CSHAS 2016: Gannets Galore!

A special blog post this evening on account a particularly special day spent with one of the most recognisable seabirds in the North Atlantic, the gannet.

Surveying over the Celtic Deep, some 50 nautical miles south of Wexford, we came across an area of fishing activity with several trawlers in operation which attracted the attention of an impressive number of seabirds, most notably gannets, of which thousands and thousands were to be seen here, there and everywhere!

At one stage early this morning, our survey trackline took us right through the middle of a resting flock numbering some 5,000 birds which made for quite the sight when they started parting either side of us and taking flight. Several hundred began following RV Celtic Explorer allowing for truly amazing eye level views of these stunners as they cruised alongside, making use of the updrafts created by the headwind deflecting off the starboard side of the ship.

Visiting the breeding seabird cliffs at Great Saltee in Co. Wexford for the first time at the age of eight will always remain on of the key moments in my ‘seabirding’ career. Seeing, hearing and smelling the gannet colony there will be etched into my senses forever. Since then I’ve spent many hundreds of hours surveying gannets at breeding colonies, migration watch points and from ships, during which time it can be all too easy to become complacent and have them turn into an endless stream of ‘white blobs’ to count for the sake of counting. Today it was a pleasure to take some time off and simply watch them, re-igniting my fascination as they effortlessly tracked the ship often just metres away.

It’s difficult to convey the sheer magnitude of today’s events in a series of pictures, but hopefully the following will give you some idea of what it was like… 

Gannet studies (c) Niall T. Keogh

Large flocks associated with active fishing vessels (c) Niall T. Keogh

Gannets and lesser black-backed gulls (c) Niall T. Keogh

Brightly coloured rope is often used by gannets in courtship displays and also to adorne their nests which can lead to entanglement, usually around the legs but this one had some wrapped around the lower mandible. (c) Niall T. Keogh

Check out the dewlap on this gannet! (c) Niall T. Keogh

The RV Celtic Explorer seabird team weren't the only ones keeping a close eye on all the gannet action today. Up to 100 great skuas (Bonxies) were seen among the flocks, waiting for the opportune moment to strike! (c) Niall T. Keogh

(c) Usna Keating

Meadhbh's view of the gannet action from the crow's nest (c) Usna Keating

It is also worth mentioning that with so many large, sated seabirds flying close overheard for the day, some ‘faecal impact’ was inevitable and I’m glad to report that Gary was the lucky recipient. Here he is looking delighted with himself prior to the delivery of gannet guano…  

(c) Usna Keating

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

Celtic Sea Herring Acoustic Survey 2016

Introduction 

Every year since 2004, an acoustic survey of the winter spawning herring stock which can be found in the Celtic Sea off southern Ireland has been conducted by the Marine Institute from the state research vessel, RV Celtic Explorer. The Celtic Sea Herring Acoustic Survey (CSHAS) will be carried out once again this year across three weeks during October. Working alongside the fisheries survey, a team of seabird and marine mammal observers will be on board, documenting the distribution and abundance of top marine predators often associated with herring and sprat in the Celtic Sea region.

Proposed tracklines for the October 2016 Celtic Sea Herring Acoustic Survey

The seabird team hails from the Marine and Freshwater Research Centre, GMIT and is led by PhD student Niall Keogh. This year marks the fifth in which seabird surveys will be carried out during CSHAS. Building data time series such as this forms the basis for Niall's research on seabird ecology in Irish offshore waters as well as feeding into the Celtic Sea Ecosystem Tipping Points project.

Gary Kett has joined the seabird team this year after spending the summer as a research assistant at the Shannon Dolphin and Wildlife Foundation in Kilrush, Co. Clare.

Meadhbh Quinn will carry out marine megafauna surveys for Irish Whale and Dolphin Group (IWDG) from the crow's nest, continuing long term monitoring of whales, dolphins, seals, turtles etc. during CSHAS over the past twelve years by the group. In addition to acting as coordinator for the Shannon Dolphin and Wildlife Foundation centre in Kilrush, Meadhbh is also the current Membership Officer for IWDG.

