6 March
2008 - Designating protected areas for harbour
porpoises implies identifying areas of high
porpoise density with particular focus on
the distribution during the breeding season.
This report collates all relevant data on
movements and density of the harbour porpoises
in Danish and adjacent waters in order to
identify key habitats, i.e. areas with high
density, for harbour porpoises in Denmark
that may be useful when designating protected
areas under the Habitats Directive.
Comprehensive data from
satellite tracking, aerial and ship surveys
as well as acoustic surveys from ship have
been collected from 1991 to 2007 in Danish
waters.
In this study the primary
source of data for identifying key habitats
is satellite tracking of 63 harbour porpoises
in the period 1997-2007. The only major
areas that were not covered by the tagged
animals were the Southern North Sea and
the waters around Bornholm .
In the Southern North
Sea , data from aerial surveys was used
to identify high density areas. Data from
the area around Bornholm were too limited
to determine harbour porpoise distribution
and density. In northern North Sea and Inner
Danish Waters acoustic ship surveys and
aerial surveys were used as an independent
method to confirm the presence of the high
density areas found by analysis of the satellite
tracking data.
The high density areas
are described separately based on the management
units proposed based on previous population
structure studies.
Four management areas
are proposed but only in three areas there
are data sufficient to identify high density
areas. The three areas are:
1. The Inner Danish
Waters (south of Læsø in Kattegat
) through the belts andØresund to
the Western Baltic (west of Bornholm )
2. The Skagerrak /northern
North Sea/northern Kattegat (north of Læsø
and north ofRingkøbing)
3. The southern North
Sea (south of Ringkøbing)
Each high density area
is ranked based on our current knowledge
of population structure, density, seasonal
variation in distribution and other relevant
information.
The rankings are defined
as
1=high importance,
2=medium importance
3=lower importance
Sixteen areas were found
to have high density and were ranked as
follows for the three areas (rankings in
parentheses):
Inner Danish Waters:
1. Northern Little Belt (2), 2. Southern
Little Belt (1), 3. Southern Samsø
Belt (2), 4. Northern Samsø Belt
(3), 5. Northern Øresund (1), 6.
Store Middelgrund (2), 7. Kalundborg Fjord
(1), 8. Great Belt (1), 9. Smålandsfarvandet
(3), 10. Flensborg Fjord (1), 11. Fehmarn
Belt (1), 12. Kadet Trench (2)
Northern North Sea :
13. Tip of Jylland (1), 14. Skagerrak (along
Norwegian Trench, 2)
Southern North Sea :
15. Horns Rev (1), 16. German Bight (1)
Contact: Senior scientist Jonas Teilmann
