Sunday, 3 February 2013

COTF4 Day 8: West Connemara & Galway Bay

Our last day of surveying was spent heading south along the Connemara coast and then east into Galway Bay, following a similar route to that taken on Friday.

A few small groups of common dolphins were seen at various stages throughout the day. Their larger and more elusive relative, the white-beaked dolphin was noted again, with two animals seen surfacing just off the bow at 11:30am not far from where we saw the group of 6 on Friday. The final sighting of the survey was of 2 harbour porpoise as we entered Galway Bay, between south west Connemara and Inishmore. The total cetacean list for the trip comes to an impressive seven. That’s nearly one species for every day of surveying which is excellent by Irish standards. In addition to this veritable wealth of whales and dolphins, we came across another species of marine mammal today…common (harbour) seal! Two individuals were seen on separate occasions, popping up out of the water in order to have a good look at us!

The seabird team was kept busy for the first couple of hours by yet another large milling flock of gannets, fulmars and gulls. Estimates of 500 fulmars (including at least 7 ‘blues’), 400 gannets, 150 kittiwakes, 50 great black-backed gulls and 30 herring gulls probably just scratched the surface of what was really present. An amazing sight all the same! These cleared by mid morning and only small numbers of birds were noted for the rest of the day. Quality was provided by another glaucous gull, this time a nice fresh juvenile which followed us for some time about 4 nautical miles west of Slyne Head. Once entering Galway Bay we clocked a few inshore species like guillemotrazorbillshag and common gull which was new, bringing us to a total of 16 species recorded on transect since the survey began overall.

And with that comes the end of another successful ‘Cetaceans on the Frontier’ survey. Our Chief Scientist, Conor Ryan sends us off with the following sentiment…

“As a marine scientist, one of the most rewarding and exciting things to do is embark on an expedition on a research vessel. We are lucky enough in Ireland to have one of the finest research vessels in the world… this is not an exaggeration. The R.V. Celtic Explorer is one of the quietest ships in the world, and as such is in demand for acoustic surveys whether for cetaceans or for fisheries. Yet we have been able to charter this platform for our research, on four occasions in five years. For students and senior researchers alike, this is a fantastic opportunity to build a unique multi-disciplinary dataset. I’d like to thank the crew of the R.V. Celtic Explorer for their unending help and professionalism; this makes our job so much more enjoyable. A big shout out to the fantastic scientific crew too – despite the dire weather in the ‘Abysmal Plain’, spirits were always high. Looking forward to COTF5 already!”

Cetacean team: Conor Ryan (Chief Scientist), Joanne O’Brien, Simon Berrow, Dave Wall, Enda McKeogh, Darren Craig, Suzanne Beck, Marie Louis, Milaja Nyk√§nen, Emilia Chorazyczewska.

Seabird team: Niall Keogh, Domhnall Finch, Vivi Bolin & Alex Borawska.

Jellyfish, plankton & microplastics team: Fergal Glynn, Paul Mayo, Diana Swores & Amy Lusher.

Over the past two weeks we’ve done our best to get as many pics of whales, dolphins, birds etc. to show the good folk at home viewing this blog the fantastic variety of fauna that inhabits the Irish offshore territory.

Today we figured we’d do something different and pay tribute to the dedicated band of researchers, students and hardcore enthusiasts who we’ve had the good fortune of spending the past two weeks with…

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.

COTF4: Calls from the Deep

In addition to visual survey effort for whales and dolphins we are also towing a 200m hydrophone behind the ship. Whales and dolphins live in an underwater world where sound allows them to communicate with each other, to find their prey and to navigate. Some species of whales spend much of their lives in the deep ocean with little or no light to see by, yet these whales use sound to ‘see’, producing clicks or sound pulses which bounce off prey and their surroundings, allowing them to hunt and to navigate in much the same way as bats do on land.

