By Bill Morris

Archey’s Frogs from Science Communication on Vimeo.

This week the film students completed their science profile project – an assignment to create a profile of a scientist or PhD student. This one was made by Wu Peng on the native Archey’s frog and the work being done by Bastian Egeter in the Zoology Department. Bastian is analyzing the stomach contents of rodents to determine if they are a contributing factor in the alarming decline of the species.

New Zealand’s native Leiopelma frogs are fascinating – they are an ancient lineage that existed in the time of the dinosaurs and have changed very little since then. They differ greatly from most other frogs around the world in a number of ways. Firstly, they do not hatch free-swimming tadpoles but “froglets” with tails. The adult have vestigial tail muscles, do not croak and have no eardrums. Also, they lack the ability to land gracefully when jumping; instead they “bellyflop.” Recent research suggests Leiopelma diverged from other frog species before the latter evolved the ability to reposition their hind legs mid-flight for a landing. This adaptation in more advanced frogs would have given them greater ability to escape predators.

New Zealand’s unique frogs are at great risk – already three of seven species have disappeared. Bastian, as well as Dr Phil Bishop and his team in the Zoology department are working hard to keep the remaining four species from extinction. For more on their work, have a look here.

Alvaro Garcia was one of our students in the Centre last year and this week I’ve been exploring his website, The Tree of Nature, and also reading his thesis about taxonomy.

Taxonomy is the way in which we classify and sort the natural world. “Creates order from chaos” is one of the definitions of life according Alvaro’s thesis and since Linnaeus first devised his system of classification, scientists have sought to do just that by trying to decipher how the millions of different species on this planet have evolved in relation to one another.

Using simple diagrams called cladograms, taxonomists can provide neat pictures of how birds separated from reptiles, how different species of monkey have evolved separately from a shared ancestor and how the hippopotamus and the whale are related.

However, the closer you look at this “tree of life,” the more problematic things become. The main branches are mostly pretty solid; it’s when you get to the fine twigs at the end of those branches that things become shaky. It’s here that the very notion of a “species” becomes far from certain.

Once it was thought that separate species could be defined by their inability to breed with one another. However since Darwin’s day it has been known that this definition is unsound – hybridization, or breeding between different species has been shown to be possible and even common, especially among plants.

These thoughts were on my mind as I got talking to a DOC employee working with kaki, or black stilts in Twizel the other day. Kaki are elegant wading birds that were once common in riverbeds and wetlands in New Zealand. They are believed to have arrived naturally in New Zealand about 10,000 years ago from Australia. Like so many other bird species in New Zealand, the introduction of mammalian predators has been devastating to the black stilt. By the mid-1980′s they verged on extinction, with the entire species numbering only about 26 birds. At its breeding centre in Twizel, the Department of Conservation collects eggs from breeding kaki and raises the chicks in safety before releasing them to the wild – where their chances of survival are still not good – the riverbeds they inhabit are stalked by feral cats and ferrets, stoats and possums for whom the birds provide an easy meal. Allowed to breed on their own naturally, kaki would most likely go extinct within a number of years. They are thus wholly dependent on human intervention for their existence.

Black stilt, or kaki. Photo: DOC

Their situation is complicated by the relatively recent arrival of another bird, the pied stilt, or kouka, which only landed in New Zealand (again, from Australia) a little over a century and a half ago. Since its arrival, the pied stilt has spread to many habitats, from alpine riverbeds to coastal estuaries. Perhaps due to its greater range, migratory habits and historical association with predators in Australia, this species has proved far more resilient to our introduced predators and has now come to greatly outnumber its black cousin.

Pied stilt, or kouka. Photo: Glen Webber www.glen.co.nz

Pied stilts and black stilts are very closely related. In fact much of the research into them has centred on whether we can actually describe them as separate species at all. The conclusions, based on physical characteristics and genetic make-up, are that we can…but only just.

The pied stilts in New Zealand are darker in colour that their Australian relations and have been found to have significant amounts of black stilt DNA in their genetic make-up. This is probably because in the years after their arrival, when pied stilts were greatly outnumbered by black stilts, they mated with the other species often. The hybrid offspring of these pairings survived and mated (or “backcrossed) with pied stilts in following generations. The black stilt genes were thus absorbed or “introgressed” into the kouka genome.

Now, the situation is reversed. As the black stilt’s fortunes have waned, there has been a strong statistical tendency for it to mate with the far more common pied stilts. This usually produces a hybrid stilt that is neither totally black, nor carries the same pattern as its pied parent.

From a conservation point of view, this is a problem. In the pairing of two different species, offspring of the heterogametic sex are likely to be sterile or poorly suited for survival (This fact of genetics is known as Haldane’s Rule.) In birds (unlike mammals) the female is the heterogametic sex, so if by chance the offspring of pied and black stilts were mostly female, these offspring would likely not reproduce. In other words each hybrid pairing is not only a lost opportunity for reproduction between the few remaining pure black stilts but also presents a greater risk of being a genetic dead-end.

