Category Archives: My general nonsense!

My ravings and rants about all things general; from quirky news stories to interesting web pages.

Let’s argue against the Shark Cull with science

There’s been a lot in the news recently about the implementation of the Shark Cull (or, as the Government put it, the “shark protection measures”) here in Western Australia.  Just as I am not a climate scientist, I am not a shark biologist, and cannot claim to be a shark expert.  However, as a marine ecologist who focuses on ecosystem scale research, I feel that I can give a relatively informed opinion!  Unsurprisingly, I am against the cull, but my arguments against it don’t completely align with those of the anti-cull protestors.

There is clearly a lot of emotion in this debate, from those for and against the cull.  This isn’t really surprising given the fact that there have been seven shark-related fatalities in Western Australia over the last 3 years.  This emotion has spilled into the argument around shark culling, and this is where I see a big problem.  The debate is being framed as an ethics debate, with external, undecided observers most likely seeing the debate as a “Shark rights vs. human rights” issue.  And guess what.  This plays right into the hands of the pro-cull side.  Although I definitely agree that animal ethics are important, human rights will always win in the battle for public hearts and minds (which ultimately, influences policy).  This emotive debate will always be won by the pro-cull side, who can conjure horrific images of people being eaten by a shark, ala Jaws.  Indeed, just this week a pro-cull commentator was arguing for the killing of sharks by raising the scenario of a child potentially being taken by a shark at a Perth beach (prizes for which logical fallacy that is!). I’m sorry, but there is no point in arguing against the shark cull based on shark rights when this is the type of argument that you face!  However, we have an ace up our sleeve on the anti-cull side; we are backed up by scientific data and logic, and scientific research can provide us with compelling evidence against the cull!  So I think we should primarily use rational arguments against the shark cull.  Plenty of actual shark experts (as well as renowned ecologist and the Eureka Prize winner, Euan Ritchie) have stated far more eloquently the detailed science against this cull, and potential alternatives, but here’s my attempt at a run down.

We’ve known for a very long time that when apex predators are removed from natural ecosystems, bad things start to happen.  We call this type of process trophic cascade, or more specifically in this case, top-down control.  The removal of the top predator allows it’s direct prey  to expand in number, and this expansion can be rapid when predation is the main controller of the prey population.  The expansion of these populations then leads increased predation or herbivory, and can potentially lead to a decimation in plants and animals lower in the food chain.  So, even though we only removed that top species (the apex predator), it had consequences for the whole food web, and can result in a distinct shift in the type of ecosystem we see.  This isn’t just a problem for the environment, these changes can lead to social and economic issues in certain circumstances.

About the most famous example of the severe impacts caused by the removal of apex predators comes from the complete destruction of the grey wolf population in Yellowstone.  Wolf populations were under severe threat in the area, and the introduction of a government-led predator control programmes (sound familiar???) led to the complete extinction of wolves in Yellowstone Park in the mid 1920s.  Over the subsequent decades, environmental conditions at Yellowstone declined severely.  This was driven by a rise in elk numbers, allowed to proliferate due to the removal of their main cause of mortality (being eaten by wolves!).  The increase in elk numbers led to huge overgrazing, in turn decimating plant populations, which led to impacts on other animals at Yellowstone.  The removal of the grey wolf caused this trophic cascade, threatening one of America’s most famous national parks at an environmental, cultural, and economic level.  The re-introduction of grey wolves into Yellowstone in the 1990s resulted in direct reduction in elk numbers to more sustainable levels, resulting in the recovery of many plant species, and also restructured populations of other animals in the ecosystem (showing the diverse and varied ecological connections and feedbacks).  In short, when we mess with the top predators, lots can go wrong, and this recipe for disaster is made worse when we factor in climate-driven changes to our environment!

The evidence for these trophic cascades after apex predator removal is widespread across lots of different ecosystems, including in the ocean, with sharks often present as apex predators.  Even in relatively pristine ecosystems with low levels of human impacts, it is clear that sharks can play a hugely important role in structuring the ecosystem.  Up in Shark Bay where I conduct most of my research, tiger sharks are the apex predator (and incidentally, are on the list of shark species to be culled as part of the policy).  The presence of large tiger sharks influences the feeding preferences of many of the herbivores like turtles and dugongs in Shark Bay, which in turn results in changes to spatial patterns of herbivory pressure on seagrass meadows (which impacts many other organisms – complex feedbacks in action!). Clearly, large sharks play a hugely important role in our ocean, and if we lose them, it will have knock on effects, that could extend to economic consequences such as negative impacts on fisheries – commercial and recreational.

