A young humpback whale found drowned off the coast of Mull died after swimming into a fish farm, vets believe.
Scotland’s first post-mortem of a humpback whale was carried out by Dr Andrew Brownlow from Scotland’s Rural College (SRUC). The results suggest the animal became trapped under a salmon pen and subsequently drowned.
Dr Brownlow said: “It is obviously very unfortunate when marine animals become entangled in this way, but it is thankfully still a relatively rare occurrence. We are still running tests on this case to investigate if there was any underlying reason which could explain this quite unusual behaviour, however it is possible this was simply a young, inquisitive, maybe hungry animal who took a wrong turning.”
He was aided by staff from the Hebridean Whale and Dolphin Trust and Aberdeen University’s Lighthouse Field Station.
SRUC coordinates the Scottish Marine Animal Stranding Scheme. Every year more than 400 marine mammals are stranded around the coast of Scotland and any cases suitable for post mortem are examined by the project.
There have only been six recorded humpback whale strandings in Scotland since 1992 (17 in the UK) and this is the first where a post mortem has been carried out.
The whale was a juvenile male, almost 23ft long and weighing just under seven tonnes. The stomach lining suggested little solid food had been ingested in the past so it is possible that the whale was still receiving milk from his mother.
The animal was found dead beneath the nets of a salmon pen. Due to the logistics involved in recovery it was around 36 hours after discovery before the animal could be post mortemed, however it was still in relatively fresh condition and therefore a reasonably confident diagnosis could be reached.
The observed pathology and stranding history would be consistent with the whale becoming trapped beneath a salmon pen and subsequently drowning.
The report also notes that young humpback whales are very inquisitive creatures which could explain why the animal was attracted to the salmon farm located at Fishnish on Mull.