Sascha K. Hooker and Robin W. Baird. 1999.
Canadian Field-Naturalist 113(2): 273-277.
Abstract
Little is known about most members of the family Ziphiidae, the beaked whales. Sowerby's Beaked Whale (Mesoplodon bidens) is known from only a handful of sightings and strandings; few descriptions of group composition or surfacing behaviour are available. During 1997 and 1998, groups of Sowerby's Beaked Whales were observed in the Gully, a submarine canyon off eastern Canada, on four occasions. Sightings were in water depths of between 550 and 1500 m. Group size varied from 3 to 8-10 individuals. A mixed composition group was observed on one occasion, consisting of at least two female-calf pairs and two to four adult males (based on the presence of visible teeth and extensive scarring). Another group consisted of three quite heavily-scarred and therefore presumably male animals. Whales were observed to dive for between 12 and 28 minutes. Blows were either invisible or relatively inconspicuous. During all surfacings the long beak projected from the water well before the rest of the head or back was visible. While surfacing behaviour was generally unremarkable, one individual tail-slapped repeatedly.
| Fig. 2. Sowerby’s Beaked Whales seen in the Gully, 8 July 1997: (a) typical surfacing appearance; (b) female and calf; (c) adult male, note the erupted white tip of the tooth; (d) adult male with M-shaped dorsal fin. Photographs (a) (c) and (d) copyrighted by R.W. Baird; (b) copyrighted by B. Müller. Please contact the photographers for permission to use any of the photos. | |
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Hooker, S.K., and R.W. Baird. 1999. Deep-diving behaviour of the northern bottlenose whale, Hyperoodon ampullatus (Cetacea: Ziphiidae). Proceedings of the Royal Society, London B. 266: 671-676. Willis, P.M., and R.W. Baird. 1998. Sightings and strandings of beaked whales on the west coast of Canada. Aquatic Mammals 24: 21-25. Whitehead, H., S. Gowans, A. Faucher, and S. McCarrey. 1997. Population analysis of northern bottlenose whales in the Gully, Nova Scotia. Marine Mammal Science 13: 173-185. Whitehead, H., A. Faucher, S. Gowans, and S. McCarrey. 1997. Status of the northern bottlenose whale, Hyperoodon ampullatus, in the Gully, Nova Scotia. Can. Field-Nat. 111: 287-292 Faucher, A. and H. Whitehead. 1995. Importance of habitat protection for the northern bottlenose whale in the Gully, Nova Scotia. pp 99-102. in: Marine protected areas and sustainable fisheries. (Eds. Shackell, N.L. and Willison, J.H.M.) Science and Management of Protected Areas Association (SAMPA), Wolfville, NS, Canada. |