So the science warns against instigating the cull, and previous attempts at using shark culls to prevent attacks on humans have not worked.  There is also no evidence of a significant increase in shark numbers or shark attacks (despite the 7 fatalities in 3 years).  It may sound like blame can be focussed solely on the state government for implementing the policies in spite of this, but the media has also played a role.  The ferocity and intensity of the language used in the West Australian media when describing sharks has left a lot to be desired, often perpetuating the fear mentality driven by films like Jaws.  Yes, shark attacks are tragedies, and tap into a primal fear that has evolved with us (the fear of being eaten!).  However, this does not justify stirring up this fear to critical levels by falsely describing sharks as ‘rogues’ and talking of ‘feeding frenzies’.  Much like in the climate debate, objective journalism seems to be missing from the shark debate.

Justified or not, there is fear within some sections of the public against sharks, which prompted the cull in the first place.  This fear does not justify the cull – imagine a world where we based all policy on emotion instead of reason!  If politicians do feel the need to be seen to be doing something about the attacks, there are plenty of other alternatives (some like tagging and increasing research funding are already being done) that are backed up by science.  Even under the current drum line policy, sharks could be towed out to sea, tagged and released away from our busy beaches, as done successfully in Brazil.

The debate over the cull has become polarising. Anti-cull protestors (with the best of intentions), have entered into a damaging debate with the pro-cull side following a narrative of ‘shark rights vs. human rights’, with the science taking largely a back seat.  Instead, let’s emphasize the science, and tell people what we all stand to lose by implementing policies such as this.  Let’s explain to people how their favourite swimming spot might change dramatically if we get rid of large sharks.  Let’s describe why catching fish might become even more difficult with large sharks gone.

And let’s not be afraid of leaving a little bit of risk and wilderness associated with our amazing natural playgrounds!

Marine science, the environment, and the 2013 Australian election

I’ve been a bit reluctant to write about the upcoming election in this blog; after all the point of this blog has never been about anything political!  However, for better or worse the state of our  environment (including our oceans) are inextricably linked to politics, so here goes…

So Saturday was federal Election Day here in Australia, ending a long campaign where both parties tried to out-negative each other!  But how much focus (or lack thereof) did the ocean, science and the environment receive in the build up to the election?

On the whole, issues related to marine science and conservation have received very little attention in the build up to the election.  The most notable announcement was probably the Coalition’s plan to suspend and review the recently implemented network of marine parks.  There main argument for this appears to be that there is a lack of scientific consensus on the issue, and that the parks unfair penalise recreational fishers.  I strongly disagree with this view. I’m not a fisheries scientist, and don’t claim to be an expert in the subject, but from all accounts marine reserves seem to widely accepted as being beneficial for marine biodiversity, and can even help fish stocks in adjacent areas through the spillover effect.

halophila ovalis, coral, tropical fish, Shark Bay,

Climate change is already causing changes in our marine ecosystems, but do the politicians have a plan to deal with it?

This is not to say that there are not remaining questions about the new marine parks, but on the whole the policy should be seen in a positive light, given the pressures our marine ecosystems (and therefore fisheries) will face in the future.  The announcement to suspend the implementation of the new marine parks is therefore deeply worrying, and not warranted.

The discussion of climate change has also been relatively limited in the election build-up, especially in comparison to the 2007 and 2010 elections.  This is in spite of an increase in both the evidence for and effects of climate change around the world.  The overwhelming scientific consensus is that the Earth is warming, and it is almost certainly as a result of anthropogenically-released carbon dioxide (and greenhouse gases).   This warming is directly responsible for significant changes in our environment (both in land and in the ocean), and is already causing detrimental social and economic consequences.  Given that these negative environmental, social, and economic consequences are more than likely going to increase in the next few decades, we should be trying to limit greenhouse gas emissions – the cost of inaction looks far too high for me!

