Understanding the Mass Stranding of Whales on Scottish Shores

In 2023, a mass stranding of 55 long-finned pilot whales occurred on Tràigh Mhòr beach, Isle of Lewis, leading to their death. A report from the Scottish government’s Marine Directorate concluded that the stranding was primarily due to the whales' social behavior rather than external disturbances such as trauma or noise pollution. The whales were following a female in the midst of a difficult birth, which prompted the pod to enter shallow waters where they ultimately became stranded.

The Guardian

The investigation led by Dr. Andrew Brownlow of the Scottish Marine Animal Stranding Scheme (Smass) highlighted that the incident was the result of a combination of biological, behavioral, and environmental factors. The report emphasized that mass strandings are rarely caused by a single factor. Instead, they often arise from the interplay of individual physiology, group social behavior, and external marine conditions. The whales' strong social cohesion likely contributed to their fatal decision to follow the distressed female into shallow waters, where they encountered an "acoustic trap" that hindered their ability to navigate back to deeper waters.

The Guardian

The findings from the Isle of Lewis incident are significant as they may inform future investigations into similar events. Notably, a subsequent stranding of 77 long-finned pilot whales occurred almost a year later on Sanday beach, Orkney, which is still under investigation by Smass. The organization has reported a concerning trend, indicating that mass strandings of whales and dolphins in Scottish waters have increased in scale and frequency by up to 300% over the past 30 years.

The Guardian

While the Smass report concluded that human-created sound was not a factor in the Isle of Lewis stranding, concerns remain regarding the impact of military and industrial noise on marine life. Recent incidents involving the stranding of 10 sperm whales in various locations, including Cornwall, Denmark, and Germany, have raised alarms among scientists. These incidents suggest that sound pollution may be driving deep-diving whales into shallow waters, where they face challenges in feeding and survival.

The Guardian

Dr. Andrew Brownlow stated, “The Tolsta event is a reminder that mass strandings are rarely the result of a single cause. Rather, they emerge at the intersection of individual physiology, group social behaviour and external marine environmental conditions.” This perspective underscores the complexity of understanding whale strandings and the need for continued research to mitigate future occurrences.

The Guardian

The investigation into the stranding of the 77 long-finned pilot whales on Sanday beach is ongoing, with Smass continuing to monitor trends in whale strandings. The organization aims to enhance its understanding of the factors contributing to these events, which may ultimately aid in the conservation of marine species and their habitats.

The Guardian