Blog readers can stay updated with our progress over the course of the next three weeks by checking in every few days here or on our Facebook page to view the latest pics and sightings. We hope you enjoy!...

From left to right: Niall Keogh, Gary Kett and Meadhbh Quinn (c) Usna Keating

Day 1: Friday 7th October

Mobilisation for CSHAS 2016 on board RV Celtic Explorer took place on Friday afternoon at Galway docks. After a safety tour and scientific staff meeting, we set sail at 8:30pm in order to make our way towards Dunmanus Bay in West Cork for Saturday afternoon where the fisheries acoustic equipment will be calibrated before beginning the survey transect lines.

RV Celtic Explorer docked in Galway and the pilot boat seeing us out safely that evening (c) Niall T. Keogh

Day 2: Saturday 3rd October

Dawn on our first day at sea saw us steaming south past the Blasket islands, Co. Kerry. After a hearty breakfast, the seabird and marine mammal observers headed out on deck for a few hours to 'get the eye in' before reaching the survey transect lines. 

From the off it was a busy morning, as is always the case in this area during autumn. Flocks of sooty shearwaters wheeled about to and fro as if in search of something hidden from our eyes, only later to consolidate themselves under groups of diving gannets which gave away the presence of lunge feeding baleen whales. All this foraging activity was due of the bounty of sprat in the area, as observed by the fisheries team monitoring what is present in the  water column underneath the ship as we go.

In total we observed four minke whales amongst feeding flocks of seabirds and had an all too brief encounter with a single humpback whale, blowing and surfacing several times as it made a beeline for a feeding group of seabirds and whales just a few kilometres to the southwest of the Skelligs.

Common dolphins followed the ship throughout, as expected. Our third cetacean species of the day will no doubt be our most abundant species for the rest of the trip. Rounding off the list of 'marine megafauna' was a single ocean sunfish, being tended to at the surface by a lesser black-backed gull (presumably checking it out for parasites to pick off and eat?).

The seabird tally for the day ended up at a respectable 16 species: gannet, fulmar, sooty shearwater, Manx shearwater, Balearic shearwater, European storm-petrel, great skua, Arctic skua, Herring gull, lesser black-backed gull, great black-backed gull, kittiwake, common gull, guillemot, razorbill and puffin. 

 Minke whale lunge feeding on sprat among flocks of gannets and shearwaters (c) Niall T. Keogh

Close up of the lunge feeding Minke whale (c) Niall T. Keogh

Skelligs (c) Niall T. Keogh

Common dolphin (c) Niall T. Keogh

Sooty shearwater (left) and a Balearic shearwater (right). Note the differences in size, structure and colour (c) Niall T. Keogh

1st calendar-year lesser black-backed gull (c) Niall T. Keogh

WESPAS Days 20 to 25: southern Celtic Sea to northern Bay of Biscay

Day 20 to 25 sightings: 23rd to 29th July 2016

After somewhat of a lull in cetacean activity in the mid Celtic Sea region, things started hotting up (literally!) as we approached the southern reaches of the Irish offshore territory and into UK and French waters. The sea surface temperature peaked at around 18°C and the ocean sunfish were out in force, as were common dolphins, with several groups seen every day ensuring the marine mammal observers were kept busy. We also recorded several breaching tuna, which looked to be bluefin and albacore. Our hoped for leatherback turtles didn't materialise however.

The outermost survey transect lines brought us close to or just over the continental shelf edge, an area of high productivity where several fin whales and even a single striped dolphin were noted. While surveying near the shelf edge along the northern end of the Bay of Biscay one evening, we spotted two very tall blows out towards the horizon line on our starboard side, presumably from fin whales. Soon after, another group of three fin whales crossed the path of the ship ahead of us from port to starboard, offering fantastic views.

Hard to beat good looks at the second largest animal on earth! 

