Sperm whale washed up at Balchladich Bay
Late in the afternoon of Tuesday 18th March 2014 Andy Summers was notified of a large dead whale which had stranded on the beach at Balchladich Bay that day. When Andy arrived at Balchladich a bit later the light was failing and the whale, which was in an advanced state of decomposition, was constantly being rocked in the high spring tide so he was not able to get too close.
Andy did manage to measure the width of the tail fluke and it was an impressive 3.5 metres with a clear notch at the centre, he also approximated the full length of the whale at 14 metres. No dorsal fin was obvious and there were clearly no throat grooves. All these indicators made Andy think this was a Sperm whale (Physeter macrocephalus).
As should be done with all whale or dolphin strandings whether dead or alive, Andy reported this one to the Scottish Marine Animal Stranding Scheme (01463 246043 or email stranding@sruc.ac.uk). From the information available the SMASS were not certain the animal was a Sperm whale and asked if Andy could revisit and check for teeth in the lower jaw – the lower jaw of a Sperm whale is narrow and contains 20 to 26 pairs of conical teeth which fit into sockets in the top jaw; there are no teeth in the top jaw. Sperm whales are not baleen whales, unlike the Fin whale which washed up near Raffin in 2007, but are the largest member of the odontocete (toothed whales) family.
We accompanied Andy on 19th March but could not see any teeth and were unable to pull the lower jaw open to look inside. However the following day, 20th March, before we could go back with a suitable lever, Jim Galway from Clachtoll arrived at Andy’s office with photographs taken earlier on the 18th when the whale’s mouth was open. These photos quite clearly showed four large conical teeth and confirmed Andy’s original identification which SMASS also then agreed with. It is possible that the other teeth had become dislodged after the whale had died but was still at sea.
This is the first recorded stranding of a Sperm whale in Assynt and sightings in the area of the Minch are very rare as, being a deep water species, they are usually seen well west of the Outer Hebrides.
While sperm whales have an extensive distribution worldwide the population in the North Atlantic is not known. They are found throughout all the world’s deep oceans from the equator to the edge of the polar pack ice and also occur in the Mediterranean Sea. Their main breeding areas include the Caribbean and around the Azores.
Sperm whales in the past were the target of commercial whalers because of the high value spermaceti oil (hence their name) inside their heads, which was used to make candles. This hunting undoubtedly depleted populations, but at the moment this species appears to be fairly abundant in all oceans. More modern threats include toxic pollutants such as organic pesticides which accumulate in their tissue and organs, entanglement in fishing nets and other marine litter together with physical damage from intense sounds, seismic, military or oceanographic detonations all of which interfere with their complex echolocation and use of sound.
D and A Haines