The Davis Strait - DCE - Nationalt Center for Miljø og Energi

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squid form an important part of their diet in some areas. The species is believed
to make seasonal migrations between low-latitude wintering grounds
and high-latitude feeding grounds. However, the distribution of sei whales
is poorly understood and the occurrence of sei whales in West Greenland
may be linked to years with increased influx of warm currents from East
Greenland (Kapel 1985). Sei whale sound signals were recorded in the Davis
Strait in August-September, 2006-07 (Simon 2010). The abundance of sei
whales in West Greenland was estimated from a ship survey in 2005 to 1,599
individuals (95% CI=690-3,705). As with fin, humpback and minke whales,
there was a high density area within the assessment area. The overall distribution
of these rorquals is correlated with high densities of krill deeper than
150 m (Laidre et al. 2010). Sei whales are considered endangered on the
IUCN Red List (2008) of threatened species and as data deficient on the
Greenland Red List (Boertmann 2007).
Blue whale, Balaenoptera musculus
Blue whales are the largest animals ever to have existed on earth and reach
an average length of 25 m and weigh up to 120 tonnes. Blue whales are globally
distributed from the low latitudes to polar waters, where dense pack ice
and the ice edge limit their northern and southern distributions (Norris
1977). As with other rorquals, it is assumed that blue whales travel between
foraging areas at high latitudes in the summer and low-latitude breeding areas
during winter. Their main prey is krill but also capelin and sandeels are
part of their diet (Kapel 1979).
Observations of blue whales in West Greenland are rare and their presence
in the assessment area is poorly known. Yet several sightings have been reported
within the assessment area between 62°-66°N and individuals have
been documented to travel between foraging areas in Gulf of St. Lawrence to
West Greenland, which suggests a shared population of blue whales between
West Greenland and Eastern Canada (Sears & Larsen 2002). Passive
acoustic monitoring in 2006-2007 revealed blue whale calls in August-
September in the Davis Strait (Simon 2010).
Globally, blue whales are considered as endangered on the IUCN Red List
(2008) because most populations, including those in the North Atlantic, were
decimated by whaling in the 20 th century. The number of blue whales occurring
in West Greenland is unknown and therefore the species is classified as
data deficient on the Greenland Red List (Boertmann 2007). In the Central
North Atlantic, blue whales are common only around Iceland/East Greenland,
when sighting surveys between 1987 and 2001 indicate about 1,000
blue whales and the population may be growing at a rate of about 4-5% per
year (Pike et al. 2010). Blue whales are extremely rare in the Eastern North
Atlantic and in the Western North Atlantic only common in the Gulf of St.
Lawrence, where about 400 animals have been photo-identified (Ramp et al.
2006). The stock structure of blue whales in the North Atlantic is unknown,
but the different timings of depletions in Norway, Iceland and the Western
Atlantic suggest that discrete feeding aggregations exist.
Bowhead whale, Balaena mysticetus
Bowhead whales are long-lived and may be more than 200 years old (George
et al. 1999). They reach a length of 14-18 m and a weight 60-100 tonnes. The
bowhead whales belonging to the Baffin Bay stock spend most of the year in
the Canadian high Arctic around Baffin Island (Heide-Jørgensen et al.
2010b). In winter (January-February) part of the population migrates to West