Sperm whale sighted off Skye

Sperm whale off Skye - Photo by Calum MacAskill

September 2011. A Sperm whale, the largest predator on the planet, was sighted in the Sound of Raasay by local man Calum MacAskill and his wife. Mr and Mrs MacAskill were returning home from a wildlife boat trip to the Isle of Rona when their attention was drawn to a splash. Through the binoculars they spotted a tail fluke and knew it was something special, "It took a few minutes to realise that we were not looking at a minke whale but had the chance of a lifetime to watch and photograph a magnificent Sperm whale. It was a privilege and an unforgettable experience."

First sighting for 3 years
Sperm whales sightings are rare off Scotland's west coast, but not unheard of. The Hebridean Whale and Dolphin Trust (HWDT) have received a number of sightings of Sperm whales since their records began, the last off Canna in 2008. The majority of these sightings come from The Minch and off Skye; where the sea bed reaches depths of over 100 metres.

Sandra Koetter, HWDTs Sightings Officer, explains, "Sperm whales are a deep-diving cetacean, making long dives to hunt for prey, which is mostly cephalopods such as squid or cuttlefish. Incidentally another deep-diving cetacean, the northern bottlenose whale, was also reported in the Sound of Raasay during August".

First Sperm whale sighting off Scotland for 3 years. Photo credit Calum MacAskill.

Information from Mr MacAskill indicates that the Sperm whale, which HWDT believes is a male, was feeding; he reported, "The whale was on the surface for approx 15 minutes before it dived with its fluke high out of water. He resurfaced after about 20 minutes."

Mr MacAskill and researchers at HWDT both noticed that the Sperm whale had uncharacteristic circular indents behind his blowhole and white colouration on his dorsal fin. Dr. Jonathan Gordon, one of HWDTs Directors and Sperm whale expert, said he'd never seen an animal with a dent like that before. He added, "If the animal was wounded by a ship collision or entanglement then it seems to have healed. The striking white on the dorsal fin appears to be a result of wear rather than calluses (which are more common in females)."

Whilst HWDT cannot confirm whether this animal has been injured due to an earlier ship strike, or possible entanglement as a juvenile, both boat collisions and entanglement are threats to cetaceans and other marine life. In recent years there have been many reports of boats hitting, basking sharks in particular in waters around the west coast; and entanglement in discarded ropes, lines, packing tape and other litter is prevalent in waters around the UK.

Nevertheless, HWDT have raised concerns and have contacted the British Divers Marine Life Rescue to alert them of a possible stranding. Another threat, to deep diving cetaceans in particular, is excessive underwater noise. With the Joint Warrior military exercise due to begin in October throughout the West Coast, HWDT are concerned that the intense noise generated by military sonar will have an adverse affect on the cetaceans found in the area and asks the public to be particularly vigilant for unusual cetacean behaviour during October.

Sightings like this remind us that the waters off the west coast of Scotland are extremely special, playing host to a great variety of species. Reporting sightings to HWDT will contribute to our knowledge of species distribution and abundance within the area. If you are lucky enough to spot a cetacean, please report your sighting online at www.hwdt.org.