SMM 2017 Conference Presentation

I’m now safely home after attending the Society for Marine Mammalogy’s biennial conference in Halifax, Nova Scotia.  It was an amazing eight days of conference talks and workshops, interspersed with plenty of networking.  As well as meeting lots of interesting new people, it was particularly wonderful to catch up with so many old friends.  Totally worth the 35hrs of one-way travel and 12hr time difference jetlag!

I’m currently preparing a detailed conference report for the Journal of Animal Ecology’s blog, but in the meantime I wanted to make my conference presentation available online.  To download a PDF version, click here.  The full abstract is provided below.  Feedback welcome!

SMM 2017 - Sarah Marley

Acoustic habitats and behavioural responses of bottlenose dolphins in Western Australia

Marley, S.A., Salgado Kent, C.P., Erbe, C., Parnum, I.M. and Parsons, M.J.G.

As human activities continue to expand across the marine environment, anthropogenic ocean noise is also rapidly increasing.  This is of concern to acoustically-specialised species, particularly those displaying a high degree of habitat overlap with anthropogenic activities, such as bottlenose dolphins (Tursiops sp.).  There is a need to describe the soundscape of coastal dolphin habitats and examine how prominent anthropogenic noise sources may impact these animals.  The Swan River in Western Australia flows through the state capital of Perth, containing over 1.4 million people, and consequently experiences a range of anthropogenic activities.  However, the river is also extensively used by a resident community of Indo-Pacific bottlenose dolphins (T. aduncus).  Autonomous underwater acoustic recorders were used to collect data throughout the Swan River, which were analysed via weekly spectrograms, power spectrum density percentile plots, octave-band levels, broadband noise levels, and generalised estimating equations.  Land-based theodolite tracking at two sites provided information on vessel traffic and dolphin behaviour, which were assessed using generalised additive models and Markov chains.  Acoustic datasets collected from 2005 to 2015 indicated that the Swan River was comprised of multiple acoustic habitats, each with its own characteristic soundscape and temporal patterns in underwater noise.  The ‘noisiest’ site from an anthropogenic perspective and in relation to dolphin communications was the Fremantle Inner Harbour (mean broadband noise level: 106 dB re 1 µPa rms [10 Hz – 11 kHz]).  Theodolite tracking at this site found that dolphins remained present during periods of high vessel traffic.  However, behavioural observations indicated significant alterations to dolphin movement speeds and activity states at high vessel densities.  Furthermore, whistle characteristics varied in conditions of high broadband noise.  This work suggests that dolphins maintain occupancy at key foraging sites within the Swan River despite the presence of vessels, but alter their behaviour in periods of high vessel traffic.

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New Paper: A Tale of Two Soundscapes

I am a little bit behind in posting about my various PhD publications.  But a pretty cool one that came out in the August edition of Acoustics Australia focused on comparing the acoustic characteristics of urban versus pristine coastal dolphin habitats.

I’ve previously spoken about the need to define the soundscape of dolphin habitats and examine patterns of when and where noise occurs.  But whilst we can monitor dolphin acoustic habitats and describe how they are now, in many cases it is hard to say how they were in the past.  We simply don’t have enough long-term datasets that capture the expansion of human activities into the marine environments – i.e. datasets that go far enough back in time to capture when the habitat was pristine and free of human influence.  Understandably, this can also make it hard to decide how we best manage man-made noise in these habitats into the future.  It’s hard to determine what noise mitigation measures are necessary when you don’t know how quiet an area is ‘supposed’ to be.

A potential solution to this conundrum for managing ‘urban’ areas is to find comparable ‘pristine’ areas which are also used by the study species, and see what differences exist.  Of course, this is reliant upon pristine areas still existing in the first place.  However, in Western Australia we are fortunate enough to have some areas up in the remote north of the state.

The Kimberley region in north-western Australia is one of the most remote, pristine wildernesses in the world.  The largest town in the region is Broome, which has a permanent population of only 16,000 people (although the temporary population can increase to 45,000 in the tourism season).  Broome is located on the shores of Roebuck Bay, with a relatively large population of snubfin dolphins and is also regularly used by bottlenose dolphins and humpback dolphins.  This area offers a nice contrast with the busy, urban environment of the Swan River, which flows through the Western Australian state capital of Perth.  This river is also used by bottlenose dolphins.  To create successful noise mitigation strategies for coastal dolphins, there is a need to compare ‘quiet’ and ‘noisy’ acoustic habitats.  Roebuck Bay and the Swan River offer the perfect opportunity to do just this.

