The discovery of 50 beached sperm whales in the northwest of Tasmania, sparked rescue attempts by Wildlife officials this morning. The Australian Science Media Centre has gathered comments from experts as to why this strange behaviour occurs.

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Dr Catherine Kemper is a marine mammal expert from the Australian Antarctic Division

“The word ‘stranding’ means many things. To most people, it means live animals on the beach but to a scientist is encompasses anything from a carcass washing up to ‘mass strandings’ of many live animals. Whale and dolphin strandings have been happening for thousands of years. We have evidence of 2000-year-old strandings of sperm whales just north of Adelaide. Aboriginal people used to take advantage of stranded whales for food.

Mass strandings do not occur in all species of whales and dolphins, just the ones that are highly social and that live in the open ocean. The reasons for this is probably that these species are not used to being near shore and their social behaviour involves ‘following the leader’ even if it means to their death. (This is putting a human context on the situation, I know, but it helps the lay person to understand a complex system.) Some of the species that tend to mass strand are; sperm whales, common dolphins, offshore bottlenose dolphins, pilot whales.

The cause of most strandings of live animals is usually not known. There is some evidence that the earth’s magnetic fields may disrupt the navigation ability of some whales in some places. Tasmania and New Zealand have many mass strandings because the open ocean species live close to the coast (ie. the continental shelf is very narrow) and the coast is complex with many bays and inlets. South Australia has few mass strandings (thank goodness) because the shelf is very broad and the coast rather simple.

Recent evidence from some strandings, particularly the deep-diving beaked whales, shows that low-frequency and powerful underwater sounds can result in animals stranding. The theory is that they surface too quickly, probably having become seriously disturbed by the sounds. US naval operations have been implicated in these events. These sounds can also cause physical damage to the inner ear. There is no evidence of this in Australia but then little work has been done here.

South Australia has anything from 50 to 80 reported strandings each year so these events are not unusual. The cause of death of these animals is usually unknown but we investigate as many as possible and find disease, birthing problems, old age, entanglement in fishing gear, boat collisions, intentional killing by humans and others are the major causes. I have summarised the data for South Australia (no one else has done this in Australia) and found that 50 % were unknown cause of death, 20% were unintentional human-related (eg. entanglement, boat collisions etc.) and 5% were intentional killings (illegal, of course)”

Dr Nick Gales is a marine mammal expert from the Australian Antarctic Division

“We know that sperm whales live predominantly in the waters off the shelf break, in the deep sloping waters offshore and they feed in those waters. When you get events like that very low pressure system passing to the south of Tasmania that we had over the last 2 days, with storm force winds, where those waves reach the shallow waters, it becomes incredibly mixed up with sediments. This becomes incredibly confusing for animals that use sound in the water column to navigate in the shallower waters. On those occasions, animals that are bound together very tightly by social bonds like this predominantly female group of sperm whales and their young, tend to move as one organism virtually, and if navigation is confused, on occasion a mistake will be made where they end up on shore. I think this is just what happened on this occasion.

There is no real way of predicting these except maybe a slightly higher incidence in some areas through confusing the symmetry or on stormy events when whales happen to be in close and their prey is in close. The main advances in science have been in trying to deal with those animals once they are ashore, understanding a lot more about the animals from access to them and most recently in actually tracking animals that are able to be refloated and pushed out to sea to look at survival, the movement of these animals and to improve our knowledge of their offshore habitat. Refloating sperm whales is almost impossible, it has been done on a few occasions, in Tasmania mainly, but they are so large and so difficult to refloat that actually returning sperm whales is quite a rare event.”

Associate Professor Rob Harcourt is Director of Marine Science and a Senior Lecturer at Macquarie University

“Sperm whales are deep-diving pelagic social whales, they swim in groups of females, many of which are related, and they are deep-divers that hunt mainly squid, but they do eat fish and a few other things as well. Therefore they are usually found far offshore, except in areas where the water is really deep close to shore.

But in particular years, the line of productive waters, which a combination of large-scale weather systems and weather frontal systems, is closer to the Australian Coast, and in those years there is a greater frequency of strandings, of all sorts of Pelagic cetaceans.

The thing about these animals is that they are large, highly-social animals, that stay together for decades and normally the only encounters they have with firm substances like the ocean floor is when they are diving deep down to feed. So they can get confused and they tend to stick together so if one of ends up coming in too close to shore, they all tend to do the same thing. A normal response to stress at sea, if they are being predated by killer whales for example, is to flee, so that’s why they tend to strand.

It is very sad but we get a huge amount of information as a result of these strandings, a lot of information about how long they live, what they eat, and their relationships within the pods comes from these stranding events. So even though it’s a tragedy for individual whales, its opened up a window into how we understand these animals.”

Dr Karen Evans is part of the Pelagic Fisheries and Ecosystems Stream of CSIRO Marine & Atmospheric Research and is a Research Associate with the University of Tasmania. She has conducted research looking at why whales beach themselves.

