Survey Ends

So our survey has come to an end. We recorded 100 hours of simultaneous visual cetacean and seabird surveys, passive acoustic monitoring, sea surface temperature, salinity, depth and echosounder fish marks. About 220 hours of acoutic files from the hydrophone were recorded, half of which were analysed in real-time (the reaminder being recorded over-night).

Notable findings were a large aggregation (7 to 10) fin whales on the western slopes of the Mid-Atlantic Ridge feeding during spring/winter, when most other baleen whales are in low latitudes on their breeding grounds. A group of 5 sperm whales in Irish waters just west of the Porcupine Seabight was also a significant finding and 3 sightings of striped dolphins in Irish waters when the water is at its coldest was an unexpected (given their preference for warmer waters). The acoustic monitoring showed that sperm whales are present almost continuously over abyssal plain waters (>4000m) during this time of year both east and west of the Atlantic Ridge, but not on shelf edge or shelf waters.

The bird survey confirmed that puffins do head out in to the mid Atlantic for the winter months - they were observed regularly and singularly along our transect. Kittiwakes were seen each day, whereas fulmars were not. There were no storm petrels seen. Gannets were absent from the western Atlantic area of our survey where glaucous gulls were abundant. A group of Manx shearwaters 50 strong were seen in the final hour of our 15 day survey just off the Old Head of Kinsale, and nowhere else along our route. 

"Deck of Cards", Cobh. (Conor Ryan)

There is a chance that the Marine Institute at Memorial University of Newfoundland will charter the Celtic Explorer next year. If this is the case then we look forward to repeating this survey, given the success of this one.

Kittwake crossing the wake of the Celtic Explorer (Conor Ryan)

Home Sweet Home

We came aloongside in Cork City, just behind the Celtic Voyager at 1400 today after making our way swiftly through Cork Harbour on a nice breezy sunny afternoon. I will post pictures tomorrow, but the highlights of today included a large pod of 250-300 common dolphins and 50manx shearwaters southeast of Galley Head this morning.

Nearly Home

N51 47', W10 18'. Wind F6-F7, swell 6m, sea temp. 11.5C, air temp 10C. Depth 450m. 150nm west of Dursey Island, Co. Cork.

It was a quiet morning over the abyssal plain, but conditionals were marginal for carrying out visual surveys. We persisted nonetheless with the help of Ipods (shuffled song of the day: Pearl Jam, All Those Yesterdays). 4 hours watch in the morning produced just one group of 9 pilot whales which approached the ship head-on at speed before diving away. They were heard clearly on the hydrophone. After lunch about 10nm from the Porcupine Bank shelf-break the sun lit up a whale beneath the surface to our port side (conveniently enough, as the glare to the starboard was awful). A big blunt square head, forward blow and wrinkled skin indicated sperm whale, then another, and more - 5 in total spread over an area of about 500 square metres. They were logging on the surface in 3000m of water, probably recovering after a long dive. This is the largest group of sperm whales I have seen, although not unprecedented in Ireland.

Later on we had a couple of small groups of very enthusiastic bow-riding common dolphins, using the bow wave as a springboard, particularly on the larger swells. Emily recorded gannets, fulmar, great skua, kittiwake, and puffin.There was a gang of great skuas on patrol which seemed to check-in regularly throughout the day before keeping their distance again.

Tomorrow morning we should find ourselves inshore along the West Cork coast, steaming northeast for Cork Harbour with an ETA of about 1400. The wind is forecast to be on our backs yet again so it should make for comfortable sailing.

Fat Tuesday

N51, W19. Wind F6-F7, swell 5-6m, partly cloudy, Air temp 12C, sea temp 12.5C, ship speed 10.5knots, depth 4000m. 

Sunrise this morning

Today we crossed the Thulean Rise followed by a deep trench (4500m) and now we are out over the abyssal plain, easting towards the Porcupine Bank and the Irish EEZ. It was very quiet once again on the cetacean front - not easy watching conditions with sea state 6 and glare, however the visibility is good. Our regular tea (and fruit cake) breaks were had, along with conversations such as 'do animals have a sense of dignity'.

Spot the cetacean in this

On the hydrophone Alessandro recorded one small and distant group of dolphins. At about 2230 tonight, I heard low frequency whistles/moans which are from a large odontocetes (my knowledge of acoustics is sketchy, but they did sound a lot like the killer whales we recorded last summer! But pilot whales would be more likely I suppose).

Emily saw kittiwake, great skua, puffin and fulmar. One of the kittiwakes was oiled and appeared to try and land on the ship.

In other news; we had pancakes for dessert and Alessandro broke his record for not being sea-sick - 5 days, not bad!

Mid Atlantic Ridge

N52 29 W25 52, wind westerly F6 - F7, swell 3-4m, Sea Temp 11C, Air Temp 9C.

Half way home! We are north of our intended destination (Cork) as we are taking the great-circle-route which is the shortest distance given the curvature or 'bulge' of the earth.

Today was challenging to say the least - conditions were marginal for seeing cetaceans given the choppy sea and glare. But at least the swell is low and we have the wind on our backs, making life on board very comfortable. There were no sightings (and only 1 hallucinated beluga whale about 6 hours into the day) . Not a peep through the hydrophone either unfortunately. We spent the day traversing the Mid Atlantic Ridge - a known cetacean hotspot for sei whales and striped dolphins during the summer months and a migratory pathway for humpack and blue whales too. All is quiet here now though, maybe we will start to hear sperm whales again tonight as we head out over the abyssal plain.

EK60 screen-grab showing the sea bottom (red) profile of the Mid Atlantic Ridge as we crossed it today between the Hecate and Faraday Seamounts.

