The Western European shelf edge pelagic acoustic survey 2016 provided me with an opportunity that I couldn’t turn down, to work aboard the R.V. Celtic Explorer. Having kept an eye on this ship over the past few years through the form of blog posts and updates from the likes of cetaceans on the frontier or indeed transatlantic surveys, the Irish states flagship research vessel has lingered in the back of my mind since the start of secondary school.
The crowded chatter emanating from the final day of Galway’s Sea fest rang out when I arrived to board what would be my floating mobile home for the remainder of the month. Given the festival was winding down that evening, I opted to wait for the others outside the docks gates to chance a look for the city’s resident bottlenose dolphin off the adjacent Nimmo’s pier. Not long after scanning the mouth of the Corrib, the dolphin made an appearance, my first sighting (technically of this trip!).
This summer the IWDG have offered me a place aboard three vessels of varying size and objectives, far earlier than I would have expected as I start out in the world of blubber. Coincidentally, with each trip, the size of the vessel became ever larger and the roles given whilst aboard, increasingly more scientific!
It took a few days to find my bearings on board with the basics I’d take for granted ashore often appearing in a different guise afloat, along with the collection and processing of data be it visual observations or vocalisations through the new IWDG towed hydrophone, but the input and insights of Mick Marrinan and Dr. Joanne O’Brien made the former and latter tasks seem like second nature within a few days.
Climbing up the white washed ladder leading to the 18m high crow’s nest towering above the bridge was a surreal experience. The view was obscured off Galway’s Slyne Head by drizzly, increasingly “wet” rain but being perched upon the very nest I’d read about all those years was just as good as summiting Everest (without the physical/financial cost!).
The first few days were quite dreary as you’ve read in Micks update but my luck finally came about with a Common dolphin sighting straight ahead and bearing towards the Explorers bow like car crazed sea dogs. Surveying for cetaceans at sea is very different to a cliff top vantage point, especially when you move with the swell your scanning, concealing potential sightings on occasion. But as always you’re at the mercy of the weather!
During times of low blubber sightings, the seabirds swirling off the ships sides were often welcome distractions especially when birds like Arctic/Pomarine Skua, Wilson’s Storm-Petrel and Cory’s Shearwater were about as it was the first I’d seen of them.
It was great to see work on ObSERVE-Acoustic take place where three AMARS used for SAM (static acoustic monitoring) were recovered from the continental shelf edge having been left at the bottom since last March recording the vocalisations of any passing cetaceans. It was a tense wait to determine whether the AMARs would respond but after popping to the surface flawlessly at three stations there was nothing to worry about.
Picking up where Mick left off, the 15th felt like an in-between day as we were North of the Blaskets yet cruising East towards where we’d be on standby for the night near the Dingle peninsula where a few Humpback whales had been sighted in recent days. The sightings that Friday consisted of a flurry of Common dolphins throughout the day with one lone Minke in the morning making a brief appearance. That night a plan was hatched to try to make the most of the morning when we were expecting to pass the Blasket Islands from the North but unfortunately due to time constraints with the upcoming crew changeover in a two days’ time, the Explorer didn’t loiter at night like she normally did and when we got up early the next morning we were well North West of the island archipelago on a CTD station.
Conditions on Saturday the 16th were initially somewhat dower with a consistent misty rain which reduced visibility and soaked us in the process. Later in the morning some long-finned pilot whales were sighted just before we turned from the shelf edge and motored East, back to the Blaskets.
The first cue that we’d arrived inshore was an ever increasing reports of common dolphins, much to my dismay while keeping up to speed when logging each sighting! Then came the first sight of land (in a way) when the Foze rocks West of the Blaskets veered into view below the low hanging cloud loitering across Dingle bay, the mainland and the adjacent Blasket islands. It was surreal seeing just the cliff base of an Tiaracht and inishvickillane clear the fog while the remainder of the islands were caked in cloud. The one by one, the sightings began to trickle in.
