BEHAVIOR OF SOUTHERN RIGHT WHALES, EUBALAENA AUSTRALIS , 

 FEEDING ON THE ANTARCTIC KRILL, EUPHAUSIA SUPERBA 



William M Hamner,^ Gregory S. Stone,^ and Bryan S. Obst^ 



ABSTRACT 



Southern right whales, Eubalaena australis, were observed in 3 successive years on the western side 

 of the Antarctic Peninsula. These whales do not appear to be from the well-documented Valdes, 

 Argentina population. The whales we observed were feeding on Antarctic krill, Euphausia superba. 

 When krill were at the surface right whales surface-skimmed at high speed, with upper jaw lifted 

 above the water surface. In heavy weather one right whale "tail-sailed" at slow speed, with head 

 submerged and apparently feeding. When krill were organized in subsurface schools, right whales 

 engaged in subsurface feeding, diving repeatedly in place, apparently working a given school. One 

 whale swam directionally to the only known large school of krill in the area and fed intensively, 

 rested on the surface, then began a second feeding bout. Whales hyperventilated, false fluked, and 

 fluked prior to feeding dives. These are the first detailed observations of feeding behavior of right 

 whales in Antarctic waters and suggest that coastal Antarctica may have been (and may become 

 again) a regular part of the summer feeding range of the species. 



Right whales are among the rarest of the great 

 whales, having been hunted almost to extinction 

 a century ago. The southern right whale, Eubal- 

 aena australis, has been studied only recently 

 and only during the austral winter when the 

 whales aggregate inshore to bear calves and to 

 mate (Clarke 1965; Payne 1976, 1986; Best 1981; 

 Aguayo and Torres 1986). Because right whales 

 were commercially extinct by the mid-1850's, 

 very little has been learned about their ecology 

 from the 20th century whaling industry. Informa- 

 tion on feeding, migration, stock structure, and 

 reproductive biology was collected for most other 

 Antarctic mysticete whales during the heyday of 

 whaling in this century (e.g.. Mackintosh 1965; 

 International Whaling Commission reports 1964- 

 present). The small number of surviving right 

 whales (ca. 29c of historic levels in the Southern 

 Hemisphere, Breiwick and Braham 1984) has 

 made it difficult for researchers to study this spe- 

 cies. Our current understanding of its feeding and 

 calving ecology in the Southern Hemisphere 

 comes from observations made primarily off 

 Peninsula Valdes, Argentina (Payne 1986). 



In Antarctic waters south of lat. 60°S, more 

 than 30 sightings of right whales have been re- 

 ported previously (Berzin and Vladimirov 1981; 

 Goodall and Galeazzi 1986; Ohsumi and Kasa- 



iDepartment of Biology, University of California, Los Ange- 

 les, CA 90024. 

 2College of the Atlantic, Bar Harbor, ME 04609. 



Manuscript accepted September 1987. 

 FISHERY BULLETIN: VOL. 86. NO. 1. 1988. 



matsu 1986). Most were in the vicinity of the 

 South Orkney Islands, 9 were near the Antarctic 

 Peninsula, 6 were in the Pacific sector of the 

 Antarctic, and 2 were south of Africa. We have 

 observed southern right whales during 3 consecu- 

 tive austral summers near the western shore of 

 the Antarctic Peninsula, and the sightings re- 

 ported herein and in Stone and Hamner (in press) 

 are the most southerly as well as the most de- 

 tailed observations. 



We sighted one individual during the 1983- 

 84 austral summer (also recorded by Captain 

 P. Lenie in the log of the RV Hero ; Goodall 

 and Galeazzi 1986), two individuals in 1984-85, 

 and eight in 1985-86, four of which we indi- 

 vidually identified. In 1986 a fortunate combina- 

 tion of fair weather and available ship time 

 permitted us to make the first extended uninter- 

 rupted observations on the behavior of right 

 whales feeding on the Antarctic krill, Euphausia 

 superba. 



METHODS 



Right whales are distinguished by the absence 

 of a dorsal fin and regions of cornified skin (cal- 

 losities) on the head, jaws, and chin. Individual 

 whales were identified by standard methods, 

 using video tapes and telephotographs of head 

 callosities and scarring patterns on the head and 

 back (Payne et al. 1983; Kraus et al. 1986). When 

 possible, we dropped large disks of plywood of 



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