Journey to the ends of the Earth; Tempted by some of the most unspoiled environments on Earth, Sarah Marshall takes l a cruise through New Zealand's Subantarctic islands.
GAS mask clasped to my face, I stumble through a thick cloud of sulphurous fumes as helicopters circle overhead. It's a snapshot pertaining to the Apocalypse and not, as is in fact the case, a bunch of tourists on a cruise holiday.
But a visit toWhite W Island, a 200,000-year-old live marine volcano in New Zealand's Bay of Plenty, is my introduction to the wild, largely uninhabited and relatively unknown outlying islands that hang from the country like a precious necklace in the South Pacific Ocean.
Thanks to the absence of any endemic land predators, several ecologists have described New Zealand as being the best example of how life might function on another planet, and in particular, the Subantarctic islands promise to be like nowhere else on Earth.
Far further south than White W Island, the five UNESCO World Heritage W Subantarctic clusters - Antipodes, Auckland, Bounty, Campbell and The Snares - serve as some of the world's most important wildlife sanctuaries.
Yet of the 1,200 visitor permits available each year, that quota is rarely filled, an indication of just how tricky it is to get here in the first place.
Silversea is one of the very few cruise lines offering the itinerary on their adventure-seeking vessel Silver Discoverer, combining expeditionstyle travel with the comforts of butler service and Moet & Chandon on tap, and I've joined them for the inaugural voyage.
Beginning in Auckland on North Island, we travel south. Eradicating invasive species - and that appears to include Homo sapiens - is key to restoring these one-time Gardens of Eden, overrun by rats, sheep and combine harvesters.
It's true that Pitt Island - part of the Chatham archipelago - looks, somewhat disappointingly, a bit too much like home; rolling hills and grazing livestock were a European introduction.
Ten people on the island (a third of the population) are direct descendants of 19th century settler Frederick Hunt from Lincolnshire, and I'm amazed they've maintained the strength of will (not to mention the gene pool) to live in such a remote place for so long.
A sense of isolation becomes more acute during our long stretches at sea, which I grow to love. Although I could spend days listening to lectures, watching documentaries or burning off decadent gourmet dinners in the ship's high-tech gym, instead, I choose to be out on deck.
While crossing the Chatham W Rise, we see sperm whales spouting 5m diagonal blows, fluking and leaving a trail of smooth 'footprints' in the water.
Pelagic birds - ranging from graceful, balletic albatrosses, to Wedgewood blue fairy prions and Wgnarly-beaked northern giant petrels - hang in our slipstream, then disappear into the horizon where grey sea and sky become one. Their swooping flight patterns are as hypnotic as a swinging pendulum.
Rough seas pummel us with 6m waves and, as the bow rears upwards and crashes back down, rainbows form in an explosion of spray.
During one protracted two-day storm, our vessel tips like a see-saw, sending plates, cutlery, waiters and even guests sliding across the dining room in a way I thought only possible in slapstick comedies. One old lady loves it so much she begs for a re-run.
But fierce weather brings out the best in the landscape and wildlife.
A 15-minute trip through the Bounty Islands, a rare breeding ground for colonies of Salvin's albatrosses and erect-crested penguins, proves to be the highlight of my voyage. As wind batters the granite outcrops, birds hang in the ledges, literally clinging to the precipice of existence.
The waters are so challenging to navigate that it's the only trip our captain will make this season.
Fortunately, the storms soon subside and we're able to explore our next stop, the Antipodes Islands, on a Zodiac tour. Here, waterfalls cascade down columnar rocks, formed like the pipes on a church organ, and trickle over a stratified 'mille-feuille' of volcanic ash.
Parakeets hide in the grassy tussocks, and northern rockhopper penguins weave past slithery tendrils of sea kelp snaking in the water. On land, moulting elephant seals are easily mistaken for enormous boulders, and irritable New Zealand sea lions watch us suspiciously.
After so many days at sea, we finally set foot on land at Campbell Island, although we can't just merrily skip ashore. In 2003, the most southerly of New Zealand's Subantarctic islands was declared rat-free and officials are determined to keep unwanted visitors (including animals, insects and seeds) at bay.
Our boots are scraped and dipped in disinfectant, and clothing intimately probed with a vacuum cleaner. Only then are we allowed on shore, where purpose-built boardwalks run through the grassy nesting grounds of 99 per cent of the world's southern royal albatross population.
The vast ocean void offers little sense of scale, but up close it's possible to appreciate the sheer size of these mighty mariners who spend most of their lives at sea, only touching land every two years to breed.
Yet now, on terra firma, they appear so vulnerable.
They're not alone. On my way back to the beach, I'm ambushed by some fiercely territorial sea lions, and a plastic camera tripod suddenly feels like lame protection.
My second disconcerting seal encounter takes place on Enderby Island, part of the Aucklands. We visit W a wooden castaway store used for emergency supplies by 19th century sailors, where only a jar of salt now remains, and hike across bouncy tundra sprouting with supersize cabbage plants known amusingly as megaherbs.
Sea lions seem to lurk behind every wiry mound of tussock grass and, once disturbed, they give chase with alarming speed, fins rotating like the blades on a propeller.
"Stand your ground," shouts our expedition guide Keith Springer. But with 400kg of spluttering, barking blubber on my tail, I'm sent scuttling down the hill in the direction of the castaway store, weighing up how long I could survive on salt.
Far friendlier residents are the yellow-eyed penguins nesting in the dense silver rata forest and bellbirds whose syrupy electronic song is the sweetest music to my ears.
More symphonies from some of nature's greatest composers are performed on Ulva Island, much closer to the mainland. Although not part of the Subantarctics, it's still swathed in primeval forest and, in the absence of predators, is an ornithological paradise.
Above us, parrot-like kaka birds A feed on the red flowers of a rata tree, while below, a Stewart Island robin hops on the ground to mimic rain and lure out worms. We sit a metre away W and he doesn't even flinch.
Once home to neighbouring Stewart Island's first post office, people would sail here to collect or send mail and spend the day enjoying nature.
Volunteer guide Kari Beaven shows V us the tough leaves of muttonbird scrub, used as "the first postcards" and legally franked until 1970.
Thousands of miles from home, I wonder how many months it would have taken to send a letter - or even leaf - across the globe. Even today, E New Zealand's Subantarctic environments are so far from our own reality. True, you have to travel far, but fortunately not to another planet.
FACTFILE |SARAH MARSHALL was a guest of Silversea (www.silversea.com) who offers a 14-day trip from Auckland to Dunedin, visiting the Subantarctic islands, on December 20, 2015, with suites available from PS8,750, including all food and drinks and excursions.
Air New Zealand (www.airnewzealand.co.uk) offers daily flights to Auckland from PS1,070 economy return. For more information about the destination, visit www.newzealand.com/uk
A sea lion charging out of the water on Enderby Island
Tourists landing on Enderby Island and, left, the Silver Discoverer at anchor
Above right, a kaka bird feeding on the flowers of a rata tree and a yelloweyed penguin coming out of the surf