Hankering back to ancestral pasts [Elektronische Ressource] : constraints on two pinnipeds, Phoca vitulina & Leptonychotes weddellii foraging from a central place / vorgelegt von Nikolai S. Liebsch

Hankering back to ancestral pasts [Elektronische Ressource] : constraints on two pinnipeds, Phoca vitulina & Leptonychotes weddellii foraging from a central place / vorgelegt von Nikolai S. Liebsch

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Hankering back to ancestral pasts:
constraints on two pinnipeds,
Phoca vitulina & Leptonychotes weddellii
foraging from a central place



Nikolai S. Liebsch

Mai 2006




















Hankering back to ancestral pasts:
constraints on two pinnipeds,
Phoca vitulina & Leptonychotes weddellii
foraging from a central place




Dissertation
zur Erlangung des Doktorgrades
der Mathematischen-Naturwissenschaftlichen Fakultät
der Christian-Albrechts-Universität
zu Kiel



Vorgelegt von
Nikolai S. Liebsch
Kiel / Swansea

Mai 2006































Referent/in: Prof. em. Dr. D. Adelung
Korreferent/in: Prof. Dr. M. Spindler
Tag der mündlichen Prüfung: 06. Juli 2006
Zum Druck genehmigt: Kiel, den .....................................................

Der Dekan
Table of Contents
ABSTRACT 1
ZUSAMMENFASSUNG 3
CHAPTER 1 INTRODUCTION 7
CHAPTER 2 MATERIALS AND METHODS 10
2.1 STUDY ANIMALS, SITES & PROJECTS 10
2.1.1 HARBOUR SEALS - NORTH SEA – MINOS 10
2.1.2 WEDDELL SEALS - WEDDELL SEA - ANT XXI/2 12
2.2 DEVICES 15
2.2.1 THE DEAD-RECKONERS 15
2.2.2 THE SATELLITE TRANSMITTER 18
2.2.3 THE IMASEN (INTER-MANDIBULAR ANGLE SENSOR) 19
2.2.4 THE RELEASE MECHANISM 21
2.2.5 THE HOUSING AND ATTACHMENT 22
2.3 PRELIMINARY TRIALS ON CAPTIVE ANIMALS 25
2.3.1 IMASEN TRIALS 25
2.3.2 ATTACHMENT TRIALS 26
2.4 DEPLOYMENT AND RECOVERY OF THE DEVICES IN FREE LIVING SEALS 28
2.4.1 DEVICE PROGRAMMING 28
2.4.2 CAPTURE AND IMMOBILISATION 29
2.4.3 DEVICE ATTACHMENT & RECOVERY 31
2.5 TREATMENT OF COLLECTED DATA 34
2.5.1 DIVE ANALYSIS 34
2.5.2 MOVEMENT ANALYSIS 35
2.5.3 FEEDING ANALYSIS 44
2.5.4 DATA MERGING 45
2.5.5 PSEUDO- AND OVER- REPRESENTATION
CHAPTER 3 RESULTS AND GENERAL INTERPRETATION 46
I3.1 HARBOUR SEALS - NORTH SEA – MINOS 46
3.1.1 AREA USE 47
3.1.2 BEHAVIOUR 52
3.1.3 IN SEARCH OF THE DEFINITION AND FUNCTION OF DIFFERENT DIVE TYPES 54
3.1.4 FEEDING 66
3.1.5 TORTUOSITY OF TRACKS: AREA INTEREST INDEX (AII) 70
3.1.6 DIVE TYPES ACCORDING TO PROPOSED FUNCTION 78
3.1.7 DIEL RHYTHMS IN DIVING BEHAVIOUR AND DEPTH EXPLOITATION 83
3.2 WEDDELL SEALS - WEDDELL SEA - ANT XXI/2 86
3.2.1 AREA USE 86
3.2.2 BEHAVIOUR 88
3.2.3 IN SEARCH OF THE DEFINITION AND FUNCTION OF DIFFERENT DIVE TYPES 89
3.2.4 FEEDING 96
3.2.5 TORTUOSITY OF TRACKS: AREA INTEREST INDEX (AII) 98
3.2.6 DIVE TYPES ACCORDING TO PROPOSED FUNCTION 102
3.2.7 DIEL RHYTHMS IN DIVING BEHAVIOUR AND DEPTH EXPLOITATION 107
CHAPTER 4 DISCUSSION 108
4.1 DEVICE EFFECTS 108
4.2 ERRORS & LIMITATIONS 108
4.2.1 ERRORS IN DEAD-RECKONING 108
4.2.2 LIMITATIONS OF THE IMASEN 113
4.3 UTILITY OF THE IMASEN 114
CHAPTER 5 SYNTHESIS 117
5.1 ECONOMIC STRATEGIES 118
5.1.1 DIVE EFFICIENCY 118
5.1.2 FORAGING RANGE 122
5.1.3 INTEGRATED EFFICIENCY 123
5.2 GENERALIZED MODEL 128
BIBLIOGRAPHY 133
TABLES 145
II ACKNOWLEDGEMENT 149
ERKLÄRUNG 151











































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