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

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

Blue Whiting Acoustic Survey (BWAS) 2017

Introduction

The Marine Institute's RV Celtic Explorer will once again be taking part in the Blue Whiting Acoustic Survey (BWAS) this year (18th March to 7th April) over the Rockall Trough, starting with the Porcupine Bank in the south and working north to the Rockall Bank and beyond before heading back to Galway via the west coast of Scotland.

This fisheries acoustic survey will assess the spawning stock of blue whiting which can be found in the deep waters along the Rockall Trough in early spring. A team of observers will be on board again this year in order to carry out a survey of marine mammals and seabirds found in this region. 

Proposed survey transects for BWAS 2017. The RV Celtic Explorer route is marked in green  (click to view larger image) (c) Marine Institute

Sean O'Callaghan is our dedicated Marine Mammal Observer (MMO) for the trip and he will carry out visual surveys for marine megafauna (whales, dolphins, seals, turtles etc) for the Irish Whale and Dolphin Group (IWDG) from his perch in the crow's nest, continuing the long term monitoring project during BWAS since 2004 by the group. Sean is in his third year of the Applied Freshwater and Marine Biology degree at GMIT and is no stranger to marine mammals, having been involved with previous IWDG surveys both inshore and offshore on RV Celtic Explorer, RV Celtic Mist and RV Song of the Whale over the past year alone as well being involved with the new IWDG North Kerry Local Group.

Surveying for cetaceans will not be limited to just visual detection as a hydrophone will be towed underwater behind the ship while travelling along the transect lines. This will allow our Passive Acoustic Monitoring (PAM) operator Aude Benhemma-Le Gall to listen out for the calls made by whales, dolphins and porpoises. Aude is based in Galway this year to work on her thesis as part of the International Master of Science in Marine Biology and Conservation (EMBC+) which will focus on static acoustic monitoring of harbour porpoise at the Galway Bay Marine and Renewable Energy Test Site.

The seabird team from Marine and Freshwater Research Centre, GMIT is led by PhD student Niall Keogh who is collecting data on offshore seabird distribution, abundance and behaviour in Irish waters through visual surveys for the fourth year in a row now during BWAS. This will be the first of four surveys on RV Celtic Explorer which Niall will join this year in order to undertake seabird surveys for his research. Carlota Vialcho Miranda is another EMBC+ student working on her thesis in GMIT (distribution, abundance and habitat use by the coastal population of Irish bottlenose dolphins) and will be joining the seabird team this year with Niall for her first experience of Atlantic seabirding! 

The BWAS 2017 marine mammal and seabird team (L-R): Aude, Niall, Carlota and Sean

The RV Celtic Explorer is one of four research vessels taking part in the Blue Whiting Acoustic Survey, with vessels from Norway, the Faroe Islands and the Netherlands also involved. William Hunt is on the Norwegian vessel (FV King's Bay) as MMO for MaREI with Laila Higgins on there also through the Foreign Vessel Observer Scheme. The Dutch vessel (MV Tridens) will also have Ailbhe Kavanagh (MaREI) as MMO and Gary Kett as the representative for the Foreign Vessel Observer Scheme. So between us all we should manage some great coverage of the Rockall Trough area over the next three weeks.

Blog readers can stay updated with our progress and view the latest pics and sightings over the course of the survey by checking in every few days here on the blog, by liking our Facebook page or by following the #BWAS2017 and #RVCelticExplorer hashtags on Twitter. 

The marine mammal species we typically see during BWAS trips are those which prefer the deep water habitats around the Rockall Trough to the west of Ireland and Scotland. These include long-finned pilot whale (usually the most abundant species seen) and sperm whale (frequently seen) as well as occasional sightings of the mysterious beaked whales (Sowerby's and Cuvier's beaked whales have been recorded during BWAS in recent years). Along the slopes of the continental shelf edge we expect to see fin whales and have been lucky with sightings of striped dolphin and white-beaked dolphin in such areas last year. Over the shallow shelf waters we would hope for Minke whale, common dolphin, harbour porpoise and grey seal. Killer whales were seen during BWAS 2013 and a repeat performance would be most welcome!

Long-finned pilot whales (c) Niall T. Keogh

Common dolphin (c) Niall T. Keogh

White-beaked dolphin (c) Niall T. Keogh

Fin whale (c) Niall T. Keogh

Sperm whale blow (c) Niall T. Keogh

Sperm whale (c) Niall T. Keogh

Seabird species diversity during BWAS is generally found to be lower than on other survey trips which occur later in the year (especially in autumn). During March and April, most of our seabirds will be preparing for the approaching breeding season and as such might already be back at or close to their colonies. Furthermore, those species which would have migrated here from further afield for the autumn are probably already back at their own breeding grounds in the Mediterranean or sub-Antarctic. That being said, we can expect to see an interesting mix of species over the next few weeks as the tail end of the winter season changes into spring.

Fulmars, gannets and kittiwakes will make up the large bulk of the birds recorded offshore, where they will be actively foraging in order to get themselves into good condition for breeding. Small numbers of Manx shearwaters, great skuas and lesser black-backed gulls will be seen most days, having spent the winter further to the south and now making their way back north to their colonies. A handful of scarcer Arctic breeders such as little auk, glaucous gull and pomarine skua should be encountered too and we sometimes record more unusual species for the time of year such as great shearwater, sooty shearwater and Leach's storm-petrel which would be more associated with late summer and autumn in Irish waters. 

Fulmar (c) Niall T. Keogh

'Blue' fulmar (right-hand bird) (c) Niall T. Keogh

Gannet (c) Niall T. Keogh

Great skua (c) Niall T. Keogh

Glaucous gull (c) Machiel Oudejans

Little auk (c) Niall T. Keogh

As spring migration of birds gets underway, we can also expect to see some terrestrial species on or around the ship while offshore. This often happens during periods of bad weather (mist, rain, high winds) when birds can become tired or disorientated and land on the ship to rest or circle it in flight. Usually we will see species which are on their way to Iceland for the breeding season and those which land on the ship are often songbirds such as redwing, meadow pipit or wheatear, which can be brought down by bad weather. Conversely, flocks of pink-footed geese or whooper swans can be seen passing overhead in V-formation on clear, sunny days. From time to time something more unusual can turn up, such as bizarre sightings of water rail and collared dove during previous surveys which were well away from the nearest point of land. These are thought to be birds which migrated too far past the west coast (known as 'overshooting') and usually occur when easterly winds prevail. 

Redwing (c) Inge van der Knapp

Snow Bunting (c) Larry Manning

Willow Warbler (c) Niall T. Keogh

Water Rail (c) Niall T. Keogh