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Standing Committee on Climate Change, Environment and the Arts
Australia's biodiversity in a changing climate

SCHAUBLE, Dr Chloe Sarah, Acting Director, Climate Change and Science, Great Barrier Reef Marine Park Authority

WACHENFELD, Dr David Raymond, Director, Ecosystem, Conservation and Sustainable Use, Great Barrier Reef Marine Park Authority

CHAIR: I welcome the witnesses to today's hearing. Thank you for appearing before the committee. Although the committee does not require you to give evidence under oath, I should advise you that this hearing is a legal proceeding of the parliament and therefore has the same standing as proceedings of the House. We have received a written submission to this inquiry from you. Do you wish to present any additional submissions or make an opening statement to the committee?

Dr Wachenfeld : Many thanks to the committee for the opportunity to appear as witnesses. If I may, I would like to make a brief opening statement. I might divide this statement into two short parts—first just a little background on our organisation and then some specific comment about the current situation in the Great Barrier Reef in relation to climate change and biodiversity.

We are an independent statutory authority in the Australian government with a little over 200 staff based mostly at our headquarters in Townsville, but we do have small offices in Canberra, Rockhampton, Mackay and Cairns. The main object of the act of parliament that we administer is to provide for the long-term protection and conservation of the environment, biodiversity and heritage values of the Great Barrier Reef region, but it is a multiple-use marine park, so it is a secondary objective of our act to allow ecologically sustainable use of the region for a variety of purposes, including fishing, both recreational and commercial, tourism, science and so on. The marine park and our management of it is based on principles of ecosystem based management and ecologically sustainable use, and our main tools are zoning plans, plans of management and permits.

Given the nature of the marine park and the issues that affect it, collaboration and partnership are absolutely key to our management of the marine park, particularly partnerships with Queensland government, traditional owners, scientists, tourism and fishing industries, and recreational users. Also, very importantly, people in the catchments, such as local government, graziers and farmers, and schools are critical components of our partnership network. We have a very strong focus on education and stewardship because how people behave in and around the marine park is very important. We deliver that through a variety of programs but most noticeably the Reef HQ Aquarium, which is in Townsville and is the world's largest living coral reef aquarium, and also our Reef Guardian Stewardship program.

Having given that brief overview of our organisation and how we do our business, I might just turn specifically to climate change. Certainly, climate and ocean change are, without question, the greatest long-term threats to the health of the Great Barrier Reef. Many, perhaps most, of the physical and chemical changes that climate and ocean change are causing will damage or, in some instances, have already damaged the biodiversity and environment of the marine park, as well as the industries and communities that depend on it. In 2009, the Great Barrier Reef Marine Park Authority produced an outlook report, where, although in the past we had done state-of-the-environment reports for the Great Barrier Reef, this was the first time we did that but also had a forward look at the outlook. Regrettably, our conclusion in 2009 was that the outlook for the Great Barrier Reef was poor, and this was mostly driven by considerations relating to climate and ocean change.

I might speak briefly about what I call the decade of extreme weather. Between 2002 and 2011, we had a long series of extreme weather events. We had six severe-category cyclones in a period of seven years, which between them covered most of the 350-odd thousand square kilometres of the marine park. Most of the major rivers that feed into the Great Barrier Reef had record-breaking floods during that period, and we also had the hottest summer on record for the Great Barrier Reef in 2002. Not surprisingly, that series of weather events cumulatively has had some pretty serious impacts on the Great Barrier Reef.

Probably most notable is some science that was conducted by the Australian Institute of Marine Science, which they published a couple of weeks ago. They have been monitoring coral on the Great Barrier Reef since 1985, and in the intervening 27 years the Great Barrier Reef has lost approximately half of its coral cover. There are three main drivers of that loss: 48 per cent of it is caused by cyclones and storms, 42 per cent by crown-of-thorns starfish and 10 per cent by coral bleaching. I think the results of that program are a startling wake-up call to us all about the Great Barrier Reef. But they are also an important demonstration of the importance of well-organised, integrated long-term monitoring programs, because it is only with those that we can actually understand the condition of our natural environment and how it is changing.

