Cetacean Observation on the Transatlantic 2017

Cetacean Observation on the Transatlantic 2017

Written by:
Hannah Keogh

Cetacean observation is carried out from the crows nest some 17m above sea level. The sea bird observers are on the bridge deck below, also contributing to the cetacean sightings. Double platform methodology works well for optimal viewing. Observation is carried out from sunrise (considering the time difference as we approach further west) until the light dims. All species and counts are recorded on a PC Logger system, along with associated GPS readings.
51’44 N 36’08 W

19TH April 2017   
The team awoke eagerly to the first sightings of the day- a pod of bottlenose dolphins Tursiops truncatus, followed shortly by a group of long-finned pilot whales Globicephala melas. Throughout the day encounters consisted of four more groups of bottlenose and pilot whales. 

Figure 1 Bottlenose dolphins by Hannah Keogh

20th April 2017

The morning kick started with a mixed aggregate of pilot whales and bottlenose dolphins all heading east. Later in the day pilot whales were observed associating with white sided dolphins Lagenorhynchus acutus. Short-beaked common dolphins Delphinus delphis were also observed further offshore preforming their usual acrobatic flare. A total of 6 encounters of pilot whales was witnessed throughout the day.

The highlight of the day was a sighting of 14 sperm whales Physeter macrocephalus logging and blowing at the surface. There were three groups of 2, 4 and 8 individuals, one small individual was seen along-side an adult.

We also had two encounters of migrating humpback whale Megaptera novaeangliae, with one fluking (diving).

The day ended fantastically with a view of ~30 pilot whale of all sizes. They were seen almost porposing out of the swell.

Figure 2 Humpback whale by Paul Connaughton

Figure 3 White sided dolphin by Paul Connaughton

21st April 2017

7 species of cetacean and 1 elasmobranch (a basking shark) were spotted today!

Far off and far out a whale blows around 1,500m away. The height and straightness of the vapour suggests possible blue whale.. one can only wonder about what lies beneath.
A blubber bonanza of pilot whales and white sided dolphins, at a depth of 3,650m, appeared over the West European Basin; followed by a magnificent view of two sub-adult sperm whales. One swam across the bow of the ship within 200m and dove; slipping into the abyss.

Sightings for the rest of the day consisted of a large pod split into smaller groups, of white sided dolphins with a sprinkle of pilot whales mixed in for good measure, surrounding the ship at all angles.

A mixed pod of bottlenose and white sided dolphins, and a separate encounter of three rissos dolphins Grampus griseus emerged not long after.

As we cruise closer to the Mid Atlantic Ridge the ocean’s sea state dropped to an “Atlantic” zero, with a film of fog in the distance making the horizon hard to distinguish. A logging porpoise Phocoena phocoena was spotted by the birders, which baffled them immensely at this depth, the words pygmy and sperm whale were whispered.. a second sighting later in the day confirmed porpoise to be in the area.

There were a few unidentified large baleen whales and small whale in the distance, which left much to the imagination.

However, as the evening approached a sei whale Balaenoptera borealis was spotted by sea birder Paul Connaughton, and then later in the evening by myself and the Captain Kenny. All excitement on deck! A first for many! Satellite tagged sei whales has shown the migration route of sei whales begins in the Azores islands, via the Charlie-Gibbs Fraction Zone (CGFZ) (mid Atlantic) and on to potential feeding grounds in the Labrador Sea (Olsen et al. 2009). We are currently east of the CGFZ. Perfect timing for migration.

Figure 4 Sperm whale dive sequence by Hannah Keogh

22nd April 2017

The day started with the usual suspects- a group of pilot whales. Up on till lunch time, 12pm UTC, we saw many blows and large baleen whales such as sei, fin (the 11th species seen on the survey) and humpback! The afternoon was very quiet on the cetacean front, plenty of sea birds though. With 689.2NM until we arrive at the port of St.John’s Canada, there is plenty of species yet to see :)

Olsen, E., Budgell, W.P., Head, E., Kleivane, L., Nøttestad, L., Prieto, R., Silva, M.A., Skov, H., Víkingsson, G.A., Waring, G. and Øien, N., 2009. First satellite-tracked long-distance movement of a sei whale (Balaenoptera borealis) in the North Atlantic. Aquatic Mammals, 35(3), p.313.