Cetaceans: Balaenopterids

Humpback whale Megaptera novaeangliae

Minke whale Balaenoptera acutorostrata

 

For images, click on thumbnail to enlarge (all photographs © Sean K. Todd 2000, use by permission only)



Humpback calf #1a (of adult #2)



Humpback calf #1b (of adult #2)

Humpback adult #2a (mother to calf#1)

Humpback adult #2b (mother to calf#1)

Humpback adult #2c (mother to calf#1)

Humpback adult #4a

Humpback adult #4b

Humpback calf #5c (of adult #6)

Humpback adult #6a (mother to calf#5)

Humpback calf #7c (of adult #8)

Humpback adult #8a (mother of calf#7)

 

A pod of minkes (1)

A pod of minkes (2)

 

Balaenopterid whales (or rorquals) are baleen whales with pleated throat grooves that can expand to accomadate the huge gulps of prey that they can consume. The two species enountered on this trip were the humpback and minke whale, although blue, fin and sei whales, also rorquals, are seen in the Antarctic.

Photographs of humpback whale flukes will be used to help photo-identify individuals observed during the cruise. Matching efforts, to animals previously catalogued in the Antarctic Humpback Whale Catalog, are currently underway. Matches with previously photographed animals will help understand further the nature of distributions and migrations in this population.

Photo-identification of humpbacks requires capturing the ventral side of the animal's fluke for details of pigmentation and trailing edge morphology, as well as observing the dorsal fin morphology. We took these shots using a Canon GL1 digital video camera purchased on behalf of Allied Whale by Abercrombie and Kent Global Foundation. The images below are freeze frame video-captures. Using video to photo-identify animals rather than 35mm still cameras has advantages and disadvantages. While you can capture the entire surfacing sequence on video, it currently lacks the resolution of still photography. Also, witnessing the event live can be somewhat confusing with multiple surfacing events happening simultaneously. With video playback, and careful examination of the images, we can deduce which animal is which.

The below animals are identifed by number (#1, #2, etc.). The letter following the number indicates sequential shots of the same animal (ie, #2a, #2b, and #2c are all the same animal). As can be seen, a number of mother-claf pair assocations were observed.

These animals were encountered mainly in Dallman Bay, 64°30'S, 062°50W (see map).

 

Humpback calf #1a (of adult #2). Note diagonal black scar on left, with streak of diatoms (brown) on opposite diagonal. Frame capture from Canon GL-1 digital video

Humpback calf #1b (of adult #2). Note diagonal black scar on left, with streak of diatoms (brown) on opposite diagonal. Frame capture from Canon GL-1 digital video

Humpback adult #2a (mother to calf#1). Note the series of white rings in the center of the fluke. Frame capture from Canon GL-1 digital video

Humpback adult #2a (mother to calf#1). Note the series of white rings in the center of the fluke which are much clearer in this shot. Frame capture from Canon GL-1 digital video.

Humpback adult #2a (mother to calf#1). Note the series of white rings in the center of the fluke. Frame capture from Canon GL-1 digital video

Humpback adult #4a. Frame capture from Canon GL-1 digital video

Humpback adult #4b. Frame capture from Canon GL-1 digital video

Humpback calf #5c (of adult #6). Even a photograph of a half fluke may be useful. Note the distinct trailing edge and triad of white dots on an all black fluke. This animal, photographed while on its left side, is also exposing part of its right flipper (leading edge visible). Frame capture from Canon GL-1 digital video

Humpback adult #6a (mother to calf#5). Note the 'x' mark on the far left of the fluke close to the leading edge. Frame capture from Canon GL-1 digital video

Humpback calf #7c (of adult #8). A mostly all white fluke with siginificant diatomaceous growth (brown). Frame capture from Canon GL-1 digital video

Humpback adult #8a (mother of calf#7). A mostly all white fluke with siginificant diatomaceous growth (brown). Note the clean white diagonal streak on the right. While probably not useable next year, this distinction was enough for us to identify the animal during several sightings on one day. Frame capture from Canon GL-1 digital video

A pod of minke whales. This group had up to 8 members - in the North Atlantic we don;t usually see minkes pod in such high numbers. reasons for this higher number may be because of food and/or predator concentrations. Frame capture from Canon GL-1 digital video

 

In this shot of the pod of minkes, one can just make out a grey discoloration forward of the left hand animal's dorsal fin - with a better resolution photograph, this mark could probably used for photo-identification. Frame capture from Canon GL-1 digital video

 

Go to Allied Whale's Photo-identification page