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

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very low annual reproductive output is counterbalanced by a very long expected
life of 15–20 years or more. These seabirds are therefore particularly
vulnerable to additional adult mortality caused, for example, by an oil spill.
If a breeding colony of birds is completely wiped out by an oil spill it must
be recolonised from neighbouring colonies. Recolonisation is dependent on
the proximity, size and productivity of these colonies. If the numbers of
birds in neighbouring colonies are declining, for example due to hunting,
there will be no or only few birds available for re-colonisation of a site.
Breeding birds
A large number of seabird species breed in the assessment area (see section
4.7.5) and the majority are associated with habitats along the outer coastline
(sea-facing cliffs or on low islets), which are highly exposed to drifting oil.
Such exposed areas are almost inaccessible to oil spill response due to remoteness
and often harsh weather conditions. A further risk situation is
when adults swim away from the colony accompanying their chicks, e.g.
auks and seaducks. Some will move further inshore to find sheltered areas;
others (e.g. murres, being flightless) will move offshore and disperse over
extensive areas. Two of the species breeding in the assessment area, Atlantic
puffin and common murre, are rare breeders to Greenland and listed as near
threatened or endangered, respectively, on the Greenland Red List, while
two other species, Iceland gull and white-tailed eagle (subspcies), are endemic
to Greenland (Boertmann 2007). The two auk species are also colonial
breeders, which mean that a large proportion of the Greenland population
risk being wiped out by a single oil spill.
Staging, moulting and wintering birds
A large oil spill in the assessment area may potentially affect seabirds from
many areas of the North Atlantic, due to Southwest Greenland being an international
important foraging area throughout most of the year. The visitors
include non-breeding birds from Europe and the southern hemisphere
(e.g., black-legged kittiwakes and great shearwaters, respectively), moulting
birds from Canada (e.g., harlequin ducks) and wintering birds from a range
of breeding areas in the North Atlantic (e.g., murres). Just in the coastal area
of Southwest Greenland, the number of wintering birds is estimated to be
more than 3.5 million and a very large proportion of these are found within
the assessment area. In addition, king eiders utilise the shallow water offshore
on banks and an unknown but large number of murres, puffins, kittiwakes
and especially little auks utilise areas further offshore (Boertmann et
al. 2004, Boertmann et al. 2006). A large number of eiders, murres and little
auks are also assumed to pass through the assessment area when migrating
back and forth to breeding areas in the northern Baffin Bay or eastern Canada
(Mosbech et al. 2006a, Mosbech et al. 2006b, Mosbech et al. 2007,
Boertmann et al. 2009). The number of birds potentially affected by a large
oil spill in the assessment area could therefore be extensive. On their northwards
spring migration through the Davis Strait, murres and little auks are
assumed to follow the ice edge of the western pack ice, where also oil will
tend to accumulate in case of a spill.
11.2.8 Oil spill impacts on marine mammals
Marine mammals are relatively robust and can generally survive short periods
of fouling and contact with oil, except for polar bears and seal pups, for
whom even short exposures can be lethal (Geraci & St. Aubin 1990).