214
3
present Address: Institute for Terrestrial and Aquatic
Wildlife Research (ITAW), University of Veterinary
Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum,
Germany
4
National Institute of Polar Research, 10-3, Midori-cho,
Tachikawa-shi, Tokyo 190-8518, Japan
*corresponding author: Dominik.Nachtsheim@tihohannover.de
Keywords: Weddell seal, Leptonychotes weddellii, Shelf
ice, Foraging ecology, Bio-logging
The Weddell seal (Leptonychotes weddellii) inhabits the
Antarctic coastal ecosystem and aggregates in areas characterized by a stable fast ice layer. Due to their extreme diving
capabilities, they are able to exploit both pelagic and benthic prey resources. They mainly feed on fishes but occasionally also take cephalopods and crustaceans. Weddell
seals instrumented with still-picture camera loggers in the
Drescher Inlet, eastern Weddell Sea, detected an unknown
cryo- benthic community underneath the floating ice shelf.
Images show dense aggregations of invertebrates that likely
represent an attractive food horizon for Weddell seals. In
this context, we conducted a retrospective analysis of dive
profiles collected in the Drescher Inlet to identify favored
hunting depths of Weddell seals and correlate those to the
local physical and biological environment. A total of 34
adult Weddell seals were instrumented with dive loggers in
the course of six summer field campaigns between 1990 and
2016. An automated broken stick algorithm was used to
separate each dive profile into different segments. Segments
with a high sinuosity were considered to indicate hunting.
Segments characterized by a straight dive trajectories (low
sinuosity), were assumed to be transit phases with no hunting activities. A tri-modal distribution of mean hunting
depths suggests that Weddell seals concentrated their foraging activities in three depth strata. A peak in hunting depths
below 370 m corresponds to the sea floor of the Drescher
Inlet, indicating demersal foraging. A second peak between
110 and 160 m matches with the depth of the underside of
the floating ice shelf, which suggests shelf ice associated
foraging. The third peak probably represents hunting in the
pelagic realm. Our investigation highlights the importance
of the shelf ice underside as an attractive food horizon for
Weddell seals suggesting a re-evaluation of trophic interactions and bentho- pelagic processes in the coastal Antarctic
ecosystem.
6.2.4 Diet of Red-Throated Divers Within
an Important Wintering Site, the German Bight,
Analyzed with Molecular Tools
Birgit Kleinschmidt
1,2
*, Monika Dorsch
2
, Stefan Heinänen
3
,
Julius Morkūnas
4
, Ramūnas Žydelis
3
, Claudia Burger
2
,
Georg Nehls
2
, Rosemary Moorhouse Gann
5
, William O. C.
Symondson
5
, Petra Quillfeldt
1
1
Department of Animal Ecology and Systematics, Justus
Liebig University Giessen, Heinrich Buff Ring 38, 35392
Giessen, Germany
2
BioConsult SH, Schobüller Str. 36, Husum 25813,
Germany
3
DHI, Agern Allé 5, Hørsholm 2970, Denmark
4
Klaipeda University, Vilhelmo Berbomo g.10, 92221
Lithuania
5
Cardiff School of Biosciences, Cardiff University, Sir
Martin Evans Building, Museum Ave, Cardiff CF10 3AX,
UK
*corresponding author: Birgit.Kleinschmidt@bio.unigiessen.de; b.kleinschmidt@bioconsult-sh.de
Keywords: Red-throated diver, Diet, North Sea,
Piscivorous, Next generation sequencing
The red-throated diver (Gavia stellata) is a strictly protected piscivorous migratory species, breeding primarily in the
arctic regions and wintering in temperate coastal waters of the
northern hemisphere. With high diver abundances in late winter and spring, the North Sea, especially the German Bight,
represents one of the major resting sites for West Palearctic
birds within the wintering season. The North Sea also represents a changing habitat with an increasing offshore windfarm
development, and as red-throated divers are known to be sensitive with anthropogenic disturbance, this development can
lead to conflicts. For habitat choice, resource availability, such
as prey accessibility, might be essential, but the overall knowledge about diet choice of red- throated divers at the North Sea
is rare. However, for conservation, a better understanding of
dietary composition of red-throated divers within this important wintering and staging habitat is crucial to understand
habitat choice and distribution of red-throated divers. We used
standard molecular tools and Next generation sequencing to
analyze fecal samples of red throated divers captured within
the German Bight in 2015 and 2016 in winter and spring to
obtain information of diet composition. Comparing the results
of 28 samples we found a similar pattern between years. At all
we found a wide ranged spectrum with 16 prey species of 11
families including flatfish, sand eels, and gobies but mackerel,
gadoids, and clupeids as most abundant prey species. The
results for the North Sea about dietary composition contribute
existing knowledge that red-throated divers are in general
opportunistic feeders with a preference for high energetic key
species, such as for this area Atlantic herring and Atlantic
sprat, and therefore indicate the importance of the occurrence
of these prey species within utilized areas of red-throated divers, and extent the results known so far.