Fin whale (c) William Hunt

 Fin whale (c) William Hunt

Fin whale (c) William Hunt

Fin whale (c) John Power

(you can just about make out the white colour to the right-hand side of the lower jaw in this pic, a diagnostic ID feature for the species)

We had some really nice sightings of bottlenose dolphins too, both near the shelf edge and also over the shallower shelf waters. Each group seemed to give the ship a wide berth, travelling past at distance. We tried to take as many pics as possible to see if we can match them to any known group (bottlenose dolphins with distinctive notches, scars and colourations on their dorsal fins are catalogued across Europe). It would be great to find out which group these animals belong, 'offshore' or 'coastal'?

Bottlenose dolphins (c) William Hunt

Common dolphin (c) William Hunt

Common dolphins (c) Mick Marrinan

Ocean sunfish (c) William Hunt

Sightings of cool marine wildlife have not just been limited to daylight hours. While on transect lines, the ship stops on station at night from midnight to 4am as part of the method for surveying boarfish. During this time a whole manner of life is attracted to the waters around the ship, illuminated by the lights. Fish such as saury start appearing in their droves to feed on gathering plankton which in turn attract predatory species like garfish, blue sharks, common dolphins and even seabirds such as fulmars and European storm-petrels (plus a grey phalarope one night circling the ship, calling!). 

This nocturnal wildlife spectacle has provided the night shift scientists and crew with endless entertainment (the blue sharks stealing the show, hands down). Even some of us day shift observers had to stay up way past our bed time in order to witness it!

Blue sharks (c) John Power

Blue shark (c) John Power

European storm-petrel circling RV Celtic Explorer at 2am (c) Niall T. Keogh

The seabird list finished up on a total of 26 species with the latest additions being Barolo shearwater, grey phalarope and yellow-legged gull. 

Barolo shearwater (which breeds on Atlantic islands such as the Canaries) was a real highlight as it is a rarely observed species around Irish and UK waters but more often seen in the Bay of Biscay, so the bird we saw travelling north with a Manx shearwater just inside the UK offshore territory some 270km southwest of Scilly was perhaps just about on the edge of its perceived regular range, although it seems we have a lot more to learn about their occurrence closer to home as this tracking study has shown.

A flock of 17 grey phalaropes was flushed ahead of the ship on the evening with lots of fin whale activity near the shelf edge along the north side of the Bay of Biscay. These pelagic waders (which feed on zooplankton) will already be on their way south to wintering grounds off the west coast of Africa. On examining pics of the flock, it appeared that quite a few females were present. Grey phalaropes breed in the High Arctic, where the males incubate the eggs and safeguard the chicks during the breeding season while the females leave soon after the eggs have been laid so it is not surprising that we have seen a flock of mostly females this far south already. Their work is done!

A quick check of the gull flock following the ship while west of Brittany yesterday afternoon produced a single fresh juvenile yellow-legged gull, as expected, but enjoyed immensely by the gull enthusiasts on board (...enthusiast, to be precise!).

Otherwise, the past week for the seabird team has been spent soaking up excellent views of yet more Cory's shearwaters and great shearwaters, a very good showing of European storm-petrels and some long-tailed skuas. A few more Wilson's storm-petrels were also seen, bringing the tally for the trip up to 13 individuals. 

Cory's (left) and great (right) shearwaters (c) William Hunt

Cory's shearwater (c) William Hunt

Great shearwater (c) William Hunt

Juvenile lesser black-backed gull (c) Niall T. Keogh

 Gannet (c) William Hunt

Gannets (c) William Hunt

After 25 days at sea, the Western European Shelf Pelagic Acoustic Survey (WESPAS) has come to an end. We are docking in Falmouth in Cornwall this morning from where we will make our way home to Ireland, giving us plenty of time to reflect on the fantastic marine species which we have had the privilege of seeing over the past few weeks. From here the RV Celtic Explorer will make its way to Germany to  undertake another survey.

We'll finish up with a pic of the final species list for the survey and a heartfelt thanks to Chief Scientists Ciaran O'Donnell and Graham Johnston (Marine Institute) for their continued support of offshore marine mammal and seabird surveys and to the officers and crew of RV Celtic Explorer for all their valued assistance throughout the cruise. Until next time...