Our Changing World

Thursday 5 March 2015, with Alison Ballance, Ruth Beran & Veronika Meduna

On This Programme

Tracking Rig Sharks

By Alison Ballance

The rig shark (Mustelus lenticulatus) is also known as spotted dogfish, after the golden 'bambi'-like spots on its back. It feeds on crabs it finds in the mud on the bottom of estuaries, and has grinding plates rather than sharp teeth.

The rig shark (Mustelus lenticulatus) is also known as spotted dogfish, after the golden 'bambi'-like spots on its back. It feeds on crabs it finds in the mud on the bottom of estuaries, and has grinding plates rather than sharp teeth.

Photo: Malcolm Francis/Coastal Fishes of NZ

Shark researcher Warrick Lyon holds a small rig shark. This shark was too small for the GPS tracking system, but has been tagged with a numbered fishery tag.

Shark researcher Warrick Lyon holds a small rig shark. This shark was too small for the GPS tracking system, but has been tagged with a numbered fishery tag.

Photo: RNZ / Alison Ballance

Tracking rig sharks in Pauatahanui Inlet is proving to be a difficult job at the best of times for shark researcher Warrick Lyon, let alone when the electronic tags keep getting ‘stolen’ off the sharks. I joined Warrick on a recent research trip into the estuary, and although it was only 8am he had already had an eventful morning.

“A fisherman caught my shark!” he told me as he picked me up from the boat ramp. “It was towing a GPS transmitter that tells me the location of the shark; the transmitter floats on the surface and there’s a 6-metre long nylon tether down to the shark. So the shark swims along the seafloor and that’s where they like to be, and the tag floats on the surface, and it was the tether between the two that the fisherman caught.”

To make matters worse, Warrick was actually talking to the fishers at the time!

As he describes in his Shark Tracker blog, the chances of this happening are incredibly small: ‘I’m guessing that there are between several hundred to several thousand rig sharks in Porirua Harbour during the spring and summer, so what are the chances that the ONE I have tagged gets caught? I’ll do some simple math for you it’s between 0.00002% and 0.000005%, that’s a pretty low. What made it even more unlikely was that I was talking to the fishers at the time, telling them about my research, and if they ever caught one of my tagged sharks could they please return the tag to me. Then one of them caught my rig shark.’

Warrick Lyon has developed a GPS tracking system that uses a floating tag, built into the empty housing of a torch, which is connected to the rig shark by a 6-metre long nylon tether.

Warrick Lyon has developed a GPS tracking system that uses a floating tag, built into the empty housing of a torch, which is connected to the rig shark by a 6-metre long nylon tether.

Photo: RNZ / Alison Ballance

Warrick is a technician at NIWA and is carrying out research into rig sharks for a PhD at the University of Auckland. The first stage of his research is to find out how adult rig use Pauatahanui Inlet during the warmer summer months when they use the estuary as a breeding ground. To do this he has worked with NIWA’s Peter De Joux to develop an innovative electronic tracking system, which uses GPS and allows him to track individual sharks in real time. A system of routers around the estuary act as a smart network that transmit the location of the tag to a base computer sited in Mana, overlooking the estuary. GPS cannot transmit through water, yet rig sharks spend their lives on the bottom of the estuary looking for the mud crabs that make up most of their diet. The solution was to allow the tag to float on the surface. The tag transmits every 30-seconds, which provides a very detailed picture of what the sharks are doing.

This track covers two days, and shows a male rig shark moving around Pauatahanui Inlet. The track ended when a fisher snagged the GPS tag's tether causing it to break.

This track covers two days, and shows a male rig shark moving around Pauatahanui Inlet. The track ended when a fisher snagged the GPS tag's tether causing it to break.

Photo: Warrick Lyon

Warrick Lyon's GPS tracking system for rig shark (right, a small shark being released into the water) in Pauatahanui Inlet relies on a network of routers (left) positioned around the inlet to send GPS locations to a central computer.

Warrick Lyon's GPS tracking system for rig shark (right, a small shark being released into the water) in Pauatahanui Inlet relies on a network of routers (left) positioned around the inlet to send GPS locations to a central computer.

Photo: RNZ / Alison Ballance

Warrick’s research builds on previous work which has investigated the importance of Pauatahanui Inlet as a rig breeding ground. As part of this research NIWA’s Malcolm Francis used acoustic tags to study the broad-scale movement of juvenile rig in the estuary.

Surveying Small Sharks in Estuaries ( 12 min 32 sec )

Rig is also known as spotted dogfish or spotted smoothhound. It is called gummy shark in Australia, and is commonly used in fish and chips under the name lemonfish.

