Saturday, 2 February 2013

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 puffingreat skua and herring gull added to the regular numbers of gannetskittiwakes 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.

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