The conclusion therefore is that efforts should be directed at conserving the remaining black stilts and preventing further hybridization between the species. After all, hybridization in this case is almost certainly aided by human influence – the modification of riverbed environments has provided more favourable habitat for the kouka, while introduced predators have reduced the kaki’s population such that the tendency to hybridize with their more common neighbour is greatly increased.

Of course even if black stilts did become extinct, a tiny portion of their genes would live on within pied stilt bodies, which already contain introgressed kaki genes. And it wouldn’t be the first time this has happened.

The more we learn about hybridization, the more it becomes clear that it is not only common in nature, but in some cases may actually provide an evolutionary advantage. When hybrids backcross with one or both of their parent species, their genes are “introgressed” into the original species. In most cases these hybrid genes are a disadvantage to the animal or plant because they are not well-adapted to the environment they are born into – the hybridization has confused the process of natural selection and therefore individuals with introgressed genes are less capable of survival and will eventually die out. However in many cases, the hybrid genes are not disadvantageous and in some instances may actually provide a benefit to the species. If so, the species will, through natural selection, carry that gene forward through future generations. Natural selection will favour individuals which carry that gene and so its effect will be magnified across the population through the process of “positive selection.”

Humans and Neanderthals, separate hominid species that co-inhabitated Europe during the Pleistocene are believed to have hybridized, and Neanderthal genes introgressed into the human genome, to the extent that most people of European and Asian descent carry up to 4% Neanderthal genetic material. (African-descended people do not, because Neanderthals did not exist there.)

Research does suggest that at several stages of  our evolutionary history we have interbred and taken on genetic material from other hominoid species long after we went our separate ways down the evolutionary path. Like artists stealing ideas, we borrowed from our neighbours’ genetic strengths before leaving them in our wake. For example, the microcephalin gene, which relates to brain size during early development is believed to have been introgressed by humans from a separate archaic hominid species around 37,000 years ago and since that time has been subject to strong positive selection. Where the microcephalin gene arose from and what advantage it gave us, remains unclear. It has been theorized that it is a remnant from Neanderthal encounters, but this remains unproven. It has also been suggested that introgressed Neanderthal genes helped humans battle viruses.

The extreme end of this process is where hybridization is so successful that it results in a completely new species. Examples of this, at least as far as is currently known, are rare. The red wolf of north America (now extinct in the wild) is believed to be a hybrid of the grey wolf and the coyote, while the Lonicera fly, which feeds on an imported honeysuckle that has only existed in the United States for 250 years is believed to be a hybrid of two other flies, and has apparently developed as a unique species in that short time.

The closer you look at the genetic distances between closely-related species, the more complex things appear – and this blurriness has real-life implications, especially when it comes to conserving endangered species like the black stilt. In the case of this beleagured bird the question; “what defines a species?” determines whether there is even a species to save.

And now, because I know it’s the only reason you started reading this…here’s a picture of a zonkey:

by Bill Morris

This week we mourn the loss of Sir Paul Callaghan. With his passing we lose a formidable, visionary mind who chose to devote his talents to his home country rather than heading off for greener pastures overseas. He was that rare combination; a brilliant scientist and a compelling science communicator. And with his vision of a “100% Smart” New Zealand society, he had the ability to unify New Zealand in a prosperous yet environmentally-friendly future.

At ScienceTeller in 2011, SCITED speaker Peter Biggs spoke of Sir Paul and other creative New Zealanders as being the vanguard of a new “New Zealand story” – a story in which our artists, scientists and thinkers are celebrated as much as our sports heroes; a story in which our innovativeness, artistry and intellectual prowess are celebrated alongside our more traditional national characteristics such as rugged strength and stoicism in the face of adversity.

This new national identity is crucial if we are to become a leading nation in the 21st century and this is why Sir Paul’s death leaves such an enormous void.

Speaking at a public lecture at Otago University on 2011, Sir Paul described Dunedin as the “perfect model” for developing the knowledge-based society he envisioned. Under this new paradigm, New Zealand would produce high quality exports for niche markets that did not make unsustainable demands on the environment. It would be an equitable and just society – a place where highly-skilled people would want to live. In respect to this, he slammed current and previous governments’ “short-term thinking” in regards to their reluctance to fund research and development.

With its world-class university, international businesses like NHNZ and the high quality of its surrounding natural environment, Sir Paul saw Dunedin as the perfect model for the future of this country. He saw the city as a place of “robust environmentalism”, rather than “phoney clean and green” rhetoric and marketing.

A perusal of  the Dunedin City Council’s long-term draft plan, which arrived in letterboxes in the last few days, reveals a city scrabbling to recover from heavy debt. For what its worth, the draft plan provides the public with an opportunity to make submissions on the future of the city. It’s an opportunity to consider whether Dunedin is choosing to measure up to Sir Paul’s vision, or not.

