MOMENTOUS MUSIC NZ ` the largest land mass above sea level of a vast continent that broke away from Gondwanaland. 23 million years after the landscape emerged from the ocean depths, it's still as diverse as it is unique. Remote corners of this world have seldom been seen. Isolated and rugged, unique plants and creatures have evolved that are found nowhere else on Earth. Since the arrival of human life, this wilderness and many species have been under threat, some lost forever. But today almost a third of this dynamic country is being protected. 14 national parks have been established to preserve this diverse landscape and the multitude of life that live here. Gus Roxburgh is an environmental specialist and adventure guide who's heading out to explore the country's wilderness and discover the often unseen backcountry world of these national parks. 125 years after the first national park was created, he wants to capture a sense of what these ever-evolving conservation parks have become, through the people who work and play and preserve the wilderness that is our national parks. And I think you'll find it's quite possibly the best backyard in the world. Copyright TVNZ Access Services 2013 SOARING MUSIC Abel Tasman National Park, a sanctuary renowned for its idyllic coastal landscapes, inlets and golden beaches. MUSIC CONTINUES At just 225km2, our smallest national park is home to a myriad of ocean, shore and forest wildlife. BIRDS CALL But aside from its reputation as a summer paradise, there is a dramatic and secretive side to this park ` the incredible carved granite terrain of its heavily forested interior, with an underworld of 450-million-year-old marble and some of the deepest caves in NZ. Just 150km inland is Nelson Lakes National Park. Perched at the northern extreme of the Southern Alps, pristine lakes are cradled by mountain and beech forests. Within these lakes resides an enduring NZ mystery ` ancient creatures with astounding life histories. And high in its alpine reaches is a lake believed to have the clearest fresh water on Earth. Abel Tasman and Nelson Lakes conservation parks are contrasting islands of wilderness at the top of the South Island, where ancient terrain and timeless forces support rich and diverse ecosystems. BIRDS SING MOMENTOUS MUSIC CONTINUES Whoo-hoo! I've been visiting Abel Tasman National Park since I was a kid. Without a doubt, it's a real beauty and in a region boasting some of the highest sunshine hours in the country. From up here it looks like a beautiful blue, green and golden jewel. Commercial microlight pilot Trevor Leighton has flown visitors over Abel Tasman National Park thousands of times and never tires of the view. And it's not hard to see why. Oh, mate. It's just stunning. The park's interior is another story ` altogether wilder, heavily cloaked with hard beech forests and far more inaccessible. This backcountry is rugged, isolated and, compared to the beaches, seldom sees people. It's an amazing landscape, formed from marble and riddled with some of the biggest sinkholes in the Southern hemisphere. Over millennia, they've become complex cave networks. In a constant process of erosion, water drains and carves its way through the ancient rock. At its extreme, erosion has carved a dark heart into Abel Tasman National Park, in an ominous landform known as Takaka Hill. It's here that the deepest sinkhole is found ` Harwoods Hole. With its 183m vertical shaft and 357m length, it dwarfs cavers and is reminiscent of Middle Earth. EERIE MUSIC Watch out for some of these big cracks. Yeah, they're like crevasses, aren't they? Yeah, they're like crevasses, aren't they? They are. Botanist Simon Walls' passion for the mysterious landscape of the mist-cloaked Takaka Hill runs deep. He's spent a 35-year career fascinated by the unique flora and the crazed-looking rocks. It's tortured-looking. It looks like someone's got their fingernails and gone down these, but they're almost like tiny little mountain ranges in miniature. This is called karst, and that's the name that describes this sort of landscape, where, um, dissolving processes have been dominant. It's just the mild acid that's in the rain, and also, um, the vegetation produces an acidic litter that filters down through these rocks. The marble started as the skeletons of sea creatures. But any fossils were long ago transformed through a 450-million-year process of compression, contortion, heating and uplifting. There's not much soil, but it's loaded with calcium, just right for a selection of plants called calcicoles. They're tough things. They're