The bird survey was far more productive. Our young great black backed gull woke up this morning after sunrise and flew away, where to I'm not sure, it was very far from home. Emily recorded kittiwakes, puffins and great skua. Notably, there have been no fulmars seen for the past 2 days.

Tomorrow our route will take us over the East Thulean Rise - a submarine mount that climbs to 1500m and drops away on its eastern side to 3000m.

Our Very Own Time Zone

N51, W34. Water 9C, Air 6C. Wind F2-F3 northerly, Swell 3-4m. Ship speed 10 knots.

Today we had our very own special time zone (GMT +0.5) as we tried to catch up with GMT gradually. But as of lunch time we are on GMT (a bit prematurely, giving dark mornings but 'summer' evenings). 

Fulmar over our wake yesterday morning (Conor Ryan)

Conditions were ideal for watching from dawn till dusk today with complete cloud cover (preventing glare), visibility of >15km and sea state 2 to 3 and no showers. There were noticeably fewer birds today, however we had s surprising visitor - a 3rd winter great black backed gull that appeared to have an injured leg(s). It was unable to stand and spent the day sleeping on the bow (catching the attention of the odd passing skua). For a coastal species, the Mid-Atlantic Ridge is not a good place to be with an injury I imagine, maybe it will stay on board until we reach the Irish coast. There were several great skuas today, kittiwakes, a single gannet (lost? but with a purposeful westerly flight), Brunnich's guillemot, puffin and little auks.

Great Black Backed Gull tending to it's dodgy leg on the bow of Celtic Explorer

There were 7 cetacean sightings, however 6 of these were made in the last hour as we approach the Mid Atlantic Ridge. One pod of 12 patterned dolphin species (most likely to be striped dolphin) were spotted early on in the day avoiding the ship about 3km distant. After dinner a pair of sperm whales were seen moving out of the way of the ship and then logging on the surface - this was the first sighting of sperm whales despite them being heard regularly on the hydrophone (not surprising considering their capacity to stay under for up to an hour at a time).

Immature Glaucous Gull seen yesterday, none observed today (Conor Ryan)

An hour before sunset we hit an aggregation of fin whales - 5 sightings of 7 individuals. These were lunging on the surface, some even taking half-breaches. Being so high up on the crow's nest gave some great views of the lunge-feeding in motion - a side-ways lunge to the right, the tail constantly fluking and circling in a clock-wise circle before lunging again. There may have been a sei whale amongst the fins, but the fading light made species ID tricky. The MAR is a well known location for sei whales.

Fin Whale lunge-feeding, note the white lower jaw. It is unusual to get an 'upright' lunge like this (Conor Ryan)

Upper jaw of a fin whale lunge-feeding. Western slopes of the Mid-Atlantic Ridge. (Conor Ryan)

The hydrophone picked up sperm whales (10 detection events, mostly in groups) and pilot whales (3 detection events) as well as unidentified dolphins (5 detection events) today. We are picking up plenty of radio interference (the crew were wondering what language the sperm whales were speaking last night as they unexpected heard voices in the dry lab). Some of the voices were very excited and speaking about soccer (Alessandro is not gone mad from monitoring the PAM, I swear).

So tomorrow we will be on the MAR proper, heading down hill again by first light, across some more abyssal plain and then over the East Thulean Rise and the Porcupine Bank in the following days. Lets hope the weather continues to stay favourable, we've been very lucky so far and feels more like the Irish Sea than the Mid Atlantic!

View aft from the crow's nest yesterday in a following wind.

Click-Fest

50, 25' N, 40,11' W. Wind F4-F5, swell c.4m. Ship speed 9 knots. Occasional rain/hail/sleet/snow/frozen-mist showers. Sea temp 12C (but plummeting to 7C occasionally), air temp, 5C.

It was a lot 'milder' today than previous days - thankfully the crow's nest windows are no longer fogging up, and I was able to wash the salt off them without the window cleaner freezing. It was a productive day for cetacean detections, thanks to the wonders of PAM (Passive Acoustic Monitoring). With a following sea and a clean sound, Alessandro recorded pilot whales, unidentified dolphins and sperm whales frequently throughout the day. The sperm whale clicks were coming in at such a high rate that they crashed the computer at one point. These detections were not matched with sightings despite 7 hours of effort, given that conditions were tricky and we are dealing with deep-diving species. I did spot an unidentified large whale only 300m from the ship - it was most likely a fin whale given the powerful blow, large fin and brown hue to its back.

Pilot Whale whistles visualised on the spectrogram from the hydrophone (Alessandro Pierini)

Pilot whale burst pulse sound (function not really known, but VERY loud!) on the left and sperm whale clicks (used for searching for prey - echolocation) on the right (Alessandro Pierini).

There are groups of sperm whales clicking away in a mad frenzy at the moment - it sounds like a load of people breaking stones with little hammers, with the occasional dolphin whistle thrown in (most these are at a frequency too high for me to hear, but everyone else can hear them fine!). It is surprising that we have so many detections of cetaceans out here over the abyssal plain, given it has a reputation for being a 'desert'.

Profile of the water column and benthos from the EK60 - an active acoustic device which is used to record fish / plankton during the transit. Biomass can be estimated from the 'marks'. No clear marks on this screen-grab, but there are some fish near the surface. The abyssal plain is about 4200m deep here with the odd rocky feature.

Birdyology: Emily recorded kittiwakes (groups of >40 doing sudden climbs and dives), little auk, Brunnich's guillemot, great skua, lesser black-backed gull and fulmar.