Cetacean strandings on the Scottish coast: coastal accessibility factors lead to underreporting

Abstract

Introduction
Cetaceans are abundant in the waters surrounding Scotland. These animals are occasionally found stranded along the coastline, and data recording the locations of these stranding events has been collected over the past several decades. There are many factors which may influence the location in which an animal is reported to have stranded. Some of these factors are environmental and influence the location of a stranding. Others relate to human activity and influence the likelihood of the event being reported.

This study examines whether stranding reports are influenced by human accessibility, thereby leading to an incomplete understanding of the true prevalence of strandings.


Research aims
Three central research questions are posed, exploring whether areas with limited coastal access may have underreported strandings. The questions relate to whether the frequency of reported strandings is impacted by: human population density, road networks, cliff height.

Methods
Each hypothesis is initially examined using visual data analysis to compare maps of stranding locations with the variables of interest. Geographically weighted regression modelling is then carried out with various combinations of the variables. The results of each model run are examined to determine which combination of variables best describes the stranding locations.


Key Findings
The results suggest that there is a relationship between reported strandings and road network density. Areas with greater road access exhibit higher reported stranding densities, which may suggest that strandings are underreported in regions with poor road access.


Human population density and – to a lesser extent – coastal topography also showed a visual relationship with strandings density. However, these factors did not significantly improve model fit. Therefore, the results of the study do not support a strong relationship between these factors and strandings density.


Implications for Conservation
These findings suggest that the current data on cetacean strandings may be subject to underreporting in areas with sparse road networks. Addressing this bias could improve the accuracy of stranding records, leading to a more comprehensive understanding. This can inform conservation strategies and aid efforts to protect these mammals and their habitats.

Popular Abstract

Scotland is famous for its untamed landscapes, rugged coastline and dramatic oceans. Our coastal waters are home to healthy populations of cetaceans, from the small porpoise to the enormous sperm whale. But could it be that the remoteness of the land leads to a poorer understanding of the coastline and therefore these marine mammals?

Every year, dozens of whales, dolphins and porpoises are found stranded along Scotland’s coast. These animals are discovered by beachgoers, dog walkers and hikers and are reported through a volunteer network. Over the years, this valuable data has enabled us to build up an understanding of where the animals most often strand. This can in turn help us to understand more about the health of our seas, and the distribution of cetaceans around our coast.

However, a stranding can only be reported if there is someone there to report it. It is possible that there could be many unknown strandings in remote parts of the country that are never spotted, and therefore never reported. This could mean that there are gaps in our understanding of where strandings truly occur.

The aim of this study is to explore how these gaps might be caused by how many people are able to access the shore. For example, areas with low human population may have fewer reported strandings. Similarly, if there are few roads in an area then it may be more difficult to reach the coast and discover strandings. It could even be the case that access to the shore is made difficult by high cliffs.

To understand these factors, maps are created to illustrate the most common stranding locations. These are then compared to similar maps showing human population, road networks, and cliff height. Statistical models are also used to understand the precise relationships between the various factors.

The study finds that strandings are less likely to be reported in areas that are poorly served by roads. In particular, the north-west coast shows a very sparse road network and a lower number of strandings than the rest of the country. There appears to be some relationship with human population too, although this is not as strong.

The outcome of this study suggests it is possible that we could adjust our existing data, or perhaps improve monitoring efforts in areas that are suspected as being underreported. In the long run, this could help us to devise new ways of protecting these marine mammals and their habitats around our coast.

• author: Macdonald, Kathleen Isla
• supervisor: Jonathan Seaquist; Oskar Löfgren
• organization: Dept of Physical Geography and Ecosystem Science
• course: GISM01 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Earth and Environmental Sciences
• keywords: geography, GIS, geographically weighted regression, cetacean, whale, dolphin, stranding, Scotland, coast, spatial analysis
• publication/series: Master Thesis in Geographical Information Science
• report number: 186
• language: English
• id: 9186201
• date added to LUP: 2025-03-10 09:56:29
• date last changed: 2025-03-10 09:56:29