Dear MARMAM colleagues,
On behalf of my co-authors I would like to share our recent publication in Royal Society Open Science (open access):
Oihane Fernandez-Betelu, Virginia Iorio-Merlo, Isla M. Graham, Barbara J. Cheney, Simone M. Prentice, Rachael Xi Cheng and Paul M. Thompson (2023) Variation in foraging activity influences area-restricted
search behaviour by bottlenose dolphins. Royal Society Open Science. https://doi.org/10.1098/rsos.221613
Abstract
Area-restricted search (ARS) behaviour is commonly used to characterize spatio-temporal variation in foraging activity of predators, but evidence of the drivers underlying this behaviour in marine systems is sparse. Advances in underwater
sound recording techniques and automated processing of acoustic data now provide opportunities to investigate these questions where species use different vocalizations when encountering prey. Here, we used passive acoustics to investigate drivers of ARS behaviour
in a population of dolphins and determined if residency in key foraging areas increased following encounters with prey. Analyses were based on two independent proxies of foraging: echolocation buzzes (widely used as foraging proxies) and bray calls (vocalizations
linked to salmon predation attempts). Echolocation buzzes were extracted from echolocation data loggers and bray calls from broadband recordings by a convolutional neural network. We found a strong positive relationship between the duration of encounters and
the frequency of both foraging proxies, supporting the theory that bottlenose dolphins engage in ARS behaviour in response to higher prey encounter rates. This study provides empirical evidence for one driver of ARS behaviour and demonstrates the potential
for applying passive acoustic monitoring in combination with deep learning-based techniques to investigate the behaviour of vocal animals.
Please, do not hesitate to contact me should you have any questions regarding our work (oihane.fernandez@abdn.ac.uk).
Kind regards,
Dr Oihane Fernandez-Betelu
Research Fellow
Lighthouse Field Station,
Institute of Biological & Environmental Sciences,
University of Aberdeen,
Cromarty IV11 8YL.
Tel: 01381600548
