COTF6 Day 3: A Killer Spree!

We found ourselves over the South West Porcupine SAC at 8am this morning in order to retrieve Static Acoustic Monitoring (SAM) devices which were moored back in May (supported by Woodside) in order to gather acoustic detections of cetaceans present there throughout the summer months. After the SAM devices were safely on board we steamed North East across the top of the Porcupine Seabight to the second SAM site of the day, conducting continuous visual surveys in between.

Crew of the R.V. Celtic Explorer retrieving the SAM equipment (c) Róisín Pinfield

Frequent sightings of fin whale blows were present from the off, with at least three individuals confirmed in relatively quick succession. After that, baleen whale activity ceased for the day but the cetacean observation team was kept busy with frequent sightings of common dolphins with groups of up to 60 animals including calves coming in to inspect the vessel. Another two ocean sunfish were also logged today, drifting by at close range.

And so the day continued, with sightings tipping away at a fine pace. Nobody would have predicted the events that would unfold after lunch however when at 13:30 the call came over the walkie-talkies from Rossa and Róisín of “KILLER WHALES!!!”. Two enormous, black, triangular dorsal fins came looming out of the water together on our starboard side no more than 50m out! Needless to say our full attention was now focused on them! The ship was manoeuvred in order to attain photo-ID pics (which now became our top priority) but the whales did us a massive favour and made several passes alongside us at close range allowing for excellent views of the eye masks, dorsal fins and on some occasions, tail fluking! As the minutes ticked by at incredible speed our count increased from two to three to five to seven. A mix of large fins and medium to small fins were noted, indicating a family group. After 20 minutes or so of fantastic viewing with photo-ID images secured, the group of killer whales split off on their own track and we left them to it continuing back on our survey route.

Killer whale (c) William Hunt

Killer whale (c) Joanne O'Brien

Killer whale tail fluking (c) Joanne O'Brien

Killer whale tail fluking (c) Joanne O'Brien

A superb encounter with one of the world’s most instantly recognisable and much loved cetaceans aside, the sighting of today’s killer whales was an important find for the Cetaceans on the Frontier survey. These offshore animals are infrequently seen so another ‘dot-on-the-map’ has been added to the distribution database which will build on a slowly increasing understanding of their pattern of occurrence and ecology. The photo-ID images secured today are quite simply priceless and will be catalogued and compared to an international database of killer whale images, hopefully coming up with a match or providing some baseline data to work with should future sightings be made.

Killer whales in Irish waters seem to have a real element of unpredictability about them. Some of the Marine Mammal Observers present today have many hundreds of observation hours and thousands of at-seas miles under their belt without having encountered killer whales before today, whist for some of the students joining us on the trip for their first time offshore, things could not have worked out better! Whether informed planning or blind luck had anything to do with it still does not detract from how absolutely amazing the 20 minutes we had with these animals this afternoon was. Smiles all round!

Killer whales with a Great Shearwater and a Fulmar in attendance (c) William Hunt

The seabird team had a busier day all round compared to yesterday with a mixed species flock off the stern throughout. The avian highlight was undoubtedly the continuous presence of trailing great shearwaters, frequently coming along our port side showing down to 50m at times! Birds seemed to be joining and leaving this group every few hours or so, making a final tally hard to conjure up but the single highest count we had was of 31 birds in one flock. Several sooty shearwaters were mixed in with the greats, the single highest count of those being four, otherwise the associating flock was made up of your usual gannets, fulmars and lesser black-backed gulls. Amid the commotion of killer whale activity, a nice mixed species group of seabirds followed their every move, with great skuas and gannets tracking from the air. Great shearwaters and European storm-petrels skirted over the killer whales on surfacing and with them the second Wilson’s storm-petrel of the trip. A serious combo of rare marine fauna in one field of view! The remaining species of note observed today included a single adult Sabine’s gull, a dark morph pomarine skua, a juvenile kittiwake, four great skuas, 11 Manx shearwaters and 40+ European storm-petrels.

Great Shearwater (c) Róisín Pinfield

Great Shearwater flock (c) Jason McGuirk

This evening we arrived at the Hovland Mound SAC where the crew of the R.V Celtic Explorer retrieved the second lot of SAM devices of the day. Tonight we head South East towards the Belgica Mound SAC for the third and final batch of SAM devices after which we will zig-zag our way along the Eastern edge of the Porcupine Seabight, hoping for something big and blue.

And we better not let tonight’s blog post go by without highlighting the steadfast dedication of Donegal supporters on board the R.V. Celtic Explorer…

The Donegal flag proudly flown from the M6 weather buoy by the R.V. Celtic Explorer's own Brian Sharkey (c) Damien McCallig

COTF4 Day 7: Sperm Whales & a Killer Whale!