With Sir Paul’s passing at this deeply divisive juncture of New Zealand society, we’ve lost a great leader in a time of great need. It’s up to those of us left in his wake to strive towards seeing his work achieved. If you didn’t know much about Sir Paul or his vision for New Zealand, I urge you to honour the memory of a great New Zealander by taking 20 minutes of your day to watch this video of one of his speeches from last year.

Rest in peace, Sir Paul.

Sir Paul Callaghan opened the Centre for Science Communication in 2008. Lloyd Davis, Director of the Centre writes;

“Sir Paul Callaghan was a great advocate for science and for communicating science to the public. In both he excelled personally and it was fitting that he should  have given the inaugural Distinguished Communicator Lecture to open New Zealand’s first Centre for Science Communication in February 2008. In some way, we are one tiny part of his legacy. The Centre extends its sympathies to Sir Paul’s family.”

by Bill Morris

This week the Centre for Science Communication is privileged to host a lecture from Professor Jonathan Boston, who lectures in Public Policy at the University of Victoria. Professor Boston will also be speaking at our SCITED talk on Thursday at lunchtime. In both of these talks he will be discussing climate change – the difficulties of addressing the problem and the outcomes of the UN convention on climate change in Durban last year.

The human species is fast approaching a crisis point at which economic growth based on unsustainable depletion and destruction of natural resources will inevitably fail. Last year the OECD released a report entitled “Towards Green Growth.” The report’s introduction states that in the aftermath of the recent/current global recession;

“A return to “business as usual” would indeed be unwise and ultimately unsustainable, involving risks that could impose human costs and constraints on economic growth and development. It could result in increased water scarcity, resource bottlenecks, air and water pollution, climate change and biodiversity loss which would be irreversible.”

Citing this report, Professor Boston wrote in a recently released article that;

“There is no consensus on whether long-term exponential economic growth is technically feasible. Many experts are sceptical. As the distinguished economist Lord Stern has put it: ‘A picture of indefinite expansion is an implausible story of the future.’

The result of failed economic growth on our world will be starvation and war. How then can we reconcile the hunger of our economy with the health of the natural system on which it depends?

In his article, Professor Boston argues that an “absolute decoupling” of growth and negative ecological impacts must occur if we are to have continued economic growth throughout the 21^st Century. In other words, we need to shift to an economy in which almost every resource is recycled or reused; which relies primarily on renewable energy and in which current pollution levels are massively reduced. The shift must be global and on a scale unprecedented in all of human history.

Professor Boston’s SciComm talks come in the wake of a recently released report from the New Zealand government’s Green Growth Advisory Group; a report which the Green Party co-leader Russel Norman has reservedly welcomed; describing it as “a timid acknowledgement of the growing global and domestic green economy and the opportunities and risks that creates for New Zealand.”

The report draws attention to New Zealand’s high carbon-emitting export sector and the value of our “clean-green,” image and calls on the government to engineer a shift towards greener growth. Its findings are completely at odds with the government’s current drive towards mass resource extraction; offshore drilling, coal mining and subsidized irrigation.

There are people who are trying to architect a new future for the planet; to create a new economy that doesn’t destroy the host upon which it feeds. It appears, however, that the government of our country exists in a very different world altogether.

 Come down and hear Professor Boston on Wednesday 14th, 5pm at St David’s Lecture Theatre (get there early as this will be popular). Then call in to the Centre for Science Communication on Thursday 15th at 12 midday for his SCITED talk.

 by Bill Morris

Photo: Stockxchng

This week is Seaweek, a chance to learn and be inspired by the beautiful ocean that surrounds our country. We should all be well aware by now that the oceans of the world are in serious peril, plundered by overfishing, littered with pollution and susceptible to dramatic change as a result of climate change. Those who have worked in and around the ocean for years in New Zealand can tell you the changes have been rapid and dramatic.

Lloyd Davis, the director of the Centre for Science Communication recently wrote this article for the Otago Daily Times in which he describes how Pacific Island fishermen, by targeting the bigger species such as parrotfish, grouper and snapper are draining their reef systems’ resources. It takes several kilos of small fish to allow a big fish to grow. Lloyd’s article discusses the work of scientist Michel Blanc, who believes islanders should be consuming the smaller sardines and anchovies, which are just as nutritious and appealing to eat.

I once visited a tuna farm in Australia where I witnessed hundreds of tonnes of sardines being shoveled down the throats of “farmed” bluefin tuna. While some of the sardines were caught locally, many more were caught off the coast of America and shipped across the ocean to feed these tuna. The tuna, caught wild in the Great Australian Bight, were being fattened in pens for sale to foreign markets as whole fish. In the markets of Tokyo each tuna would collect many thousands of dollars.

