Natalie Sinclair

Natalie Sinclair

Marine Science, University of St Andrews

Tenure since 2017

Decibels and Whistles: The masking effect of noise on wild bottlenose dolphin (Tursiops truncatus) communication

Underwater sound is an important source of information for marine mammals. Marine mammals use underwater sound to learn about their environment, listen for predators and prey, and to communicate with others. However, marine mammals also hear sounds that they are not interested in such as waves crashing, rainfall or the sound of other animals swimming. These uninteresting sounds come together to create background noise. Marine mammal communication sounds (or signals) such as whistles and songs have evolved to be heard within this natural noise. However, more recently, humans have added noise from many different sources such as shipping and marine construction. This new and varied noise can cause marine mammals not Natalie Sinclairto hear each other because the new noise masks the sound, such that the intended receiver cannot hear or understand the sound. While a sound may still be heard (or detected) in the presence of noise, portions of the call or song may be masked, making the sound unrecognizable. This masking can cause problems, especially in social animals such as the bottlenose dolphin. So far, research into masking by noise has taken place in captivity and has focused on determining when an animal can no longer detect a sound within noise. This study will be the first to investigate masking of natural sounds in wild marine mammals. Furthermore, this study will be the first to examine when a signal in noise goes from being detected and understood to detected and not understood. 


Natalie graduated first in her class from the University of Glasgow with a first class integrated Masters with honours degree in Marine & Freshwater Biology, for which she was awarded the Graham Kerr Memorial Award for Excellence in 2016. Natalie was also the highest ranked student in 3rd and 4th year of her degree. She was accepted onto the competitive masters in science programme through which she worked for one year in industry at Scottish Natural Heritage where she gained experience of conservation policy while working on a range of projects including leading a commissioned research project. Natalie has shown initiative in attainment of further research experience in all her summer breaks at university. This has included working as a research assistant, gaining a Carnegie Vacation Scholarship to perform research in bioacoustics and also securing a Reed Eselvier New Scientist Scholarship to complete an internship in cetacean research. This additional work has surmounted as experience and skills in a diverse range of research methodologies from respirometry to acoustic analysis, genetic analysis and camera monitoring.

Natalie’s Carnegie Vacation research project used passive acoustic monitoring to detect individual variation in water rail (Rallus aquaticus), her honours project explored haul-out physiology in moulting harbor seals (Phoca vitulina) and her master’s project used remote time-lapse photography to monitor attendance of guillemots (Uria aalge) outside the breeding season at two colonies in the Northern Isles of Scotland.