“Strandings of whales, both single and mass, have occurred for centuries. Ascertaining the causes of whale strandings has perplexed both the general community and scientists for many years. Why should an animal completely adapted to the marine environment end up on the beach? For some animals we can determine the cause: old age, disease, injury, chase or harassment; but for many the question as to why they stranded remains unanswered. Theories as to why whales strand abound, but little quantitative research has been conducted into this, one of the most puzzling of biological mysteries, and to date no research have identified causes common across all unanswered cases.

We analysed a long term data set of whale strandings in south-east Australia (Tasmania and Victoria) and observed a clear circa-10 year periodicity in the number of whales that stranded each year. When aspects of the regions climate were investigated, this quasi-decadal cycle in the number of whales that strand was found to coincide with the regional persistence of both zonal (westerly) and meridional (southerly) winds. Periods of maximum whale strandings occurred during times of persistent westerly and southerly winds. During periods of persistent westerly and southerly winds colder, nutrient rich waters are driven closer to the south-east region of Australia, potentially enhancing biological activity in the water column and the abundance of prey in coastal regions. These findings suggest that climate, and its links to higher coastal productivity in years of strong winds, may provide a powerful distal influence on whale strandings by re-distributing whales into coastal regions (as a result of a change of prey distributions), increasing the number of whales available to strand in the region. Our study provides the first clear test of existing hypotheses for this mysterious behaviour, and provides managers with a powerful predictive tool to enable them to prepare for years of peak stranding activity.”

Illustration by ExhibitEase LLC - Steven W. Marcus

After thousands of years of extinction, the woolly mammoth has its DNA decoded this week in Nature. The study marks the first report of nuclear genome sequencing for an extinct animal. Using DNA extracted from samples of hair, the authors were able to collect together the near-complete nuclear genome of the woolly mammoth.

The team used samples from several different mammoth species found preserved in the permafrost to piece together the jigsaw puzzle. Although there are still pieces missing, the authors believe that the sequence of the woolly mammoth is around 80% complete. The findings identify genes shared with its modern elephant cousins, and offer insight into elephantid evolution. Here Australian experts comment on the importance of this research and look at whether we could soon resurrect the mammoth.

Feel free to use these quotes in your stories. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

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Dr Michael Bunce is Head of the Ancient DNA Laboratory at Murdoch University, Western Australia

“The field of ancient DNA has come a long way since the first study in 1984 which obtained a tiny fragment of DNA from an extinct species called the quagga, a zebra-like – 25 years later scientists are now putting the finishing touches on the first genome of an extinct species; the Woolly Mammoth.

The Mammoth together with the Dodo and Neanderthals are iconic examples of extinctions that have long fascinated human culture. The completion of the first draft genome is a significant accomplishment that is soon be ‘trumped’ by the completion of the Neanderthal genome.

Sequencing 4 billion bases of DNA is a huge undertaking and is made possible by a new generation of DNA sequencing equipment that breaks up the DNA into small pieces then randomly determines the DNA code, a technique called ‘shotgun’ sequencing.

The important scientific contributions that whole genome studies make is through comparisons of the DNA sequences with other species, here the researchers have compared the DNA to that of the African Elephant and to the human genome. By comparing the differences between genomes we can start to answer one of the most fundamental questions about genetics – what gene(s) are responsible for what physical characteristics? For example compared to their African cousins what genes ‘altered’ to make Mammoth better adapted to the cold environment?

Does this genome sequence mean that in a few years we can bring back the mammoth? – far from it. Just because we know the DNA code of something does not mean we can genetically tinker with it to the extent required to recreate extinct organisms – this kind of progress is still a pipe-dream.”

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Dr Jeremy Austin is the Deputy Director of the Australian Centre for Ancient DNA at The University of Adelaide

“This study on mammoth genome sequencing is an important step forward for ancient DNA research. It clearly demonstrates that partial (and possibly complete) genomes can be obtained from extinct species to provide new information on evolution. This is very exciting for a number of reasons. Evolutionary biologists may now be able to ‘see’ evolution of genes under selection in real time by accessing genetic information from historical and ancient samples. Evolutionary biologists will also have a much larger suite of genetic markers to understand the process of molecular evolution and species response to environmental change. However, there are a number of caveats associated with this study. Firstly, mammoths are probably the best preserved extinct animals from which to obtain ancient DNA. The samples used in this study have been preserved in permafrost (essentially a natural deep freeze) for the last 20,000 years. Remains of most extinct animals are not nearly as well preserved and DNA survival in the majority of extinct species will not be as good as in mammoths. Secondly, they only obtained a partial genome. They did not recover the complete genome of a mammoth, despite sequencing two different mammoth specimens. Thirdly, despite the exceptional preservation of the specimens and use of hair for obtaining DNA fully 20% of the sequence obtained appears to be contamination from bacteria or other sources. Fourthly, the authors acknowledge that the mammoth sequences obtained contain errors, approximately 1.5 incorrect bases for every 1000 base pairs of actual sequence. This may not seem much to most people but we already know that many fatal genetic disorders are single point mutations (i.e. one wrong base in a gene). Thus the current mammoth genome may contain up to 6 million ‘incorrect’ base reads (if my quick maths is correct!).