Despite the challenges that climate change is posing, the major political parties are proposing policies that do not go far enough!  Labor are aiming to reduce emissions by 5% of 1990 levels, while the Coalition will reduce emissions by as much as their Direct Action plan will allow (predicted to be much lower than 5%).  For serious change to occur, we must reduce emissions by far more than this 5% target and Australia, as a wealthy nation, should be setting a global example by being at the forefront of lowering emissions.  Climate change has received far less attention than it deserves during this election campaign, as it is one of the greatest challenges facing humanity.  I worry that we (and future generations) will look back at this election and note that progression towards dealing with climate change moved backwards in 2013.

This post wasn’t meant as a comprehensive review, so I’m not going to go on too much longer.  However, there have also been worrying announcements regarding changes to the Australian Research Council funding process (the Coalition plan to limit “waste” by preventing funding to projects that – in their opinion – do not meet their priorities), and removing protection status from 170000 hectares of the World Heritage Listed central highlands area in Tasmania.

Now that the election is over, let’s just hope that the environment will be given enough attention over the next 3 years, though I’m not too optimistic based on what the election coverage has been like.

Impacts of climate change on marine communities, seagrass dieback, and a trip to the Abrolhos Islands!

You may have noticed a lack of posts over the last few weeks.  No holiday for me though, here’s a quick taste of some of the other stuff I’ve been up to!

Impact of climate change on marine coastal ecosystems – A masterclass with Nuria Marbá
I was lucky enough to be invited along to present some research at a masterclass at the Institute of Advanced Studies led by Nuria Marbá in late March.  Nuria is a highly respected marine ecologist, and is mainly focussing on researching how coastal communities will respond to climate related stressors such as increased sea surface temperature.  Nuria gave a fantastic talk on the responses of a variety of different coastal ecosystems to projected future warming; from seagrass meadows in the Mediterranean to seaweed communities off the coast of Greenland.   In particular, the seagrass Posidonia oceanica – the real foundation species of the Mediterranean Sea – is at real risk from a combination of increased temperatures and future human activity.  P. oceanica has historically been able to resist disturbance events through extremely long life spans – a study led by Sophie Arnaud-Hound in 2012 suggest that some clones are thousands of years old!!!  However, this long life span is coupled with extremely slow recovery, and it is the really fast rate of expected change in temperature that is expected to cause the P. oceanica meadows to really struggle.  Above average temperatures in the Mediterranean in the last decade has already resulted in significant shoot mortality (Marba and Duarte 2010 Global Change Biology), and the predictions for seagrass response to future warming events look even scarier – with the present consensus being a “functional extinction of P. oceanica meadows by the middle of the century (2049±10), even under relatively mild greenhouse-emissions scenario” (Jorda et al. 2012 Nature Climate Change).  This is all pretty sobering stuff considering that P. oceanica forms the basis of key ecosystems in the Mediterranean Sea.

Closer to home, I presented some initial research that was conducted looking at the effect of the 2011 Marine Heatwave on seagrass populations in Shark Bay.  We travelled up to Shark Bay in March 2011 (right in the middle of the heatwave) as part of a separate research project, and noticed two striking features – water temperatures were far higher than normal, and the dominant seagrass Amphibolis antarctica (wire weed) had experienced severe defoliation (leaf loss) in certain parts of Shark Bay.  Closer analysis showed that the areas worst affected were adjacent to the recently flooded Wooramel River, so we hypothesis that a combination of elevated temperatures and decreased light availability may be leading to the loss of leaves.  Effectively, we believe that the increased temperature increases respiratory demand (the seagrasses get ‘hungrier’ for light) whilst the decreased light availability stops that demand being met.  We are re-visiting previous study sites where defoliation was noticed in an attempt to measure the recovery of the seagrasses; so I’ll keep you posted!

Defoliation in Shark Bay seagrass meadows

A healthy Amphibolis antarctica meadow (left) and a defoliated meadow in Shark Bay (right). We believe a combination of low light availability and elevated tempertaures has led to this loss of leaf material.

Other workshop presentations included a discussion on the impacts of the same marine heatwave on marine communities (in particular, macro algae) up and down the West Australian coastline by Thomas Wernberg, carbon sequestration impliactions from Oscar Serrano-Gras, and a discussion of the effects of warming on feedback in algal assemblages from Scott Bennett.  All in all, a fantastic workshop that will hopefully have positive benefits for the management of marine communities in the face of continued warming of our oceans.