Putting aside the dubious sustainability of this fishing method, the waste of the feeding system was obvious. It takes over seven kilos of sardines for a bluefin tuna to gain an extra kilogram of weight. A large tuna requires its own bodyweight of smaller fish each ten days just to survive. The tuna were being doubled in size during their time in captivity to a weight of around 25 kilos, so each tuna that ended up on the market floor in Tokyo had been fed hundreds of kilos of sardines.

Anyone who’s fried up a fresh sardine in butter knows they are one of the most delicious fish to eat- in my opinion better than tuna. Demand for the flesh of the big tuna species is driving these spectacular animals towards extinction. In the process companies that fatten tuna are vacuuming up the protein resources of the sea in order to convert them to expensive tuna flesh that most people in the world would never dream of being able to afford.

If we are to have any hope of feeding the hungry world this century, we need to put an end to such incredibly inefficient and inequitable processes. The big fish of the ocean like tuna, marlin and groupers have been heavily overfished, often to the point of extinction. A well-published study has found that up to 90% of the big fish species in the world are already gone. The wealthy nations of the world are devouring these big fish at the expense of the ocean and ultimately, the percentage of the world’s population who will starve to death when global fisheries collapse.

A 2010  National Geographic study coined the term “Seafoodprint,” to display how individual nations consume the world’s fish resources. China, Japan and the United States were the top consumers -the United States made the top three not because its per-capita fish consumption is high, but because the fish Americans tend to eat are big ones, including tuna and Chilean Sea Bass (actually Patagonian or Antarctic toothfish), which have already consumed massive amounts of smaller fish to attain their size.

At least a partial answer to the looming seafood crisis could be  to find ways to encourage people eat smaller fish like sardines instead of top predatory fish like tuna. Not only are they far more common, but eating smaller fish is healthier as they don’t have anywhere near the levels of mercury and other toxins associated with apex predators like tuna. Currently most of the sardines caught in the world are fed to larger fish in fish farms or to caged pigs and chickens.

To mark SeaWeek, The Centre is staging a film screening of some of our sea-related films at the Otago Museum on Friday 9th March. Come down and show your support.

Sea Lion pup (Auckland Islands) Photo: Bill Morris

The recent instance of a New Zealand sea lion being shot on the Otago Peninsula highlights the ignorance surrounding the sea lions that occur along our coast. The person who fired the .22 bullet that festered inside this animal for days or weeks before killing it may never be caught – if they are, they could face up to six months jail and fines of up to 250,000. Those who are aware of the precarious situation these sea lions face would probably argue a distinctly more medieval form of punishment might better suit the crime.

Anyone who’s spent a bit of time exploring the beaches around Dunedin will have encountered sea lions. They are one of the most interesting and exciting forms of wildlife in our region, yet many people know very little about them. A lot of people don’t realize that these animals once bred in great numbers around our coasts; that the breeding colonies in the sub-Antarctic Islands are the probably the fringe remnants of the original New Zealand sea lion population and that the species is in peril of extinction.

Research has shown that the sea lions around Otago spend significantly less time foraging for food and travel far shorter distances than their counterparts in the Auckland Islands. This may be because the coasts of Otago are central to their historical natural habitat. Their lives are easier here and that is why they are, slowly, returning to breed on the Otago Peninsula.

However, the last few years have seen a number of instances of sea lions in the region being harassed, beaten and attacked by dogs. People seem incapable of leaving space for wildlife and a few actively seek to trouble, injure or even kill them.

Students from the Centre for Science Communication regularly film sea lions as part of their studies and a few have made them the subject of their final film projects. One of my favourites from recent years is Kat Baulu and Alistair Jamieson’s Whetu Rere – The Sea Lion and the Comet. 

A few weeks ago my girlfriend filmed a young female sea lion scratching its back on a park bench at Aramoana. By identifying the tag number we found out that the animal’s name is Carleigh, that she was born in January 2011 and that her mother is called Teyah (Thanks Katie Wise). A visit to the New Zealand Sea Lion Trust’s website shows Carleigh’s family tree – it highlights just how small the Otago population is and therefore how vulnerable. We need to do everything we can to make a space for them here alongside our city.

By Bill Morris

In the mornings I often ride my bike along the 13 kilometre stretch of road from Port Chalmers into Dunedin city. Once I’ve survived the onslaught of massive logging trucks and buses along that road I’m able to duck off onto the cycle lane, a peaceful section that takes me alongside the railway track and the harbour, past the yacht club and yards of shipping containers to the Ravensbourne fertilizer plant and wharf. The sulphuric tang of super phosphate strikes my nostrils as I ride past the plant, its tangle of steel pipes and towers steaming away in the morning sun. A ship is pulled up alongside the wharf and cranes are hauling scoops of sulphur from its bowels. The Ravensbourne plant is one of only two in New Zealand that manufacture superphosphate by mixing imported phosphate rock with sulphuric acid. The end product, commonly known as “super” by New Zealand farmers, is the fertilizer that has fuelled New Zealand agriculture for 150 years.  It is essential to farming and thus to our economy, but a crisis looms – our hungry world is running out of phosphate.

