BEHAVIOR OF BOWHEAD WHALES, BALAENA MYSTICETUS, 

 SUMMERING IN THE BEAUFORT SEA: A DESCRIPTION' 



Bernd Wursig,2 Eleanor M. Dorsey,^ Mark A. Fraker,^ 

 Roger S. Payne,^ and W. John Richardson'^ 



ABSTRACT 



Behavior of bowhead whales summerinj^ in the Canadian Beaufort Sea was observed from an airplane and 

 occasionally from shore during 1980-82, mainly during August. Behavior varied between years. In 1980, 

 whales alternated periods of socializing with periods of feeding in several different ways: near the bottom (as 

 evidenced by surfacing with mud), in the water column (suspected during long dives), and skim-feeding at 

 the surface. In 1981, more time was spent apparently feeding in the water column, with some socializing and 

 skim feeding. In 1982, almost all activity appeared to be feeding in the water column. In 1980, most whales 

 studied were in water only 10-40 m deep. In 1981 they were farther from shore and in > 20 m depth, and in 

 1982 long (10-30 min) dives were common in depths of 40-600 m. Variability in distribution and behavior 

 presumably was related to availability of prey. 



Besides feeding and scx-ializing, we saw sporadic bouts of aerial activity (breaches, tail slaps, etc.) and 

 log play. During 1981 and 1982 we observed young-of-the-year calves apparently waiting at the surface 

 while adults fed below. In 1982, two such lone calves played with debris in the water. 



During near-surface skim feeding, whales often associated in V-shaped or echelon formations, with up to 

 14 animals staggered behind and to the side of each other, all moving in the same direction at the same 

 speed, with mouths wide open. We hypothesize that such coordinated movement may increase the efficiency 

 of feeding on concentrations of small invertebrates. 



In recent years, much has been learned about 

 behavior of several species of baleen whales (e.g., 

 Payne 1983). Most long-term studies of whales have 

 been carried out during winter, when social inter- 

 actions, mating, and calving occur more often than 

 feeding. Recently, however, detailed studies have 

 been conducted in summer, when whales are pri- 

 marily feeding (e.g., Dorsey 1983). 



This paper describes the general behavior of bow- 

 head whales, Balaena mysticetus, in the summers of 

 1980-82. A companion paper gives a quantitative 

 description of the surfacing, respiration, and dive 

 patterns (Wursig et al. 1984). This study was done to 

 provide background data necessary to interpret 

 observations of bowhead behavior in the presence of 



'This paper has been reviewed by the U.S. Minerals Manage- 

 ment Service (MMS) and approved for publication. Approval does 

 not signify that the contents necessarily reflect the views and 

 policies of MMS, nor does mention of trade names or commer- 

 cial products constitute MMS endorsement or recommendation for 

 use. 



^Moss Landing Marine Laboratories, P.O. Box 450, Moss Land- 

 ing, CA 95039. 



'New York Zoological Society, Weston Road, Lincoln, MA 01773; 

 present address: Center for Long Term Research, Inc., Weston 

 Road, Lincoln, MA 01773. 



"LGL Ltd., Environmental Research Associates, 22 Fisher 

 Street, King City, Ontario LOG IKO, Canada; present address: 

 Sohio Alaska Petroleum Co., Pouch 6-612, Anchorage, AK 99502. 



^LGL Ltd., Environmental Research Associates, 22 Fisher 

 Street, King City, Ontario LOG IKO, Canada. 



offshore industrial activities (Richardson et al. in 

 press). 



The Western Arctic population of bowheads 

 winter in the Bering Sea, and migrate north and east 

 to the eastern Beaufort Sea in spring. During sum- 

 mer (late June to early September), most are off 

 northwestern Canada in Amundsen Gulf and the 

 eastern part of the Beaufort Sea (Fig. 1). In the com- 

 mercial whaling era in the 19th century, many bow- 

 heads apparently summered in the Chukchi and 

 western Beaufort Seas off Alaska (Townsend 1935), 

 but bowheads are no longer present in significant 

 numbers off Alaska in summer (Dahlheim et al. 

 1980). The eastern Beaufort Sea is believed to be a 

 major feeding area for bowheads (Fraker and Bock- 

 stoce 1980), but previous to 1980 there had been no 

 comprehensive studies of bowheads in that area. 



METHODS 



Aerial Observations 



We observed from a Britten-Norman*^ Islander air- 

 craft based at Tuktoyaktuk (Fig. 1). The Islander has 

 two piston engines, high wing configuration, and low 



^ Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



Manuscript accepted October 1984. 



FISHERY BULLETIN; VOL. 83, NO. 3, 1985. 



357 