Can we bring a mammoth back to life? As for the much touted thylacine cloning project, the answer is still no for the reasons outlined above. A genome sequence does not make a living organism. Currently we only have a partial mammoth genome, with a sizeable number of errors in the genetic code. It’s a bit like trying to build a car with only 80% of the parts and knowing that some of the parts are already broken. Even if we did have the genome in its entirety we still have the problem of knowing what is a real mutation versus what is sequencing error or DNA damage. At a genome scale this in itself is an almost insurmountable problem. After this we have the issues of how to construct artificial chromosomes, how much epigenetics is involved and many other cell and tissue culture hurdles.”

For the latest information on the national response and a situation update from the Australian government, click here.

For a useful source of information about the outbreak put together by the University of Melbourne, click here

The NSW Department for Primary Industries have detailed information on the situation in NSW online

The Queensland Department of Primary Industries also have a generic fact sheet available online

Feel free to use these quotes in your stories. If you need assistance tracking down an expert in this area, contact the AusSMC on 08 8207 7415 or email us.

Dr James Gilkerson is President of Equine Veterinarians Australia and Director of the Equine Infectious Disease Laboratory at the University of Melbourne.

“Equine influenza (EI) affects horses much like human flu affects humans; the horses get sick, stop training, have to be rested in the stables and can take weeks to get better.”

EI represents significant financial cost to the industry, in the order of hundreds of millions of dollars to date.

The government’s ban on the movement of horses within Australia is central to restricting the spread of EI, but this in turn has severely interrupted the horse breeding season.

EI is exotic to Australia, and the quarantine systems Australia has in place have been successful in preventing the introduction of the virus into the country until this current situation. Obviously there has been a breakdown in the system somewhere, but controlling the spread of EI is our top priority.

As the President of Equine Veterinarians Australia, I support more funding for biosecurity and EVA fully supports the efforts of the veterinarians who are trying to control the spread of this virus.

Although EI vaccination is available in other countries, Australia does not vaccinate its horses and there is no commercially available supply of EI vaccine in Australia. It is the decision of the Chief Veterinary Officers of Australia and the states as to whether Australia will implement a vaccination program, which is done in accordance with the equine influenza response plan. Essentially, they must consider how widespread the flu outbreak is, the number of horses at risk of infection and how successfully the outbreak is being contained.”

Graham Wilcox is Professor of virology in the School of Veterinary Biology and Biomedical Sciences at Murdoch University and is a world renowned expert on animal viral diseases.

“It is not surprising that equine flu has been brought into Australia. When you import horses from countries where the flu is endemic it’s really just a matter of time. We will know from how it spreads over the next few days whether or not the virus is likely to become endemic here.

Equine influenza is not normally fatal but it takes a long time to get over it. Just like human flu, the horses will feel weak and it will take time before they are well enough to race again. But an outbreak like this is devastating for the industry because mares and stallions can’t be moved around for the breeding season. The impacts of this will probably be felt for at least 2-3 years.

There are reasonably effective vaccines available and it is perhaps the time to initiate a public debate about whether and when we should consider using vaccines to control the disease in Australia.”

Professor Greg Tannock is a Virologist at the RMIT¹s Dept of Biotechnology and Environmental Biology in Melbourne. Professor Tannock is an expert in bird flu and flu vaccines.

“The virus is unlikely to result in the deaths of many horses. Like humans they’ll experience illness of differing severity for a while and then they’ll recover. But the implications for the industry in Australia are enormous.

This is the first time that equine flu has been seen in Australia and so it’s not surprising that there are very few people, if any, who have actually handled the virus. Scientists have not been allowed to work with the equine flu virus. But this will all change if equine flu becomes endemic in this country. There is no doubt that research programs will be undertaken if and when this happens.

There are fast, mainly molecular tests available to detect equine flu viruses, which are important because of the urgency of the situation. In addition, serological tests would need to be undertaken to determine how widespread has been the infection. These are also important because, as with human influenzas, not all horses that have the virus will show signs of the disease. Serology will take much longer but will establish whether equine influenza has become endemic (or a permanent feature) of the Australian equine population. It’s too early to say if routine vaccination, common in countries such as the UK and America, will be needed.”

Sharanne Raidal is senior lecturer in veterinary physiology at Charles Sturt University, NSW

“There hasn’t previously been a need to vaccinate as the best protection so far has been keeping it out of the country. The first priority now is to ensure eradication of the virus and this is best achieved by strict compliance with DPI instructions.”