey of the ocean as a great white froth on the surface of the sea.
Marine geologist Helen Bostock said the deposit could be a mixture of ash and pumice from an underwater volcanic eruption. There was only one way to find out – sample it. By the time we reached the deposit, the ash had dispersed, but blocks of pumice were bobbing past us in the water.
Sometimes science is about using whatever tools you can find when faced with a serendipitous opportunity. At Helen's request, a couple of young Navy ratings lowered buckets, tied to a rope, off the gun deck and down into the water. There was a big cheer when they came up with a few small pieces of pumice – brand-new, freshly-minted rock – in the bucket.
But from where? We have some people on board from Geonet, whose role is to monitor seismic and volcanic activity around New Zealand. They say that Monowai, an undersea volcano north of Raoul Island, has been showing activity for the past five days.
Helen says that when she gets the pumice back to her NIWA [National Institute of Water and Atmospheric Research] laboratory, they will do a chemical analysis. “It's like genetic fingerprinting,” she says. “Each volcano has it's own chemical signature”. If this pumice matches Monowai, or one of the other existing volcanoes, that's where it's from. If it doesn't match anything, it could be from a new volcano.
While we were outside pumice spotting we saw more petrels and an Antipodean albatross. And then, at last, a whale! Not a humpback, which are known to follow this path on the annual migration from the tropics to their Antarctic feeding grounds, but a minke whale.
We're now sailing at about 17 knots, and should reach Raoul Island overnight. We're all hoping for calmer seas.
Humping and dumping, Kermadecs style
Last night, when Lieutenant Tim Oscar, the Officer of the Watch arrived at the bridge for his midnight to 4am shift (seriously, that's what they do, all the lights on the bridge are turned off and they watch the sea) he noticed something strange. He turned the ship's spotlights on and discovered the ship was ploughing through the wall of pumice we were looking for yesterday.
The ship travelled through it for half a nautical mile, and he estimates it was two feet thick and extended sideways as far as the eye could see. “It was like being in an icebreaker hitting an ice shelf,” he said this morning. He described it as “the wierdest thing I've seen in 18 years at sea”. It was too dark and the ship was going too fast to stop and take samples, so he noted down the latitude and longitude (29 59.43 degrees south and 179 25.598 degrees west) and motored on through it.
We arrived at Raoul Island in the early hours of the morning and anchored at 7am. The local wildlife took an immediate interest in us: a pair of Tasman boobies joined the petrels we began seeing yesterday and then a mako shark and a small pod of dolphins began playing close to the ship.
Clinton Duffy, the shark specialist on board, says that while mako sharks have been seen further out to sea in this area, there's no record of any within the marine reserve. That doesn't mean they're not usually here, but just that this marine environment is largely unexplored – every science expedition results in new species being identified.
Today was all about logistics, with a big joint effort between the Army, the Navy and the Air Force to get Department of Conservation and GNS Science staff and supplies onto the island. People travelled to the island on a RHIB (rigid hull inflatable boat) while supplies – I saw food, beer, roofing iron and a yellow boat – were all hooked beneath the Seasprite helicopter and carried onto the island. Around here they call this “humping and dumping”.
At the same time, the marine biologists on board were getting ready to start their field work. On a reconnaissance trip to find the best diving spots, University of Queensland PhD student Libby Liggins collected sea urchins for her research into genetic connectivity. Tomorrow we're searching for dolphins with Rochelle Constantine. Tonight, we're opening the stern ramp at the back of the ship and trying to attract sharks for Clinton Duffy's research project.
Wish us luck.
Shark fishing with Clinton Duffy
What was I saying about science and serendipity? On Thursday we had an unexpected haul of pumice fresh from an underwater volcanic eruption. Last night we went fishing for Galapagos sharks and found something better.
Clinton Duffy, Department of Conservation shark biologist, is here to study Galapagos sharks, one of the top predators in the Kermadecs. Once it was dark outside, we lowered the stern ramp to water level, turned on the floodlights and threw a berley bag – a mesh bag filled with minced pilchards – into the inky blackness.
Dressed in red overalls and a life jacket, Clinton grabbed a fishing rod, put a shiny lure on the line, and cast into the ocean. Other scientists, Navy ratings and students soon joined in, taking turns at holding the fishing rods, cutting up squid to throw into the sea, or standing by with a net.
Finally, at 9pm, a shark. Melania Napa'a, a student from Sir Edmond Hillary Collegiate School in Otara, reeled in a small brown shark about 32 inches (80 cm) long, with black tips on its dorsal fins, white margins on its other fins, and tiny white spots all over it. It was not a Galapagos shark but we could tell by the look on Clinton's face that it was something pretty special.
