Saturday, 30 July 2016

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... 

Saturday, 23 July 2016

WESPAS Days 14 to 19: The Celtic Sea - a song of sun and fog

Day 14 to 19 sightings: 17th to 22nd July 2016

After the hectic day off the Blaskets on 16th July (see previous blog post), we made for Castletownbere in West Cork to carry out a mid-cruise crew change and take on some fresh provisions (which included a new coffee machine and fresh bananas!). Here we said goodbye to Dr Joanne O'Brien and Killian Coakley (GMIT) and said hello to William Hunt (MaREI/UCC) who joins the marine mammal observer team for the remainder of the trip.

The Marine and Freshwater Research Centre GMIT/Irish Whale and Dolphin Group team (from left to right): Sean O'Callaghan, Mick Marrinan, Killian Coakley, Dr Joanne O'Brien, Niall Keogh and John Collins

William Hunt (MaREI/UCC) on duty in the crow's nest

On leaving Castletownbere, we were treated to some nice sightings at the mouth of Bantry Bay just west of Sheep's Head. Common dolphins were plentiful, surfacing regularly among flocks of Manx shearwaters, auks and European storm-petrels and interspersed among these, a couple of minke whales, harbour porpoise and Atlantic grey seals.

Just as we cleared the bay, the dreaded fog set in, something which we were to be be plagued with for the next few days. This limited our survey effort during daylight hours with visibility often down to less than 100m. What made it all worse was that we could tell that just beyond the fog, somewhere, was bright sunshine and calm seas! 

Minke whale (c) Mick Marrinan

Common dolphins (c) John Collins

In time the conditions improved and as we made our way further offshore along the southbound survey tracklines into the Celtic Sea. The fog began to dissipate and we got our fair share of the glorious weather which everyone back home was out enjoying at the same time. And it was hot! 

With the wind at our backs and a following sea, we were fortunate to have a couple of days of superb survey conditions which produced some surprising sightings. Cetacean and seabird numbers were relatively low but the light easterly winds associated with the high pressure allowed some unusual migrants to make their way to the ship including a bat which spent some time flying around the crow's nest approximately 102km southeast of Galley Head, Co. Cork! Pics were posted online to see if it could be identified but without some clear shots of the ear and exact measurements of the wing it is unlikely that the issue will be resolved 100% (but thanks to everyone who made suggestions).

This follows on from a record of what is thought to have been a Leisler's bat, also present on RV Celtic Explorer at sea south of Cork in October 2015, so this sighting is not without precedent.

In addition to turnstone and whimbrel which were recorded west of Galway earlier on during the trip, other terrestrial migrants seen around the survey vessel in the Celtic Sea included a flock of 4 dunlin, a common swift (looking very out of place), a lost racing pigeon and a silver y moth!

Bat species (c) Niall T. Keogh

Racing pigeon (c) Niall T. Keogh

Quite a few jellyfish about too including mauve stinger (Pelagia noctiluca), compass jellyfish (Chrysaora hysoscella) and by-the-wind sailors (Velella velella). Lots of sightings of ocean sunfish also, including a group of three together and even some smaller individuals seen breaching fully out of the water! These oceanic wanderers eat jellyfish so looks like it's good times for them at the moment.

Velella velella (c) Niall T. Keogh

It has been an exciting few days for the seabird team with rare or scarce species dominating the tallies. We are out here at the perfect time of year for recording cool seabirds such as Cory's shearwater, great shearwater and Wilson's storm-petrel. Several hundred of the shearwaters have been noted, along with several instances of Cory's shearwaters tracking foraging groups of common dolphins. Fantastic to see these two top marine predators in close association, working the same aggregations of pelagic fish.

Among the flocks of European storm-petrels dancing over the water, a few Wilson's have been picked out (much to the delight of the observers) and while skua numbers have been low, all four expected species have been seen: great, pomarine, Arctic and long-tailed.

