Monday, 10 April 2017

BWAS 2017: End of Survey

Blue Whiting Acoustic Survey 2017 Week Three: Saturday 1st to Thursday 6th April

The final days of BWAS 2017 were largely uneventful, at least in terms of sightings, due to the arrival of a low pressure system which created some rough seas for our journey back home to Galway.

A couple more sightings of long-finned pilot whales on the last stretch of survey transect between the Rosemary Bank and the Hebridean shelf were the last cetacean sightings of the survey, after which we turned south and headed through The Minch. This is an area where we would have hoped for the likes of white-beaked dolphin, Risso's dolphin and even killer whale but unfortunately we found ourselves battling slowly into a head-on southerly wind and rough seas making carrying on with survey effort a somewhat futile exercise.

Our arrival into Galway was met with the final sighting of the trip overall, that of 'Nimmo' the apparently resident bottlenose dolphin which was seen foraging at the mouth of the River Corrib just off the tip of Nimmo's Pier. It is likely that it will remain here through the spring and perhaps as late as July so if you are in Galway, make sure to pop down for a look (and report any sightings of it to IWDG).

BWAS 2017 species lists

'Nimmo' the Galway Bay bottlenose dolphin (c) Andrew Power

So another successful survey overall with plenty of seabirds and cetaceans recorded over some fantastic offshore habitats during what is always a very enjoyable research cruise. Many thanks to our Chief Scientist, Graham Johnston (Marine Institute) for the opportunity to come along again and continue the survey collaboration and further thanks to Captain Denis Rowan and the rest of the RV Celtic Explorer crew for their help and hospitality over the past three weeks.

We'll sign of with a selection of pics of the scientists and crew of RV Celtic Explorer and some of the wildlife observed during BWAS 2017...

MMO on watch in the crow's nest (c) Carlota Vialcho Miranda

Crow's nest views (c) Aude Benhemma-Le Gall

Sperm whale (c) Aude Benhemma-Le Gall

Common dolphin (c) Aude Benhemma-Le Gall

Long-finned pilot whales (c) Aude Benhemma-Le Gall

Fin whale (c) Aude Benhemma-Le Gall

A well wrapped up seabirder! (c) Aude Benhemma-Le Gall

Gannet (c) Aude Benhemma-Le Gall

Great black-backed gull (c) Aude Benhemma-Le Gall

PAM operator (c) Carlota Vialcho Miranda

CTD being deployed to collect information on water temperature, salinity etc. (c) Aude Benhemma-Le Gall

Crew getting ready to bring in the net (c) Aude Benhemma-Le Gall

Catch of blue whiting on the deck (c) Aude Benhemma-Le Gall

Blue whiting (c) Aude Benhemma-Le Gall

Measuring fish (c) Aude Benhemma-Le Gall

Creatures from the murky depths! (c) Aude Benhemma-Le Gall

Squid (c) Niall T. Keogh

Sunset (c) Carlota Vialcho Miranda

Monday, 3 April 2017

BWAS 2017: Rockall Trough Part Two - Cetaceans

Blue Whiting Acoustic Survey 2017 Week Two: Saturday 25th to Friday 31st March
by Sean O'Callaghan (IWDG Marine Mammal Observer)

The second week of BWAS marine mammal surveys got off to a blank start initially but the following day (Sunday) really signaled the start of a far more productive period.

Survey progress map for 31st March 2017 with thick lines show areas covered (c) Marine Institute

Not long after ascending into the crow’s nest to start the day's effort and while getting myself ready (equipping the necessary gear for the day along with applying some sun cream!) the seabird team began their observations from the bridge deck and spotted the first whales of the day which appeared initially 500m off the starboard bow, lazily surfacing, all the while moving closer to RV Celtic Explorer. Their slanted blows and boxed body shape gave them away as sperm whales and the three of them (one obviously large individual with two smaller individuals, probably juveniles) came within 100m of the vessel before diving under the bow. Moby Dick's relations up-close and personal, a great start to the day! 