First the common dolphins made themselves known, often under sizeable swirling aggregations of European storm-petrels. Then a Minke whale lunged through the first bait ball we crossed. Its slick rostrum sliced the surface while engulfing a fraction of the bay. Numerous more Minke and common dolphin sightings continued to stream in the more Easterly we moved along with the occasional grey seal sticking up statically at the surface watching us veer by. Puffins began to appear in bulk bobbing along the surface in mixed rafts of this year’s crop of fledglings and hardened adults followed by a brief glimpse of two harbour porpoises, the ninth cetacean species of the survey to date! But to finish off the blubber and bird bonanza, the sight of some forty bottlenose dolphins, appearing to log at the surface around 300m from the ship was most unexpected. It was the largest grouping of the species I’ve ever seen and at first they were drifting towards us, offering a tantalising opportunity to obtain photo identification shots, but just as they edged within range, they all diverter their course away to the South with one individual slapping the water with its tail fluke!
The fog that had plagued our efforts earlier, returned just after the Explorer turned Southwest out of Dingle bay and by the Skelligs, alas only two sightings were made of dolphins which approached the vessel briefly while the islands themselves remained out of view as we headed South for the crew changeover the next morning in Castletownbere. While it was a whistle stop cruise in the bay, it was unfortunate that we didn’t connect with the humpbacks in the area especially since we passed right through the area they had been observed in the day before but the mist hampered any chance of picking out any blow in the distance. The feeding frenzy was fantastic to see, especially the interactions between the storm-petrels and dolphins and while visibility was often poor, the sea conditions around the islands with no swell and a sea state of two, it was the calmest I’ve been out in the bay!
It was quite odd seeing land so close to the ship on the morning of the leg three crew changeover in Castletownbere, the fog from the previous day still remained but we could see the village itself when the Explorer stopped outside the harbour for the at sea transfer of personnel and restocking of the ships provisions using the vessels small boat the Tom Crean. While Dr. Joanne O’Brien and Killian Coakley of the SBO (sea bird observer) team departed, William Hunt came aboard as an additional MMO (marine mammal observer).
Clearing the Beara peninsula and motoring by Sheep’s head, the fog lifted for a brief spell allowing the observers on watch to spot a nice mix of species from multiple common dolphins breaching from various directions to two harbour porpoises and minke whales, but yet again the bane of the trip in recent days, the fog returned once again shutting down our chances to spot anything more distant than 100m, unless some dolphins decided to approach the ship!
The following two days (18th and 19th) were much the same with increasing and decreasing visibility which was dictated by the fog but some common dolphin and minke whale sightings were logged on occasion.
There were some prolonged periods where no cetaceans were sighted but thankfully (for the benefit of our sanity) we were inundated with offshore seabirds on occasions which once again provided a welcome break from scanning the seemingly lifeless surface of the Celtic sea!
While fin whales had been sighted off the Cork coast around this time, there was no sign of the planets second largest creature along our tracklines South of Cork but we still managed to sight more common dolphins coming up to the 21st where we’d steadily ambled South heading toward the Northwest of France.
It’ll be odd not following the same routine back on the solid substrates of land but I wouldn’t have it any other way. WESPAS has afforded me a phenomenal experience to date thanks to the IWDG.
Sean O’Callaghan
Sean is a long standing IWDG member carrying out recording and regular effort watches in south and west Kerry. He has just completed his second year of the Applied Freshwater and Marine Biology degree at the Galway-Mayo Institute of Technology.
All images by Sean O'Callaghan
26 July 2016
For the last few weeks three marine mammal observers from the Irish Whale and Dolphin Group have been present on board the state research vessel, R.V. Celtic Explorer, as she continued on the second and third leg of the Western European Pelagic and Acoustic Survey (WESPAS). WESPAS is a new multidisciplinary research cruise representing the largest single vessel acoustic survey program in Europe. It is the consolidation of two existing acoustic surveys into one, the Malin Shelf herring acoustic survey along with the western boarfish acoustic survey. During the trip the MMOs will be carrying out dedicated visual and Passive Acoustic Monitoring (PAM) of cetaceans encountered as the ship travels along the pre-determined track lines of this extensive survey.
