Dept. to assist with investigation into Cuvier's Beaked Whales Deaths

7th Sep 2018

7th September 2018

After a number of emails to the Deptartments of Defence and Foreign Affairs, the Tánaiste and Minister of Foreign Affairs, Simon Coveney has "instructed his Department, in consultation with the National Parks and Wildlife Service, to initiate discussions regarding the large number of stranded Cuvier's beaked whales with the UK authorities". He states that he shares the concerns expressed by the Irish Whale and Dolphin Group and "thanks the IWDG for bringing this to our attention". The Department also stated it would be pleased to update us once such discussions have been finalised.

The number of Cuvier's beaked whales stranded on the Irish coast continues to rise and now stands at 19 and at least 16 in Scotland which has made it the largest UME (unusual mass stranding event) of beaked whales recorded in the stranding history in the UK and Ireland. The UK have recently stated they will launch an investigation.  Unfortunately the condition of the stranded individuals precludes post-mortem examination to assess cause of death but drift modelling to identify their provinance and discussions with the British Navy and NATO should be included in this investigation. 

The IWDG welcome the Departments response and look forward to hearing from them.


26th August 2018

Cuvier's Beaked Whales Ziphius cavirostris appear to be one of the more common beaked whale species but are seldom seen alive, with most information about them found by examining stranded animals. They live in deep water offshore, typically around deepwater canyons near the edge of the continental shelf and regularly dive for 20-40 minutes following a series of breaths at the surface. They are thought to be the deepest diving of the whales and in 2014 one animal was tracked to a depth of 2,992 metres with 138 minutes between breaths!

Between 3 August and 22 August 2018 a minimum of 16 Cuvier's beaked whales were found washed up dead on the Irish coast (minimum as it excludes animals reported which may have been already recorded, carcasses washed ashore unreported and carcasses which may have sunk at sea before washing ashore). During the same period, at least 13 were found in Scotland and 2 in Iceland. Previous studies have suggested that only a small number of dead animals actually get washed ashore and recorded, so the number of dead animals may be significantly higher.

The collage shows some of the photos of 16 strandings sent to IWDG by members of the public. Nothing on this scale has been recorded for this species in Ireland before although it is worrying that there was 11 recorded strandings of this Cuvier's beaked whales in Ireland over several months in late 2014 and 2015. In previous years, annual strandings for this species would typically have been 0 - 3 for an entire year. No cause of death has been established for any of these animals, mainly due to the fact that all washed ashore in poor or very poor condition, so all we are left with is speculation. The Irish strandings were recorded in Galway (3), Mayo (5), Sligo (3) and Donegal (5) and the condition of the carcasses suggested all may have died around the same time. This makes causes such as disease, plastic ingestion etc seem unlikely as these would tend to be spread out over a longer time period and perhaps geographical range. The behaviour and distribution of this species makes large scale fisheries interaction also seem unlikely.

While we can't say for sure, we do know from events around the world that beaked whales are susceptible to death or injury directly (temporary/permanent hearing damage) or indirectly (gas embolism - the 'bends' possibly due to a drastic change in behaviour) due to extremely loud man-made oceanographic noise such as that produced by low and mid frequency naval sonar and certain types of acoustic survey used to examine the sea floor and below. Mass strandings of beaked whales coincidental with naval exercises have been recorded in Greece, the Canaries and the Bahamas (The Irish navy does not use these types of sonar). While no definite cause has been established, this needs to be recognised as an unusual mass stranding event (UME) in an effort to identify the cause(s) and perhaps prevent a future re occurrence.

Mick O'Connell

IWDG Strandings Officer