Ornithological Observations in the Greenland Sea
Fridtjof Mehlum & Morten Bilet
Objectives of study
Large numbers of seabirds are found in the Greenland Sea and the
Fram Strait region (Mehlum 1989). It is believed that most of
these birds breed along the western coasts of Spitsbergen. The
different species have their own habitat preference at sea. Previous
studies in Svaibard waters and elsewhere have shown that seabird
distributions at sea are often associated with physical features
which concentrate prey or make prey more easily available to seabirds.
These features might be frontal zones between different water
masses, eddies, ice-edges, coastal upweiling zones and shelf-breaks.
The main task of the present study was to collect supplementary
data on seabird distribution in the area and correlate these distributions
with physical oceanographic and bathymetric features.
Materials and Methods
The abundance of seabirds was recorded by standardized transect
methods (Tasker et al. 1984). A 300 m standard transect
width was applied. The observations were entered directly (real
time) into a pen computer (Grid). All birds observed within the
transect were recorded. A Visual Basic computer programme was
made for coding the observations and for minimizing the handling
time of each observation. The computer clock was synchronized
with the ships main clock. The ship's geographical position (GPS-system)
was entered to the field computer every 1/2 - 1 hour during periods
with steady course and speed, and otherwise upon changes in speed
or direction. An East-West transect was conducted at 79'N, from
the coast of Spitsbergen and into the marginal ice zone in the
Fram Strait. Several transects were made within the Marginal
ice zone, as well as several crossings of the outer iceedge.
A ca 330 km long transect was made just East of the ice-edge from
77°13'N, 05°15'W to 75°00'N, 13°35'N. The rest of the cruise
was conducted in ice- free waters, and comprised a West-East transect
at 75°N and a northward transect in the central Greenland Sea,
followed by a West-East transect at 78°N towards Isfjorden.
Preliminary results
The main species of interest were alcids (Alcidae). The Little
Auk (Alle alle) and the Brünnich's Guillemot (Uria Iomvia)
dominated by numbers. Similar to what has been recorded on
previous cruises west of Spitsbergen there was a peak in Brünnich's
10-min periods, Little Auks, 23-24 AUG. 1993
Fig. 1. Number of Little Auks (Alle alle) observed during
the transect from 77 to 75°N. The data are aggregated into 10-minute
observation intervals.
Guillemot numbers at the shelf break at the 79°N transect. Farther
West the numbers decreased rapidly to background level. In contrast,
the Little Auk was abundant at the ice edge and in ice covered
waters. On the latitudinal transect at 75°N Little Auks were
abundant only in the western part, supporting the hypothesis of
a SW migration of Svalbard birds. Brünnich's Guillemots were
low in numbers, but most observations were made generally more
to the south than in the case of Little Auks. Parents with young
were seen in the southwestern part of the study area, which support
the existing ringing data showing that the main wintering area
for Sva]bard birds is in SW Greenland.
References
F. Mehlum, 1989: Summer distribution of seabirds in northern Greenland
and Barents Seas. Norsk Polarinstitutt Skrifter 191, 1-56.
M.L. Tasker, P. Hope Jones, T. Dixon & B.F. Blake, 1984:
Counting seabirds at sea from ships: a review of methods employed
and a suggestion for a standardized approach. Auk 101, 567-577.