Coral is probably the standout story in terms of impacts of extreme weather, but certainly other components of the biodiversity of the marine park have shown very worrying trends. The seagrass monitoring that we have is not as long-term or robust as the coral monitoring in terms of the number of sites we have and their geographic spread. Nonetheless, we are pretty confident that seagrass through most of the Great Barrier Reef Marine Park is also at an all-time low. Since the late 1990s we have been monitoring strandings of animals such as dugongs and green turtles, which depend upon seagrass for their food, predominantly. For both dugongs and green turtles, 2011 saw more than double the previous number of stranded dead animals. For both of those species, the overwhelming primary cause of those strandings was starvation. As well as large numbers of animals dying, particularly in the case of the dugong, we have large numbers of animals moving, seeking better forage in other parts of the marine park.

I should hasten to add that for both the coral and the seagrass the status in the far north part of the marine park is far better than that in the southern urban part. This is due to a mixture of things. There is obviously less coastal development and fewer water quality issues in the extreme north. Also—and I do not know if this is purely good luck or if there is some systematic reason—the extreme weather events we have had have had less of an impact in the extreme north. So, the condition of the marine park is not even throughout; it does vary quite a bit, with the north generally having maintained its health much better over the last 20 years or so.

Obviously as managers of the Great Barrier Reef and of a marine park there is nothing we can do directly about climate and ocean change. Instead, our focus is on local and regional actions that can reduce other pressures on the reef and maximise its health and resilience. These actions will give the reef the best possible chance in the face of climate change. Of particular importance amongst these resilience strategies is the Great Barrier Reef Zoning Plan, the primary purpose of which is to protect biodiversity in the marine park, and the Reef Water Quality Protection Plan, including Reef Rescue, the objective of which is to halt and reverse the decline in water quality. I think these really are the two flagship programs in protecting the biodiversity of the marine park and improving its resilience.

Very importantly—and this is a new and emerging part of our business—we are also working closely with people in the industries that use the reef to build their adaptive capacity and to help them help to maintain and improve ecologically sustainable use. Climate change is just as much an issue for those people and their industries as it is for the reef and its environment itself.

To conclude my remarks, we all know that the Great Barrier Reef is one of the most spectacular and iconic parts of the world's marine environment. We are making significant progress in protecting it from local and regional pressures, and these efforts are widely regarded as world's best practice. Nonetheless, the reef is very much at a crossroads, and it is really the future trajectory of climate and ocean change that will drive the long-term future of the health of the Great Barrier Reef.

CHAIR: Thank you very much for those opening remarks. Dr Schauble, did you want to add to those comments?

Dr Schauble : No, I think that is a good, complete opening statement.

CHAIR: Could I start by asking if you could explain for my benefit—and maybe that of others—given that cyclones account for 48 per cent of the damage that has been observed, the process by which that damage occurs? What do the cyclones do that causes the destruction to the corals?

Dr Wachenfeld : There is probably a range of sorts of damage that occur with a cyclone and it varies from one cyclone to another. Cyclones, obviously, cause very high-wind speed. High-wind speeds drive wave action. Wave action causes extreme physical disturbance to the seabed. We have seen that there is an exponential relationship between environmental damage and wind speed—in other words, small increases to the maximum wind speed of severe cyclones make big differences to the environmental damage that they cause. So corals and seagrasses are reasonably robust to normal tidal wave action and water movement but, when we talk about cyclonic waves that are in the order of 10 to 20 or more metres, they cause severe damage when they interact with the physical environment of the seabed.