Our hydrophone (basically an underwater microphone) detects sound over a wide frequency range from the very low Hertz (below the human range of hearing) up to 150 kilohertz (way above the human range of hearing). We humans can hear in the 14 hertz to 18 kilohertz range so this means we can hear dolphin whistles (which lie below 20kHz), sperm whale clicks (100 Hz to 32 kHz) and the lower frequencies of dolphin clicks (which generally peak at 40-60kHz). We cannot hear the higer frequencies of dolphin clicks and we cannot hear porpoise clicks (which peak at 120-150 kHz) at all! 

However we can see these high frequency clicks using a computer and some software which turns noise into images via a spectrogram readout and a click detector. On the 26th January we detected some porpoise clicks to the west of the Aran Islands (see image below), with the clicks having a peak frequency of about 140kHz. These animals were also detected visually by the observers. So far we have made acoustic detections of harbour porpoisecommon dolphinbottlenose dolphinpilot whale and sperm whale. As we track our way northwest we are keeping an ear on the seas for more calls from the deep…

 Harbour porpoise clicks (c) Dave Wall

Pilot whale clicks (c) Dave Wall

It is thanks to the generosity and expertise of our colleagues in Ocean Science Services of the Marine Institute; the National University of Ireland, Galway; P&O Maritime and of course the officers and crew of the R.V. Celtic Explorer, that we are able to conduct such innovative deep sea acoustic research during this cruise. 

Dave Wall
(Irish Whale and Dolphin Group)

Friday, 1 February 2013

COTF4 Day 6: Cold Waters

With the weather starting to settle, we decided to make a break for it this morning and head back out into the blue!

We began our surveying at the mouth of Galway Bay, between the west end of Inishmore and the south west corner of Connemara. From there we headed west by north west along the Galway coast, passing the Skerd Rocks, Slyne Head & Inishshark. The seas were pretty choppy so we watched inside, from the bridge which was just as well given that a few heavy squalls blew through!

Big waves! (c) Emilia Chorazyczewska

The most noticeable feature of the day was the switch from those species encountered more frequently in warmer water habitats such as the Porcupine Seabight to those found more often in colder waters such as the Rockall Trough which isn’t so far away once north of Galway Bay.

A couple of sightings of a lone bottlenose dolphin was the first cetacean of the day and an important one at that as it was seen just outside the new cSAC (candidate Special Area for Conservation) for bottlenose dolphin along the Connemara coast. These are ‘inshore’ bottlenose, seemingly quite different in behaviour, morphology and genetics to those we encountered offshore several days ago.

The undoubted highlight of the day however came when Marie spotted up to 6 white-beaked dolphins close in off the starboard side of the bow at 4pm, some 11 nautical miles west of Inishshark. A new cetacean species for many of us onboard!

White-beaked dolphins are a cold water species, restricted to shelf or near-shelf habitats of the North Atlantic. It has been suggested that rising sea temperatures could have an adverse effect on their population by driving them further north into areas with less suitable habitat. They are usually reported only a few times a year in Irish waters and rarely this close to land so a fantastic record all round! 

Our final cetacean encounter was of two bow riding common dolphins, completing the hat-trick of dolphin species for the day.

White-beaked dolphins. Tall dorsal fin with a smudged white blaze behind it are excellent ID features (c) Conor Ryan

  You can just see the white 'beak' here from which the species gets its name (c) Conor Ryan

On the seabird front, numbers of fulmars were the highest recorded on the survey so far with a total of 9 ‘blue’ fulmars amongst them, including a ‘double dark’ bird (almost looked like a sooty shearwater!). An immature glaucous gull passed by quickly about 6 nautical miles south of Slyne Head and a couple of puffins were noted also but the prize species was most certainly little auk! Four birds were seen in total, just west of Slyne Head. Little auks are the smallest species of auk in the Atlantic, breeding on Arctic cliffs and island in their millions. They also have the curious habit of feeding heavily on copepods (a type of plankton) whereas other auks which we are more familiar with, eat fish such as sandeels and sprat. In winter, they get pushed south to Ireland during bad weather so with the storms that have raced through the Atlantic over the past week its no surprise we came across some today. 
Smaller numbers of gannets, kittiwakes, great black-backed and herring gulls,razorbills and guillemots were seen otherwise.

Forecast is for some good surveying conditions tomorrow so we’re off to the shelf edge!