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Summary
The populations of both the common seal and grey seal are
monitored annually to follow developments in the number
of seals. The monitoring is done from light aircraft which,
with their cruising range and bird’s eye view, are well suited
to the job. For management purposes, the common seal in
Denmark is divided into four populations on the basis of
genetic differences and tagging data: the Wadden Sea, the
Limfjord, the Kattegat and the western Baltic Sea. Monitor-
ing in the Wadden Sea is undertaken by the Fisheries and
Maritime Museum, while the Department of Bioscience at
Aarhus University makes the counts in the rest of the coun-
try. The Wadden Sea population is a continuous population
with a distribution in Danish, German and Dutch waters.
Since the deaths of half the population in an epidemic in
2002, there has initially been an average increase of 12 % a
year, but in recent years the growth rate has declined a little.
In 2011, the population in the Danish section of the Wadden
Sea was estimated at 4,950 common seals. The population
in the Limfjord was estimated at 1,500 in 2010. The popula-
tion in this area has fluctuated considerably, and it has not
increased over a period of ten years. The population in the
Kattegat was estimated at 7,700 in 2011. This population
has grown by 9 % a year since the ravages of the epidemic
in 2002. The population in the last area, the western Baltic
Sea, was estimated at about 1,400 in 2011. On the basis of
the counts in the various areas, the total Danish population
of common seals was 15,500 in 2011.
After an absence of 100 years, the grey seal has estab-
lished itself in recent years as a permanently breeding spe-
cies in Denmark. The Rødsand seal reserve at Gedser is cur-
rently the most important breeding site, but a few pups have
also been found at other localities. However, the grey seal
still does not breed in the Danish section of the Wadden Sea
despite growth in both the German and Dutch waters.
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