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!
Dr Sarah Marley 