beautifully adapted. They've been, um, adapting to these conditions for a long time. EERIE MUSIC But the centrepiece of Takaka Hill is the ancient and foreboding Harwoods Hole. Not a good place to slip here, Simon. No, I'm keeping down in these cracks. That's it, huh? That's it, huh? About as far as we can go. That's it, huh? About as far as we can go. < On the edge. A massive 50m across with formidable 80m-high walls, this is the edge of the abyss. Carved by flowing water, over time the stream feeding the waterfall took another course, forming a new sinkhole elsewhere. Harwoods Hole was left a waterless cave. It remained unexplored until 1958, when the first to descend the 183m was a schoolboy. MUSIC CONTINUES Its underground hollows have since been explored many times, but this cavernous geology has an eerie demeanour. I don't like it here. (LAUGHS) It's a place of dread for me. I've seen it, and I don't want to go any closer. It's fine. (LAUGHS) The rainwater of Takaka Hill sits in a high catchment, then flows underground and out to the park's creeks and rivers. Here, the water encounters a distinctly different rock, part of a soft 100-million-year-old seam called Separation Point Granite. And as the water flows, it moulds and shapes, carving out deep canyons. Although Abel Tasman has these canyons in abundance, they've remained virtually unexplored until recently. All right, Gus, you ready? OK, just sit down on the edge, hold on to your end and just go for it. All right. Yeah, nice one, Gus. Well done. Yeah, nice one, Gus. Well done. Whoo-hoo! Dutchman Toine Houtenbos has a guiding concession for a stretch of the Torrent River running down to the coast. It's a route this canyoning enthusiast pioneered, allowing a unique glimpse of the mysterious interior. I mean, I guess this is, like, the bit of Abel Tasman that no one sees back here. I've never been here. I've been coming all my life. I'm actually quite pleased to be able to show you a place where you haven't been yes, Gus. Abel Tasman is all about the coast and the beaches as people know it. The canyons are definitely unexplored sort of terrain. There's a sense of exploration, of not knowing what's around the next corner. Analysing the river carefully from a safety perspective was Toine's first priority. The first time we go down, we're all quite sort of tense, cos we bring a whole bunch of equipment, but how much do you take if you don't know what's there? Well, after you, mate. Well, after you, mate. No, I'll let you do this one first, mate. Just in case you're not going. I'll give you a head start. I'll give you a push, some encouragement. I'll give you a head start. I'll give you a push, some encouragement. OK, here goes. ROCK MUSIC There's no doubt that water will find its way. As it traverses the weakest points, the granite is carved. The first time we saw Torrent River, we were blown away, So we explored some of the bigger ones, um, further into the park, and, uh, they're all amazing. It just makes me wonder what else is out there. ROCK MUSIC MUSIC CONTINUES This is a thrilling way to explore an ancient forest waterway. And the journey ends with a graceful slide into an icy cold pristine pool. The interior's remained virtually untouched. But on the coast, humans have had a huge impact. The park's story includes overcoming years of ecological devastation, and the clock is ticking for its last human residents. SOARING MUSIC Abel Tasman National Park. Like most of NZ before human life arrived, the coastal forests were lush and full of birdsong. Ancient hard beech, black beech, rimu and rata forests reigned supreme. It was in this lush and plentiful environment that early Maori thrived. So, Anika, would they have been living on these beaches? So, Anika, would they have been living on these beaches? Yeah, all along these beaches here. 'From the local Ngati Rarua and Te Atiawa people, 'Anika Young and Ropata Taylor have deep connections to this ancestral land.' The top of the South Island is, you know, highly prized for its kaimoana, for its seafood. Our people, they had small encampments along these beaches ` occupation sites ` and it was seasonal, so they'd come, you know, during the summer months. In October 1841, Maori made a deal with incoming European settlers Arthur Wakefield and the NZ Shipping Company. They met our ancestors on the beach at Kaiteriteri, and in exchange for vast tracts of land, reservations were created. They had a different approach to living with the environment to our ancestors. It was European settlement that ultimately challenged the land. From the 