Prepping the Roebuck Bay acoustic gear

I chose to compare the pristine soundscape of Roebuck Bay with the Swan River’s anthropogenically-noisiest site, the Fremantle Inner Harbour.  I used autonomous underwater acoustic recorders to monitor the soundscape at these sites, and assessed these using a combination of weekly spectrograms, power spectrum density percentile plots and probability densities, octave-band levels, broadband noise levels, and generalised estimating equations – i.e. a shedload of nifty acoustic analyses.

What these essentially showed were that these two sites are very different in their acoustic characteristics.  In Roebuck Bay, biological sounds (such as crustaceans and fish) were the most prevalent sound sources, with very few instances of vessel noise.  However, in the Fremantle Inner Harbour, man-made noise dominated.  This worked out to a 20 dB difference between sites on average, and the frequencies used by dolphins for communication were more likely to be masked in Fremantle Inner Harbour based on elevated noise levels.

In this study, I was also lucky enough to get some acoustic recordings of sounds produced by snubfin and bottlenose dolphins in Roebuck, and could use these for a comparison with the sounds produced by bottlenose dolphins in Fremantle.  This helped me to discuss the potential consequences on Roebuck Bay dolphins if noise levels were to increase at that site.  Such information is going to be useful going into the future, as several coastal developments are currently planned for Roebuck Bay.

To find out more, check the paper out online or contact me!

Snubbies are happy little dolphins – hopefully they stay that way! (Photo: Sarah Marley)

 

New paper: Behavioural and acoustical responses of dolphins to vessel traffic and noise

Last night, my sixth (and final) PhD paper was published in the journal Scientific Reports!

In earlier papers, I established that the Swan River is a pretty noisy place.  One of the noisiest sites from an anthropogenic perspective is the Fremantle Inner Harbour, which experiences high levels of vessel traffic.  However, during my initial visual observations I discovered that dolphins continued using the harbour, even though it was a busy noisy environment.  So in this latest paper, I searched for evidence of dolphins responding to boats and noise at a subtler scale.

To do this, I used a combination of visual and acoustic monitoring techniques.  I found that dolphins significantly increased their movement speeds when vessel traffic occurred at high levels.  Similarly, dolphins also changed their behavioural budgets at high vessel densities, spending more time travelling and less time resting or socialising.

I monitored dolphin movement speeds and behaviours, to see how these changed as vessel traffic increased

I also looked for acoustic responses, by measuring nine characteristics to describe the shape and frequencies of dolphin whistles in different noise scenarios.  I found that all nine of these characteristics varied with increasing levels of broadband noise, and that the response was particularly strong for low-frequency noise.

I used nine characteristics to describe dolphin whistles

I’ve spoken before about the importance of scientific publishing, in terms of career brownie points for researchers.  So I’m pretty chuffed to have completed publishing my PhD!  To view the full list of papers from this and other projects, check out my Publications page.  Now to deal with all the ‘leftover’ PhD data that I collected, but didn’t get around to including!

Associate Editor of Austral Ecology

Today I received my first email addressed to “Dear Dr Marley…

And as if that wasn’t enough of a buzz, the email itself was to welcome me onboard as a new Associate Editor for the scientific journal Austral Ecology!

The daunting world of academic publishing…

Most scientific work is published in an academic journal.  The idea is that a piece of work is reviewed by your peers, who can either reject it as unacceptable or recommend it for publication (often after implementing some improvements).  So everything that appears in academic journals has generally been vetted by at least two experts in the field through this ‘peer review’ system. This is to ensure the quality of work being published, as researchers are judged by their publications when applying for jobs and grants.  In some cases, the survival of whole university departments depends on their publication records.

But it’s not just about churning out article after article.  There are thousands of journals out there for different scientific fields, each of which with its own level of prestige.  And your success as a scientist depends on getting your work published in good-quality journals.

Austral Ecology is the official journal of the Ecological Society of Australia (ESA), and is the premier journal of basic and applied ecology in the Southern Hemisphere. This includes experimental, observational or theoretical studies on terrestrial, marine or freshwater systems.  ESA is the main professional association for ecologists in Australia, with over 1,500 members across the country.

The most striking ecological system I’ve ever worked in – the Kimberley of NW Australia

As an Associate Editor, I will be responsible for managing several manuscripts per year.  This involves finding suitable peer reviewers for each article, and making recommendations of the suitability of that article for publication based on the reviews received.

From my own experience, I know that a good editor makes all the difference.  When publishing my first paper, I received excellent support from the journal editor, who guided me through this overwhelmingly daunting process.  I have also received support from an editor in the past when a peer reviewed behaved less-than-professionally when assessing my work.  I believe having a good editor can make all the difference for authors – and I look forward to contributing to this process.