Sperm whales (c) Niall T. Keogh

Sperm whales (c) Sean O'Callaghan

Sperm whale dive sequence (c) Sean O'Callaghan

An hour later, two tall blows were picked up out towards the horizon some 2.5km off the bow and when we reached the area both whales passed the vessel, decent views giving them away as fin whales on the move. The most elusive of the Sunday sightings was of an unidentified beaked whale picked up once by Aude through her binoculars while I was on a break. To round the day off we had a few common dolphins make an appearance off the port side showing no interest in the ship which has been the case for most of the survey. We had caught up with the fishing fleet on the northern side of the Porcupine Bank that day and had views of some of the large factory trawlers.

Maartje Theadora (c) Niall T. Keogh

The next batch of activity happened two days later along the shelf edge some 60km west off Mayo where more common dolphins were sighted in the morning while a group of long-finned pilot whales were recorded visually and acoustically simultaneously a kilometre and a half of the port side in the evening (really displaying how both survey methods can complement one another). While trying to get record shots of these pilot whales a distant blow from a large whale was inadvertently captured in their midst’s just as a group of offshore bottlenose dolphins powered past the starboard side to be picked up by those on watch in the bridge along with the seabird team who were up from dinner to see the pilot whales. Unfortunately these dolphins didn’t hang around and continued off in synchronised breaches which were the best that could be captured by the camera. Another day another species for the list!

Offshore bottlenose dolphins (c) Sean O'Callaghan

Wednesday was a day for housekeeping with heavy rain in the morning coupled with poor sea conditions which were unsuitable to watch or safely work in. Thursday was an unexpectedly interesting day, we had moved north into Scottish waters off the Hebrides with a species list standing at six but there was more transects to go yet. The weather had eased off and we were back on effort again. After turning onto a new transect at around 15:00, Aude started to hear a strange sounding whistle on the hydrophone, seemingly getting closer as time passed by. Continuing to watch from the crow's nest with the possibility of a new species in the area it didn’t take long to spot a large, grey, odd-shaped ship lingering on the horizon. We had heard that the survey tracklines might take us past a military exercise later in the day involving submarines, so with the navy-style appearance of the distant ship coupled with the consistency of the whistles being detected on the hydrophone, it became obvious that sonar was being used. About 30 minutes after the first ship was seen, another four appeared on the horizon to the east around the same time as the first marine mammal sighting of the day was made; a group of ten or so common dolphins moving west ahead of us at high speed! The sonar was detected for a further three hours, during which time another lone common was sighted but seemed unphased by the sound (in contrast to the previous sighting). Further sightings of common dolphins, two unidentified large whales and our first Minke whale of the survey capped off the day nicely as we continued north along the shelf edge and over shallow waters. 

Common dolphin (c) Niall T. Keogh

Navy vessels taking part in the 'Operation Joint Warrior' exercise (c) Sean O'Callaghan

Friday proved to be a fruitful day while over the deep Rockall Trough waters near the Anton Dohrn Seamount, with twenty long-finned pilot whales less than 200m off the port side just after conducting a fishing tow and before the day's watch effort began. This group of pilots engaged in some interesting behaviour such as 'spy-hopping'. Later on a lone Atlantic white-sided dolphin was seen to surface twice, giving tantalisingly brief views of the colourful side pattern but just not enough to put it down as a "definite" sighting for that species.

The day ended as the drizzle closed in from the east, with a lone large blow picked up from the crow’s nest some 3km away. Subsequent rain knocked the survey off effort for a while but as soon as it cleared we were met with the sight of a single fin whale lunging in front of the bow almost on cue in perfect sea conditions! It lunged a further three times as we steamed by, making for a nice end to the week despite heavier rain closing in!

Long-finned pilot whales 'logging' at the surface (c) Sean O'Callaghan

Long-finned pilot whale 'spy-hopping'! (c) Sean O'Callaghan

Lunge-feeding fin whale (c) Sean O'Callaghan

Fin whale lunge-feeding sequence (c) Sean O'Callaghan

Our man in the crow's nest... Sean wonders what species is next up for the marine mammal team! (c) Niall T. Keogh

Saturday, 1 April 2017

BWAS 2017: Rockall Trough Part One - Seabirds

Blue Whiting Acoustic Survey 2017 Week Two: Saturday 25th to Friday 31st March

Survey tracklines over the past week have been focusing on the deep waters of the Rockall Trough and also along the continental shelf edge that borders it to the east, between Mayo and off West Scotland.

