Killer whale, John Coe in Dingle Bay, 5th March 2018.

5th Mar 2018

Yesterday morning, Monday 5th March was a rare day of calm seas, but was all the motivation that IWDG's Nick Massett needed to brush the snow off his RIB and headed out into Dingle Bay, with crew Britta Wilkens and Simon Crompton to see what the cetacean activity was like. They weren't disappointed.  Initially they picked up a small group of c20 common dolphins, followed by a solitary early season minke whale. But 10 minutes later his gaze was diverted to a pair of very tall, black dorsal fins, which can really only mean one thing....killer whales.

At a glance, Nick knew that one of the duo was perhaps the best known killer whale in these Isles, "John Coe", or W01 of the Scottish West Coast Community Group, whose core feeding area is the Hebridean Isles. John Coe is relatively easy to identify from the large notch on the base of the trailing edge of his dorsal fin (see animal to left of top image).  Colleagues from the Hebridean Whale & Dolphin Trust can confirm that John Coe was seen exactly seven days ago in Scottish waters, as he was observed this day last week off the Isle of Mull, which tells us a lot about the movements of this highly mobile apex predator. During this mornings encounter, John Coe was travelling with another adult male killer whale, and they travelled 4.5 nautical miles in a southerly direction over 37 minutes. All images attached here were taken by Nick during this morning's memorable encounter.

Killer whale sightings in any Irish waters are rare events, and they seem to be getting rarer. The chart below plots the trend in sightings of killer whales Orcinus orca validated by IWDG in Irish waters over the past decade, and assuming that the sighting scheme can detect gross trends, then the limited data we have suggests that in recent years anyway, sightings of killer whales in Ireland's whale sanctuary are on the decline. The reason(s) for this are uncertain, but it has long been known that this group which comprised nine individuals may soon become extinct as they've had zero recruitment (births) in well over 25 years. In Jan 2016 one of the adult females belonging to this group, known as "Lulu", was found dead on the island of Tiree, Scotland, and is thought to have died after becoming entangled in fishing rope in January 2016. But the post mortem examination showed she had one of the highest concentrations of toxic pollutants ever recorded in a marine mammal. Andrew Brownlow, head of the Scottish Marine Animal Stranding Scheme, said: “Given what is known about the toxic effects of PCBs, we have to consider that such a high-pollutant burden could have been affecting her health and reproductive fitness.”

Anyway, this morning's sighting is a timely reminder that even in the midst of weather chaos, there is always the potential to observe wonderful marine wildlife, somewhere along the Irish coast, if you have calm seas and a good platform. Unlike other species such as our minke and humpback whales, killer whales are unpredictable and sightings of them are hard earned. So the trick to spotting them in Irish waters is really quite need to put in plenty of observation time up on those cliffs!  As always IWDG really appreciate any sighting reports of any cetacean species in Irish waters; and sightings with good quality images or video are particularly useful.

Big thanks to Nick Massett for sharing these wonderful images with us, and for his dedication in recording and reporting his observations to IWDG.


Chart: Number of Killer whale sightings in Irish waters in past decade, © IWDG 2018

By Pádraig Whooley, IWDG Sightings Officer.



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