Introducing Dr Marley!

Last week, I received official notification that my PhD was conferred!  In normal-speak, this means that Curtin University has fully accepted my PhD and that I can now use my new title!

In a nice coincidence, that same day my printed and bound thesis copies were ready for collection.  So I had the double pleasure of holding my academic babies AND referring to myself as Dr Sarah Marley!

In that moment, all I could remember were the highlights and golden times.  The amazing experiences, friends and discoveries that happened along the way.  The opportunity to do something novel and exciting.  I was reminded of how happy I was to start my PhD, giving my top three reasons for doing so to be curiosity, love of research, and enjoyment of being challenged.  And although the end of the PhD was certainly challenging, when I was holding the final, finished project as an official Dr of Dolphins, all I could think was:

Totally. Worth. It.

New Paper: Spatial and temporal variation in dolphin acoustic habitats

There is a growing awareness of underwater noise in our oceans and the potential impacts of such noise on marine life, an issue which was the major theme of my PhD thesis.  This is particularly relevant for “acoustically-specialised” species, such as dolphins.  However, before we can start investigating the effects of noise on these animals, we first need to define the soundscape of dolphin habitats and examine patterns of when and where noise occurs.

We get a glimpse of them at the surface – but what about their acoustic habitat beneath the surface? (Photo: Sarah Marley)

This description of noise in dolphin habitats formed my third PhD chapter, which has now been published online in the scientific journal Frontiers in Marine Science.  In this paper, I examine spatial and temporal variability in the soundscape of the Swan River using over 11,600 hours of acoustic data collected from five sites within the river system across eight years.  Multiple sound sources were recorded at these sites, but the prevalence of these sounds at each site differed, giving each location a characteristic soundscape.  Consequently, some sites were ‘noisier’ than others.

Deploying acoustic recording equipment with help from Fremantle Ports. Spot the dolphins in the background! (Photo: Jeanette Murray)

Want to know more?  The full paper is available online! I’d love to hear your thoughts 🙂

Marley et al. (2017) Spatial and temporal variation in the acoustic habitat of bottlenose dolphins (Tursiops aduncus) within a highly urbanised estuary.  Frontiers in Marine Science, 4: 197.

And watch this space, as the remaining three PhD papers should be going up online in the next few months!

 

 

Ph-inishe-D: PhD Submitted!

The sun is shining, the sky is brighter, the birds are singing…

Since I submitted my PhD for examination, the world has become a happier place.

I actually submitted just over five weeks ago, but only now am I really starting to feel human again.  Part of the reason for this was that submission took place two weeks after I finished writing the thesis, thanks to an unforeseen administrative error.  This resulted in me turning up at uni, support squad in tow, and being told that I wasn’t allowed to submit.  Hello world crashing down…  But t went in, eventually.

PhD submission day, complete with support crew and toy dolphins! (Note, this was taken prior to submission debacle - hence manic expression of relief on my face)

PhD submission day, complete with support crew and toy dolphins!  (Note, this was taken prior to submission debacle, hence manic expression of relief on my face)

The other reason for my vacant expression of the past few weeks is that completing a PhD is exhausting.

I’ve seen my fiance finish his PhD.  I’ve seen some of my best friends finish their PhDs.  I’ve seen my officemates finish their PhDs.  I thought I had a pretty good idea of what to expect.  But it’s a unique experience, individually tailored, and nothing can really prepare you for The End.  I still can’t particularly face writing about it now (why burst this happiness bubble?), but one day I’ll explain the whole thing in detail.  Probably after I’ve dealt with the eventual examiner comments.

So now for my long-awaited period of rest and relaxation!  Well, not quite…

I’ve spent the past six weeks on a Publication Scholarship, which essentially means the uni has been paying me to turn my thesis chapters into scientific publications.  One is submitted, another two should sneak in this week, and the final paper is due for submission in April.  Around this, I have also been working on grant applications, giving presentations, submitting conference abstracts, preparing for a trip to Europe, and attending a surprising number of meetings.  The last has actually been the most daunting – after several months of PhD lockdown, limited social interaction and working from home, it’s weird having to converse with dozens of people at once.  This combined with the ‘mushy brain syndrome‘ typical of recently-submitted PhD students has left me with a strong need to lie down in a dark room after meetings.  But I’m slowly improving.  And as much as I love my PhD project (no, I didn’t end up hating it!), it is actually quite nice to work on other things and bounce between different research projects.