A trip to the Houtmans Abrolhos!
For one week at the start of April I was lucky enough to help out Luke Thomas with his research into coral resilience at the beautiful Houtman Abrolhos.  The Houtman Abrolhos is a chain of small islands located 80km off the coast of Geraldton, Western Australia.  They are really special as they are the highest latitude true coral reef in the Southern Hemisphere.  As such, they may represent an important site that could potentially act as a refuge or a stepping stone for some coral species to move south as temperatures increase.

Acropora research at the Abrolhos Islands

Luke taking samples to investigate coral resilience at the Houtman Abrolhos.

Luke is trying to figure out the genetic connectivity of the corals in the Houtman Abrolhos with those in other locations along the West Australian coast, such as those found in Shark Bay, Ningaloo Reef, and Cygnet Bay.  This will help to determine the resilience of the coral reef communities in the Houtman Abrolhos to future changes in climate (Luke explains things much better than I do here!).  We also carried out some ecological experiments on kelp beds at the same time, so it was a full week of research!  But luckily the weather held up for us and we had some stunning dives – hopefully I’ll be able to post some more photos at a later date!

Kelp research at the Abrolhos Islands

Some fantastic visibility led to some incredible kelp dives (20m depth at this site!) Photo: Gary Kendrick

The inaugural Oceans Institute Student Conference
March also seen a landmark for the UWA Oceans Institute – the first student conference was held at the University Club at UWA.  There were a huge range of talks that showed the breadth of research at the university – everything from tracking marine plastics to studying the biology of pteropods!  And even me trying to get everyone excited about phosphorus cycling in seagrass sediments (what’s more, I was awarded joint first place for the presentation, and won a return trip to Rottnest Island – fantastic!).  One of the highlights from the conference was a talk by renowned marine ecologist Callum Roberts about the pressures facing coral reef ecosystems over the next 100 years.  He was quick to emphasise that warming temperatures aren’t the only threat, with human impacts such as overfishing and pollution likely to lead to worsen negative impacts on these reefs.  Sobering stuff.  On a brighter note, the day as a whole went well, and I think that the 2013 OI student conference will set the benchmark for many more successful conferences in years to come!  Big thanks to Liza, Eric, Renee and the rest of the organising committee!

‘Worldwide diebacks of seagrass ecosystems’: A seminar from Ole PedersenI also had the pleasure of heading along to a seminar from Ole Pedersen; a 2013 Professor-at-Large at UWA.  Ole is one of the authorities in the ecophysiology of aquatic plants (including seagrasses!) and is primarily based at the University of Copenhagen, but is over for a two week stint to do some work in Western Australia!  Ole’s seminar focussed on two potential causes of dieback of seagrass – hypoxia (lack of oxygen) and sulphide intrusion (effectively poisoning!).  Ole has played a leading role in the creation of microsensors that can be used to measure oxygen and sulphide concentrations in the field, and his research indicates the both hypoxia and sulphide intrusion could lead to further loss of seagrass communities as ocean temperatures rise!  I’m lucky enough to be helping Ole and Jens Borum (also visiting from the University of Copenhagen) out with some of their experiments into the potential responses of West Australian seagrass species to changing concentrations of carbon dioxide in the water column, so I should be able to also keep you posted on that research!

As you can see, a busy few weeks, which is why the blog has taken a bit of a back seat!  Rest assured I hope to blog more over the next few weeks!

Marbá, N., & Duarte, C. (2009). Mediterranean warming triggers seagrass (Posidonia oceanica) shoot mortality Global Change Biology, 16 (8), 2366-2375 DOI: 10.1111/j.1365-2486.2009.02130.x

Jordà, G., Marbà, N., & Duarte, C. (2012). Mediterranean seagrass vulnerable to regional climate warming Nature Climate Change, 2 (11), 821-824 DOI: 10.1038/nclimate1533

Marine Ecology or Marine Biology….what’s the difference!?!?!?