Phosphorous is a mineral that occurs in all living things and is essential to life. Plants require phosphorous for photosynthesis and animals for cell growth and hormone activity.   New Zealand soils are naturally quite phosphorous-deficient. Farmers in the 19^th Century discovered that the application of superphosphate, which in those days was manufactured in Australia, vastly improved productivity, to the degree of up to 75%. From that point on, agriculture in this country was built on superphosphate.

In the 20^th century, large concentrations of phosphate (from bird guano) on the Pacific Island of Nauru were heavily exploited by Britain, New Zealand and Australia, to the point that the island’s reserves became depleted and its natural environment devastated.

Today most of the world’s phosphate comes from fossilized shell-bed deposits in Morocco and Western Sahara, a tiny desert country that Morocco invaded in 1975. Since the invasion Morocco has held Western Sahara in an iron grip, excluding the area’s original inhabitants, the Sahrawi, behind a 2,700 kilometre fortified sand wall that is the largest military installation on Earth. While the Sahrawi people live in refugee shanty-towns on the other side, the Moroccan government exports the wealth of Western Sahara, in the form of raw phosphate rock, to countries all around the world, including New Zealand.

Demand for phosphate has risen dramatically in the last decade, fuelled by the rapid agricultural development of China and India as well as the demands of crops for biofuel production. In 2007 the price of phosphate more than doubled, causing many New Zealand farmers to start questioning the future of this vital resource. The green pastures upon which we produce the tons of milk and meat that drive our economy, are, after all an artificially created environment, kept viable only by the heavy addition of phosphates.

There is no argument that the world’s phosphate resources are finite and rapidly diminishing. In 2008 the dramatic price spike caused some to argue that we had reached, or long-passed “peak P,” a concept analogous to the more widely known Peak Oil – the point at which supplies of phosphate fall behind demand and we begin sliding down a negative-sloping curve toward poverty and famine. However, others, such as grassland agronomist Peter Cornish, argue that the situation is not as dire as it seemed in 2008 – there are still substantial phosphate reserves to be exploited, but they are harder to get to or, as in the case of Western Sahara, fraught by political instability and uncertainty.

A potentially lucrative source of phosphate exists on the sea floor off New Zealand’s coast   – 100 million tons of phosphate nodules formed by the concretion of decaying organic matter over millions of years. Two companies are already exploring the Chatham Rise with a view to mining there in the next few years. However the environmental impacts of this activity are not well-understood. In Namibia there has been very vocal opposition to similar plans from fishermen who fear it will be highly destructive of benthic ecologies and could have major impacts on fish life off that coast.

Driving south from Dunedin along State Highway One, just before Milton, the abandoned Ewing’s phosphate works stands testament to an industry that sprang up in these South Otago hills in the early 1900′s. It’s ironic that these hills are now greened by imported phosphate, when a century ago, over a quarter of a million tons of phosphate were mined right here. The rising global price for the commodity has encouraged local farmer Tony McDonnell to re-open the quarry on his farm and now Ravensdown fertilizer sells his locally mined rock alongside imported phosphate.

Ewings phosphate works, Clarendon. Image: Freepik

When Ewing’s was in operation a century ago, phosphate was cheap and the effects of its regular application not so well understood as they are today. It made the grass grow and in huge quantities and so it became an established and accepted part of every farmer’s yearly budget. Today we know that only about half of the phosphate that is applied by farmers is taken up by plants in the first five years – the rest is stored in the soil – building up over the decades so that there is actually a huge amount of phosphate going to waste. Some of this is also washed into waterways where it damages freshwater and marine ecologies. There are also growing concerns about the build-up in our soils of cadmium, an element found in phosphates that in high levels can damage soil health and be toxic to humans.

If phosphate prices, along with shipping costs (in relation to rising oil prices,) continue to soar, more effective use of this mineral will become essential if farmers in New Zealand hope to survive this century. Substantial amounts of phosphate can be recovered from animal and human waste and processes for achieving this need to be more fully explored.

Seen in the light of dwindling phosphate reserves, New Zealand’s agricultural prosperity begins to look like a brief, artificial blooming of wealth based on a false economy. One farmer I talked to told me that without phosphate, New Zealand would be a third world country. The extent to which we are able to curb our dependence on phosphate or at least find ways to use it more efficiently may soon determine the validity of his words.

Image:DOC

By Bill Morris

On a glorious hot North Otago day over the weekend I dropped a cicada pattern in front of a cruising brown trout – instantly the fish turned and went for my fly. In haste I struck, but too early. The cicada yanked out of the predator’s jaws and I was left empty-handed and cursing loudly, adrenalin and disappointment mingling in that moment. The spooked trout charged off into the depths of the stream, pushing an ominous bow-wave ahead of it. As the ripples of the small drama settled, the water returned to the calm of the morning heat, its glassy surface broken only by the occasional swirl of another rising trout.