1850s, colonists milled the coastal forests and burned what remained. It was seen as a period of great progress, but it was a time of ecological devastation. We often planted our gardens around existing forests. They deforested the area, and it became farmland relatively quickly, and that created erosion. It, um` It` There was a major loss of biodiversity. But the land fought back. The granite bedrock didn't allow for fertile soil and repelled the farmers. They eventually abandoned their struggling pastures and crops to a rampant spread of introduced gorse. Today, little remains of that era. And with the aid of weed control and native replanting, the forest is regenerating. Adele Island is a predator-free sanctuary. BIRDS CALL The birdsong in this region was once described by Captain Cook's botanist, Joseph Banks, as 'the most melodious wild music ever heard'. BIRDS CHIRP, SING Now the island's a vanguard for the Abel Tasman Birdsong Trust, a project to bring back the birds ` a poignant but hopeful reminder of what was and what can be. The mana of the place is coming back, isn't it? Slowly. Yeah, absolutely. It takes all of our efforts, and, uh, and so, yeah, it's great to work collaboratively with others that also think that this place is pretty special. The Abel Tasman region has a distinct quality that has always drawn men and women from around the world. One of them, Perrine Moncrieff, is considered the mother of this national park. As a founding member of NZ's Native Bird Protection Society, this upper-class Briton's mission was to save NZ's wonderful forest and birds. In 1936, she gifted her land in Tasman Bay as a scenic reserve. And six years later, her greatest achievement, the park, was born. In 1942, it was the 300th anniversary of Dutch explorer Abel Janszoon Tasman's first contact with the area. What a great spot you've got here. This is fantastic. Love what you've done with it. We` We like it. Rollo Wilkinson of Bark Bay is one of the park's last remaining bach owners. His presence here is a reminder of times gone by. When he passes on, his lifetime lease on this pocket of land will be up. It could also mean the end for this little house on the shore. When I die, I presume they'll come down here with the sledgehammers and knock the place down. Uh, I don't really know what they'll do, but when you're dead, you don't care. (LAUGHS) Well, I think it would be a real pity to see this place go. It's like a little time capsule here. Rollo's land was acquired by the government in the 1960s as a new part of the national park. He remembers Perrine Moncrieff advocating for his rights to remain in his home. She was a lovely person, really, even though I only met her a couple of times. I think she was the original greenie, and, um, she really looked after nature and the birds, and she was interested in all those things. What was here when you guys showed up in '58? Was there anything else going on here? The track? 10ft-high gorse. 10ft-high gorse. Really? Yeah, there was no track in those days, no. And, uh, there was no outboard motors. The only access was by sea. Since then, change has been part of Rollo's view. The motors have got bigger and the boats have got bigger, and there's more people around. There's a lot of young girls and fellas travelling by themselves. Tramping and walking by themselves. So, I guess, after 55-odd years of coming here, Rollo, what keeps you coming back year after year? The scenery. GENTLE MUSIC Abel Tasman National Park is one of the most accessible and popular of NZ's national parks. MUSIC CONTINUES Totaranui is one of the country's busiest campsites, in peak season hosting up to 1200 people a day. The Abel Tasman Coastal Track sees at least 150,000 people a year, making it the most used of NZ's nine Great Walks. From native forest birds to little blue penguins, this park is an incredible slice of paradise. GENTLE MUSIC And after years of overfishing, these waters are once more abundant with one of the ocean's most playful characters. SOARING MUSIC Abel Tasman National Park is in large part defined by its relationship with the sea. As the estuaries and inlets receive and release the tides, the park's physical boundary becomes one with the marine environment, and animals depend upon its bounty. Maintaining this place of conservation is as much about the ocean as it is about the land. Responding to the impact of humans here is an ongoing process. Yeah, a lot of these tidal lagoons, you know, a lot of people don't even know they're here. You know, you wouldn't actually see the entrance to these if you're just