Our Changing World has previously joined Malcolm Francis as he took genetic samples from rig in Pauatahanui Inlet to find out how the species is related to Australian gummy sharks.

Shark Genetics ( 13 min 31 sec )

You can follow Warrick's research on his blog, Facebook page or on Twitter.

SEAWEEK

Seaweek 2015 runs until 8 March. The theme this year is ‘Look beneath the surface – Papatai ō roto – Papatai ō raro’. There are events taking place around the country, and you can find more details on the Seaweek website.

TRACKING RIG SHARKS AUDIO:


Giving up Smoking - How Good are E-cigarettes

Researcher and public health doctor Associate Professor Chris Bullen from the University of Auckland, is supportive of electronic cigarettes (e-cigarettes). “If people are going to continue to use them for the nicotine and to prevent them relapsing back to smoking tobacco…that’s got to be a good thing,” he says.

A photo of Chris Bullen with some e-cigarette

Chris Bullen with some e-cigarettes

Photo: RNZ / Ruth Beran

The term e-cigarette is used to describe one of a vast range of devices that vaporise a solution of propylene glycol, vegetable oil and sometimes nicotine. “The official term that’s used increasingly [is] electronic nicotine delivery systems or ENDS,” says Bullen. With the spread of new products coming on the market people that do not necessarily use batteries or an integrated circuit, the terms being used is ANDS or alternative nicotine delivery systems. “Essentially what they are is something that looks vaguely like a cigarette that most of the time delivers nicotine in a vapour or aerosol form to people to inhale,” says Bullen.

E-cigarettes do not combust tobacco or produce smoke. “It only produces vapour when the user sucks on it and the vapour comes out of their mouth and then it vanishes almost instantaneously,” says Bullen. In this way, e-cigarettes provide a form of behavioural replacement, as they look like cigarettes.

“It really does remarkably replicate much of the behavioural characteristics of smoking a cigarette but without all the harms of combusted tobacco leaf and the 3 -4,000 other chemicals in that toxic cocktail which we know is one of the most dangerous products on the planet,” says Bullen.

E-cigarettes do not have 20-30 years of follow up studies for lung cancer or heart disease like tobacco cigarettes. However, Bullen believes that there is “almost certainly no doubt that these things are safer to individuals who use them than using a cigarette”.

Most people using these products are doing so to try and quit smoking or to cut down the number of cigarettes they smoke. “The evidence suggests about 6 or 7 out of 10 people who use them use them to cut down the number of cigarettes for their health or saving money because they usually work out to be cheaper than buying tobacco,” says Bullen. “About 3 or 4 out of 10 will use them to try and actually quit. Whether they succeed or not is another story.”

For example, a cigarette smoker who has tried e-cigarettes says: “Of all the options that I’ve tried (and I’ve tried patches, I’ve tried the nicotine inhalers) it’s easily …the most effective in terms of curbing your cravings and all of that sort of stuff.”

There are some considerations about the use of e-cigarettes though that also need to be looked at. For example, young people may take up smoking if exposed to e-cigarettes. “I think young people like to experiment with risky things,” says Bullen. “However the data that we’ve looked at from all around the world in a range of countries suggests that the numbers of children or adolescents who don’t smoke, who experiment with e-cigarettes and then go onto use them, is actually very, very small. It’s less than 1%.”

Bullen and his team conducted a randomised controlled trial called the ASCEND study looking at the effectiveness of e-cigarettes as a tool to quit smoking. The study was completed in mid 2013 and took 3 years to get underway and recruit about 660 participants from Auckland. The participants were all people who wanted to quit smoking who were heavy dependent smokers, each smoking on average about 20 cigarettes a day. People were randomised into three groups, one group received an e-cigarette with nicotine, another group received an identical e-cigarette that didn’t deliver nicotine, ie it was a placebo, and the third group received nicotine patches, the gold standard for people who want to quit smoking.

The study replicated the real world of obtaining these products. “So the people who were randomised to the patches received a QUIT voucher which they had to take to a community pharmacy to get their patch,” says Bullen. Both e-cigarettes groups "had the products couriered to them with some instructions, just as if they were ordering them over the internet.” In New Zealand, buying e-cigarettes with nicotine can only be done on the internet. “Both groups were able to contact QUIT line for some behavioural support counselling if they wanted to do it. And about 40% of those in each arm did,” says Bullen.

The groups were followed up for six months, after receiving the product for three months. After six months people who said they’d quit smoking came in to have a carbon monoxide breath test. Carbon monoxide is present when smoking tobacco cigarettes but not present when using e-cigarettes. Bullen and his team found that “the proportions of people who had actually quit verified by carbon monoxide testing in all three arms was practically the same.” So the results were modest, showing about 5 to 10% of people successfully quitting smoking after six months which is a similar figure to someone using patches from the supermarket, and receiving no counselling.