A few of you may be wondering why the blog is called ‘Confessions of a Marine Ecologist” and not ‘Confessions of a Marine Biologist”.  After all, if you ask a group of school kids what they want to be when they grow up, more than a handful would happily answer “marine biologist”, but I would happily put money on none answering “a marine ecologist”!  Even when I decided I wanted to study life in the ocean, I searched for courses on marine biology, not marine ecology!  And I myself often wondered why people I was introduced to describe themselves as ‘marine ecologists’ instead of ‘marine biologists’.  So what’s the difference?  And, more importantly, why do I feel the need to describe myself as a marine ecologist that will almost definitely get me less traffic and fewer looks of admiration from non-scientists (incidentally, these looks of admiration are quickly replaced by confusion when you explain to people that you work on seagrass instead of dolphins or turtles!)

Coral Reef Community at Ningaloo Reef, Western Australia

Why do we find marine organisms in some places but not others? This question is at the heart of all marine ecology!

Let’s start at the difference between the two.  Marine biology is the study of life in the oceans.  The mention of marine biology invokes thoughts of dolphins, turtles, and maybe even some pretty coral-reef fish from Finding Nemo!  However, marine biology is a whole lot more than that, investigating all life in the ocean, from the phytoplankton (very small) to the blue whales (very big).  In short, marine biologists concentrate on studying their chosen species, answering questions like “What type of fish is that?”, “How do the bodies of whales cope with extreme depths?”, and “How do sharks sense their environment?”.  All in all, some pretty cool stuff in my opinion!

So what makes us fully fledged marine ecologist different from our biologist counterparts?  Well, I think that marine ecology is even cooler than marine biology because as marine ecologists we link what we know about the biology of a given species with other plants/animals and the environment as well.  This allows questions to be explored like :”Why do ecosystems that are so depleted in nutrients (like the Great Barrier Reef) have such high biodiversity and productivity?”, “What will happen to the local seagrass and fish population if we build a new jetty here?”, and “How does the presence of keystone predators (like sharks) effect not only turtle and dugong numbers, but the type of plants we see on the seafloor?”.  Nature is extremely complex, and I believe that we can only  gain a limited understanding of how nature works by simply looking at individual species in isolation.  This is where marine ecology comes in….we attempt to understand how species interact with one another and their environment (things like temperature, nutrient/food availability, light……even human-related disturbances).  When we consider that we live in a world where climatic conditions are changing at an unprecedented rate, we need marine ecology to help make predictions about how marine species will respond to such environmental changes, and how best to mitigate against any potential losses.

If we were splitting hairs, ecology is technically a form of biology, but I felt the need to write this post given how passionately I see some researchers stating that they are in one camp or another. Most importantly, we need to have marine biologists and ecologists to help us understand marine organisms and how they interact with the environment and each other.  But as an ecologist (albeit a biased one!) what gets me excited isn’t just finding out how the amazing plants and animals we find in the ocean work, but how they interact with each other and their environment, explaining why we see certain species in some places and not others!

So hopefully this little rant has shed some light on the importance of us marine ecologists!  Though I’m still not holding my breath for any school kids to profess a desire to become a marine ecologists any time soon!

My 2013 PhD Resolutions

So the New Year is upon us, so there is no better time to thrash out what I hope to acheive throughout the year (in an informal, non-official way!)

1) Publish!!!
Boring I know, and this isn’t really a new resolution (and is probably part of 99% of PhD students resolutions) but I think it is important nonetheless!  I had a fairly good year for publications in 2012; with 1 paper as a lead author and a further 3 as  co-author (not too bad for the year where I transitioned from an honours student to a PhD student).  If I was setting myself a target, I would like to at least maintain that rate (so another 4 papers this year), with at least 2 of those as the lead author.  I’m also trying to forage into writing a review (slightly intimidating giving my opinion on a body of literature that has been worked on for several decades!) so it should be interesting!

2) Interact more with the public!
I guess this resolution was the reason for me starting this blog!  As PhD students we are often required to give presentations to other academics (either in-house or at conferences), but we don’t often interact with the public!  So my second resolution is to get more messages out there to the public in plain English…either electronically or through outreach programs!

3) Learn how to teach properly
Last year, I took a lead role in helping with demonstrating in a couple of units at the university – ‘Marine Systems’ and ‘Ecological Processes’.  I found it fantastic, and it’s definitely true that to teach something, you need to know it inside out!  I’ve been lucky enough to be granted a Postgraduate Teaching Internship for 2013 at UWA, a scheme that gives postgraduates some intensive training and allows them to teach (including giving lectures) in a couple of units through the year.  I’m hoping to post all the teaching materials I come up with on this blog, so watch this space!

