Doubtful sound

Coffee Powered

Up at 5:00am, I force down a cup of coffee before I throw my luggage into the back of my tiny Toyota Starlet. Layers and layers of field clothing, polypropylene long johns, polyester windfleece, wool socks caps, rubber boots, -4 degree sleeping bag, camera, and food for three people for two weeks all make their way into the back of the mighty starlet. She sputters to life in the brisk pre-dawn air and in two minutes I'm on highway one heading southwest from Dunedin on my way to Manapouri 300km to the west.

A 5am departure is necessary because the ferry leaves to cross lake Manapouri at 9:45, and the mighty starlet isn't the swiftest thing on the road. I once got her up to 150km/hr (100m/h), but that was downhill with a tailwind :-) Cruising through the darkness is relaxing, and other cars are few and far between at this hour. The engine humms as I twist and turn through the hills and plateaus of central Otago. Down the presidential highway past Gore the sun finally peaks over the hills behind me and starts to shine on the distant mountains ahead.

As I speed on I find myself descending into a world of grey. At first it seems like a bank of fog, but shortly rain begins to pelt the windscreen. No drama here though, I've made good enough time to arrive in Manapouri well before the ferry departs. After a year of travelling and making field trips to various South, its finally starting to feel like I know what I'm doing.

I arrive at the Real Journeys wharf in Manapouri with plenty of time to load everything onto the boat, and drink a flat white (a latte without foam). As I'm loading our groceries onto the boat, Bruce, the captain asks me if I'm another dolphin researcher. When he finds I that I am sort of a dolphin researcher he mutters something along the lines of, "How many researchers do those dolphins need?" I search for a minute for a response, and unprepared for such a confrontation I lamely respond something about the lack of acoustic information, and how it's somehow important to get it.

How many researchers do the dolphins need? Its a surprisingly good question. Flustered and defensive I finish packing my gear on the boat and head back up the gangway. I remind myself that I'm here studying doing my research because its what I want to do. It doesn't matter what Bruce thinks. It doesn't matter what anyone else thinks either, at least I'm enjoying my life. The dolphins may not need me to study them, but that isn't the point. Its a poor justification, and it doesn't sit well with me. Actually it all just plain sucks. I realize that I don't know nearly enough about what is happening in Doubful sound. I don't really know why the dolphins actually need any researchers at all.

Power Station

Its gray in Manapouri as the Fiordland Flyer makes its way across the lake to the West Arm Power Station. The power station is a monumental engineering achievement. It uses the lakes 178m (540ft) elevation to generate the massive amounts of electricity required to run the Bluff Aluminium smelter. The high temperatures required to extract aluminium from the ore require large amounts of energy. The cost of the energy required to separate the ore is so large that aluminium is one of the few non-organic waste products that is actually cheaper to recycle. Nevertheless nearly all of the power generated by the Manapouri Power Station is used to smelt Australian alumina ore.

Australian ships carry their load of alumina ore across the Tasman Sea to Bluff. Back at Manapouri water runs through the power plant it eventually makes its way into the large pipes that will carry it down 178m and through the 10km (6mi) of tunnels to be discharged through the Deep Cove tailrace in Doubtful sound. As the water falls, potential energy is converted to kinetic energy which turns giant turbines that spin coils and magnets and convert kinetic energy into electricity. The electricity travels over 150km to the smelter in Bluff. The smelter converts the Australian alumina ore into aluminium, which is then loaded back into ships and transported and sold all over the world as foil wrap and beer cans.

West Arm Power Plant is a monumental engineering achievement, but that's not only due to the fact that its the largest hydroelectric power plant in New Zealand. The remote location of the plant presented its own engineering challenges, and further difficulties involved drilling 10k straight through a mountain to maintain lake levels. The construction of the plant also required building the most expensive (at the time of construction) road in New Zealand. Furthermore, the notable design features mentioned above arose out of concern for the environment.

The original plans for the power station included building a dam and raising the level of lake Manapouri. This sparked wide public concern, and spawned a massive environmental campaign to Save Lake Manapouri. Without going into all the details, the story ends with the government deciding not to raise lake levels, but instead to build the power plant to operate within the lakes natural levels. Massive environmental damage has been avoided for lake Manapouri, and everyone is happy. Many people think of the Save Manapouri movement as the birth of New Zealand's environmental movement. However until recently little concern has been given to the effects of rerouting the fresh water in Manapouri to the marine environment in Doubtful sound.