Interestingly, in Cyclone Yasi we saw a phenomenon that I am not aware that we have seen before but was interesting and spectacular in its effects. Because of the pressure wave of the cyclone, a very large volume of warm water was pushed across the Coral Sea, and when it hit the edge of the continental shelf on which the Great Barrier Reef sits, that water had to go somewhere. A lot of it just went down the continental shelf, so you had warm water 200 metres flowing downwards, which is very unusual in the marine environment, but a lot of that water was pushed up onto the shelf and caused very strong currents. We saw, as a consequence, for example, scouring of sandy environments as deep as 30 metres. We might normally think that at 30 metres the environment might be at least somewhat protected from wave action, but the sheer volume of water being pushed across the shelf was scouring the communities. We do not have very good monitoring programs at those sorts of depths because it is much harder to work, but surveys that we did indicated that quite lush areas of seagrass in about 30 metres off Townsville were completely scoured and removed by Cyclone Yasi.

So those are some of the examples—the other one of course is that cyclones are typically associated with very large amounts of rainfall. If that rainfall significantly reduces the salinity of the water, that can stress marine organisms as well—for example, if the shallow coral on the top of a coral reef is exposed to reduced salinity water because of rainfall, they will stress and die. I would hasten to add that is a secondary impact. The primary impact of cyclones is direct physical damage.

CHAIR: Thank you for that, which confirms what I probably thought. The progress that we are making, given that from this last report, it appears that the level of coral was much lower than what we thought three years ago—I think all three members here went out there and were also at the last hearing some three years ago; we heard from scientists out there at the time. Given the damage that has been done and your comments about progress being made, do you envisage that the level of coral is likely to rise again—that is, will become healthier in years to come—as a result of the action taken or are we likely to see even more destruction?

Dr Wachenfeld : Unfortunately, I am going to have to say yes to both of those questions, because we are doing an extremely good job of managing pressures on corals and biodiversity generally in terms of activities in the marine park. If you look at coral reefs and tropical marine ecosystems around the world, many of the human activities that are destroying them in other parts of the world—such as very poorly controlled tourism industries, anchor damage, overfishing and destructive fishing practices such as dynamite—we have under control in Australia, particularly in the Great Barrier Reef, so our problems are not so much generated by immediate local activity in the marine park. Although the problems are harder and less tractable in terms of managing the catchment and improving land use in order to halt and reverse the decline in water quality, we have made enormous progress. The UNESCO World Heritage Reactive Monitoring Mission that was here in March was extremely impressed that not only are we genuinely tackling the downstream effects of land use water quality problem but we are making demonstrable progress to solving the problem. I think we are probably one of the few jurisdictions in the world that is really grappling that land water interface issue and starting to be successful.

All those are reasons why we have or are in the progress of successfully tackling local and regional problems. I think those activities are lending great resilience to the reef ecosystem. It does still have great resilience. Just a couple of weeks ago we had a survey team out looking at the footprint of Cyclone Yasi, and we were already seeing some new recruit corals indicating that, while obviously it would take some years for recovery, the recovery process from Cyclone Yasi has already started in many places. There is great reason from all those things for optimism. The reef is still resilient. It still can bounce back if it is given an opportunity to do so, and the activities that we have been doing are exactly the right thing to promote resilience.

The obvious reasons for caution are, as we have seen over the last decade, prolonged periods of extreme weather events which cause really severe damage. Every one of the kinds of extreme weather that we have seen that damage the reef are either already demonstrated to be changing with climate change, such as temperature, or are predicted to change with climate change, such as rainfall variability, driving flooding and drought cycles, and cyclone intensity.

The answer to your question is in the short term, as long as we do not have any more extreme weather for a while. The coral cover will go up and many components of the biodiversity of the reef will show signs of recovery. They will demonstrate that all-important resilience. But over the decades to centuries as future bouts of extreme weather occur, driven as they always are by La Nina and El Nino events, those bouts of extreme weather will be getting more extreme as time goes by. So every time something like this happens the impact to the reef will be greater and the reef will spend more and more time in an impacted trying-to-recover state rather than just in a full healthy state. Even a system as large and robust and resilient as the Great Barrier Reef can only take so much of that kind of extreme weather damage before its resilience is used up effectively. That is why we do believe that in the long term it is the trajectory of climate change that will drive the long-term health of the Great Barrier Reef.