The seabird list for the survey is now up to 23 with the most recent additions being shag, common tern and long-tailed skua.

Great skua (c) Niall T. Keogh

European storm-petrels (c) Sean O'Callaghan

Wilson's storm-petrel (c) Niall T. Keogh

Great shearwater (c) Niall T. Keogh

Cory's shearwaters (c) Niall T. Keogh

Occupational hazard... airborne gannet poo hitting the crow's nest
(and the marine mammal observer!)

Monday, 18 July 2016

WESPAS Day 13: Blaskets Bonanza!

Day 13 sightings: 16th July 2016 

We hit the mother-load today along our survey tracklines to the west of the Blasket islands, Co. Kerry!

The day started with a group of 15 long-finned pilot whales on the eastern edge of the Porcupine Seabight some 70km NW of the Blaskets. This was soon followed up by a sighting of a blow from a large baleen whale.

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

As we approached the Blasket islands from the west we started picking up quite a few groups of common dolphins, a Cory's shearwater and a great shearwater.

Cory's shearwater (c) Niall T. Keogh

As we got to within 15km southwest of the Blaskets we entered a period of crazy cetacean and seabird feeding activity which lasted over an hour and included 11 minke whales, c250 common dolphins, c40 bottlenose dolphins, 2 harbour porpoises, several Atlantic grey seals and thousands of European storm-petrels, Manx shearwaters, puffins and guillemots along with a few sooty shearwaters, great skuas and a pomarine skua thrown in for good measure.

We didn't know which way to look! 

Minke whale surfacing sequence (c) John Power

Common dolphin (c) Mick Marrinan

Atlantic grey seal (c) John Collins

Manx shearwater (c) Niall T. Keogh

European storm-petrel (c) John Power

Unfortunately the weather sorted that out for us soon after and the visibility reduced to less than 100m. We couldn’t see the Skelligs even though we passed right by them!

An Tiaracht shrouded by misty cloud (c) Niall T. Keogh

One of our marine mammal observers on the ship, Sean O’Callaghan (GMIT), hails from The Kingdom and gives us a local’s perspective on the event:

“The Blaskets were brimming with marine life yesterday afternoon when the Celtic Explorer headed East by Inishvickillane before turning off into thick mist along the Southern side of the outer bay.

It was the calmest conditions I've ever been out there in and shortly after passing the Foze rocks the seabird life began to increase in numbers with hundreds of European storm-petrels zipping around, revealing the presence of a bait ball along with the common dolphins and single Minke whale feasting on the fish!

Cetacean and seabird feeding frenzy: minke whale (centre) flanked by Manx shearwaters and common dolphins (c) John Power

Puffins began to appear in large rafts bobbing on the surface the further east the Explorer cruised. Some harbour porpoises (the ninth species for this survey) briefly appeared before disappearing again.

Adult and juvenile puffins (c) Niall T. Keogh

Puffin escaping from the ships track! (c) John Collins

Juvenile and adult guillemot (c) Niall T. Keogh

Common Dolphins and minke whales consistently kept appearing in increasing numbers for a time off Inishvickillane but the appearance of some 40 bottlenose Dolphins was the highlight for me.

They surfaced slowly ambling towards the ship for a time but turned around 300m away where one of the Dolphins began to tail slap the water. After looking at some of my dodgy photos of these Dolphins, there was at least one calf present. 

Bottlenose dolphins (c) Niall T. Keogh

Bottlenose dolphins (c) John Power

When the Explorer turned to head South West, the mist that had lifted during the afternoon descended again where you wouldn't see anything unless the animals came to you as the case was when two bunches of Dolphins appeared briefly later that evening.

Unfortunately the two humpbacks that were in the area the previous day weren't encountered but in my biased view, it's been the best day so far on this survey!”

Gulls resting on the bow of RV Celtic Explorer (c) John Power

Great black-backed gull (left) and lesser black-backed gulls (right) (c) Niall T. Keogh