were used; the usual crew of two observers, one recorder, 

 and one person resting aft rotated hourly to reduce observer 

 fatigue. For the study period 1976-78, the Grumman Goose 

 was by far the more frequently used aircraft. 



Information recorded included species identification; num- 

 ber of adults and/or calves; local time of sightings; geo- 

 graphic position to 1 square nmi obtained from an onboard 

 Global Navigation System-500; perpendicular angular dis- 

 tance from aircraft to animal(s) taken with an optical read- 

 ing clinometer (Model PM-5/360 PC, by Suunto Oy of Fin- 

 land); animal activity; and environmental data on weather, 

 visibility, and ice. Complete documentation of aerial survey 

 methodology used for this research is reported in Krogman 

 et al. (1979) 8 . 



Laboratory Activities 



Ice and land camp results are presented by locality by year. 

 Length of season, total number of hours watched, percent of 

 total hours watched, total number of whales counted, and 

 indices to total number of whales passing by the counting 

 camps are presented. Bowhead abundance indices for spring 

 seasons 1976 and 1977 were computed as the sum of the 

 products of rates per day for each day times 24 h. Histo- 

 grams showing the daily index are used to illustrate temporal 

 distribution that occurred during each field study. Indices are 

 presented for bowheads only. The temporal distribution of 

 white whales was too clumped to calculate a meaningful 

 index. 



Aerial survey results are presented in computer plots show- 

 ing effort and sighting data. Numerical results accompanying 

 the figures include the total number of adults and immatures 

 observed, average group size, and standard deviation (SD) of 

 average group size. A plot of all tracklines flown in 1976 and 

 1977 is displayed in Appendix II. 



REVIEW OF BOWHEAD STOCKS 



Rice (1977) recognized four bowhead whale populations or 

 stocks worldwide: 1) From Spitsbergen west to east Green- 

 land, called the Spitsbergen stock by Tomilin (1957) or Spits- 

 bergen-Barents Sea stock by Jonsgard'; 2) in Hudson Bay, 

 Davis Strait, Baffin Bay, and James Bay, called the West 

 Greenland stock by Tomilin (1957) or Davis Strait stock by 

 the International Whaling Commission (IWC) Committee of 

 Scientific Advisors (IWC 1978); 3) Bering, Chukchi, and 

 Beaufort Seas, called the Bering-Chukchi stock by Tomilin 

 (1957), Bering Sea stock by the IWC (1978), or the western 

 Arctic population by Durham (1972)'° and Bockstoce (1977); 

 and 4) in the Sea of Okhotsk. Mitchell (1975) recognized five 

 stocks, treating a Hudson Bay stock as isolated from the 

 West Greenland stock. Figure 1 is an overview of the species 

 distribution prior to commercial exploitation. 



Commercial whaling severly reduced the Spitsbergen stock 

 during the 17th century, the West Greenland stock during the 

 18th century, and the western Arctic-Bering Sea and Okhotsk 

 Sea stocks during the 19th century (Tomilin 1957; Braham 

 and Krogman footnote 2; Bockstoce 1978"). 



Spitsbergen-Barents Sea Stock 



Bowheads from this stock apparently wintered south of the 

 area bounded by the eastern coast of Greenland, Iceland, 

 and Jan Mayen Island, to Spitsbergen (Tomilin 1957). Their 

 northeasterly spring movement was associated with the reces- 

 sion of the ice front, with some whales arriving at Spitsber- 

 gen in April (Clark 1943). By early summer, most of the 

 population was found between Greenland, Spitsbergen, and 

 the Barents Sea, with some animals occurring south along the 

 coast of Greenland when sea ice coverage was extensive (Vibe 

 1967). A southerly migration was made during autumn along 

 the Greenland coast and open winter areas of the coast. 

 From an initial population estimated at 25,000 (IWC 1978), 

 the Spitsbergen-Barents Sea stock underwent a gross reduc- 

 tion in size as a result of intensive commercial whaling (Vibe 

 1967). This stock is now considered to be nearing extinction 

 (Jonsgard 1981, footnote 9). Reeves (1980) recently com- 

 pleted a review of the stock. 



West Greenland or Davis Strait Stock 



Recent information on the seasonal distribution of bow- 

 heads in this stock is lacking. However they apparently winter 

 in southern Davis Strait from Godhaven southwest to approx- 

 imately lat. 60°00'N. Migration to summering grounds is 

 closely associated with the northerly retreat of the ice front. 

 The summering area and migration routes include northeast 

 Baffin Bay as far north as Smith Sound (Clark 1943), the 

 waters between the islands of the Canadian Arctic Islands 

 and as far west as Barrow Strait (Gilmore 1951), Lancaster 

 Sound, and Prince Regent Inlet (Lubbock 1937). Animals 

 apparently winter also in Hudson Strait and southcentral and 

 western Hudson Bay. In summer, animals move to the north- 

 western part of Hudson Bay and Foxe Basin (Gilmore 1951; 

 Ross 1974). Sex and age segregation within the population 

 was reported by Southwell (1898) to be that older males 

 occurred more often in open water than females and young 

 who were associated with the pack ice front. The initial stock 

 size was estimated at 6,000 and the current level is believed to 

 be 10% of that (IWC 1978). However, since so few animals 

 have been seen in this century, it seems likely that the present 

 population size is smaller than the 10% estimated. 12 Mans- 

 field (1971) believed the stock was recovering; recent studies 

 have not confirmed this (Davis and Koski 1980). 



Western Arctic-Bering Sea Stock 



"Krogman, B. D., R. M. Sonntag. and H. W. Braham. 1979. Arctic Whale 

 Task aerial survey format 1979 version. Unpubl. manuscr., 30 p. Natl. Mar. 

 Mammal Lab., Natl. Mar. Fish. Serv., NOAA. 7600 Sand Point WayNE., Bldg. 

 32, Seattle, W A 981 15. 



*A. Jonsgard, University of Oslo, Oslo, Norway, pers. commun. 7 February 

 1979. 



"Durham, F. E. 1972. Biology of the bowhead whale {Balaena mysticetus L.) 

 in the western Arctic. Unpubl. manuscr., 93 p. Univ. Southern Calif., Dep. 

 Biol., Los Angeles, CA 90500. 



The distribution of bowheads in the western Arctic-Bering 

 Sea stock prior to commercial exploitation (1848) can be in- 



"Bockstoce, J. R. 1978. A preliminary estimate of the reduction of the west- 

 ern Arctic bowhead whale (Balaena mysticetus) population by the pelagic whal- 

 ing industry: 1848-1915. Unpubl. rep., 33 p. U.S. Mar. Mammal Comm., 1625 I 

 St. N.W., Wash., DC 20006. 



I! R. Davis. LGL Ltd., Toronto, Can., pers. commun. 30 June 1979. 