Now I just need to keep my fingers crossed for some successful grant applications so this research can continue…

New Video: The Dolphin and the Sound

As you know, I’m fortunate enough to be sister to the amazing wildlife film-maker Lisa Marley.  I’ve written about her documentary on Scottish raptor poisonings here previously (and incidentally, this work is currently touring the film festivals – scroll to the end for details!).  But in June, we actually worked together on a short film project as part of the Aquatic Noise 2016 conference I attended in Dublin.

The conference held a public evening involving short lectures around the theme of underwater noise, and also invited submission of videos on this topic.  Lisa and I worked together to create a short film describing the effects of human noise on coastal dolphins, similar to the idea of my 3MT speech – but with much cooler visuals than just me standing on a stage!

I wonder if anyone recognises the locations involved in this production?  Suggestions on a postcard please…!

So now I have a professional video to highlight my research AND had the awesome experience of working on a creative project with my sister.  And all without a single sibling squabble to be seen!


“Red Sky on the Black Isle” lastest screenings:

  • Hebrides International Film Festival (on Lewis, Harris, Uist and Barra; UK):  14-17 September 2016
  • Aberdeen Film Festival (UK):  17 October 2016
  • Festival de Menigoute (France):  27 October 2016

Follow the film’s Facebook page for more updates!

Conference Attendance – Aquatic Noise 2016

Last month I had the privilege of flying to Dublin to attend this year’s “Effects of Noise on Aquatic Life” conference, also known as Aquatic Noise 2016.  Not only was I able to present the first two chapters of my PhD thesis, but I was able to contribute to the conference itself as part of the Media Committee.

Members of CMST attending the Aquatic Noise 2016 Conference in Dublin

Members of CMST attending the Aquatic Noise 2016 Conference in Dublin

Over 300 people from 23 countries attended the week-long conference, including representatives from universities, government research institutions, fisheries, and industry groups.  Talks were given regarding a variety of acoustic topics, including descriptions of noise sources, sound propagation analyses, and the responses of numerous animal species.  Conference attendees also included ten members of my lab, the Centre for Marine Science and Technology (CMST).  It was great to head overseas as a team, presenting our research to an international audience!

Poster PicMy talk was part of the student speed sessions – five minutes to describe our research and findings, followed by an evening poster session where we had the chance to answer questions, engage in discussions, and network.  I feel the talk went well, despite my nerves.  I’m much more used to interactive presentations involving members of the public than presenting to seasoned professional scientists.  But even without any audience participation, dramatic displays or unexpected explosions, I think I did alright!  You can view my poster by clicking here:  Marley AN2016 Poster.

Marley Dolphin Presentation AN2016

Being on the Media Committee meant I was part of a team responsible for promoting the conference, particularly our public evening.  This was attended by over 70 members of the public, who had an evening of lectures and short videos (more about this in my next post!).  I was also involved in live-tweeting the conference.  This was a way of extending the conference reach to the masses, scientists or otherwise, by posting summaries of each talk on Twitter under the conference hashtag.  I’ve now summarised each day of talks as a separate story using a combination of Tweets from myself and other conference attendees, which are available for anyone to read using the links below:

https://storify.com/sarahmarley86/aquatic-noise-2016-day-1

https://storify.com/sarahmarley86/an2016-effects-of-noise-on-behaviour-and-physiolog

https://storify.com/sarahmarley86/aquatic-noise-2016-day-3

https://storify.com/sarahmarley86/aquatic-noise-2016-day-4

https://storify.com/sarahmarley86/aquatic-noise-2016-day-5

New Paper: Fish Choruses in Darwin Harbour

ICES Journal ArticleAs well as working on my PhD, I’m also lucky enough to be involved in other projects at the Centre for Marine Science and Technology (CMST) from time-to-time.  Now the results from one of these projects have been published in the ICES Journal of Marine Science.

A couple of years ago, I was asked to review acoustic data from Darwin Harbour, in the Northern Territory of Australia.  I’ve written before about the variety of sounds produced by fish, and in the Darwin data we found oodles of different fish choruses.  Fish sounds can be species and size specific, and such en masse sound production often has behavioural associations, for example by corresponding with feeding or reproduction.

So there is a lot of information to be gained by listening in on fish!

In this paper, we recorded nine different types of fish choruses and investigate their patterns of occurrence.  Environmental conditions such as lunar patterns, time of sunset, temperature, tidal information and salinity levels all contributed to the context of when particular choruses were heard.  These results are useful not only to scientists but also to fisheries managers, as it provides improved knowledge regarding species distribution, fish habitat-use, identifies spawning seasons, and monitors behaviour.  Which, when you can’t see fish below the surface, is often difficult data to collect!

The full paper (doi: 10.1093/icesjms/fsw037) is available here.