Kingsley: Number and distribution of Delphinapterus leucas. in James, Hudson, and Ungava Bays, Canada 



745 



Table 4 



Distribution of beluga whale observations and estimated numbers of beluga whales in eastern Hudson Bay between the Nunavik 

 area, the Nunavut Settlement Area, and the Equal Use and Occupancy Area. 



Observations (%) 



Mean number per observation 



Estimated numbers CA ) 



Nunavik area 



Nunavut Settlement Area 



Equal Use and Occupancy Area 



23(361 

 25 (39) 

 16(25) 



4.2 

 1.4 

 1.2 



774(71) 

 211(19) 

 111(10) 



eastern Hudson Bay were not larger in 1993 than they 

 had been in 1984-5, but instead were very likely lower. 



Sightings of beluga whales in eastern Hudson Bay 

 showed that they were widely distributed in the shallow 

 water between the mainland coast and the Belcher Islands 

 (Fig. 4). Thirty-six percent of sightings were outside the 

 areas defined by the Nunavut Agreement (Table 4). but 

 these were on average the larger gi'oups, and represented 

 71*^ of the total numbers. Beluga whales were distributed 

 also around the Belcher Islands, particularly to the north, 

 and as far west as the survey extended. There was no 

 evidence of a discontinuity in the east-west distribution. 

 The sui-vey results were consistent with the hypothesis of 

 a single continuous population distributed from the coast 

 out to the survey limit. However, it is not known for sure 

 whether all the beluga whales in the study area were 

 among those that frequent the estuaries on the eastern 

 Hudson Bay mainland coast, nor whether they would be 

 available to hunters there. It remains possible that the 

 beluga whales using those estuaries are only a fraction of 

 the total numbers counted in the survey area. The question 

 of single or multiple summering stocks in eastern Hudson 

 Bay is important in designing strategies for managing 

 exploitation by residents of the communities on the Belcher 

 Islands and on the eastern Hudson Bay coast; aerial sui-vey 

 results alone can not provide conclusive answers. 



The north-south extent of the sightings in eastern 

 Hudson Bay was hmited, as in 1985; no beluga whales 

 were seen on the northernmost transects, and there was 

 no continuous distribution extending into areas farther 

 north. There are no large estuaries to attract summering 

 beluga whales to the eastern Hudson Bay coast north of 

 the Nastapoca River, and there are no reports, even anec- 

 dotal, of beluga whales spending the summer in those 

 areas. Thus it is unlikely that significant additional num- 

 bers would have been detected if this survey had extended 

 farther north. 



The estimate of numbers in Ungava Bay was uncertain. 

 In James Bay. beluga whale groups were widely distributed. 

 In Hudson Bay, densities were lower, but sightings were 

 frequent and widely distributed. In Ungava Bay very few 

 beluga whales were seen, indicating a very low density. 

 Population estimates from the transect sui-veys, based on 

 or 1 sighting per survey, are imprecise, but small, of the 

 same order as the highest daily total counts on survey 

 and reconnaissance flights combined, and consistent with 

 the maximum of about 25 beluga whales in the Muealic 



River estuary in summer estimated by Finley et al. ( 1982). 

 The present survey could have resighted the same small 

 group of about that size, or subgroups of it, on different 

 flights. The largest sighting from land was 17 individuals, 

 on 24 August 1993. Smith and Hammill (1986) sui-veyed 

 Ungava Bay in 1985, and saw few beluga whales; they 

 were unable to make a population estimate. 



Most sightings were made in and near the Whale River 

 estuary, but a few, small, scattered groups were also 

 sighted elsewhere in Ungava Bay (Table 3). Residents of 

 the area see beluga whales in summer, but not in large 

 numbers and not all the time (Brooke^; Brooke^; PortnofP). 

 Ungava Bay communities capture beluga whales in most 

 years, but often outside the bay and outside the season 

 when they inhabit their summer grounds. Neither survey 

 results nor harvest statistics provided a basis for consider- 

 ing a trend in summering stock size. 



Estimates from line-transect survey analysis were 

 conditional on the use of the Richards curve as a sighting 

 cui-ve. Both the hazard-rate curve and the normal curve 

 fitted the data worse. Maximum detection was not obtained 

 until 470 m from the aircraft, owing to its having flat 

 windows. Similar visibility restrictions have been estimated 

 in other surveys. In a line-transect aerial survey of nar- 

 whals in Scoresby Sund, in which the survey plane had flat 

 windows, there were poor sighting rates out to a sighting 

 angle of about 40° from the vertical (Larsen et al., 1994) 

 and in an aerial survey of cetaceans in the Gulf of St Law- 

 rence, in which the survey aircraft had shallow bubble 

 windows, maximum detection was not achieved until 35° 

 from the vertical (Kingsley and Reeves 1998). The loss of 

 visibility close to the aircraft militates in favour of lower 

 flying heights if surveys must be carried out in flat-win- 

 dowed aircraft and raises concerns about detection, if the 



^ Brooke. L. F. No date. A report on the 1994 Nunavik beluga 

 and walrus subsistence har\-est study. Unpublished report pre- 

 pared for the Department of Fisheries and Oceans. 104. rue 

 Dalhousie. Quebec P.Q. GIK 4B8. Canada, 29 p. 



' Brooke. L. F No date. A report on the 1995 Nunavik beluga 

 and walrus subsistence hai"V'est study. Unpublished report pre- 

 pared for the Department of Fisheries and Oceans. 104. rue Dal- 

 housie, Quebec P.Q, GIK 4B8, Canada, 29 p. 



** Portnoff.M. 1994. The 1993 Nunavik beluga whale and walrus 

 subsistence harvest study. Report prepared for the Department 

 of Fisheries and Oceans, 104. rue Dalhousie, Quebec P.Q. GIK 

 4B8. Canada by Nunavik Graphics, Montreal, 61 p. 