CHAIR: My last question. Setting aside the factors that are contributing to climate change, is there anything else that we could be doing at a local level to try and protect the reef that we are not doing which immediately comes to mind?

Dr Wachenfeld : I do not think there are any proven tools in the toolbox that we are not already using. I think there are two things. One is to make sure we maintain our focus on the tools we already have and although, as I have said, we are making demonstrable progress with management in the catchment and improving water quality, there is still a lot more to be done, so it is important to maintain that focus. The other side of it is to think about and invest in research and development to find new ways of protecting and using the reef. An example of that would be research that we have begun in collaboration with the Great Barrier Reef Foundation and their scientific partners into looking at how we might use genetic techniques in the future. These are long future ideas but we need to start research and development now.

Essentially, if you look at some of the scientific and technical analyses of natural resource management generally and marine environment specifically, such as the very recently released CSIRO report into Queensland's biodiversity under a changing climate, those analyses are saying that while we can continue to focus on traditional natural resource management strategies and they still have some value, we are going to have to move beyond those into a new paradigm of more adaptive management and adaptive strategies and thinking about what other strategies we might try because climate change is going to bring us unprecedented challenges.

Dr WASHER: David, you said that UNESCO is impressed with what you are doing on the terrestrial side to improve water quality and run-off—I guess to reduce silt and chemical and other pollutants. What is actually happening there that is changing to improve these things?

Dr Wachenfeld : I have to confess that I am not an expert in that side of our work, but I will give you the overview that I have. Essentially, there is a great deal of work working with farmers and landholders to improve their management practices by helping them improve, particularly, fertiliser application, pesticide application, drainage systems and tillage systems. You can greatly reduce the export of soil and agricultural chemicals from the land into our freshwater systems and then into the reef. Of course, the good news about those sorts of improvements is that they are very much win-win. There is no advantage to the landholders to have soil and expensive chemicals washed off the land and lost, so it is both an environmental and a social and economic win to improve our systems so that we are keeping the soil and the agricultural chemicals on the land and not allowing them to flow out into the reef environment.

Dr WASHER: That is good. Thanks.

Ms MARINO: Thank you for that. In your submission you touched on the novel strategies that you would be using for adaptation. Is that the genetic type reference you have just made? What else is in that basket of strategies where you are saying you need novel approaches? What else is there that you can see that you are going to have to be using in your box of tricks from here?

Dr Wachenfeld : I might give you a couple of examples. Obviously sea turtles are one of the groups of animals where we are quite concerned about impacts of climate change. I would say it is not entirely future; we have already seen significant mortality of turtle nests in an extremely warm summer at one of the mainland nesting beaches, so we can already see, if you like, a signal of what the future is going to bring in terms of what extreme weather can do to turtles. The biggest green turtle rookery in the world is at Raine Island, which is at the northern end of the Great Barrier Reef Marine Park. There is an issue there which we think is largely a natural one, in fact. The topography of the island is such that sometimes the turtles get stuck in a particular part of the island, and they can even flip onto their backs. Unfortunately, once they flip they cannot flip back again themselves. Obviously if we have marine park rangers on the island at the time then we will help them out, but it is a very remote, difficult place to work; we do not have people there all the time. We have installed fences during the last season to trial keeping the turtles away from the parts of the island where they will fall over and land on their backs, and we have been quite successful at drastically reducing the number of dead turtles from that sort of activity.

That is a signal of a possible paradigm shift in how we think about managing the Great Barrier Reef. We have always been very careful to do our best to hold back human pressures, and that has been our main way, because essentially we feel that the reef can look after itself as long as we hold back the human pressures to a sustainable level. But in this case we are actually stopping the turtles falling over and getting stuck in what may well be—probably is—a natural process, but the bottom line is that we understand the range of threats to turtle populations and we need to do everything we can to help them out. So that is an example that we are now going to expand. We are going to try and do more of that to try and reduce that source of mortality even further.