According to Bullen, the immediate success rate from the study was quite dramatic for e-cigarettes, but then it tailed off and eventually all three arms of the study were similar. The success rate for the placebo e-cigarette was about 5% compared with about 8% with the nicotine e-cigarette group, but this figure was not statistically significant.

There was no difference in adverse health events between the two groups after six months.

“There was no evidence of any, at least medium term, adverse events,” says Bullen. “So I’m pretty confident they are certainly a safer product than smoking tobacco.”

A one-day symposium entitled “E-cigarettes: Opportunity or threat?” will be hosted by the University of Auckland’s Centre of Addiction Research and held at the University’s Business School at the City Campus on 12 March 2015. It is expected to be the first New Zealand gathering for stakeholders interested in e-cigarettes.


Science of Complex Systems

by Veronika Meduna Veronika.Meduna@radionz.co.nz

'We want to go right from the data through to how you make decisions about the way we manage the world around us.' _Shaun Hendy

From left to right: Mark Gahegan, Laurie Knight, and Te Pūnaha Matatini director Shaun Hendy.

From left to right: Mark Gahegan, Laurie Knight, and Te Pūnaha Matatini director Shaun Hendy.

Photo: Sarah Hikuroa

Te Pūnaha Matatini, a new Centre of Research Excellence focusing on complex systems and networks, is taking the idea of multi-disciplinary research to a new level. Economists team up with ecologists, physicists explore questions in biology, and mathematicians worry about the health of the environment.

The centre’s director, Shaun Hendy, says Te Pūnaha Matatini literally means ‘a meeting place of many faces’, but he sees it as a metaphor for complexity. By bringing together researchers from a wide range of disciplines, he hopes the team will develop new approaches for transforming complex data into insights for making better decisions.

Essentially, is it about understanding networks – regardless of whether they play out in the environment, society or business. “Traditionally or economic models are either very macro and high level and don’t have a lot of detail in them, or they are very low level and very much about individual businesses. In between there’s a complex space where networks of businesses and people interact.”

Shaun Hendy has long been interested in networks and how they can be applied in innovation, and to that end he has worked with economists. “But then I realised that the people who have the best understanding of networks are ecologists because they’ve had to grapple with ecological networks for a long time and have developed a deep understanding of networks. That’s only recently been applied to economics.”

Photo: Sarah Hikuroa

The approach Te Pūnaha Matatini investigators take is to go beyond data mining. “That’s only one aspect,” says Shaun Hendy. “Then we want to build models that explain the data and then, beyond the models, the goal is to use those models to make decisions.”

The projects already underway include a collaboration with Predator-free New Zealand, and University of Canterbury mathematician Michael Plank is interested in exploring the impacts of commercial fishing on marine ecosystem. To that end, he is teaming up with University of Auckland anthropologist Melinda Allen. “We already have ecological models of population dynamics of fish species today, but anthropologists have data on historical catches from middens. We can use those to test our theories and models. It’s not something you can replicate now because fishing has had a huge effect on the state of the ocean and the state of the fish populations, but this data gives us a window into how it used to be and what it was like before there was this massive fishing pressure.”

Tava Olsen, at the University of Auckland’s business school, is exploring innovations in supply chain systems, or value chains. “It’s not just about moving goods from here to there but sometimes it’s more virtual when we’re thinking about services.”

For University of Auckland cosmologist Richard Easther, the interest lies in developing new ways of using big data well to help make policy decisions. “As a physicist, I’m looking for opportunities to apply the technology of physics to problems that aren’t physics.”

He says some of the deep questions that we’ll have to answer in the future may not come from physics but more likely from biology and social science.

“Understanding cities for instance. Cities are systems that are built out of small pieces but behave in large and complex ways. You’re never going to have a physical theory of the city that’s the same as the physical theory of an atom, but the style of thinking that physicists have has applications outside of physics.”

For Shaun Hendy, the ultimate goal is for New Zealand to make its own decisions.

'I’d like to think that we were making decisions that are very specific to ourselves, based on our understanding of our unique location in the world, our population, our history, who we are - and having that really inform our decision making.'


Eagle Rays - An Inner City Wildlife Spectacle

By Alison Ballance

The eagle ray (Myliobatis tenuicaudatus) has pointed wings which it flaps like a bird as it swims.

The eagle ray (Myliobatis tenuicaudatus) has pointed wings which it flaps like a bird as it swims.

Photo: Malcolm Francis/Coastal Fishes of NZ

It’s in the middle of our capital city, but Frank Kitt’s lagoon on the Wellington waterfront is home to a remarkable marine wildlife spectacle, with up to a dozen eagle rays congregating in the lagoon during summer.

