A dead whale that washed up on a beach in the Highlands suffered an agonising death after becoming snared in fishing gear.
A report into the incident also highlighted a “real concern” that such entanglements are having a “significant impact” on the population of humpback whales in Scottish waters.
The juvenile humpback whale was found on a sand bank at Loch Fleet nature reserve, in Sutherland, on May 4.
In a report, the SMASS said: “We are confident the cause of death was drowning due to entanglement, and based on the lesion pattern, most likely in rope around 12mm in diameter.
“No rope remained attached to the carcass – only abrasions and bruising where the rope had dug into the skin remained.
“The extent of these lesions suggested the animal had struggled to get free for several hours before running out of energy and drowning. There was around 100 litres of fluid around the lungs, likely aspirated seawater.
“This young animal was otherwise in very good body condition and had been feeding well but not recently.”
‘Not the first time’ whale entangled
The necropsy showed it was not the first time the whale had been entangled, as there was evidence of old, healed scars on the tail and tailstock where the rope had dug in.
“Somehow, the animal had become free and the wounds had had time to heal, this time sadly it was not so lucky,” the report adds.
“As with many of the entanglement cases reported to SMASS, carcasses wash up without any material attached – it seems they are cut out at sea and only tend to wash up when there is an onshore wind. Although we can’t be 100% positive about the origin of the rope which entangled this animal, the pattern would be highly consistent with creel rope.
“Humpback entanglements reported to SMASS are rare – fewer than 20 cases over the past decade – but, of those we were able to examine, entanglement was the cause of death in every single one of them.”
Action needed to reduce entanglements
Recent research by the Scottish Entanglement Alliance – made up of academics, NGOs, government officials and the fishing industry – suggests around 95% of entanglements go unreported.
Researchers said creel fishers are working with them to identify ways to limit harm to marine mammals, but stressed more is needed to be done “urgently”.
SMASS added: “There is also a real concern that mortality due to entanglement is having a significant impact on the populations of humpback whales in Scottish waters.”
Humpback whales were once hunted to the brink of extinction in Scottish waters, but in recent years the Hebridean Whale and Dolphin Trust has noticed an increase in the number of sightings.
It is unknown whether this represents a genuine increase in population size, a range shift into Scottish waters, or more vigilant reporting from members of the public.
However, research published earlier this year suggested more than 30 whales are snared by fishing gear in Scotland every year.
Conversation