8 Apr 2018

8 Apr 18 - Atlantic Odyssey - Day Eleven: At Sea From South Georgia To Gough Island - Strap-toothed Beaked Whale

We saw a good selection of Seabirds species on the penultimate day at sea on the crossing from South Georgia to Gough Island (as detailed in the previous Post). However, the Seabirds are not the main reason why I will remember the day. The main reason is I saw my first Strap-toothed Beaked Whales which helped to start getting me more hooked on Cetaceans. I've had a lot of enthusiasm to see Cetaceans for over 20 years since the annual trips I was going on in the late 90s to the Spanish port of Biscay from Portsmouth. However, by the time I left the Plancius I was really hooked on Cetacean watching from boats. This is going to be an expensive new passion.
Strap-toothed Beaked Whale: The initial view on the surface before it quickly disappeared
Strap-toothed Beaked Whale: Fortunately, it came up again fairly close to the ship. Another typical Beaked Whale view, which gives a rough idea of the size, shape & that it is a Beaked Whale. But not enough to identify it on these views
Few things got me more excited when I was on deck than a shout for a Beaked Whale. I tried to get onto the Beaked Whale quickly, as generally you don't get long views & then to grab as many photos as possible to assist with the subsequent identification. There are 22 species of Beaked Whales & the group includes many of the least known Cetaceans. Beaked Whales tend to live in deep water, are generally unobtrusive as despite being a medium-sized Cetacean (between 4-13 metres in length), they don't seem to have strong blows like the big Whales, generally don't jump out of the water like Dolphins, generally don't seem to associate with boats like Dolphins or hang around on the surface like some of Blackfish group of Cetaceans. What they are good at is generally not spending a lot of time on the surface, quietly & quickly disappearing back under the water, occur on their own or in small groups & are generally tricky to identify. Given how tricky they can be to identify & the brevity of views, then getting good photos is crucial. It will also be very useful in then allowing the records to be documented & submitted (Marijke & Hans from the Expedition staff were diligently recording lat/long positions of the Cetaceans, Turtles & good Seabirds, Sharks etc on the Odyssey). In some cases, Marijke said she would have to forward the photos of some of our Beaked Whale sightings to Beaked Whale experts to hope they would be able to identify then.
Strap-toothed Beaked Whale: One of the most important parts to photograph on a Beaked Whale is the beak. However, this involves knowing when & where it will surface, so that you can be photographing the beak as it breaks the surface. This is very hard to get right. Most people's photos of Beaked Whales will start with the back & fin, as by the time you see it appear & react the beak has already disappeared back below the surface
Strap-toothed Beaked Whale: I seem to remember Hans dashing into the bridge & asking them to stop the Plancius as the Beaked Whales were close to the ship. Fortunately, they did & we had an incredible performance
Strap-toothed Beaked Whale: Very quickly this individual just quietly slipped below the water again
Having just started watching from the bridge wings, I found out the good way what a great viewpoint this was for seeing Cetaceans. It was a good high viewpoint & overall it allowed much better views of Cetaceans. Often they would be lost in the waves from the lower decks. Plus either Marijke or Hans, both excellent experienced Cetacean watchers, were almost always on the bridge wings when we were at sea. Having worked out it was the best viewpoint on the ship for me, I rarely spent time elsewhere on the other decks for the rest of the trip. The other bonuses of the bridge wings for me were Marijke & Hans were spending more of their time looking for Cetaceans. As the trip progressed, I was also focusing more on Cetaceans, once any potential new Birds had been seen. Finally, both Marijke & Hans were very keen to share their extensive knowledge on identification & behaviour of the Cetaceans we were seeing. My Cetacean knowledge grew significantly during the Odyssey & subsequent West African Pelagic.
Strap-toothed Beaked Whale: This individual popped up unexpectedly close to the Plancius & I didn't manage to get it all in. It is just possible to see some pale colouration on the rear of the fin
Strap-toothed Beaked Whale: This pale colouration on the rear of the fin is one of the features of Strap-toothed Beaked Whale
The next photos are of a second individual: there is a lot of pale colouration on the body in front of the fin & the fin has a different shape.
Strap-toothed Beaked Whale: Note the paleness on the sides of the body in front of the fin. This is another feature of Strap-toothed Beaked Whale
Strap-toothed Beaked Whale: Another photo of the sides of the body
Strap-toothed Beaked Whale: A close up of the fin of the second individual showing the distinctive kink in the back of the fin. Note, the paleness on the body doesn't continue behind the fin & the fin is dark
This individual appeared at right angles to the Plancius.
Strap-toothed Beaked Whale: The blow hole is just visible
Strap-toothed Beaked Whale: Finally the fin appears
Strap-toothed Beaked Whale
Strap-toothed Beaked Whale: Another surfacing individual
Strap-toothed Beaked Whale: The fin breaks free of the water & looks like this is the individual with the pale rear fin
Finally, this individual surfaced & allowed another important id feature to be photographed.
Strap-toothed Beaked Whale: Another feature of Strap-toothed Beaked Whale are the diastoms on the body
Strap-toothed Beaked Whale: A close up of the diatoms
Strap-toothed Beaked Whale: Another photo of the diatoms. These diatoms are caused by patches of microscopic algae
It was great to see a new Beaked Whale & to get these great prolonged views. It is believed that Strap-toothed Beaked Whales have a continuous distribution in the Southern Oceans from 35 to 60 degrees South. They largely eat squid, but are thought to also eat fish & crustaceans.

The day after I drafted this Post, I had an email from Marijke who had followed on these Strap-toothed Beaked Whales by sending photos of them, including some of my photos, to a couple of Beaked Whale experts. Here was the response:-
Many thanks for your contribution of photographs regarding our beautiful Beaked Whale encounter on 8 April 2018 when we were in transit to Gough Island. Their identification has been confirmed. They are Strap-toothed beaked whale (Mesoplodon layardii). It was a group of sub-adults/females. Based on an encounter earlier this year, Beaked Whale expert Robert Pitman learnt more about the colour development of these Whales off Australia and now our encounter has taught him even more. I also have discussed this encounter with Todd Pusser - who has studied stranded Beaked Whales. They both are now quite convinced they were Strap-toothed Beaked Whale. The white of the beak, the white-tipped dorsal and the strong black-and-white patterns develops with age. This explains why some Whales did not have a white tipped dorsal yet and why it was visible on only one Whale although only faint. Marijke

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