Track lines covered by RV Celtic Explorer during NW Herring (North) and WEPAS survey
Taking over from the indomitable Hannah Keogh (IWDG), who was the sole observer for leg 1 (north through The Minch, then south to the west of the Outer Hebridies and finishing off to the west of south Donegal), myself, Michael Marrinan (IWDG), along with Sean O’ Callaghan (IWDG/GMIT) and John Collins (IWDG/GMIT) joined the survey on the 4th of July in Galway docks. Our trip would take us from where Hannah finished her leg, south to west of Brittany as we cruised in and out to the shelf edge (see figure 1).
Leg 2: Our first two days of sailing, the 4th and 5th of July, saw poor weather with high winds and therefore no sightings and it wasn’t until the morning of day three, between Inishturk and Inishboffin, that we encountered our first cetacean. As the crew deployed the CTD instrument (which measures conductivity, temperature and depth) to collect data for research into radium levels in seawater being carried out by NUIG, a minke whale (Balaenoptera acutorostrata) was spotted cruising towards a flock of diving gannets and swooping shearwaters. Though we had waited a few days for this first glimpse of blubber, it was well worth it, as on a foggy and misty morning the minke whale slowly swam across our stern, from starboard to port, at about 600m and then swam from stern to bow at about 700m. The animal disappeared for about 5 minutes and then suddenly appeared no more than 70m to the port bow. In for a quick look see, and then, away. This was the first of three sightings for that day the highlight of which was a breaching minke whale seen all to briefly over the shoulder of the intrepid Dr Joanne O’Brien by the ever alert John Colins as they both discussed the workings of PAM in the dry lab.
Minke whale
Over the next few days, although the weather and sea state had improved, fog and mist hampered our efforts. Sightings were once again scarce as we sailed in and out to the shelf edge, a couple of sunfish (Mola mola), the largest bony fish in the sea, and one cetacean sighting, that of a group of common dolphins (Delphinus delphus), showing up at around 17:30 on the 7th. The common dolphins had been noticeable by their absence up until now, with several of us noting that we had not gone so long on a survey before without encountering this lively species.
Early the next morning brought us a grey seal which seemed to be associating with a Cory’s shearwater, we were some 250km west of The Aran Islands, a long way from home for the seal some would suggest, however grey seals are known to be wide ranging and can stay at sea for extended lengths of time while foraging. That, however, was that for the day and with rising sea state, that was that for the next day also.
Around 09:03 on Sunday the 10th we encountered another shelf edge staple, long finned pilot whales (Globicephala melas), about 350km west of loop head. We had three separate sightings over the next half an hour; most likely these were small contingents of a larger group and with an estimated 20-25 animals, it is always nice to meet these guys who seem genuinely interested in the boat. But the best sighting of the day has to go to the Sowerby’s beaked whale (Mesoplodon bidens) that was seen cruising past the ship from bow to stern through the mist and rain and sea state of 7. As the weather did not allow for external observations this cetacean was seen from the bridge by a mixed group of observers that included MMOs, twitchers and fisheries observers. The evening finished with only our second sighting of our old friends the common dolphins and one sighting through the mist of an unidentifiable dolphin. We all agreed that the day had been a vast improvement over the previous week, but nothing could have prepared us for what was coming over the next few days.
Common dolphin
Part of our cruise included the recovery of static acoustic pods that had been deployed along the shelf edge in order to record the vocalisations of passing cetaceans as they cruised along this area of high productivity. In order accomplish this, the Celtic Explorer would have to deviate from its pre-determined track and take a route along the shelf edge. Joy for the MMOs on-board as here was a chance to encounter more beaked whales and hopefully some of the giants of the sea.
Reaching the shelf edge at the crack of dawn on Monday the 11th, we were all up and at them early and registered our first sighting at 06:00, Common dolphins, by 10:30 we had seen three groups totalling between 20-30 animals. Then our first behemoth, at 11:02 a blow was spotted at around 2.5km, a large baleen whale for sure, but what species? About ten minutes later the animal was spotted again, about 700m off the starboard bow and it was clearly a smallish fin whale that had come in to check us out.