cruising past on a boat. Nathan Faave's been coming into the park his whole life. He knows of the smaller inlets which remain well-kept secrets. The track doesn't come down here, does it? No, from Shag Harbour here, the track is a few kilometres away, so the only way in here is really on the water or a massive bush-bash. (CHUCKLES) 'Nathan, a world champion adventure racer, 'was one of the first sea-kayak guides to work in Abel Tasman from the late 1980s. He witnessed the transformation in visitor numbers, with up to 400 kayakers on the water during peak days. When I was a kid coming over here in the '70s, the park was a real different place. There was a few people walking the track, but nowhere near the extent that there is today. It was really just a few locals coming up here and doing a bit of fishing, a bit of summer camping. The fact that it hasn't really sold itself as a winter destination enables the park to recover, so if it was busy 12 months of the year, it would really struggle, but I think cos it gets six, seven, eight months of the year to basically revitalise itself, have a rest and get ready for the next season, it seems to manage itself really well. Meanwhile, the rhythms of these hidden inlets are governed by the tides, some of the most dramatic in the country. It's hard to believe it was five hours ago that Nathan and I were paddling in here. Came in right through that gap there. And it might look placid in Abel Tasman, but one thing that moves fast around here is the tide. Abel Tasman has one of the largest tidal ranges in NZ, with up to 5m between high and low tide. The estuaries change from wide lagoons to expanses of sand laced with streams. This fluid line between the land and the ocean is part of the feeding ground that is the Tonga Island Marine Reserve. GENTLE GUITAR MUSIC In the 1990s, studies revealed a scarcity of fish life off the Abel Tasman coast. Now fishing is prohibited within the 1835ha bordering the park and extending one nautical mile offshore. Along with the Adele Island predator-free sanctuary to the south, this reserve is a direct response to declining wildlife. Seal populations in particular are now recovering along the Abel Tasman coast. This is Gus. This is Gus. Gidday, Harley. How you doing? 'Harley Trafford, a budding marine biologist, spends his summers in the marine reserve as a seal swim guide. 'His father, Ian, is a sea-kayak pioneer and photographer.' The seals are really really playful. We've got good weather. I think it's gonna be a good morning out there. Seal populations have increased all along the Abel Tasman coastline, making underwater encounters highly likely. UPBEAT MUSIC Today we're especially lucky. They're curious and coming in close, but it is advised not to touch them. These pups are about 3 months old, and this is their nursery. They're looking at their mum with those big eyes saying, 'Can I go play?' Look at this guy just looking straight down on us. I'll get a quick photo of him. They still wanna know what's going on, and they still want the higher ground. Ooh. Beautiful. Beautiful. But it's not all fun and games for mother seal. It's a lot of work. They're pregnant 12 months and looking after a pup for 12 months of the year, and throughout, they have to feed themselves, look after themselves as well. Are the blokes just hanging out, or are they off fishing too? Uh, out fishing, basically. They're not very good fathers. Deadbeat dads. Here for the mating season, and they leave again. They're away all winter out getting big and fat and putting on that energy for next summer. With two layers of fur, the seals pups are set for their lives in the ocean. They're beautiful little things, aren't they, those babies. They're a bit like sausages with flippers on. They'll head out to sea at about 8 months old. But for now, the Tonga Island Marine Reserve is home. That was really magic this morning. Abel Tasman National Park faces numerous challenges. From the impact of pioneers who felled trees and burnt the ground, to pressure from wildlife, weeds and humans too. But this, our smallest national park, has been given an incredible opportunity. Though shrouded in secrecy, it's a gift for a new era. It involves a family, who wish to remain anonymous, pledging $25 million over 30 years to restore the park. This extraordinary gesture is called the Janszoon Trust. What won't be a secret will be the dramatic impact. From pest control to reintroducing valuable species, it's a chance to show what's possible ` a blueprint, perhaps, for our other estates. Meanwhile, Nelson Lakes National Park