Kingsley: Number and distribution of Delphinapterus leucas, In James, Hudson, and Ungava Bays, Canada 737 



N 

 75 



70 - 



65 



60 - 



55 -- 



50 



105 



95 



85 



75 



65 



55 



45 W 



Figure 1 



Map of northeastern Canada, showing the locations of the 1993 beluga whale aerial sui-veys in 

 James Bay, eastern Hudson Bay, and Ungava Bay. 



systematic transect sui-vey was flown over offshore areas 

 of James Bay, eastern Hudson Bay, and Ungava Bay (Figs. 

 1-3 ). However, summering beluga whales often form dense 

 coastal concentrations, which are inefficiently estimated 

 by sample survey. Therefore, coastal surveys were also 

 fliown in eastern Hudson Bay and Ungava Bay to check 

 whether large numbers in concentration areas might have 

 caused serious errors in the results of sample sui-veys. To 

 the same end, watches were kept over known estuarine 

 concentration areas from vantage points on land in 1992 

 and 1993. 



Methods 



Beluga whales concentrate in and around the mouths of 

 rivers in summer, and this habit largely defines accepted 

 stocks ( Brown Gladden et al., 1997 ). Therefore aerial surveys 

 for stock assessment are normally carried out in summer in 

 these areas. The survey area for this study comprised James 

 Bay, the eastern Hudson Bay arc north to 59°N and as far 

 west as 80°20'\\', and Ungava Bay. This area was similar to 

 that covered by the previous aerial sui-vey of these stocks in 

 1985 (Smith and Hammill, 1986). Beluga whales are uncom- 

 mon in summer along the northern part of the eastern coast 

 of Hudson Bay and the southern coast of Hudson Strait 

 (Finley et al., 1982; Smith and Hammill, 1986); therefore the 

 sui-vey did not include these areas. 



The transects in James Bay and eastern Hudson Bay 

 were systematically spaced east-west lines similar to those 



used in 1985 (Smith and Hammill, 1986) (Fig. 2 ). They were 

 on exact 10' lines of latitude (i.e. 18.52 km apart) from the 

 southern end of James Bay at 51°10'N as far as 58°50'N 

 near Inukjuak, and additional lines were interpolated at 

 5' (9.26-km) intervals between 55°35'N and 57°35'N, i.e. in 

 the central part of the Hudson Bay arc. 



The survey of Ungava Bay was also based on systematic 

 designs (Fig. 3). South of 59°30'N, the initial design had 

 north-south transects on every IS'*' minute of longitude, 

 a spacing approximately equal to 7.5 minutes of latitude 

 ( 13.9 km). North of this line the transects lay east-west on 

 every tenth minute of latitude, i.e. 18.52 km apart. 



Earlier sui^veys of Ungava Bay had detected few beluga 

 whales (Finley, 1982; Smith and Hammill, 1986). Inuk 

 hunters had suggested that flying at different times in 

 the summer might produce different results; therefore the 

 Ungava Bay sui-vey was flown twice: in mid-July and in 

 late August. In both sui-veys, sections of the coastline were 

 followed and surveyed when ferrying to and from transect 

 blocks, so that the coastline, particularly near the logistic 

 base at Kuujjuak, was repeatedly covered. 



The transect sui-vey of James Bay and eastern Hudson 

 Bay was flown in a Cessna 337 aircraft, at 1500 feet (457 m) 

 above sea level at about 130 knots, (67 m/s), and navigated 

 by GPS. The aircraft was equipped with flat windows. 

 Obsei-vers sat in the two seats behind the pilot. Line- 

 transect survey methods were used, in which all sightings 

 were recorded with their distance from the transect line, 

 and a sighting curve was subsequently calculated to correct 

 for the decreasing detectability of targets with distance. 