Another example would be what we have done in the past when we have had crown-of-thorns starfish outbreaks. This is a starfish that eats coral and is responsible for 42 per cent of that coral decline that I mentioned. Periodically its populations explode and go into outbreak, and that is when they cause a lot of damage to coral. In past outbreaks, we have focused primarily on controlling starfish populations on sites of high value to the tourism industry. We are doing that again now, because there is another emerging outbreak in the northern part of the marine park—not the extreme north but north of the centre, if you like. So we are focusing again on protecting high-value tourism sites, but we are also beginning to experiment and work with the scientists about how to make those techniques for controlling the starfish more effective and, in doing that, hopefully leading to a scale where we can control their populations at a level that makes a difference to the reef ecosystem as a whole. I have to say that is an extremely ambitious undertaking. These animals appear in their tens or hundreds of thousands—possibly even millions at the peak of an outbreak; this is not an easy thing to talk about. Again, this is a signal of changing ideas around management of the reef; as we see these signals of extreme biodiversity decline we are exploring new ideas of how we might push the envelope and protect the reef even better.

Ms MARINO: That recent research showed 48 per cent of the damage being caused by cyclones and crown-of-thorns et cetera, and we watched the effects of the cyclones and the flooding. Given that you worked so closely with everyone in the catchment, and how you really have no control over the amounts of topsoil when you have a flood, is there any discussion around mitigation strategies in that event with those within the catchment itself—those who manage the land? I know you have a very good relationship with a lot of the farmers in that part of the world. Are there any other suggestions or ideas for managing that when you have an absolute downpour?

Dr Wachenfeld : There are no radically new or different ideas. There is ongoing work to improve riverbank vegetation which slows erosion, to make sure that drainage systems put in place the facility for sediment to be trapped on the land before it gets taken out into the marine environment. But you are absolutely right; it is the big floods that really do the damage of washing away soil and agricultural chemicals. One of the concerns with climate change, not just for the reef but also for agriculture, is that if rainfall becomes more variable, which is the prediction, we will get longer, more intense droughts followed by more intense flooding. The challenge of controlling erosion and the transport in flood periods of fertilisers, pesticides and soil from the land out into the marine environment will get worse. Our focus is essentially to keep improving the current practices that we have, and at this stage we do not have any magic bullet to stop that.

Ms MARINO: I just wonder whether there was any additional research happening, or any practical research, because farmers are nosy and the catchment would be just as keen.

Dr Wachenfeld : Absolutely, they would. I am not aware of any but I might take that on notice and get back to you. I will investigate that a bit more.

Ms MARINO: It is just out of interest. I do not know what the answer is, but let us have a practical look at how it could be managed, if not controlled, better.

Dr Wachenfeld : That is certainly worth investigating.

Ms HALL: I will continue talking about the recently released AIMS report that attributed a lot of the devastation to extreme weather events and crown-of-thorns population. I apologise for being late and I hope no one else has been down this track. I want to know to what degree climate change impacts on those extreme weather events and, subsequently, the biodiversity of the reef. Does climate change play a role in the increased numbers of crown-of-thorns starfish population on the reef? I think it is really scary when each female has 100 million eggs—that makes it really difficult.

Dr Wachenfeld : Yes. There are very confident predictions that some of the physical and chemical parameters of the reef environment will change with climate change. Probably the most concerning of those is temperature. Many organisms that inhabit the reef environments are very temperature-sensitive; they are not capable of withstanding extremes of temperature beyond what they have historically seen, and corals are a prominent example of such a thing. The future modelling is extremely clear and confident that long-term average temperatures are going to increase. As a consequence, when we get heatwaves they will be more severe than they have been in the past, and that is of great concern on its own. Even if there was nothing else, that is of great concern in looking at the future of the reef. I think it would be safe to say that we have already seen heatwaves in the last 10 to 15 years cause concerning impacts to corals, to sea birds and to sea turtles. So this is not just about possible future scenarios. We are already seeing the early signals of these things.

