Numbers and distribution of beluga whales, Delphinapterus leucas, in James Bay, eastern Hudson Bay, and Ungava Bay in Canada during the summer of 1993

Issue:

Author(s): 
Kingsley, Michael C. S.
Cover date: 
2000
PDF: 
Pages: 
736-747
Abstract: 

Aerial surveys to estimate the numbers of beluga whales, Delphinapterus leucas, were flown in James Bay, eastern Hudson Bay, and Ungava Bay in Canada in the summer of 1993 on transects systematically spaced 5 or 10 nmi apart. In James Bay and eastern Hudson Bay line-transect methods were used. In Ungava Bay strip transects were used, and off-transect sightings were also recorded. Beluga whales were also counted on coastal fl ights in eastern Hudson Bay and Ungava Bay. James Bay and eastern Hudson Bay were surveyed in August; Ungava Bay in July and again in August. Watches were kept from land at estuaries in eastern Hudson Bay in 1993 and in Ungava Bay in 1992 and 1993. The estimates of detectable beluga whales (uncorrected for diving and observer errors) were 3141 (SE=787) in James Bay and 1014 (SE=421) in eastern Hudson Bay. A further 115–148 beluga whales were seen near the coast of eastern Hudson Bay during the coastal survey, but mostly away from traditionally used estuaries. The estimate for James Bay was nearly three times the previous estimate, made in 1985, possibly because ice cover in James Bay was much lower in 1993 than in the 1985 survey. The 1993 estimate for eastern Hudson Bay was close to that for 1985. No beluga whales were seen during aerial transects in Ungava Bay, but they were seen off-transect and on coastal flights, mostly in or near the Whale River estuary in southern Ungava Bay. The largest group sighted and the greatest number seen in any day consisted of 20 individuals, a minimum size for the summer population in Ungava Bay. An upper 90% confidence limit for summer numbers is imprecisely estimated at 150. Neither the coastal surveys nor the land-based observations in Hudson Bay and Ungava Bay indicated the presence of large, dense herds that might have been inefficiently sampled by transect survey.