Conditions this morning were excellent for surveying (by recent standards anyway!); sea state 3, swell about 2m, visibility clear to the horizon, bright & dry. Just as well too as today was the last big effort for this year’s survey, located right over the shelf edge west of Mayo to boot.

Fergal bagged the first of the days cetacean sightings as he finished up his night time plankton surveys with some dolphins (probably common dolphin) following the ship at 07:30am.

Right from the start it was clear that it was going to be another good day for fulmars, with a flock of 80+ (including several ‘blues’) trailing the R.V. Celtic Explorer from dawn. More and more birds began to join in and by mid morning up to 500 fulmars and 150 kittiwakes were wheeling about off the stern, generally making any attempt at accurately surveying seabirds impossible!

As soon as the numbers of fulmars peaked, Enda spotted a blow straight off the bow at 1.5km. A whale! Several of us latched onto the area where the blow originated with binoculars and witnessed several more, small and bushy spouts from roughly the same spot in quick succession before a large tail fluke loomed high up out of the water and sank away. This behaviour left us pretty confident that we had just seen a sperm whale! Word then came through from Dave on PAM (read more about his exploits on the hydrophone here) that sperm whales were clicking in the vicinity.

The blows continued and as we got closer, more and more body of the surfacing whale could be seen until we were treated to some reasonable views of the steep nose, long flat back and stumpy dorsal fin on initial surfacing followed by a thick tail stock with ‘knuckles’ seen when fluking. At least two animals were seen blowing at the surface and a third may also have been present.

Most of the scientific crew managed to connect with views of a sperm whale or at least the blows so spirits were high thereafter. A great species seen in good conditions and over good habitat. This is what it’s all about!

 Sperm whale surfacing sequence part 1: blow and forehead (c) Emilia Chorazyczewska

 Sperm whale surfacing sequence part 2: back and dorsal fin (c) Marie Louis

 Sperm whale surfacing sequence part 3: dorsal fin and tail stock knuckles (c) Conor Ryan

Sperm whale surfacing sequence part 4: tail fluke (c) Conor Ryan

Whilst still savouring the elation from this encounter, the next hit of cetacean fuelled adrenalin kicked in when Dave (who was now on watch) called ‘KILLER WHALE AT 1000m’!!! Some ‘slight’ panic ensued, but after assessing in which direction and distance he was looking, it wasn’t long before we caught sight of a massive black fin slinking into the water. There was no doubt about what we had just seen but it was a tantalisingly brief view. A short while later, amidst a cloud of fulmars, a surprisingly tall blow was followed by that unmistakable white eye patch on black, tall dorsal fin and pale saddle. Our first proper view of a Killer Whale in Irish waters!

The killer whale was some distance out, over half a kilometre at its closest point, and was moving quickly north but a few more views of the body on surfacing along with several blows and dorsal fin views left the lucky half a dozen or so of us who saw it thoroughly satisfied to say the least! Both the sperm whales and killer whale were seen about 55 nautical miles west by north west of Achill Island (within sight of land) over c.1,000m of water. The sperm whale record is notable in that they tend to be found in deeper waters.

 Alex did very well to get this shot of the killer whale dorsal fin (right of centre) slipping away below the surface, yet still quite tall looking even though its not fully out of the water. Fulmars nearby for scale! (c) Alex Borawska

To finish things off, Conor managed to spy a few pilot whales surfacing close to the ship from the port hole in his cabin around dusk! 

As mentioned previously, large numbers of fulmars kept the seabird team busy throughout the day. It is likely that most of these birds followed us for several hours at a time, so exact numbers were hard to calculate. Up to 1,000 birds max would seem a reasonable tally for the day. Of these fulmars, about 20 were of the ‘blue’ Arctic variety, spanning the full spectrum of colour from intermediate (coded as 'L') to double dark (coded as 'DD'). Great to get a good prolonged look at the variation exhibited by these colour morphs. A couple of little auks were seen again today, one of which at close range, whilst singles of puffin, great skua and herring gull added to the regular numbers of gannets, kittiwakes and great black-backed gulls.

A double light morph (coded as 'LL') fulmar, the most common type seen around Ireland (c) Marie Louis

Blue fulmar (left) and double light morph ('LL') fulmar (right) (c) Alex Borawska

 A fairly standard looking 'D' blue fulmar (c) Alex Borawska

 A striking double dark 'DD' blue fulmar (c) Alex Borawska

 Double dark 'DD' blue fulmar (c) Alex Borawska

Sampling for microplastics continues and Amy informs me that 100,000 litres of water have been filtered so far which should give her plenty to look at back in the lab in GMIT! Fergal will be dropping some CTDs and plankton nets tonight then we’ll steam back to Galway tomorrow with a strong wind at our tail, surveying as we go.