Other examples of physical and chemical parameters that we know are going to change with climate and ocean change are ocean acidification—where the carbon dioxide dissolving into the ocean lowers its pH—that is an extremely simple physical process; it is going to happen. Sea level rise is also very clear. It is happening now; it is going to continue to happen; that will have impacts for the reef ecosystem.

For some of the other things that may change with climate change, the predictions are less certain—for example, exactly what is going to happen with cyclone intensity. The predictions are that the mean maximum wind speed is going to increase. As I said before, there tends to be an exponential relationship between wind speed and environmental damage, so small increases in mean maximum wind speed of a severe cyclone are quite worrying for the environment. Changes to ocean currents are another one. And also changes to rainfall variability. The certainty of the predictions in the climate models around exactly what is going to happen with those is lower, but, nonetheless, the predictions are in a worrying direction for the environment of the reef. So there are some very firm predictions that are concerning; there are other predictions that are concerning but about which there is less scientific confidence about exactly what will happen. I cannot help but feel that the extreme weather we had between 2002 and 2011 sends an extremely concerning signal about how sensitive the reef is to extreme weather and how we can easily see cumulative impacts of floods and heatwaves and cyclones in quite a short period of time.

The second half of your question was, I think, about the possibility that climate change might impact crown-of-thorns starfish. I would have to say there has not been a huge amount of very specific work done on that. Probably the greatest concern would be that there is very strong scientific evidence that what is causing unnatural outbreaks is nutrients being washed off the land, causing blooms of phytoplankton, which in turn are the food for the larvae of the starfish. Under natural conditions very few of those larvae would survive to adulthood and therefore we would have very low populations of starfish; whereas, under conditions with enhanced nutrients, many more of the larvae survive—and, as you said, a single female can produce up to one hundred million eggs, so there is an awful lot of larvae out there—and that is what leads to an outbreak.

If we think about how that interaction will be affected in the future with climate change, the obvious issue is that the major driver of getting those nutrients off the land and into the marine environment where they affect the crown-of-thorns larval survival is floods. So, if climate change is going to change rainfall variability and lead to longer periods of drought followed by more intense floods, I do not know what that means but there is a very real chance it will affect crown-of-thorns outbreaks. I could imagine—and I am honestly just imagining—that it could go either way. In other words, long periods of drought might mean fewer crown-of-thorns outbreaks; but followed by massive floods might mean worse outbreaks than we have ever seen before. But I have to say: that is no more than an educated guess; that is not the results of research.

Ms HALL: Thank you. The other thing I would like to ask you is: how do you think the expansion of the Barrier Reef, taking in a wider area, the proposals that have been put forward for the Coral Sea and moving the boundaries out, will impact on the long-term sustainability of the Barrier Reef?

Dr Wachenfeld : I am not sure I understand the question.

Ms HALL: I know you don't. I can see by—

Dr WASHER: I think Jill is talking about the increased size of the marine parks.

Ms HALL: Yes, marine parks. Sorry.

Dr Wachenfeld : You are talking about the national system of representative marine protected areas.

Ms HALL: Sorry, yes, the marine park. I said 'Barrier Reef', didn't I? My apologies.

Dr Wachenfeld : Obviously, ecologically speaking the Great Barrier Reef and the Coral Sea are interconnected systems. The Great Barrier Reef Marine Park Authority manages the marine park which has an eastern boundary that is just off the shelf break. Although the government has plans to put in place new marine protected areas, those are not an expansion of the Great Barrier Reef Marine Park; those are just new and different areas. We are not particularly involved in the implementation or planning of those.

Ms HALL: Do you think you would have a role to play if it was expanded?

Dr Wachenfeld : I would have to take that on notice, but I am not aware of any discussions to that effect.

Ms HALL: Your body is seen as a resilient model for managing a very special area and I do not think I have heard anything negative about the way you manage the Great Barrier Reef. Recently when we visited the alps area it was suggested that a similar body could be established to manage the area. Do you have any thoughts on that?

Dr Wachenfeld : In relation to the alps, no, I do not have any specific thoughts.

