CSHAS 2016: Megafauna madness over the Celtic Deep

Day 15: Friday 21st October

Skipping ahead a bit here since the last blog update but doing so in order to share some notes and pics from an absolutely superb day spent watching an impressive abundance of 'marine megafauna' over the Celtic Deep, well to the south of Co. Wexford.

As the first rays of dawn broke, a peek out the cabin porthole revealed a flat calm sea and visibility clear to the horizon line. After a quick breakfast we were on deck and ready for action. Within minutes the seabird team picked up a small group of harbour porpoise off our port side which when radioed in to the marine mammal team was met with a reply of "we're watching more off to our starboard!". After trying (and failing) to spot some porpoises during the inshore legs of our transect lines off Cork, Waterford and Wexford over the past two weeks, we were surprised to finally encounter them this far offshore and what's more, we weren't expecting to see so many! Every time we scanned we seemed to find more and more porpoises and at one stage a single scan across the view-shed revealed no less than 58 animals! Final tallies for the day almost reached 200 animals!

Consulting with the Marine Institute fisheries scientists in the lab who were monitoring the underwater acoustic images being recorded by the ship, it was clear that there was a lot of activity going on below us with masses of plankton, krill, forage fish (herring) and even a plethora of bluefin tuna showing up! This abundance below water was certainly mirrored at the surface and in addition to the harbour porpoises we noted lots of common dolphins, racked up no less than fifteen sightings of Minke whales, two fin whales (one of which crossed right in front of the bow at close range), a single humpback whale, an Atlantic grey seal, several breaching bluefin tuna and even some blue sharks swimming at the surface (being able to see the latter is a testament to how calm the conditions were).

No doubt there was some duplication in sightings at play due to the close proximity of the parallel survey transect lines, yet the marine mammal observers in the crow's nest still amassed an impressive total of 78 sightings involving up to 500 animals!

After a ten hour day out on deck we are all a little tired and more red in the face than usual so I'll finish up and let the following selection of pics tell the rest of the story...

Ideal conditions over the Celtic Deep (c) Niall T. Keogh

Harbour porpoise (c) Niall T. Keogh

Blue shark 'knifing' at the surface (c) Niall T. Keogh

Blue shark clearly visible underwater! (c) Stephanie Levesque

Bluefin tuna (c) Niall T. Keogh

This common dolphin showed exceptionally well, actively surfacing just metres away from the ship. Closer examination of the pics suggest it may be unwell. The protruding rib-cage and sunken appearance behind the skull (known as a 'post-nuchal depression') indicate that it is in poor body condition (c) Niall T. Keogh

A couple of perfectly healthy looking common dolphins (c) Meadhbh Quinn

Minke whale showing the typical, falcate (sickle shaped) dorsal fin (c) Gary Kett

Minke whale showing a straighter, more erect shape to the dorsal fin (c) Meadhbh Quinn

This humpback whale spent quite some time logging (resting) at the surface (c) Meadhbh Quinn

But after a while the humpback eventually treated us to a nice tail-fluke! (c) Meadhbh Quinn

Fin whale surfacing sequence (c) Meadhbh Quinn / Niall T. Keogh

Irish Whale and Dolphin Group marine mammal observers: Meadhbh Quinn and Gary Kett

Marine and Freshwater Research Centre GMIT seabird observers: Stephanie Levesque and Niall Keogh

Celtic Sea sunset (c) Gary Kett

CSHAS Days 5 to 10: Sunny Southeast and the Celtic Deep

Day 5 to 10 sightings: Tuesday 11^th to Sunday 16^th October

We have been playing a game of cat and mouse with some of the largest animals in the ocean over the past week… the whales are currently winning out!

While enjoying excellent weather off Cork during the first few days of the survey, both fin and humpback whales were being seen from headlands in West Waterford (many thanks to Andrew Malcolm for the updates!) but by the time we reached this area the weather had deteriorated to the point such that no large whales were spotted. 

High pressure conditions with easterly winds allow for fantastic visibility and a stunning mix of colours at sunrise and sunset (c) Usna Keating

Similarly, while enjoying the gannet spectacle over the Celtic Deep, our fellow seabird and cetacean surveyors on RV Cefas Endeavour (taking part in the Peltic Survey) encountered up to 12 fin whales on their transect lines just east of us! We saw two Minke whales ourselves that day and as delightful as they are, we were somewhat dismayed to learn that their larger cousins eluded us once again.

