Unlocking the enigma of Scottish harbour porpoise fine-scale habitat use

Harbour porpoises (Phocoena phocoena) are the most abundant and widespread cetacean in Scottish waters but are vulnerable to anthropogenic pressures such as noise from aquaculture and wind farm construction, bycatch in fisheries, and climate change. As a result, various national and international laws and agreements aim to protect porpoises from these pressures. In addition to general protection and inclusion in decision making processes, porpoises were the reason for the designation of one of Europe's largest protected areas, the cSAC along the west coast of Scotland in 2018.

Porpoises are found in a range of habitats throughout Scottish waters. However, these habitats are not used equally with some favoured year round and others at particular times. This project will seek to understand the drivers for these differences, making use of existing datasets collected using passive acoustic monitoring (PAM). PAM is a commonly used technique to establish presence and relative abundance of echolocating porpoises in specific locations over extended time periods, using fixed or towed underwater acoustic detectors (hydrophones). Across both the east and west coasts, several projects have been collecting PAM data from fixed stations for up to a decade. While these data have all been collected for slightly different purposes, they have all used similar methods and so this project seeks to consider them at a more holistic level to better understand porpoise ecology and how and why porpoises use different environments. Most Scottish PAM studies to date have focused on large-scale trends in usage, however their use has also revealed intriguing patterns of habitat use that vary at fine-scales (<1km). Some of these differences have been found to occur over subtly different seabed habitats, depths and time scales. Integrating these data with environmental parameters is likely to help reveal and provide insights into which fundamental ecological and/or anthropogenic drivers underpin porpoise distribution and habitat use in Scottish waters.

In this project, the student will have the opportunity to combine and explore previously independent datasets collected for a variety of reasons from across Scotland. Doing so will provide opportunities to better understand biases in standard survey methods and reveal wider patterns of habitat use by porpoises. In addition there may be the opportunity to collect new data to better test some of the environmental relationships that emerge. Discoveries associated with this project have the potential to provide information for conservation management efforts particularly in terms of improving monitoring strategies.

This project will bring together previously disparate datasets, the student will deal with large datasets and the inherent challenges these bring (particularly extensive manipulation and error-checking). Analysis of these datasets will likely involve sophisticated statistical modelling approaches.