faces its own challenges. It too is a place where battles are being fought. And it's a sanctuary for a mysterious native with an incredible life story. INTENSE MUSIC The South Island's Alpine Fault slashes its way across Nelson Lakes National Park. The terrain is dramatic. It shifts from vertiginous mountains, down immense scree slopes, to alpine tundra and beech forest valleys. Lakes Rotorua and Rotoiti are flooded basins carved by prehistoric glaciers. To Maori who travelled across the upper South Island, they were made by Chief Rakaihautu digging with his giant stick, or ko, in search of water. Like Abel Tasman, pockets of Nelson Lakes National Park are under threat. These forests have been besieged by a small yet brutal predator ` an introduced wasp which preys on the defenceless honeydew bug, aphid-like insects which live within the bark of beech trees, feeding on the sap. Excess sugar is excreted from their long anal tubes ` year-round energy-rich droplets for birds, lizards and insects to feed on. WASPS BUZZ But the wasps compete for the honeydew drops and eat the whole tube, killing the bugs. Left to their own devices, the wasps will decimate the food supply. I used to say, 'This is a national park. Where's all the birdlife and all that?' But then when you saw what was going on and understood that they're actually starving our native fauna out of business. 'Drew Hunter is a Rotoiti local dedicated to getting rid of the wasps around the lake village. 'It's in an area known as a mainland island, where pest control is an intensive effort.' This is what we're looking for. If you have a look down here, this is our entrance with the wasps coming out, and what we've got to remember is it's mid-December, so the nest is just starting to gear up, and I'd say that we'd have about, say, 10 to 15 flights a minute coming out of that nest. But if we leave that till the end of March, that nest would just become horrific. We could get up to 120 coming out and 120 going back in. They can get up to 10000 wasps. In '95, me and my mates took out in the` just in the St Arnaud village area and these environs, 800 ` 800 nests and, uh, it's about 1996. But we found by doing that, the next year it dropped down to 600, because I think by getting the nests and having the hammer on them, until we've got it now where we average about 300 a year. Can you see that, Gus? See the white in there? Can you see that, Gus? See the white in there? < Yep, yep. We'll give her a... Now, that's all we need. So if we back off and get out of it, you might see some wasps come out covered in white. They'll start queuing up at the entrance, cos once they see that powder, they don't like it. So if we watch that there... In an hour, the poison will have killed off the wasps. The obvious return of birds to the forest shows it's clearly worth the hard work. You quite enjoy hunting these, Drew? You quite enjoy hunting these, Drew? It's good fun. Yeah, I really enjoy it, and you know that you're` you know that you're getting an effect from it. So you're not a fisherman, not a deer-stalker; you're more after the wasps. More after this, yeah. Stoat-trapper, possum-trapper and, uh, wasp-buster. BIRDS CALL GENTLE MUSIC The pure waters of Lake Rotoiti are home to one of the greatest mysteries of NZ's natural history ` NZ longfin eels. They can live for over one hundred years and at the very end of their lives embark on an incredible ocean journey. In less enlightened times, these endemic eels were much maligned, with bounties on their tails. Now they are listed as threatened. And while size restrictions apply to catching longfins nationwide, eel fishing is banned in this national park. The lake is an ideal place to discover their incredible longevity and their mysterious travels. Look at this. Whoa, holy cow, that thing's full. 'Dr Don Jellyman has been studying Rotoiti's eels for over 40 years. 'He approximates their age by catching and measuring them.' So, these are all girls? So, these are all girls? Uh, yeah, they will be. So, these are all girls? Uh, yeah, they will be. I hope they're not too stroppy. (LAUGHS) That's for you to find out, I'm afraid, but we've got some anaesthetic so we can quieten them down for measuring. 'Eels have a reputation as serious biters, especially if provoked. 'They're also extremely slippery. We'll have to sedate them before handling.' Put the whole bag in. Yep. So I've got some anaesthetic in there. I might add a bit more and, uh... See? You did that gently, and they were just pretty quiet. OK. So there's anaesthetic in there? What do you use? I use clove oil, actually. I use clove oil, actually. Wow. So that'll just chill 'em out? Relax 'em? Yeah. It'll take a minute or two, and then you'll just slowly see them just start to become just lightly unconscious. 