The Road Less Travelled

With the Fiordland Flyer docked at West Arm, I transfer my gear and groceries to the Real Journeys bus for transport over Willmot Pass. A patch of blue sky reveals snow capped mountains above and beyond the West Arm Visitor Center. I slap sand flies as they try to bite my fingers and face. They are persistent and even in the winter there is little you can do to avoid bites. I slap them knowing full well that it will make no difference and that my fingers will itch tomorrow.

The punters browse the carefully crafted displays of natural history and geology inside the visitor center, but I hardly have time to load my gear before the bus driver informs me that its time to depart.

A kea (mountain parrot) attracts attention from the punters, and delays departure long enough for me to snap a photo of it. The kea is a highly intelligent bird, and has been called an honorary mammal due to its intelligence. Sadly, like many native bird species, there are few Kea left in the wild. The Kea in Doubtful sound have learned to associate people with a potential meal and this one is no exception.

The punters clamber on, and the bus begins its slow voyage over Willmot Pass. The gravel road with no intersections and no tunnels was, as I mentioned previously, very expensive to build. It connects Deep Cove to West Arm, and it nearly all of the heavy machinery in the Manapouri Power Station was carried over the Pass during the original construction of the plant. Originally taxpayers funded the road, but nowadays the tourism companies such as Real Journeys, and Meridian Energy pay all of the upkeep for the public road. Its just as well, since the only way to actually drive on the road ferry your vehicle across lake Manapouri.


The bus climbs above the clouds to reveal spectacular fiordland views of forests and mountains. The driver, Jim, stops briefly at the top of the pass for the spectacular view of the fiords. Then its a quick drive down the hill to Deep Cove.

The Deep Cove Hostel.

Arriving in Deep Cove, Jim helps me unload my bags. I carry everything into hostel and toss my backpack on the floor. With beautiful sunny weather its no surprise to find the place empty. I wouldn't miss an opportunity to spend such an equisite day on the water no matter who was supposed to be arriving, so I can't blame them.

As I'm strugling to make room for two weeks worth of food in the already crowded freezer, Charlie, the deep cove hostel manager knocks on the door. Charlie recognizes me from my last trip into Doubtful Sound, and knows that I'm a biologist. He tells me that he is going to take a quick drive up the road to take a look at the latest Department of Cconservation (DoC) effort going on in Fiordland. He asks me if I want to tag along, and knowing that I'll have to wait until tomorrow to go out on the water I accept his invitiation. We hop into his car and drive toward the tailrace, where fresh water from Manapouri exists the long underground tunnels and pours into Deep Cove. But DoCs conservation effort has nothing to do with the Manapouri Power Station.

A dozen freshly killed possums hanging to be skinned. Charlie explains that conservation in New Zealand means killing small mammals. Possums, stoats, cats, rats, and goats are all invasive species that humans have brought to New Zealand recently, and they are all considered serious pests that threaten native flora and fauna. With no natural predators the invasives multiply and either outcompete or kill native New Zealand species. Charlie elaborates that DoC spends most of their budget on resource management and not nearly enough on pest eradication. Having lived in national parks his whole life he has been able to see firsthand the damaging effects of invasive species left unchecked. He has also seen the implementation of effective eradication programs. It is clear that he cares a great deal about New Zealand's wilderness and has an earnest desire to preserve every bit of it that he can. His frustration with the current system and conservation efforts is apparent. The dozen possums hanging here were all caught last night. Over the past few weeks over 300 possums were caught and killed in this same area. The possums not only kill native birds such as Keas, but they also damage and can kill the slow growing fiordland trees. Charlie laments that one DoC ranger killing possums is like trying to apply a band-aid to a severed limb.

We return to the hostel and Charlie has work to do. There is a school group coming in on Monday, and things are always in need of repair. The hostel was built as an outdoor education center, and grade school classes are the main clientel. Education is always touted as the true cure for conservation worries, but the cliche runs something along the lines of: what will be left to conserve when these educated children run things?

Doubtful Sound

Doubtful sound is a glacier carved fiord that lies in the southwest part of New Zealand's south Island. The region is appropriately named fiordland due to its many dramatic fiords. In addition to Deep Cove, Doubful sound consists of Hall Arm, Crooked Arm, First Arm, Bradshaw, and Thompson Sound. The marine environment in Doubtful Sound, like the terrestrial environment, is both unique and fragile. While doubtful sound is technically marine and is connected to the Tasman Sea, the large amounts of rain and runoff from the fiords create a freshwater layer that sits on top of the marine environment. This freshwater layer can be several meters deep, and it contains tannins that accumulate from soil runoff. This tannin rich freshwater layer acts like a mirror, and reflects and absorbs much of the sunlight that would normally reach the marine environment. This lack of light in addition to other oceanographic features of the sound means deep water organisms can often be found at rather shallow depths within the fiord.

