Pre-whaling subpopulation size:
This subpopulation was originally by far the most abundant of the bowhead whale subpopulations, but was heavily depleted by pre-modern commercial whaling from 1611 to the last recorded capture in 1911 (Ross 1993). The only record of catches by modern whaling refers to four taken by modern whaling near Svalbard in 1932 (Ruud 1937). Based on the catch record, a minimum initial subpopulation size was estimated by Woodby and Botkin (1993) at 24,000 whales. A modeling exercise (Allen and Keay 2006) resulted in an estimate of 52,000 but this may be too high given it assumed a net reproductive rate considerably lower than that currently observed in the Bering-Chukchi-Beaufort Seas subpopulation (see global assessment for this species).
Current subpopulation size
There is no quantitative estimate of current subpopulation size, but the available evidence suggests that it is small. Jonsgård (1982) reported no live sightings on surveys between Greenland and Svalbard and around Svalbard in 1980, but one dead probable bowhead. Based on post-war sightings of only seven individuals in Norwegian and adjacent waters up to 1990, Christensen et al. (1992) suggested that the subpopulation numbered “in the tens”. However, the Norwegian record may have given a somewhat exaggerated impression of rarity, due to lack of coverage within the pack ice.
Moore and Reeves (1993) list 37 sightings between 1940 and 1990, mainly near Svalbard and Franz Josef Land (Russian Federation). The records include two sightings (Belikov et al. 1989) of apparently quite large winter aggregations near Franz Josef Land in 1981 (“several tens of individuals”) and 1983 (“about 66 animals”). Gilg and Born (2005) list 23 definite and probable sightings off East Greenland during 1940–2004, including a probable sighting of ten individuals in 2003. Seven sightings totalling about 20 individuals were reported in the Greenland Sea in April 2006 (Wiig et al. 2007). While the number of sightings records has increased over time this may reflect increased effort rather than increasing abundance. Among the recently reported observations, no calves or small individuals have been reported. The proportion of the subpopulation that comprises mature animals is unknown. A value of 44% has been estimated for the Bering-Chukchi-BeaufortSeas stock.
Anecdotal evidence from historical whaling accounts suggests the possibility of whales from a stock to the east, possibly the Bering-Chukchi-BeaufortSeas
stock, entering into these waters at times (Shelden et al
. 1995), which would complicate the interpretation of the sightings data with respect to the size of the remnant Svalbard
stock. Whether the current subpopulation is a remnant of the original Svalbard
stock, a recolonization, or a mixture of both, is currently unclear, but ongoing analyses of DNA from old bones might throw light on this question (Borge et al