'One method of calculating the age of longfins 'is by examining an ear bone, which has rings to count like a tree. 'Unfortunately, that is only possible when they're dead.' She's all yours. It's hard to hold on to, isn't it? It's hard to hold on to, isn't it? (LAUGHS) Just turn her round. 'They grow at a rate of about a centimetre a year.' Yeah, she's... ...91. ...91. Yes, getting up there. ...91. Yes, getting up there. So that could be 91 years old? Don, will these girls live their whole lives here in Lake Rotoiti? Yeah, they will. Then, at some stage, they'll decide it's time to go to sea and reproduce. And do you know where they go to breed? We have had tags pop up, um, in the South Fiji Basin. These things are swimming all the way to Fiji? Yeah. Yeah. That's incredible. On an empty stomach, cos they don't feed. No wonder they feel pretty muscly. No wonder they feel pretty muscly. Yeah. Well, when they leave, they're in prime condition. They have to be, you know, for the energy to sustain that level of swimming. The migration takes the eels into the rivers flowing from Lake Rotoiti. They'll wait for a surge in water level before swimming down and out into the ocean ` a massive journey, up to 3000km, into the tropics. So, 20 million, 30 million eggs spawned up somewhere around Fiji ` the little babies are born. How do they get back down here? How do they get back down here? They drift, largely, just on the ocean currents. They are capable of swimming, but we've never caught any of the larvae of these longfins. So there's quite a lot you still don't know about these? > So there's quite a lot you still don't know about these? > Yeah. Yeah. Wow. > We keep finding new things about their biology and their adaptations all the time. To me, they're an incredible animal, one that I really respect. Oh, I think this is the mother, Don. Oh, I think this is the mother, Don. Yes. Oh, I think this is the mother, Don. Yes. Do you recognise this one? No, I think` I don't think I've seen her before. No, I think` I don't think I've seen her before. Wow, she is huge. 110cm. 110cm. Yeah. 110cm. Yeah. 110 years old, eh? Longfins mostly hide by day and hunt by night, and even through to their old age don't lose their incredible sense of smell ` the aquatic equivalent of a bloodhound. So, Don, a very good sense of smell from these nostrils here? Yes. Extremely good sense of smell, so they just need one molecule within their nostrils. Blood is one of the things they're most sensitive to, so any small amount of blood in the water and eels will home in on that. Time to put these girls back, huh? Time to put these girls back, huh? I think so. They've been out long enough. The key way of conservation for this species is reserve areas where nobody fishes, because, you know, their life history, you spawn once at maximum size and age. Obviously, you're vulnerable to being caught anywhere prior to that. Nelson Lakes National Park is a microcosm, an indicator of NZ's vulnerability to invaders, and an example of human intervention restoring the environment and keeping alive enduring mysteries. In its upper reaches, another natural wonder is revealed ` an alpine lake long revered for its beauty and believed to contain the clearest fresh water in the world. SOARING MUSIC The mountains of Nelson Lakes National Park form the beginning of the Southern Alps. From here, they extend some 450km. It's a rugged and windswept landscape, snowbound for much of the year and studded with jewel-like tarns. GENTLE MUSIC The national park was established in 1956. For many visitors, the only way is up. Lake Angelus is one high-altitude destination. You know, as beautiful as those golden beaches in Abel Tasman are, for my money, these alpine tarns, up in Nelson Lakes National Park, are every bit as beautiful. And coming up here was the first big overnight tramp I ever did, and aside from the flash new hut just back there, this place has hardly changed at all. About 4500 trampers stay in Angelus Hut each year. It's a harsh landscape. The wind around this 1650m-high mountain tarn can hit 200km/h. The hut's roof can hold up to 5m of snow. It's a true mountain experience ` a two-day hike in for which trampers must be full kitted, even in summer. MOMENTOUS MUSIC Cloistered in these alpine heights is another of Nelson Lake's undoubted treasures. Blue Lake, known to Maori as Rangimairewhenua, or