Slow growing black and red corals, and snake stars are prevalent here, yet species usually found in shallow coastal waters are absent. Spiny lobsters can be found here as well, and there are still a few people who set pots to catch them. However, fishing in Doubtful sound has been limited to recreational fishing, and in recent years there are few people who even do that. With people largely out of the equation, the bottlenose dolphins claim the top spot in the fiordland food chain.

These dolphins are some of the southernmost bottlenose dolphins in the world, and they are bigger than most others of their species. Dolphin research has been conducted in Doubtful sound for over a decade now. Some of the research includes population estimates, vocalization studies, and the effects of tourism. There are currently 53 dolphins that live in Doubtful Sound, and Rohan, the researcher who I'm assisting knows all of them instantly by sight. Dolphins can be individually recognized by markings on their dorsal fins, backs, or sides. While these markings may appear subtle, they are more than adequate to reliably identify an individual dolphin.


Rohan, like me, is doing a PhD in marine science, and has been studying the dolphins for about a year and a half. He's spent over 100 days on the water with the dolphins, and has over 14,000 photographs of dolphin ID shots. Each digital photo has an embedded timestamp, and an associated GPS location, as well as various behavioral and oceanographic observations. His research focuses on the dolphin population structure and habitat usage.

While previous research has shown where the dolphins are seen in the fiord, nobody has studied what the dolphins are doing underwater. An attempt was once made to attach time depth recorders to the dolphins to look at their diving behavior, but the dolphins refused to wear the tags jumping and splashing until the tags came off. Rohan and I are planning to look at their diving behavior with a different approach. We plan to use an array of hydrophones (underwater microphones) to record the dolphins from a number of different locations. The dolphins vocalize and the sounds reach each of the different locations at different times. Using a bit of mathematical wizardry and signal processing, we can use the sound arrival time differences to locate where the dolphins are underwater gain insight into their diving behavior.

Of course this is all easier said than done. The study requires the integration and flawless operation of a large number of very fussy devices. Throw in unreliable weather, and unpredictable dolphins, and it becomes evident that preparation will only take us so far. We'll need a certain amount of luck and patience for the study to be successfull.

Its been a long day, and I'm exhausted. I prepare dinner for myself, Rohan and his wife Nandika in a bit of a delirious state. They've had a full day out on the water and they have circumnavigated the entire fiord. I hope the beautiful weather holds, but in Doubtful sound there's really no way to know what weather tomorrow will bring. Sunny cloudless days are a rarity in this temperate rainforest.

After dinner I attach the time depth recorders to the hydrophone array. It is a gesture of optimism towards the weather and dolphin gods. The time depth recorders allow us to know the position of each hydrophone, which is important when trying to localize the dolphins. My experience with the gear is the reason for making the trip, and despite being ridiculously tired I sort out the recording gear so that it will be ready to go first thing in the morning. Its 9:30pm when I finish and I climb into my sleeping bag on the bottom bunk of my private room and fall asleep before my head even hits the pillow.

Nemo

Again I'm up at before sunrise --well sort of anyway. Its 7:00am, but the sun has yet to make itself visible over the steep walls of the fiords. Toast and boiled eggs for breakfast, we pack our lunch and cart the gear down the steep hill to the beach where Nemo is tied up. Nemo isn't a clownfish, and its certainly not a dolphin tied up at the beach.

Nemo is our 5 meter lasercraft aluminium research vessel. I get a kick out of calling these small boats research vessel, but technically its true. Nearly all of the marine mammal work done through the New Zealand Dolphin and Whale Trust is conducted on small boats like Nemo and Grampus, and it just goes to show that you don't necessarily need a huge ocean going behemoth to conduct quality research on dolphins and whales.

Gear loaded, wrapped in many layers feeling like the michelin man, we shove off from the beach and set out to find the dolphins. Cruising at 20 knots, the 50hp outboard drones and my eyes fill up with water. Its still too dark to wear sunglasses, but the cloudless sky is encouraging. On days like today the fiord feels more like a lake than the ocean. The water is glassy, and at times looks like a perfect mirror. I've seen several photos where it is impossible to determine which is the mountain and which is the reflection, though I've yet to encounter such conditions myself.

When its clear and calm like this, spotting dolphins becomes relatively easy. Their blow is rather obvious, even from a great distance, and with little wind, it hangs in the air longer. Rohan tells me that he has been finding the dolphins further from Deep Cove than usual on this trip. Even though it means longer days on the water, Rohan is pleased that he hasn't lost any dolphins since the last trip. All of the dolphins have been accounted for and photographed, including three new calfs from this year.