The seabird survey team from the Marine and Freshwater Research Centre, GMIT have been making the most of the good weather in recent days, with just one 'no survey' day so far due to heavy seas and strong winds (not bad for March!). Some long survey periods from the bridge deck have resulted in a total of fifteen species of seabird recorded up to the end of March: gannet, cormorant, fulmar, great shearwater, sooty shearwater, Manx shearwater, great skua, kittiwake, lesser black-backed gull, great black-backed gull, glaucous gull, little auk, puffin, guillemot and razorbill.

Gannets, fulmars, kittiwakes, large gulls and great skuas are ever present around the ship, waiting for us to haul in a net full of blue whiting. Fulmars have been the most abundant species at sea over the deep Rockall Trough waters, nearly all of which are recorded as the 'double light morph' plumage which is typical for this latitude. A handful of the darker morph, High Arctic breeding 'blue' fulmars have also been seen, although perhaps fewer than have been noted during BWAS trips in recent years. 

The first guillemots and razorbills of the trip were recorded along the top of the continental shelf edge and over shallow waters along with plenty of puffins. While west of Scotland it was noted that both 'black' and 'brown' guillemots were present, probably representing birds of different subspecies (Uria aalge aalge and U. aalge albionis respectively). The only little auks noted so far have been from the deep water region near the Anton Dohrn Seamount (a total of five birds in breeding-type plumage).

A great shearwater following RV Celtic Explorer over the deep waters to the north of the Porcupine Bank on 26th March was a real highlight. These southern hemisphere breeders (from the Tristan da Cunha island group) are typically found in Irish waters between July and October so a spring sighting is noteworthy although one was seen out on Rockall Bank during BWAS last year so perhaps a few more are to be expected out here at this time of year than previously thought?  

Perhaps the most surprising sighting so far was that of two adult cormorants flying north (with intent!) over the northern side of the Porcupine Bank some 75 nautical miles west of Achill Island, Co. Mayo! In five years of surveying offshore Irish waters, this is the first time the MFRC GMIT team have seen cormorants this far away from land (their at sea distribution is quite inshore/coastal). It is tempting to speculate that they were migrants on their way to Iceland for the breeding season? (although it seems that there are no ringing recoveries of cormorants moving between Iceland and Ireland/Britain)

Great shearwater (c) Niall T. Keogh

Various shades of fulmar (c) Niall T. Keogh

Pristine looking adult gannets are always a treat to watch up close but unfortunately we usually also see several birds per trip which are either entangled in rope/line or oiled such as those depicted here (c) Niall T. Keogh

It's not just entangled or oiled seabirds that we make an effort to record, surface marine litter surveys continue during our research trips (c) Niall T. Keogh

The always popular Atlantic puffin! Most of the birds we see at this time of year are adults in breeding plumage (like this one) but we have also seen a handful of non-breeding plumage / first-year type birds with dusky faces and smaller, dark bills (c) Niall T. Keogh

Great skuas are a constant presence around the ship, keeping an eye on the flocks of gulls following us. Small numbers of 'Bonxies' have been seen every day so far (c) Niall T. Keogh

Breeding plumage adult kittiwakes like this one have been engaging in courtship display and calling over the ship in recent days. Sounds like a seabird colony at times! (c) Niall T. Keogh

The first spring migrant of the year. Adult lesser black-backed gulls are making their way north through the Rockall Trough at the moment, having left their wintering grounds located as far south as West Africa and now heading for breeding grounds as far north as Iceland or perhaps even Greenland (c) Niall T. Keogh

Unfortunately we were unable to make out the full code on this ringed lesser black-backed gull. Wonder where it came from?! (c) Niall T. Keogh

Lesser black-backed gull preening while in mid-air. You can see it accessing the uropygial gland at the base of the tail in order to get at the preen oil needed for keeping those feathers in tip-top condition (c) Niall T. Keogh

BWAS2017 seabird team: Niall Keogh and Carlota Vialcho Miranda, Marine and Freshwater Research Centre, GMIT (c) Aude Benhemma-Le Gall

The Office! All you need for an offshore seabird survey: comfy deck chair, camera, handheld GPS, range finder stick, tablet for data entry, weather writer, waterproof bag etc. (not pictured: binoculars and copious amounts of banana bread!)

Redwing making use of the ship for a rest stop! (c) Niall T. Keogh