I grew up along these waterways and love the thrill of chasing trout here. The river is an ancient stream whose bends and channels have nurtured fish since the uplift of the mountains – native galaxiids, bullies and mud-fat eels, many of which made their way yearly up this river from the sea to breed.

Brown and rainbow trout were introduced to the river sometime in the late 1800’s and established themselves with gusto – today this is a world-renowned fishing stream and anglers come yearly from the United States, Europe and elsewhere to stalk its clear cold waters.

The construction of hydro-electric dams downstream from the 1930’s onward halted the migration of native fish species here. Eels are now rarely seen and those that are spotted are enormous. It is likely these monsters have lived here since the first dam went up, which would make them something like 80 years old. (for a powerful examination of the life of an eel in our rivers, have a look at Longfin, an award-winning Centre for Science Communication film from 2006.)

Fishing is so entrenched in our national culture that it’s sometimes easy to forget that trout are an introduced (and therefore invasive) species that has done enormous damage to our freshwater eco-systems. To the small native fish that once thrived in these streams, their introduction was the equivalent of releasing leopards into a field of lambs. While most people are well aware of the impact of introduced predators like possums and stoats in the mountains and forests of New Zealand, relatively few are as attuned to the threats facing our unique and endangered native fish species. While rare native birds are given world-class and expensive protection status, native fish such as eels and whitebait (which are the juvenile form of some of our galaxiid species) are harvested in large quantities and sold as a delicacy both domestically and internationally.

Our native fish contain within their bodies the dramatic story of our land, a story that encompasses the separation of continents, the thrusting up of enormous mountain ranges and rivers that turned tail and ran. Caught amongst this geological mayhem were the tiny galaxiids, of which New Zealand has 25 species. 20% of New Zealand’s galaxiid species are diadromous, which means they spend at least part of their lives at sea. Larvae hatched in rivers and streams are swept out to sea where they spend their first six months. These larvae have been found up to 700 miles offshore. As juvenile “whitebait,” they congregate around river mouths before making their way upstream. It is here that they are harvested by whitebaiters who can sell their catch for around NZ$70 a kilo.

At various stages, most galaxiid species in New Zealand apparently abandoned the difficult marine phase of their development and began breeding solely in the streams, rivers and lakes they called home. Isolated from one another, they evolved into the separate species we find living here today.
New Zealand, however, is no geological millpond. The clashing of continental plates threw up the Southern Alps in the last 30 million years, a process that is still happening today. As the landscape buckled, tore and subsequently fell apart, water, along with the galaxiids it contained, was moved and pushed across the land in different ways according to the new topographies. In several places in the South Island, whole rivers changed direction as uplift at one end sent the water flowing back the other way.

This reversal of one of these rivers, the Nevis in Central Otago, is reflected in the genetics of its fish. Molecular data has shown that the Smeagol galaxiid (an isolated and distinct form of the Gollum galaxiid, found only in the Nevis River) is more closely related to fish in the southern rivers the Nevis used to feed than to those in the Kawarau, into which it now drains. This is evidence this fish has evolved in isolation ever since the Nevis river changed direction hundreds of thousands of years ago. (In 2010 the presence of this little fish was instrumental in preventing the planned damming of the Nevis River for hydro-electric production.)

In other places, rivers were “captured” by neighbouring catchments as erosion broke down the ranges that divided them, or as the huge lakes of ice that joined their headwaters melted at the end of the last Ice Age. This allowed genetically separate species of galaxiid to inhabit the same waterways. Where these dramatic upheavals caused major environmental changes, such as the damming of a river to form a lake, or the reverse, other galaxiid populations would have rapidly gone extinct.

And so, like drops of mercury on a trampoline, populations of galaxiids diverged, evolved, re-connected and disappeared all across the landscape. Today these little fish can be found all over the country. In almost every branch of every river system they are genetically different. In some cases populations evolved to fit different environmental niches in the same waterway - ‘flathead’ galaxiids well adapted to riffles and rapids have been recorded living just a few metres away from ‘roundhead’ gollum galaxiids, which are better suited to the slower-moving water immediately downstream or upstream.

By studying the mitochondrial DNA of genetically different galaxiids, biologists, working in tandem with geologists, can construct an accurate picture of how New Zealand’s landscapes have changed over millions of years, and how the fish have evolved in reaction to these changes. Where geologists are in disagreement over the date of a particular event, evidence from the genetic material of galaxiids can sometimes provide the answer. The story of our country’s birth is recorded in their genes.

