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

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Killer whale, Orcinus orca
These top predators are found in all oceans, at various depths and do not
seem to have any latitudinal restrictions on their home range, other than sea
ice. However, abundance is higher in colder waters near the shore (Jefferson
et al. 2008). Killer whales feed on prey varying from small schooling fish to
large marine mammals and their high dietary specialisations divides them
into ecotypes. Examples of prey choice are herring in Norway (Christensen
1982), sharks in New Zealand (Visser 2005), sea lions and elephant seals in
Patagonia (Lopez & Lopez 1985) and either minke whales, fish or seals and
penguins in Antarctic (Pitman & Ensor 2003). Mating between different ecotypes
rarely occurs (Pilot et al. 2009). Killer whales live in natal pods where
mating occur outside the pod during interaction with other groups (Pilot et
al. 2009). Groups most often contain between 3-30 individuals but may count
more than 100 animals (review in Baird 2000).
Studies on killer whales in Greenland are almost non-existent and their distribution
is very poorly understood. Yet, Heide-Jørgensen (1988) reviewed
published and unpublished information available on killer whales in Greenland
and carried out a questionnaire-based investigation of sightings of killer
whales. He found that killer whales were observed in all areas of West
Greenland, with more sightings in Qaanaaq, Disko, Nuuk and Qaqortoq.
However sightings are sparse along the West Greenland coast (Teilmann &
Dietz 1998).
It is not known whether the killer whales found in Greenland constitute
their own population or are part of a larger population within the Atlantic
Ocean. The notion of a population in the Northeast Atlantic with a range including
West Greenland and East Canada is supported by satellite tracking
of a single individual from August to November 2009 that moved from the
Canadian High Arctic (Lancaster Sound) , via Baffin Bay and the Davis
Strait, to waters west of the Azores (Petersen et al. 2009). Due to the scarce
knowledge in Greenland, killer whales are listed as not applicable on the
Greenland Red List (Boertmann 2007). Despite the extensive studies on killer
whales in other areas of the world they are listed as data deficient on the
IUCN Red List (IUCN 2008) due to ambiguities regarding taxonomy.
Harbour porpoises, Phocoena phocoena
Harbour porpoises are the smallest cetaceans found in Greenland and reach
a length of 1.8m and a weight of up to 90 kg. It is amongst the most abundant
whale species in the North Atlantic and also in West Greenland where
it occurs from the southernmost tip to the Avanersuaq district in Northwest
Greenland (Teilmann & Dietz 1998). However, the main distribution of harbour
porpoises in West Greenland lies between Sisimiut and Paamiut
(Teilmann & Dietz 1998), which corresponds to the range of the entire assessment
area from 62°-67°N. In West Greenland the harbour porpoises inhabit
fjords, coastal and continental shelf areas and abundance decreases
with depth (Hansen 2010). Although ice formation forces harbour porpoises
to leave the area north of Disko from January to April, catch statistics show
that they are present year round in West Greenland. Yet, it is possible that
the majority leave the coast for offshore waters during late autumn and return
during spring (Teilmann & Dietz 1998).
Their main prey consists of fish and squid and in West Greenland capelin
(Mallotus villosus) is the predominant part of their diet (Lockyer et al. 2003).