Melania had hooked a smoothhound (also called a spotted dogfish, or rig shark). While there are many species of smoothhound around the world, the one that lives in the Kermadecs is a separate and undescribed species. Clinton, who says this is only the fifth specimen known to science and the first live one he has ever seen, has been working on a full taxonomic description of the fish.
Back in Auckland, he will take DNA samples, x-rays and more than 100 measurements. The shark will be kept at Auckland Museum where it will become part of the type specimen for the species.
Clinton says this new species, like the Kermadec spiny dogfish he recently described, is confined to the northern part of the Kermadec Ridge. “This part of the ridge dips very deeply, and prevents dispersal by shelf species – everything from microorganisms to big fish,” he says. “The Kermadecs really are a center of endemism.”
But back to the pumice. The engineering crew checked the ship's water filters yesterday and, along with the usual mess of leaves and seaweed, they found a lot of small pieces of pumice. These filters, which suck in water to cool the ship's engine, are about 10 feet below the sea surface, so when the ship went through the pumice raft on Thursday night it sucked up a lot of pumice with its water. Today, they're giving the water filters a thorough clean. Helen Bostock has a new collection of pumice to take back to her lab in Wellington and I have a couple of small souvenirs to take home.
Dolphin chasing, whale watching and wrestling the Galapagos shark
Today, we circumnavigated the island in a RHIB, looking for dolphins and hoping for a few whale sightings. There was no sign of the little dolphin pod that greeted us the day we arrived and no whale signs but we'll keep looking – people on Raoul island have been seeing whales every day.
In the evening, Clinton Duffy was back to fishing for Galapagos sharks (Carcharhinus galapagensis) from the stern ramp of the HMNZS Canterbury. This time he got lucky, and again, it was the Young Blake Expedition students on board who did the fish catching. The biggest of the three Galapagos sharks caught last night was 4 foot (1.2 meters) long and involved a fishing line, a net and a bit of shark wrestling from Clinton.
Once he had the shark on its back on the ramp, his team got to work measuring its length, determining its gender, and clipping off a small piece of the pelvic fin. Then, only a few minutes after it was caught, the shark was released back into the water to carry on its work as top predator.
Clinton has spent a lot of time diving with sharks and observing their behavior – “a shark patrolling the reef, doing its thing, is a thing of absolute beauty,” he says – but on this expedition, he's after their DNA.
“I'll use these samples, and others from Norfolk Island, to investigate regional genetic population structure – which should give us an indication of how isolated or connected the Kermadec sharks are to those in similar habitats in the Tasman and Coral Seas.” To complete his project on population genetics, he needs fin samples from 30 of the Kermadecs Galapagos sharks. He has 19 samples from a biodiscovery expedition to the Kermadecs last year, and now three from last night, so only eight to go.
Galapagos sharks are generally found in tropical to subtropical waters around oceanic islands and seamounts. “As far as we know, the Kermadec population is the only New Zealand population of this species,” says Clinton. The range of the adult sharks, which reach 12 feet (3.6 meters) in length, extends far beyond the 12 nautical mile extent of the marine reserve, into areas between the islands where long-line fishing goes on.
“I would like to see the entire archipelago protected,” says Clinton. “It's likely these Galapagos sharks are moving between the islands.”
Becoming a Raoulie
Kermadec petrels (Pterodroma neglecta) and Kermadec white-faced storm petrels (Pelagodroma marina albiclunis) have been landing on the deck of the ship. These seabirds breed on Raoul Island and the nearby Meyer Islands, and plummet down from their cliff-side nests to feed in the ocean. With a diet of small squid, fish and krill, they are as much a part of the marine ecosystem as the large fish predators. Sometimes, though, the birds are prey. On his last trip to the Kermadecs, Clinton found three Kermadec little shearwaters (Puffinus assimilis kermadecensis) in the belly of a kingfish.
Clinton the shark man has a soft spot for birds, too, and each time a disoriented petrel is found on the ship he takes it to the upper deck of the HMNZS Canterbury – to mimic the cliffs they nest on – and encourages it to fly off.
We had our own flight yesterday morning. The wind was up and the swell had increased. It wasn't safe to come ashore by boat so we flew to the island in the Navy Seasprite helicopter.
Where we landed, on a grassy field, the grass and surrounding trees were filled with familiar looking land birds – pukeko, tui and kakariki. But they are different to the birds we know from New Zealand – the pukeko are skinnier, the tui are greener and the kakariki are fearless.