4) Take more photos in the field!
Every time before I head out in the field, I pack my camera and tell myself that I will make an effort to take lots more photos, and it never happens!  So this year, I am resolving to actually make use of the underwater camera when I pack it!  More specifically, I need to take more photos of me and the rest of the gang doing our work in the field….it’s only when you are asked for some photos of yourself in the field that you realize you have an aversion to being in front of the lens!

5) Have more confidence in myself!
Pretty much do what it says on the tin!  Not that I’m an insecure person, but I guess building confidence in yourself as a scientist is something you should aim for every year during your PhD as you transition from a student to an early career researcher (all going well).

6) Brush up on my ecological theory by reading some seminal ecology papers!
I read….I read alot!! It’s part of the job after all; you need to find out what else has been done in your field of research, find a piece of evidence to support your argument or even find obscure methods to help you carry out an important experiment.  But, as a biogeochemist, I find that I don’t read enough of the classic,
theoretical ecology papers even though they really interest me, purely because I don’t really cite them.  So, this year I am going to make time to at least try to read one classic ecology paper a week!  Even if I get really, really busy………promise!

That’s all I can think of at the moment, I’m sure I’ll add more as time goes on, or if anyone else gives me any bright ideas!  As always, feel free to comment on anything I may have missed!

The first of many!

Sub-tropical coral patch

Yes…another PhD student trying their hand with yet another blog.  I’ve thought (too) long and hard about what to say in my first blog, but lets start with some of the reasons as to why I felt the need to start this blog, and why these will hopefully set me apart from other blogs that are out there!

  • To make marine ecology accessible to the publicAs researchers, I think we all know the feeling of going to a party with a group of non-scientists, explaining your research, and getting confused looks back!  I believe that when this happens, it is our fault as researchers, and we need to explore avenues that help raise general awareness to the public.  After all, we cannot expect the lessons we learn in our research to be conveyed to the public effectively merely through the publication of our research in scientific journals.  In short….I’m hoping to write about science in a way that my parents, family and friends find interesting and accessible!
  • To increase awareness of marine ecology: This is fairly similar to above, but I feel it deserves a separate section (my blog, my rules!).  I find that most non-scientists I meet have at least a moderate interest in marine science.  When I tell people that I am a marine ecologist, I generally hear stories back about how fish aren’t the same size as they used to be, or describing whale behaviour from the latest David Attenborough documentary.  But there is a lot more really cool stuff that we do as marine ecologists, yet the knowledge of this work outside the scientific community (and even within the community as well!) is fairly limited.  In particular, I’m hoping to raise awareness about seagrass (the organism that I study!); an extremely important yet often-ignored component of many marine ecosystems.  Hopefully this blog will act as a bridge between some of this research and the public.  We are custodians of the marine environment, and we have a responsibility to deliver what we know to the public in a way that can be understood easily.
  • To give a balanced view of marine ecology in Australia: This is more a personal gripe of mine, with marine ecology not receiving much attention in mainstream media!  I don’t expect research to be on the front page of newspapers, but with the diversity of marine life around our coastline, it really does deserve more attention than it gets!  I’d also like to try to counter some of the misinformation that is continually portrayed in much of the popular media in Australia, particularly in relation to denial of climate change and marine parks.
  • To act as a resource for up-and coming marine biologists and ecologists: In my undergraduate days, I often looked long and hard for Australian websites that gave me easily digestible information about marine biology and marine ecology in Australia.  Or websites that gave me really useful information about how to position myself best for a future career in research science.  I hope that this blog becomes a place where budding marine biologists and ecologists to come and get easy-to-understand, relevant information!
  • Selfish reasons: OK, so I admit there are also ulterior motives in creating a blog…it’ll help me keep on track with my PhD research, it helps to build an online footprint (see here for why that is important!), and it may even increase awareness with the research community about the publications I have produced (even though I want this blog to be broad and not just all about my research!).  But hey, we’re all allowed to be a bit selfish, right!

Above all, I hope this blog will have active community involvement!  I know this won’t happen overnight, but hopefully it will come in time.  I like being controversial (I think that’s the best way to start conversation!), so disagree with me, give me feedback, or even tell me I don’t know what I am talking about!  As long as no boundaries are crossed, constant feedback can only be a good thing!