The arrival of trout and salmon, combined with habitat destruction and pollution of our streams and rivers, poses a major threat to our native fish. Our sports fish are here to stay and their presence in our rivers is safeguarded by legislation drafted at a time before native fish like galaxiids were regarded as having any inherent value. As I discussed in my last post, we often encounter a dilemma in New Zealand in which the value (commercial or otherwise) of an introduced species can eclipse the conservation imperatives of a native one. Here is another example. I will always enjoy trout fishing, but I’d love to think that one day there would be places that our native fish species could thrive unmolested by these fierce predators.

As University of Otago freshwater biologist Jon Waters (whose work forms much of the basis for this article) told me, if trout weren’t already here, we would probably still introduce them today;

“We just wouldn’t put them everywhere.”

By Bill Morris 

In 2003 I was employed on Stewart Island as part of a group of commercial divers tasked with controlling the spread of the invasive seaweed undaria pinnatifida in those waters. For weeks on end, in biting southerly snow or summer sun, we would swim the lines at the Big Glory Bay mussel farms and examine every mooring, ship bottom and wharf in Paterson’s Inlet, Halfmoon Bay and Bluff harbour. If we found an undaria specimen, we’d carefully prise it off, trying to get every last piece of its root structure before destroying it. It was a war without end – every time we’d return to an infested site, there’d be more plants to collect. Undaria spores settle on a suitable substrate and germinate into gametophytes that can lie dormant, and therefore invisible, for years before sprouting into the delicate brown ribbons of the young undaria plant.

Undaria is a species of kelp native to the shores of Korea and Japan, where it is known as wakame and highly prized as a food. In Japan you might find it floating in your miso soup – the Japanese have long recognized its health benefits and have farmed it for hundreds of years. However, the algae has another less-endearing propensity – it is a ferociously successful marine invader. Undaria has a history of finding its way across the globe, establishing itself in the marine environments of other countries and easily shouldering out the native species. Within a few years, entire underwater environments can be changed – complex ecologies of sponges, algaes, and other marine life overtaken by a waving forest of the dark brown undaria fronds. The Global Invasive Species database lists undaria pinnafitida as one the 100 world’s worst invasive species. Undaria has no trouble moving around the sea – ships’ hulls provide a perfect substrate for the algae and vessels left stationary in an undaria-growing area will soon be trailing a brown lacy veil of undaria that will grow into bulky plants many metres in length if left unchecked. Undaria’s tiny spores can also be taken up in ballast water and carried across vast ocean distances.

It is believed this is how undaria arrived in New Zealand, where it was discovered in Wellington harbour in 1987. Since then, it has been accidentally carried around much of the coast and become well-established in a number of harbours from Gisborne to Stewart Island. In some places, like the Marlborough Sounds, undaria has displaced much of the native kelp and now clogs the reef systems. It causes a major headache for marine aquaculture as it binds up mussel lines and makes harvesting a much more difficult job. When I started working on Stewart island, the mussel farms in Big Glory Bay were free of almost entirely free of undaria. When the mussels were young, the lines were clean, white and held only the tiny mussel spat. As time went on the lines grew heavy and sagged deeper into the green-black gloom of the bay. The lines aged and foliated – native algaes, barnacles, sea squirts and sponges sprouted everywhere on the artificial reefs they provided, building leafy marine cities where little fish and crabs found refuge. One day, the aquaculture company imported a new batch of spat from the Marlborough Sounds – as soon as we dived in to give it its monthly check, we knew we had a major problem – the otherwise clean new lines were sprouting tiny undaria fronds everywhere. Those spat had been thoroughly checked and cleaned before being brought south, but the algae had resisted.

In 2004, the Department of Conservation abandoned its war on Stewart Island’s undaria infestation as too costly and ultimately futile. Today, the focus is on preventing its spread to other more remote corners of New Zealand’s waters, in particular Fiordland, the Chatham Islands and the sub-Antarctic Islands. This involves regular checks of boat hulls and underwater surveys of mooring lines and anchorages in those places. In 2010 a single undaria plant was found in Breaksea Sound in Fiordland. The relevant authorities have combined forces to stop it spreading from there – Fiordland’s utterly unique marine environment is at stake if they are unsuccessful. However, given undaria’s invasive proficiency, this too may prove to be a lost cause.

Since undaria established itself here, there have been calls from various parties to be allowed to harvest it commercially. It has been grown commercially in France since the early 1980’s after its accidental introduction there in 1971. Most of the demand for seaweed as a food source is in Asia, which is mostly able to meet its own demands. However, with New Zealand’s growing Asian population, a local market for fresh wakame does exist here. In addition, farmed seaweed has commercial value as a fertilizer and fish food and the hydrocolloids that can be extracted from the algae and find uses as gelling and thickening agents. Research has shown the heath benefits of eating seaweeds – they are rich in many minerals and antioxidants and may reduce cholestrol, boost immune systems and reduce joint pain. And so, just a few weeks ago, the Ministry of Agriculture and Fisheries announced it would lift the ban on commercial farming of undaria in three places – Wellington, Banks Peninsular and Marlborough. Operators will now be able to cultivate and harvest the algae in these areas, which are already infested with it.