It's very busy on the island. The new Department of Conservation team are learning the ropes and getting to know the island and its flora and fauna. The Geonet team is checking their monitoring equipment – seismographs, tsunami gauges and lake level monitors. The MetService team is repairing cyclone damage to the shed – locals call it the bomb shed – where Roulies fill the daily hydrogen balloon.
Many of the island's nikau and pohutukawa were felled by the recent cyclone, and many of the standing trees suffered salt damage from sea spray. As well as occasional cyclones, the island is prone to volcanic eruptions, earthquakes and landslides. That's enough for the birds to cope with without humans adding to the problem. Early visitors to these islands brought kiore (Pacific rat), the Norway rat, cats, pigs and goats. They've all been successfully eradicated and now the Department of Conservation is concentrating on eradicating exotic flora.
This island is only two million years old so all the native species here, on land and in the rocky reefs around the island, arrived by dispersal, from New Zealand, Australia or the Pacific Islands. We've been arguing about how the pukeko got here. We have them in New Zealand, but they can't fly more than a few feet. Some people think they blew here on a big storm. Others think that visiting Maori voyagers brought them here in their waka (canoes). After last week's excitement with the pumice, I think they came here on a raft of pumice.
Speaking of which, Helen Bostock found a line of pumice at the shoreline on Denham's Bay. It was irregular in shape, which means it's young, and she thinks it's from last week's “event”.
Whales on the starboard bow
“Whales on the starboard bow,” was piped throughout the ship this morning. Rochelle Constantine, a marine mammal specialist from the University of Auckland, raced to the armory to get her biopsy gun and camera. Within 20 minutes she and Clinton Duffy were in the RHIB in pursuit of the whales.
From the bridge the Navy watch-keepers radioed instructions to Rochelle and her team. On the upper deck, the rest of us watched as a small group of humpback whales blew, fluked and rolled in the water, taunting the scientific team with their proximity but never letting them close enough to take a sample.
Rochelle is involved in a long-running international project aimed at understanding the endangered humpbacks of Oceania – one of only two endangered humpback populations in the world. In the nineteenth and twentieth centuries, more than 200,000 humpbacks were taken from the Southern Ocean.
But now the whales are protected and things are improving, but slowly. The staff on the island do an annual whale survey. For four hours, one day a year, they sit on the bluffs and look out to sea. Last year, they saw 126 whales.
This has got Rochelle really excited. “This is the southernmost location where these whales are near land before their long journey to their summer Antarctic feeding grounds,” she says. The humpback whales passing Raoul Island breed in Oceania and feed in Antarctica, but precisely where is not known. Rochelle's long-term aim is to tag some of these whales to track their Pacific migration and find precisely where their breeding and feeding grounds are. This population of humpbacks is not recovering as fast as other populations of humpbacks and Rochelle hopes to link this to something in the environment where they feed.
On her second trip of the day, after a circumnavigation of the island, Rochelle and her team came across a pod of nine bottlenose dolphins, including one calf. They got one biopsy sample and lots of great photos of the dorsal fins – “we can tell each individual by the nicks on their dorsal fins,” says Rochelle.
Meanwhile, back on the island, the GNS Science and MetService teams are busy doing their annual checks and repairs of their monitoring equipment. Department of Conservation staff take monthly measurements of the temperature of the crater lake, monitor CO2 levels for Scripps Oceanographic Institute, and put up a daily weather balloon to monitor the winds in the upper atmosphere. There is also a tsunami gauge, an automatic weather station, a network of seismographs and a camera that transmits photographs of the caldera back to the Geonet network.
On the ship, there's been more nighttime shark wrestling. Clinton Duffy now has two smoothhound sharks to take back to Auckland Museum to form the type series of this yet-to-be-described species, and fin samples from 17 Galapagos sharks and another five smoothhounds. Most of the Galapagos sharks were young, less than two-and-a-half feet (one meter) in length, but five of the largest sharks, from about 2.8 to 3.8 feet (114 to 151 meters) long, he tagged with streamer tags. Any reports of the sharks being recaught will give Clinton information about the range of the shark.
Clinton has his quota, so that's it for the night fishing. Tonight we're having a barbecue on the flight deck.
Snorkeling around Meyer Islands
This morning, I went snorkeling around the Meyer Islands – a small island group just off Raoul Island – with the expedition scientists. Libby Liggins, Clinton Duffy and Stephen Ullrich were collecting seaweeds, corals and starfish and Helen Bostock was hoping to gather some marine sediment.