6.2.5 Protecting African Penguin Through
Adaptive and Dynamic Management
B. C. Heylen
1,2*
, L. Pichegru
3
1
EMBC+ International Master in Marine Biodiversity &
Conservation, Ghent University, Belgium
Appendices
3
present Address: Institute for Terrestrial and Aquatic
Wildlife Research (ITAW), University of Veterinary
Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum,
Germany
4
National Institute of Polar Research, 10-3, Midori-cho,
Tachikawa-shi, Tokyo 190-8518, Japan
*corresponding author: Dominik.Nachtsheim@tihohannover.de
Keywords: Weddell seal, Leptonychotes weddellii, Shelf
ice, Foraging ecology, Bio-logging
The Weddell seal (Leptonychotes weddellii) inhabits the
Antarctic coastal ecosystem and aggregates in areas characterized by a stable fast ice layer. Due to their extreme diving
capabilities, they are able to exploit both pelagic and benthic prey resources. They mainly feed on fishes but occasionally also take cephalopods and crustaceans. Weddell
seals instrumented with still-picture camera loggers in the
Drescher Inlet, eastern Weddell Sea, detected an unknown
cryo- benthic community underneath the floating ice shelf.
Images show dense aggregations of invertebrates that likely
represent an attractive food horizon for Weddell seals. In
this context, we conducted a retrospective analysis of dive
profiles collected in the Drescher Inlet to identify favored
hunting depths of Weddell seals and correlate those to the
local physical and biological environment. A total of 34
adult Weddell seals were instrumented with dive loggers in
the course of six summer field campaigns between 1990 and
2016. An automated broken stick algorithm was used to
separate each dive profile into different segments. Segments
with a high sinuosity were considered to indicate hunting.
Segments characterized by a straight dive trajectories (low
sinuosity), were assumed to be transit phases with no hunting activities. A tri-modal distribution of mean hunting
depths suggests that Weddell seals concentrated their foraging activities in three depth strata. A peak in hunting depths
below 370 m corresponds to the sea floor of the Drescher
Inlet, indicating demersal foraging. A second peak between
110 and 160 m matches with the depth of the underside of
the floating ice shelf, which suggests shelf ice associated
foraging. The third peak probably represents hunting in the
pelagic realm. Our investigation highlights the importance
of the shelf ice underside as an attractive food horizon for
Weddell seals suggesting a re-evaluation of trophic interactions and bentho- pelagic processes in the coastal Antarctic
ecosystem.
6.2.4 Diet of Red-Throated Divers Within
an Important Wintering Site, the German Bight,
Analyzed with Molecular Tools
Birgit Kleinschmidt
1,2
*, Monika Dorsch
2
, Stefan Heinänen
3
,
Julius Morkūnas
4
, Ramūnas Žydelis
3
, Claudia Burger
2
,
Georg Nehls
2
, Rosemary Moorhouse Gann
5
, William O. C.
Symondson
5
, Petra Quillfeldt
1
1
Department of Animal Ecology and Systematics, Justus
Liebig University Giessen, Heinrich Buff Ring 38, 35392
Giessen, Germany
2
BioConsult SH, Schobüller Str. 36, Husum 25813,
Germany
3
DHI, Agern Allé 5, Hørsholm 2970, Denmark
4
Klaipeda University, Vilhelmo Berbomo g.10, 92221
Lithuania
5
Cardiff School of Biosciences, Cardiff University, Sir
Martin Evans Building, Museum Ave, Cardiff CF10 3AX,
UK
*corresponding author: Birgit.Kleinschmidt@bio.unigiessen.de; b.kleinschmidt@bioconsult-sh.de
Keywords: Red-throated diver, Diet, North Sea,
Piscivorous, Next generation sequencing
The red-throated diver (Gavia stellata) is a strictly protected piscivorous migratory species, breeding primarily in the
arctic regions and wintering in temperate coastal waters of the
northern hemisphere. With high diver abundances in late winter and spring, the North Sea, especially the German Bight,
represents one of the major resting sites for West Palearctic
birds within the wintering season. The North Sea also represents a changing habitat with an increasing offshore windfarm
development, and as red-throated divers are known to be sensitive with anthropogenic disturbance, this development can
lead to conflicts. For habitat choice, resource availability, such
as prey accessibility, might be essential, but the overall knowledge about diet choice of red- throated divers at the North Sea
is rare. However, for conservation, a better understanding of
dietary composition of red-throated divers within this important wintering and staging habitat is crucial to understand
habitat choice and distribution of red-throated divers. We used
standard molecular tools and Next generation sequencing to
analyze fecal samples of red throated divers captured within
the German Bight in 2015 and 2016 in winter and spring to
obtain information of diet composition. Comparing the results
of 28 samples we found a similar pattern between years. At all
we found a wide ranged spectrum with 16 prey species of 11
families including flatfish, sand eels, and gobies but mackerel,
gadoids, and clupeids as most abundant prey species. The
results for the North Sea about dietary composition contribute
existing knowledge that red-throated divers are in general
opportunistic feeders with a preference for high energetic key
species, such as for this area Atlantic herring and Atlantic
sprat, and therefore indicate the importance of the occurrence
of these prey species within utilized areas of red-throated divers, and extent the results known so far.
6.2.5 Protecting African Penguin Through
Adaptive and Dynamic Management
B. C. Heylen
1,2*
, L. Pichegru
3
1
EMBC+ International Master in Marine Biodiversity &
Conservation, Ghent University, Belgium
Appendices