the Lake of Peaceful Lands. Scientists believe it holds the clearest fresh water in the world. It's attributed to a natural filtering process, as water descends from nearby Lake Constance, down through an ancient rock and mineral-rich landslide, into Blue Lake. What an unbelievably beautiful spot. What an unbelievably beautiful spot. I know. How deep are we here, Rob? How deep are we here, Rob? Probably about 6m. 6m here? 6m here? 6m or 7m down here. Rob Merrilees is a freshwater scientist. His top recording here is an impressive one, putting Blue Lake's clarity close to that of distilled water. We've had 80m. We've had 80m. And that is a world record? (LAUGHS) Well, I don't know. We haven't heard of anyone else who's done one, put it that way. Question is, will it measure up today? There's a little bit of organics in the lake water, very little, and it's probably just what comes down just in that little stretch of creek, and apart from that, it's as close as you can get to nano-clear water, yeah. Blue Lake's clarity is precisely measured by checking the distance a marker can be seen underwater. A black disk is suspended under this buoy and secured to the shore, then a rope's extended with distance markers along its length. A simple periscope is then used to peer underwater until the disk can't be seen any more. So, we got 10, 20, 30. We're at 35m at the moment. We'll just have a wee peek down there. We'll just have a wee peek down there. Sure. Look at that. Clear as a day. Would you like to have a look down, Gus? Look at that. Clear as a day. Would you like to have a look down, Gus? Sure. Might be hard to see as we're drifting off it. Yep. Got it. Yep. Got it. OK. The only body of water to come close to the same clarity is Te Waikoropupu Springs near Takaka in Golden Bay, which comes in at 63m. GENTLE MUSIC It could well only be about 63m today, and that's because of the rainfall we had the other day. Because the lake's come up, what, a metre with that rain? A metre with the rain, yeah. A metre with the rain, yeah. That's quite a lot, isn't it? Can you vaguely see that black shape? I can, just. I'd say that's about my limit. That's about it, is there? That's about it, is there? Yeah. I reckon that's about it. That's about it, is there? Yeah. I reckon that's about it. You're at 64m. We've beaten Pupu Springs, I think, Rob. We've beaten Pupu Springs, I think, Rob. Yeah. Yeah. > So we've still got the clearest water in NZ today. Maybe not in the world, quite. Oh well. On a good day, it's a lot better. > On a good day, you can see forever, huh? On a good day, you can see forever, huh? BOTH CHUCKLE You almost feel like you're just floating in space on this lake. You almost feel like you're just floating in space on this lake. Yeah, yeah. (CHUCKLES) You feel like you could step out there and it's only a couple of feet down, but it's 7m down. Inviting as it looks though, with a temperature of just 5 to 6 degrees Celsius, exploring the depths of Blue Lake is better left to technology. This is VideoRay Pro 4, a submersible unit which allows science access to previously unexplored worlds. OK, good to go? I'll put out the cable, yeah? Look at that. Thunderbirds are go. ETHEREAL MUSIC Underwater, and the world is transformed. The vision is like liquid air. The almost neon vegetation shimmers in the sunlight. And small freshwater crustaceans are some of the only apparent animal life. MUSIC CONTINUES It may be a mechanical eye, but this submersible allows an incredible glimpse into the world of this crystal-clear lake. And clear vision is what's needed in charting a sustainable future for both of these parks. It's a sobering thought how even tiny wasps can gravely damage a massive and pristine environment. And for Abel Tasman, it's clear the quiet winter season is vital to allow the park time to recover and regenerate after the influx of summer visitors. They may be two of our smallest parks, but visiting these places I grew up coming to reminds me that they are gems deserving to be protected forever. MOMENTOUS MUSIC Nelson Lakes and Abel Tasman National Parks, defined by mountains, lakes and honeydew beech forests, an exquisite blue, green and gold coastline, with an ancient marble mountain carved by water coursing to the sea. Diverse and rich, their legacies include overcoming significant adversity, but their journey forward will hopefully continue as treasured jewels. Captions by Brittany Stewart Edited by Pippa Jefferies. www.tvnz.co.nz/access-services Captions were made possible with funding from NZ On Air. Copyright TVNZ Access Services 2013