The death of two whales who washed up on beaches in East Lothian may have been connected to a massive military war games mission off the Scots coast.
The Sowerby beaked whales were stranded on the shoreline in Musselburgh and Gosford earlier this month.
A team of experts from the Scottish Marine Animal Strandings Scheme carried out necropsies on both the stricken animals to determine their cause of death.
No signs of infection, disease, boat strike or entanglement were discovered prompting fears they may have died from decompression sickness caused by underwater noise.
A massive international war games exercise - Groupex - took place off the east coast of Scotland between September 21 and October 15.
It formed part of the Exercise Joint Warrior 2020 mission which saw more than 6000 military personnel and dozens of warships from 11 countries taking part in a range of crisis and conflict scenarios.
The Scottish Marine Animal Strandings Scheme has now made a formal request to the Ministry of Defence for activity logs in the area.
They are also examining other sources of noise in the region.
A statement from SMASS said: “Given how sensitive beaked whales are to underwater noise, specifically naval sonar, we have to consider noise-mediated decompression sickness as a possible cause for these two strandings.
“We are therefore in the process of trying to find data on sources of noise in this region, including putting a request for activity logs to the MOD following the recent Joint Warrior naval exercises.
“These were both sub-adult males with significant trauma from the stranding process, but no other clear underlying infection or disease and, thankfully, no indication of entanglement, boat strike or ingestion of marine debris.
“Neither animal had fed recently but both were in reasonable body condition, suggesting an acute cause of death.
“Notably, both animals showed an unusually high number and distribution of gas bubbles throughout the tissues- especially lung, liver and intestinal mesentery.
“Whilst gas bubbles are not an uncommon finding during post mortem examinations, and can be a result of either decomposition or emphysema from the stranding process, a large number of bubbles, especially in deep diving species such as beaked whales, is suggestive of nitrogen emboli and decompression sickness (DCS).”
We previously told how the Exercise Joint Warrior war games were thrown into chaos just days before they were due to begin on the west coast of Scotland.
A pod of northern bottlenose whales were spotted in the Gareloch at Faslane naval base, near Helensburgh, which houses the UK’s trident nuclear subs, on October 1.
A team of rescuers were called in to assist in moving the whales back out to open water to make way for the Royal Navy ships.
After three failed attempts at herding the whales, the mission took place after it was decided that they were in deep enough water.
The MOD has been contacted for comment.