Another fascinating possibility recently raised by US research is using genetically engineered microbes capable of metabolizing the sugars in seaweeds to create biofuel. Unlike land-grown biofuel crops like corn and sugar cane, seaweed cultivation does not take up valuable arable land and there is the potential to create huge amounts of clean fuel from a relatively small area of ocean.

Turning an invasive species into a commercial venture raises interesting questions around the philosophy of conservation in New Zealand. From my own experience with undaria I know the difficulties of stemming the onward rush of a invading species in a marine environment. On the land, pine trees and gorse can be controlled in small areas, but in general their steady march across our native landscapes continues largely unchecked. Rabbits, deer, pigs, possums, stoats and cats continue to ravage our grasslands and forests despite millions and millions of dollars and many years of effort spent fighting them. When deer numbers exploded out of control and their sheer numbers began causing immense damage to alpine and bush areas, government-paid cullers were hired to try and stem the tide, however ultimately it was a lucrative commercial industry for venison that was most successful in significantly reducing deer numbers.  The experience with deer shows that commercial interests can have a positive impact in reducing pest numbers. Obviously in the case of undaria, commercial farming will do nothing to slow the spread of the algae around our coastlines – it is more about making the best of a bad situation.

The sheer volume of ocean, land and air traffic today means we are essentially powerless to stop the continued spread of plant and animal species from other parts of the world. But then species have always migrated around the world, even without the assistance of people. Long-distance dispersal has transported plants, birds and insects to many utterly remote islands. Natural environments, in biogeographical time-frames, are in a constant state of change and flux. The extent to which we try and halt this flow in our time is the dilemma our governments and the regulatory bodies charged with protecting our landscapes must face.

What are your thoughts?

By Bill Morris 

Last weekend I headed over to South Westland to do some research for a TV show. I have spent quite a bit of time in the area between Haast and Jackson’s Bay over the last few years and always love returning there, no matter what the weather!  Historically and scientifically, South Westland is a world apart from the rest of New Zealand. It is a fringe land – for most of its history beyond the reach of road and rail; a kingdom of rain and sandflies, greenstone, tumultuous rivers and long wild beaches shot with veins of gold-bearing black sand.

The people of South Westland are resilient pioneering types, many of who are descended from the area’s first pioneers and who have survived to make their home in this wild area.

South Westland is shaped first and foremost by the Alpine fault. The fault here is no abstract concept on a geological map, it is a highly visible battle line between two continental plates whose violence has thrown up the mountains that stand over the landscape and the lives of the people who live here. The mountains are what separates this land from the rest of the world, the mountains that provide the wealth of the region, mountains that make the rain and mountains that funnel that rain into the big, austere rivers that emerge out onto the coast.

During the Ice Age, this whole area was covered by an enormous glacier that emerged and merged from the separate valleys and would have reached the sea as one enormous wall of ice. Upon its retreat, six large rivers poured out of the mountains; scouring, sorting and carrying the crumbling debris from the interior. In the relatively fast (geologically-speaking) time span of just 6000 years, they built up the 10 kilometre-wide floodplain upon which the commerce and history of this region has largely unfolded.

The reason for the rapid advancement of the floodplain is simply the vast amount of material that pours out of the mountains here. The two biggest contributers of sediment are the Haast and Arawhata rivers, which between them produce over 13 million tones of suspended sediment each year, making them two of the most productive rivers in New Zealand.

Once this material has reached the coast, it is subject to the slow power of the sea, which shifts it north along the coast, forming long spits, bars and dune ridges. From the air, the remnants of old dune ridges are clearly visible and now form barriers that hold unusual patterned wetlands.

The floodplains today hold vast pakihi swamps and largely pristine native forest. The rainforest in this region is astonishingly rich. A couple of years ago, I made a video on the region with Emeritus Professor Sir Alan Mark and Katharine Dickinson in the area. Sir Alan, a tireless campaigner for New Zealand’s natural heritage, was instrumental in gaining UNESCO World Heritage status for the area which protects it from future exploitation.

Off shore, the Open Bay Islands are remnants of a limestone outcrop that survived the ancient glacier’s onslaught. Today they are a Maori-owned wildlife reserve, home to fur seals, muttonbirds, Fiordland crested penguins and an endemic species of skink. There is even a tiny population of endemic leeches on the island. The islands are the most species-rich pieces of land on the West Coast.

photo: Hugh Best

In 1810 a party of sealers were marooned on the Open Bay Islands for four years, and the remains of their hut can still be found there – the oldest European building relic in New Zealand.

South Westland is a fascinating and addictive area to explore. Check out my video for more insight thanks to one of the area’s greatest champion, Sir Alan Mark…..