The next day, while making our way north along a transect line towards the Saltee islands off Co. Wexford, excellent sea conditions and visibility allowed us to spot two sets of large baleen whale blows several kilometres off which most likely came from fin whales due to the tall and narrow nature of the blows. Another large baleen whale blow was then recorded over the Celtic Deep well to the northwest of Cornwall but the animals body (and thus identity) remained hidden by heavy swell. Slow progress! 

Rainbow over Great Saltee (c) Niall T. Keogh

Common dolphins have thankfully remained abundant, ensuring Meadhbh has been busy racking up the sightings from the crow’s nest. Mostly small groups noted but one sighting of 60+ animals bounding towards the ship with great enthusiasm in rough seas made for quite the sight. A small group of bottlenose dolphins seen on the inshore section of a transect line to the east of Cork Harbour were too distant to get usable dorsal fin pics for photo-ID purposes but it is likely that they are from the 'coastal' group, one of three populations known to occur in Irish waters. We’ve also had a sighting of unidentified dolphins over the Celtic Deep which were most likely bottlenose again.

Common dolphins (c) Niall T. Keogh

Bluefin tuna and Portuguese man o’ war continue to be seen here and there; attempts at capturing breaching tuna on camera are slowly but surely getting better…

Breaching bluefin tuna (c) Niall T. Keogh

A couple of stowaways were also reported to us by the crew! Recently fledged juvenile European storm-petrels out at sea for the first time can become disorientated during rough weather, get attracted to the lights of ships, land on the deck and then find it difficult to get airborne again. Two such birds were found nestled in the corners of the deck and whilst initially looking a little bedraggled and waterlogged, were allowed some time to rest and dry off in our special ‘stormy hotel’ (a box!) before being released safely overboard the following morning. With any luck they will survive and live long and healthy lives (some storm-petrels are known to reach 30 years old!).

Juvenile European storm-petrel (c) Niall T. Keogh

The seabird list for the trip now stands at 25 species after cormorant, grey phalarope, black-headed gull and little gull were added over the past few days. Guillemots and gannets remain by far our most abundant species recorded each day whilst plenty of interest is being added by good numbers of great skuas, yet more yellow-legged gulls (survey tally now at seven birds), occasional sooty shearwaters, puffins, Arctic skuas, small flocks of European storm-petrels, a single Balearic shearwater east of Hook Head and fantastic views of great shearwaters following the ship while some 35 nautical miles northwest of St Ives, Cornwall.

Two grey phalaropes seen just a few miles off Helvick Head (c) Niall T. Keogh

Great shearwaters (c) Niall T. Keogh

Sooty shearwater (c) Niall T. Keogh

Most great skuas seen in the Celtic Sea at this time of year are in the midst of active wing moult (c) Niall T. Keogh

Smaller numbers of pristine juvenile great skuas have also been noted (c) Niall T. Keogh

Adult yellow-legged gull following the ship over the Celtic Deep (c) Niall T. Keogh

1st calendar-year yellow-legged gull (c) Niall T. Keogh

Arrivals of migrant landbirds continued throughout with more meadow pipits, alba wagtails, swallows, redwings and chiffchaffs noted plus additions of skylark, song thrush, starling and even a tiny goldcrest (arguably one of the world’s greatest migrants… a wee bird capable of making almost 1,500km long journeys in just 20 days, across open water and weighing in at just 5 grams!).

Song thrush on RV Celtic Explorer (c) Niall T. Keogh

Chiffchaff on RV Celtic Explorer (c) Niall T. Keogh

CSHAS Days 3 and 4: off the Cork coast

Day 3 to 4 sightings: Sunday 9^th and Monday 10^th October

With a blocking high pressure keeping stormy Atlantic weather systems at bay, we had the pleasure of spending the first two days of proper ‘on effort’ surveying off the Cork coast in glorious sunshine with light easterly winds and a steady sea state of 2.

Sunrise over the Celtic Sea (c) Niall T. Keogh

Great conditions for spotting cetaceans from the crow’s nest where Meadhbh was kept busy with a constant presence of common dolphins throughout, mostly comprised of scattered small foraging groups. Some of these groups were seen corralling fish at the surface, with three or four animals swimming in tight circles together while another one or two rushed in and side slapped or tail slapped the surface after which there would be a flurry of feeding activity.

