8th May 08 on Challenger Banks with singing humpbacks Print E-mail
Written by Andrew Stevenson   

A magnificent day out on Challenger Banks on Michael Smith's Sea Slipper. With us are Duncan Headly-Coates and Dr James Martin. Crossing the canyon between Sally Tuckers and Challenger towards the eastern edge of Challenger in about 1,800 feet of water, we spotted an unidentified whale at 11.25 a.m. possibly a Cuvier's Beaked whale. The Cuvier's Beaked Whale is difficult to distinguish from many of the mesoplodont whales at sea many of which are extremely rare and some have only been seen at see a couple of times. Marine biologists believe there may be more mesoplodont whales yet to be discovered. I've sent the photo to North Atlantic whale experts to find out what they think and so far the feedback has been that this is indeed a Cuvier Beaked whale. This is the same kind of whale we saw in exactly the same position about a month ago when we were on Geoff Gardner's boat Windrush. The whale seemed to approach the boat and breathed several times on the surface and then dived (no flukes) for about 20 minutes before surfacing and breathing several times. This was consistent with its behaviour the last time we saw a similar whale. The blows were not obvious and I would guess the whale was about 15 to perhaps 20 feet long. As a beaked whale, the markings on its back are most probably from instraspecific fighting!

And here's another photo showing what apprears to be a bulbous head and perhaps even a beak.

We put the hydrophone down to listen to the whale and could hear the clicking sound characteristic of beaked whales or dolphins, but then at 11.35 we saw two dolphins about three hundred yards away so not really sure where the clicking sounds came from. At 11.45 we saw a humpback breach on Challenger and continued on our way only to see the mystery whale surface behind us exactly twenty minutes after diving. Reaching the crown of Challenger we dropped the hydrophones over but heard nothing. We did however see the blows of whales and over the course of some hours followed and kept losing a pod of four whales. I did manage to get some underwater video of the pod of whales and it was not clear from the underwater footage that there was a calf. There was often frequent activity including lobtailing, breaching, pec slapping. In one remarkable photograph that I was about to delete, we seem to have the 'smoking gun' we've been looking for regarding the supposition that the whales are feeding here. A whale having a poop! The photo below shows a whale lobtailing (more a peduncle lob) and as is clearly evident, poop coming out of its anus. The whales haven't been feeding in the Caribbean for some four or more months and this poop is a sure sign the whales are definitely feeding on the Challenger, Argus and Bermuda seamounts. If they are feeding on these seamounts, surely there must be many seamounts that they can stop at to feed during their open ocean migration north.


Periodically we would lose our pod of four whales and when we dropped the hydrophone overboard could hear the clear sounds of a humpback singing, aparently very close. http://www.youtube.com/watch?v=A-QYRlK7cd8  This 'singer' didn't appear to be one of the four whales in the pod. Judging by the behaviour of the pod, I would guess they were males and at least one female. I have recorded the long track of the singing humpback as track #30. We phoned Stevie Masters class at Saltus and the students listened in live to the humpback songs, some twenty miles from where they were sitting. We also sent them some photos by cellphone. Pretty cool I'd say!

When we set off for home close to 18.00 we dropped the hydrophone in again at the east edge of Challenger 2.2 miles from where we had dropped it previously when we heard the very loud singing, and the singer appeared to be the same but the volume was somewhat subdued. That might give us an indication when we hear a humpback sing at that volume that it might be a couple of miles away.



And some images from Michael Smith:


And the kind of shot you want to get: a still frame from the high definition video





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