An unidentified cetacean and a group of common dolphins followed our fin whale sighting and then at 16:03 about 340km west of the Dingle peninsula we had a sight that most MMOs hope to but don’t often see, a breaching beaked whale at 600m. In the excitement only a couple of grainy pictures were taken, but there is no denying the shape of the animal. Good times! But the sightings were not finished yet as later that evening we ran into what appeared to be a large group of foraging cetaceans that consisted of no less than 60 animals, these included three different species, pilot whales, common dolphins and a new one for the survey list, stripped dolphins (Stenella coeruleoalba), at least 10of them leaping and twisting in the air about 400m off our port side.
Basking shark
The following day saw common dolphins and pilot wales, but we were also visited by another new species for the survey list. While watching pilot whales in the late morning on the port side of the boat, a group of animals were seen on the starboard side. Almost discounting these animals as more pilot whales, closer inspection revealed that these were in fact a group of six offshore bottlenose dolphins (Tursiops truncatus). However, as quickly as they came they were gone, unlike their cousins the common dolphins and pilot whales, they didn’t seem too enamoured with bow ridding and frolicking around the boat but the opportunity was taken to note the difference between them and the other recognised populations of bottlenose dolphins in Irish waters, those of our coastal and Shannon estuary populations. They appear more robust than our inshore population but sleeker than the animals found within the Shannon Estuary.
Our first sighting on Wednesday the 13th was of the second biggest fish in the sea. 50m from the port side of the ship, two fins cut through the water 32km North West of Aran Mór, as a medium sized basking shark (Cetorhinus maximus) lazily swept by. About 5m in length this was not the biggest basking shark ever seen and not the only shark species encountered this trip, but it was the only one that could be identified with certainty by us cetacean guys. Three more groups of Common dolphins a sunfish and an unidentified breaching whale, basking shark or submarine rounded off the day.
Thursday the 14th started off bleak and miserable, fog and mist that had plagued us for much of the cruise returned and brought with that real rain, you know, the rain that doesn’t look like much but after standing in it for 5 minutes you are soaked to the bone? That kind of rain! High winds and a high sea state made any observations from the crow’s nest or even the monkey bridge impossible and so our survey was carried out from the bridge and not much hope for many sightings was held. But boy were we wrong!
Humpback whale
From early in the morning the sightings started to come, group after group of common dolphins appearing in and out of the heavy fog, by 14:45 we had at least 100 individuals by 19:15 that number was conservatively estimated as 305. Then as Niall Keogh, one of our seabird observers, was watching a raft of shearwaters and storm petrels all of a sudden, as a group, they suddenly took to the sky. With visibility less than a kilometre it was difficult to make out what was happening, however the reason for this sudden avian eruption soon became clear, a minke whale appeared where the birds had been stationed, lunging as it feed on whatever prey was present.
Suddenly, the first officer, Basil, shouted for a blow. As everybody scrambled to see what the fuss was about, another cry was heard “humpbacks, humpbacks!!”. Those who were present were treated to the awesome sight of three humback whales (Megaptera novaeangliae) feeding through the mist. We even had a tail fluke to finish the show along with the appearance of yet another minke. Cetacean enthusiast gold! Tired from the long day there was not one underwhelmed observer present as we headed off early for a good night’s rest because we had noticed that a lot of the animals that we had observed were, like us, heading south, so another early start in the morning would be required.
The next part of the journey would take us to the west of the Kingdom and believe me you don’t want to miss what happened over the next few days, but as there is a Kerryman on board with us, it is probably better to let him describe what occurred, given his greater knowledge of all things Kerry. All that’s left for me to do is to say goodbye, get me bins out and go up to the crow’s nest for another day of watching the sea!!!
Cheers!
Mick Marrinan, IWDG MMO onboard RV Celtic Explorer
All images Mick Marrinan