Common dolphins (c) Niall T. Keogh

In addition to the dolphins, we also observed several groups of bluefin tuna in feeding frenzy mode, their presence given away by the sudden appearance of shoals of small fish leaping out of the water which would then be followed up by frantic splashing. Every now and then we’d be lucky enough to catch a glimpse of some large, pointy, dolphin sized fish among the white water and on one occasion we got a classic view of a tuna breaching clear out of the water! Trying to predict this behaviour and get a decent pic of it is proving very difficult however!

Small fish jumping at the surface, a tell-tale sign of tuna feeding activity (c) Niall T. Keogh

A typical view of the tail end of a breaching bluefin tuna! (c) Niall T. Keogh

Despite the clear conditions, not a single blow from a large baleen whale was to be seen south of Cork, although reports were coming in at the time of humpback and fin whales off the West Waterford coast. While waiting to catch up with these ocean giants, we were content with enjoying some of the smaller predators, such as Portuguese man o’ war, of which we’ve seen just a handful (despite hundreds washing up on beaches in West Cork in recent weeks). 

Portuguese man o' war (c) Niall T. Keogh

After seeing hundreds of sooty shearwaters off the west coast of Kerry on Day 1, our venture into the Celtic Sea brought a fantastic encounter with great shearwaters in the offshore reaches of the survey transect lines, well to the south of the Old Head of Kinsale. Superb views were had of up to 175 birds following the ship just after dawn one morning.

It is interesting to see the change in seabird species present along the transect lines as we travel inshore with gulls and auks becoming more frequent as land comes into sight. Just off Ballycotton we added some new species to the survey list like red-throated diver, shag, Mediterranean gull and yellow-legged gull, the latter a scarce species of note in Ireland. 

2nd calendar-year yellow-legged gull (c) Niall T. Keogh

1st calendar-year Mediterranean gull (c) Niall T. Keogh

An immature puffin (c) Niall T. Keogh

Easterly winds and clear skies generated by the high pressure have enticed migrant landbirds out into the Celtic Sea, many of which congregate around or over the ship as they make a break for it across open water. Meadow pipits have been our most frequent visitor with up to 40 in a day passing overhead. Chances are they are heading south to Iberia for the winter, having left their breeding sites in Iceland and northern Europe before winter sets in. We’ve also seen some swallows, a grey wagtail, several alba wagtails (both pied and white wagtails), a couple of goldfinches, a redwing, a chiffchaff and even a single yellow-browed warbler!

Meadow pipit migrating overhead (c) Niall T. Keogh

LÉ Eithne and Rescue 117 on a training exercise (c) Meadhbh Quinn

COTF6 Day 5: Sunny Sightings

A perfect start to the day over the Eastern Porcupine Seabight, West of Co. Kerry (…up The Kingdom!). With a horizon clear as far as the eye could see, sun shining, cloud at a minimum, sea state of 2 and not much in the way of swell, you couldn’t ask for a better day to be out in the Atlantic in September!

Sunrise (c) Enda McKeogh

Common dolphins were as ubiquitous as they have been for the past few days, but with the sea conditions as calm as they were we could now see small groups splashing about much further towards the horizon and in a wide arc across our viewshed ahead of the ship. These progressively made their way towards the R.V. Celtic Explorer, leaping out of the water with great determination, often landing back down on their sides with a mighty splash. On closer inspection, several of the smaller, discrete groups contained calves, one of which was particularly small and provided great entertainment as it rocketed its way out of the water and towards the bow.

Common Dolphin calf (c) Enda McKeogh

Common Dolphins (c) Rossa Meade

It was a great day for long-finned pilot whale sightings, with a group of about 10 or so in our wake at first light followed up by another group of 10 later on with a small calf, which came in for a good close look at us allowing for excellent photo opportunities. A fairly abundant species with a widespread distribution in the Irish offshore territory but tied to deep water habitats and rarely seen from land so always great to encounter and see well. A firm favourite with many on board.

Long-finned Pilot Whales (c) Joanne O'Brien

Some confusingly short, bushy blows from a baleen whale which refused to show well on several occasions this afternoon had our attention focused for quite some time as it moved ahead of us on our survey transects. After much searching it eventually made a pass of the bow, surfacing on three occasions at a range of about 100m… a truly stunning view of a small, juvenile fin whale! The full suite of ID features were on offer including the white right hand side of the lower jaw, prominent ‘splashguard’ around the blowhole and whispy, grey ‘chevrons’ along the back. The small size of this animal would account for the confusing blows we saw beforehand.