I saw a bright yellow grey drummer, a yellow banded perch, lots of blue maomao, and then Clinton's Galapagos shark buddies came along. The first one I saw was a baby, the second one I saw, patrolling a deep rocky hole lined with pink coralline algae, looked bigger than me and soon there were four Galapagos sharks in the water with us.
I've snorkeled before, with stunning tropical reef fishes in the Gulf of California in Mexico, and in the black corals off the coast of Lombok in Indonesia, but I've never had a shark in the water with me. Clinton says the fact that there are so many top predators in the water here – Galapagos sharks, black grouper and kingfish – is a sign of a rare thing: an intact marine ecosystem where the top predators have not been fished out.
While the sharks and dolphins and whales – the charismatic megafauna – tend to get all the attention, they're just one part of the Kermadecs marine ecosystem that includes fish, turtles, interterbrates and plankton. Most evenings, while Clinton's been shark fishing, Helen has been throwing a plankton net in the water and hauling it up onto the ship where she preserves the plankton she collects in ethanol. The marine biologists are eager to see what she's collected in her plankton jar, because it's a missing piece of the puzzle in the Kermadecs food chain.
But that's it for Kermadecs collecting. We weighed anchor at 1300 hours and set course for the Hauraki Gulf, North Island. As we rounded Raoul Island, first a young humpback and then a dolphin raced and frolicked in the water beside us.
We've already seen a small amount of pumice in the water. From about 2.30pm, at latitude 29° 28.29 S and longitude 178° 08.75 south, we started seeing some streams of floating pumice in the water.
As I'm writing this we're approaching Macaulay Island. Like Raoul, Macaulay is the tip of a large submarine volcano and the part we're sailing over now is a large caldera speckled with active vents. We wouldn't want it to start erupting while we're sailing over it. Neither would the captain.
Down the microscope, the jar of seawater and zooplankton that Helen collected off the back of the ship has revealed larval jellyfish, tiny crabs, sea lice and microscopic organisms – things like ostracods, copepods and chaetognaths.
These animals are all clues to how the wider Kermadecs marine ecosystem works. The Kermadecs is not an area of high productivity – there are no large beds of algae or big seaweed beds to form the basis of the food chain but it is an area rich in biodiversity with many endemic species.
But so much of this area is unexplored. Scientists have yet to learn what's at the bottom of the food chain, what the fish are feeding on, where the larvae sources and sinks are, and how the Kermadec species – of fish, crustaceans, urchins, and cetaceans – are genetically connected to their neighbors on other islands.
There's a lot still to learn about the Kermadecs marine ecosystem. While Clinton and Rochelle talk about the marine environment here as being “pristine” and “intact”, only the waters up to 12 nautical miles around each island are in a no-take marine reserve. But many of the top predators here – the sharks, kingfish and spotted black grouper – move between the islands, into waters that are not protected. There is already some fishing taking place between the islands, and as other fisheries get exhausted – a Galapagos shark population off the east coast of South America was recently fished to extinction – these remote waters might become more attractive to fishing companies.
This seabed is attractive to mining companies too. Along the Kermadec arc, hydrothermal vents leak gas-rich hot water into the sea, and black smokers spew high pressure plumes of super-heated, mineral-rich water jet out of the rock, leaving chimney-like deposits of heavy minerals like iron and manganese, copper and gold. But these volcanically active areas are also hotbeds of biodiversity, home to some of the strangest creatures in the Kermadecs – giant tubeworms, forests of stalked barnacles, and clumps of giant mussels that provide food for predatory starfish and gastropods.
“Kingfish and Galapagos sharks almost certainly move outside the marine reserve, to seamounts to the north of Raoul and between the islands,” says Clinton. “The marine ecosystem is continuous between the islands, but the reserve is discontinuous. Fish moving between the islands are exposed to fishing pressures. An extended marine reserve that provides continuous protection across that full range of habitats would be desirable.”
Rochelle agrees. “It's really important that we ensure there is connectivity between the island reserves.”
We're nearly home. When you travel by water you feel very connected to the sea and I think this voyage has given all the students, crew and scientists on board a newfound connection for this northernmost part of New Zealand – the Kermadecs.
So often in conservation we're trying to restore a damaged environment to its natural state. The Kermadecs marine environment has not yet been impacted heavily by fishing or mining and is largely intact – from its plankton to small fish to top predators. Pew is encouraging the New Zealand Government to protect the Kermadec region and the rich biodiversity there by creating one of the world's largest ocean sanctuaries.