“We have three common rays in New Zealand,” says NIWA shark expert Malcolm Francis. “Two of them are stingrays, the short-tailed and long-tailed stingrays and there’s the eagle ray. Eagle rays are quite easy to identify – they have pointed wings and swim by flapping their wings up and down. The stingrays have more rounded wings, and they swim by undulating the wings.”

So, just remember that eagle rays flap like a bird, while stingrays undulate.

“They’re quite broad in their dietary requirements,” says Tim Riding, a marine biologist with the Ministry for Primary Industries. “They’ll eat crabs and bivalves, and they’ll eat them off the rocks or dig them out of the sediment in estuaries and harbours but they’re also detritivores, and they’ll consume things like dead kahawai and other dead stuff floating around, so quite opportunistic.”

Eagle rays are a common sight in Wellington's Frank Kitt's lagoon during the summer months, either swimming around or basking in the shallows.

Eagle rays are a common sight in Wellington's Frank Kitt's lagoon during the summer months, either swimming around or basking in the shallows.

Photo: RNZ / Alison Ballance

Malcolm adds that “in a lot of the northern harbours, where there’s a large area of sand flats, you can see at low tide that they’ve excavated pits that are about 30 cm across. And that they do that by taking in water from the top of their head, through little holes called spiracles at are behind the eyes, and they jet that out through the gills that are on the underside of the body. And that just creates a water flow that winnows away the sand, and exposes any shellfish or other invertebrates that are sitting in the mud.”

Eagle rays hunt for food by blasting a jet of water through their gills to stir up the sand (left); a series of pits in the estuary at low tide on Whangapoua Beach on Great Barrier Island show where rays have been feeding.

Eagle rays hunt for food by blasting a jet of water through their gills to stir up the sand (left); a series of pits in the estuary at low tide on Whangapoua Beach on Great Barrier Island show where rays have been feeding.

Photo: Malcolm Francis/Coastal Fishes of NZ + RNZ/Alison Ballance

Rays are essentially flattened sharks, with their gills on the underside of their body. A large eagle ray may have a wing span of about 1.5 metres.

Rays are essentially flattened sharks, with their gills on the underside of their body. A large eagle ray may have a wing span of about 1.5 metres.

Photo: Malcolm Francis/Coastal Fishes of NZ

Tim carried out research for his Master’s degree tracking eagle rays in small harbours on Northland. He wanted to find out how the rays navigate in these shallow, narrow and often very muddy or sandy water bodies, where visual cues wouldn’t work. He decided that the sharks were using a “rheotactic response – so they were essentially orientating to water flows, coming into the estuaries on incoming tides and leaving on the outgoing tide.”

Both eagle rays and stingrays frequent the Wellington waterfront, but it’s usually only eagle rays that come into Frank Kitts lagoon. The eagle rays seem to arrive in October or November, and stay in the area until the water begins to cool in about April. They have been seen feeding, and also mating. It is not known where the eagle rays go in winter. Genetic studies show that the population of short-tailed stingrays in northern New Zealand is distinct from the population around the lower North island and Marlborough Sounds.

The largest eagle rays that Tim has seen had a wing span of 1.5 metres, while Malcolm comments that “historically, short-and long-tailed stingrays have been recorded at up to 4 metres long, including the tail. Those animals were massive, presumably decades old although we don’t know how long they live for. We don’t see those big old animals anymore, so we’ve probably removed them from the population by catching them, particularly in nets. It’s a bit of a concern, that the smaller rays just don’t get an opportunity to become big old rays anymore.”

Orcas, dolphins and hammerhead sharks are known to hunt rays. As a defence mechanism rays have a barb at the base of their tail, which is covered with proteinaceous slime. If a ray feels threatened by a shadow from above it will strike with the barb, and if the barb punctures the skin of a human it can cause an unpleasant wound. However, Malcolm is quick to point out that rays are not aggressive and only do this in self-defence. Tim suggests a good way to avoid accidentally standing on a ray in shallow murky water is to shuffle rather than walk.

Ray experts Tim Riding (left) and Malcolm Francis (right) at Frank Kitts lagoon on the Wellington waterfront. The eagle rays that are seen in the lagoon come in a variety of colours, from grey to yellow and brown.

Ray experts Tim Riding (left) and Malcolm Francis (right) at Frank Kitts lagoon on the Wellington waterfront. The eagle rays that are seen in the lagoon come in a variety of colours, from grey to yellow and brown.

Photo: RNZ / Alison Ballance


From the Archive: Ring of Fire Expedition

Back in 2005, a team of marine biologists and geologists use a submersible to dive deep down to explore submarine volcanoes in the Kermadec Arc.