Fin Whale surfacing sequence (c) Roisin Pinfield

During this time, the Irish Air Corp Maritime Squadron Casa 253 joined by Patrick Lyne and Lucy Hunt of the Irish Whale and Dolphin Group were making their approach towards the R.V. Celtic Explorer for a flyby during a routine assessment of fisheries operations in the Porcupine Seabight area. The Irish Air Corps have provided IWDG surveyors a fantastic opportunity over the years for offshore surveying by facilitating them when possible on these trips where they target recording larger species such as baleen whales and sperm whales.

Irish Air Corps Casa 253 seen from R.V. Celtic Explorer (c) Roisin Pinfield

R.V. Celtic Explorer seen from Casa 253 (c) Lucy Hunt

The juvenile fin whale had now made its way towards a second, larger individual so a decision was made to launch the IWDG RIB ‘Muc Mhara’ in order attempt a biopsy sample for genetic and stable isotope analysis. Simon and Joanne set off in the RIB accompanied by two crew members but the whales proved too quick for a safe biopsy to be taken. The sortie in the RIB did allow for some excellent photo opportunities of the R.V. Celtic Explorer from a sea level angle!

IWDG RIB Muc Mhara (c) Jason McGuirk

R.V. Celtic Explorer as seen from IWDG RIB Muc Mhara (c) Joanne O'Brien

Other marine ‘megafauna’ got a good shout in today also with a distant sighting of what was most likely a breaching bluefin tuna, fantastic views of a multiple breaching ocean sunfish and one of the undoubted highlights of the week, a leatherback turtle which was picked up just under the water’s surface as we approached it, passing along the side of the ship at no more than 30m, followed by two superb views of it surfacing, head and ridged carapace (shell) right out the water! Leatherback turtles regularly occur in Irish waters with a widespread distribution right across the Atlantic frontier and even up into the Irish Sea. Views as good as the one we had today are hard to come by however as they often only spend brief periods at the surface so finding them in the first place is hardly an exact science.

Leatherback Turtle (c) William Hunt

Leatherback Turtle (c) William Hunt

The seabird team had barely got started with their morning’s census (some 50 nautical miles West-Southwest of the Skellig islands) when a pair of shearwaters rose up ahead of the R.V. Celtic Explorer, one a Manx shearwater, the other a much smaller and rarer Barolo shearwater! The two birds continued ahead of the ship, moving away in a Northerly direction, heading off to our port side, allowing for a perfect comparison of both plumage features and flight style between these two somewhat similar looking species (at least according to the field guides, seeing them together in ‘the field’ however is a different story… like chalk and cheese!). Barolo shearwaters breed across the Macaronesian archipelago, specifically the Azores, Madeira and the Canaries. They are a rare, infrequently recorded species in Irish waters, most often from West coast headlands in late Summer or Autumn, with just 22 records documented up to the end of 2012 (per the Irish Rare Bird Committee reports). A most unexpected and welcome sighting, certainly one of the many avian highlights of the week.

New bird species added to the trip list today included a couple of grey phalaropes, a handful of guillemots and a migrant swift flying around the ship. Seabird numbers were generally low throughout the day, a few diving gannets and milling fulmars indicating some feeding opportunities were on the cards in this area. Two great shearwaters, 10 sooty shearwaters, 9 European storm-petrels and 9 great skuas were the best of the rest. One of the two kestrels which came aboard last night was seen again this morning, leaving the ship and heading off on its merry way. A few new meadow pipits joined us over night also, one of which ended up inside the bridge and took its place in the captain’s chair while everyone was off watching the match. Good to know somebody was steering us in the right direction!

Captain M. Pipit (c) Niall Keogh

Captain M. Pipit (c) Jason McGuirk

Tonight we will zig-zag North West along the Eastern Porcupine Seabight and cross North East over the Hovland Mound SAC once more in the morning while we make our way back towards Galway. The lads on the night time acoustic monitoring shift will continue in their endeavour to decipher what whale and dolphin calls they hear coming out of the depths. Enda reports that after some analysis, a series of clicks they picked up last night almost certainly came from a species of beaked whale, a group of enigmatic, poorly understood and rarely seen cetaceans which we know occur with some frequency in the Irish offshore territory but to date have given us the slip on many occasions, often showing only briefly when they do. Tantalising stuff, but it certainly keeps us motivated!

Sunny surveyors (c) Niall Keogh