2009 29th March- Five new fluke ids and did we see the entangled calf? Print
Written by Andrew Stevenson   

  

Above are Nicole Reed from Bar Harbour, Maine who is a marine bilogist, volunteer with Allied Whale and whale researcher, Camilla Stringer, and Than Sr and Than Jr Butterfield on their boat Emerald Spray as we set off on a bumpy but productive day.

Below are the five new fluke ids we obtained today on Sally Tuckers and Challenger Banks. Each of the whales had orca bite marks on the flukes or dorsal fin probably incurred when they were calves, somewhere between Bermuda and their northern feeding grounds. The right hand images show close-ups of some of the bite marks. About one in three North Atlantic humpback whales have these scars, a reflection of how deadly the orcas (aka killer whales, even though they are dolphins) can be to any weak or unprotected calf. It also lends credence to my theory that the humpbacks are aggregating on the mid-ocean seamounts such as Bermuda to assemble into sizeable gams (schools) of around ten animals.

  

 

  

And is the photograph below on the left the entangled calf we observed on the Bermuda seamount, in fifty feet of water a fortnight ago? He was exactly where we found him two weeks ago and his behavior was very similar. Nicole saw the spout in the direction of Chubb Heads as we were heading towards Sally Tuckers. We kept a distance to observe and keep track of the calf. He tail lobbed several times and lay on his side and whacked the water with his pectoral fin and then after several minutes was joined by his mother. The calf looked like it was a yearling, seemed to have the same fluke pattern (didn't get a good id of its fluke last week). We didn't get a photo of his scarred humpback today which we could have compared and which might have confirmed his identity. And as happened two weeks ago, we lost the pair in fifty feet of water. They were very shy and elusive, but basically heading west.

  

If it wasn't the same calf and mother, then their behavior suggests to me that the mothers must leave their calves in the shallow waters of the Bermuda seamount (fifty feet) while they feed on the upwellings on the edge of the seamount in 120-200 feet of water. When nervous, the calf will lob tail or breach or pec slap and shortly thereafter the mother is at his side.

After we lost the mother and calf in fifty feet of water on the Bermuda platform we headed off to Challenger, bypassing two whales that seemed to be feeding on the western edge north of Sally Tuckers. Mike Haywood on Explorer was behind us and he stayed with the two whales which included a yearling who put on a fantastic tail lobbing display that we could see for almost half an hour as we continued to Challenger. On the edge of Challenger we dropped the hydrophone overboard but heard nothing and continued to the Crown. As if on cue, two humpbacks breached right on the crown of Challenger and we remained with a mother and calf. Not too long after we shadowed them, the mother breached about a hundred feet from the boat (none of us had our cameras ready) and soon an escort joined them. We stayed with them as they meandered and then slowly moved towards the south east edge of Challenger.

Thanks to Judie Clee on Explorer for letting everyone on board know that we are very keen to get fluke photos. The photo on the above left is my photo of the calf on the Bermuda seamount that was joined by its mother and then gave us the slip as they headed west. On the above right a photo from Federico Candiolo who was on Explorer.  This yearling whale was tail lobbing when we bypassed it on the way to Challenger. It looks to me as if the two photos are of the same animal. Presumably while he was tail lobbing, the mother was feeding. If it is the same animal, then it would appear the mother brought the calf from its position of safety in the shallow waters of the platform (where we observed it) closer to where it was feeding (where Explorer observed it).

I believe the calf we saw two weeks ago had been entangled for some time, perhaps even since last summer. If his mother is still feeding him, then he could be relatively strong, despite the entanglement and she would be thin and weak from both feeding the calf and protecting it from predators. It would make sense that she would use the upwellings here with their food supply of krill, copepods, decapods, fish eggs and small fish to regain her strength. The calf entanglement is a reminder that we should not only be careful not to throw things overboard, but also to pull ropes and nets and plastic out of the water when we see it. Lou Hollis phoned last week to say that his garden is covered with ropes and discarded nets or cargo netting that he has pulled from the water and brought ashore. I'll see if I can get photos of this for our website.

And below is a fluke from a whale that was feeding on the windward side of the edge north of Sally Tuckers which we found on our way back, in the same position as we had observed on the way out. This might have been the mother to the calf Explorer was able to observe so closely.

 Camilla's detailed notes are under 'Diary Data Sheets' section.