Ms HALL: Is the model that you use for the Great Barrier Reef transportable? Would your model only work on the Great Barrier Reef or could it be used in other environmentally sensitive areas?

Dr Wachenfeld : The strength of the Great Barrier Reef Marine Park Act model is that when you look at a sensitive and iconic environmental area that is subject to multiple impacts from multiple sources that are under multiple different governments and other jurisdictions to manage, it is probably extremely helpful to have one central body that might not have direct legislative control over all the impacts but has a mandate to look after, coordinate and report on everything to do with the health of the system, and it gives you a point of focus, if you like. In answer to your question about its transportability, I think it depends on the nature of the environment. I do not necessarily mean the ecological environment but the social, political and economic environment.

Ms HALL: I think you will find a couple of areas that might fit that model.

Dr Wachenfeld : I could imagine the model would be useful in an area where there are difficulties with a complex environment, with complex human impacts and with complex jurisdictional issues and you want a body to try to overarch all of that and bring it together.

CHAIR: I understand that some of the long-term strategies that are in place for the crown-of-thorns starfish would probably change the population numbers. Can anything be done in the short term in an immediate sense that would assist that is not being done?

Dr Wachenfeld : I would like to stress that the best long-term strategy that we have is a continued focus on improving water quality. That is critical. Let us take that as a given. At the moment, the government has already invested about $1.4 million in crown-of-thorns starfish controlled with this new and emerging outbreak. Because we have a better understanding than we have had in the past of how these things work, we have responded to this outbreak much earlier than we ever have before. So that in itself is a good thing. As I alluded to before, the primary purpose of this endeavour is still to protect the sites of high value to tourism, but we are also taking this endeavour to other locations to experiment with an adaptive process of having a broader level of control. We have also got investment in research to try to find more effective techniques. I can give you the details of that if you would like but essentially the current technique is certainly very effective.

CHAIR: Can you briefly outline what that is?

Dr Wachenfeld : The chemical sodium bisulphate, which is a generally harmless chemical—it is used to buffer pH in the swimming pools; it is even a food additive in some processes—when injected in sufficient quantities into the starfish kills them. One of the problems is that it roughly needs an injection at the base of every arm in the starfish, and starfish can have up to 20 arms, so sometimes you have to inject a starfish 20 times. It is extremely effective but it is time consuming.

Some of the research that is being conducted at this very moment is to find better ways, essentially around what is the chemical that is used to inject the starfish. There is quite a promising option in which there is a protein mixture that induces an allergic reaction in the starfish which is fatal. The big advantage is that this requires only one injection, not 20. It still requires divers, it still requires them to find the starfish, but the processing time per starfish is much faster. If we can get this to the point beyond laboratory trials so that it is ready for field trials and incorporation into an adaptive management program, we hope that this can greatly increase the efficiency of our endeavour in that regard.

Ms HALL: What about the little crabs that—

Dr Wachenfeld : Coral crabs?

Ms HALL: Yes.

Dr Wachenfeld : There are some species of corals that have symbiotic crabs that live amongst their branches. It has been demonstrated that, if a crown-of-thorns comes on to their coral head, because that is very much their home, they will nip at its feet and drive the starfish away. That is a fascinating bit of natural history. It does not really lend itself to a management tool that would allow you to get the outbreak under control.

Ms HALL: Okay.

CHAIR: I do not have any other questions. Thank you very much for giving us that overview. I think it would be fair to say that the Great Barrier Reef is an area where this committee has spent considerable time and has had several presentations over the last two or three years. Therefore, I think we have a reasonable understanding of the issues related to it, both with the good things that are being done and with the risks that are faced. This last report, probably, would have surprised all of us in terms of the level of loss of the coral reefs. It is interesting to hear your perspective on it. You will be sent a copy of the transcript of your evidence today and if there are any alterations or adjustments that you believe need to be made feel free to contact the secretariat. Once again, on behalf of the committee I thank you for appearing before us.

Dr Wachenfeld : Thank you for the opportunity.