With such a small population size and a low reproductive rate, a loss of a single dolphin is a big deal. Rohan informs me that the dolphin population here has been declining, and is down from 71 individuals when research began in Doubtful sound. He has also observed two stillborn births this year, and two dolphins have gone missing earlier in the year. Rohan explains that at the current rate of decline by 2050 it is unlikely that there will be any dolphins left in Doubtful Sound.

Off in the distance I spy dolphin blow and point and shout. We slow down, and Nandika gets the camera ready. I tend to the recording gear, making sure that it is ready for fast deployment. While we'll spend hours with the dolphins, all of the field gear has to be deployed quickly and precisely, or else the measurements are likely to be worthless. The dolphins are constantly on the move, and rarely spend significant amounts of time in a single location. We slow down to approach the dolphins, and gently ease in along side of the group in order to get side on shots of the dorsal fins for photo ID.

While the ocean is generally flat and calm when photographing dolphins, the steep mountain walls of the fiords and nearly constant cloud cover make the lighting less than optimal for taking fantastic pictures. Again, this illustrates the advantage of using both photo ID and acoustics to study these animals. Audio quality isn't affected by clouds, though rain sounds particularly interesting underwater.

After a reasonable bout of photography we pull away from the dolphins and decide on a strategy for recording them. Since the dolphins rarely stay put for very long, we try to get ahead of them so that we will be able to record them as they move towards us. It is vital to be ahead of them during recording because their vocalizations are highly directional.

It is a guessing game, and as I said earlier it involves a bit of luck to get a good recording of the dolphins. The trick is to not only guess their direction, but to guess how far ahead to go. If we don't go far enough, we won't have time to deploy all three hydrophones before the dolphins pass us. If we go too far the dolphins might change direction without us seeing it. To add another layer of difficulty, we must deploy our deepest hydrophone to 100m depth, yet there are many places in the fiord where the depth becomes shallow very rapidly, so we've got to constantly check the charts and the echosounder to make sure that our delicate hydrophone doesn't become a sediment sampler or even worse an anchor!

All of the failure points can make getting good measurements seem impossible, but I'm confident that the gear will work, and I'm confident that once we have the recordings we'll have a new window into the world of the bottlenose dolphins in Doubtful Sound. That confidence changes the challenge from an intellectual exercise into an exercise in patience. Even though we might not get a recording this time, I know that if we keep trying it will happen. Acoustic studies have a lot less immediate gratification than photo ID studies. While, I can think of very few things that are as amazing as watching the dolphins while listening to them click, whistle, bray and splash, it takes a long time to download the time depth recorders, time align the recordings, hydrophone depths, and gps tracks, analyze the sounds at each hydrophone, and compute a dolphin location.


While determining how deep the dolphins dive is important to understand how the dolphins live, it doesn't directly contribute to their conservation. The list of potential threats to the dolphins is surprisingly short, so why then are the dolphins still declining? Potential threats include: habitat changes due to fresh water from the Manapouri power station, stress from dolphin tourism, or natural decline due to reasons we don't yet understand. While fishing and bycatch are threats to other dolphin populations, there isn't anyone fishing or catching dolphins in doubtful sound. Pollution is also another threat to many coastal dolphin populations, however fiordland is a relatively pristine location (especially in terms of chemical pollution).

Previous scientific studies have shown that dolphin tourism alters the behavior of the populations that were measured over both short and long time scales. The approach of tourist vessels made the dolphins less likely to continue their current behavior, and more likely to travel. Longer term trends of the dolphins in Milford sound have shown seasonal variation in the dolphins location that inversely correlate with the location of tourist vessels. Lastly a study in Shark Bay Australia has shown that dolphins have a lower birth rate when they are exposed to high levels of tourist activity. So what steps has the New Zealand Department of Conservation taken to protect the dolphins in Doubtful Sound?

There are a handful of companies in the tourism business in Doubtful sound. While there are generally only a few boats giving tours, they do operate year round weather permitting. The highlight of many of these tours includes getting to see the bottlenose dolphins. Is it possible that these tourist operations are causing undue stress to the dolphins? The above research would clearly indicate this is a serious possibility.

After a week in the field, just as we started to get the hang of getting good multi hydrophone recordings of the dolphins, one of the hydrophones broke. It was a manufacturing defect in the cable that caused a short across the power supply and data wires. It means having to cut my trip short and address the broken gear back at the marine mammal lab where we have the tools and technology to rebuild it. We can always make another hydrophone if it breaks. We can't replace the dolphins once they are gone.