HARBOUR SEALS AND HUMAN INTERACTIONS IN DANISH WATERS Harbour seals and human interactions inDanishwaters Harbour sealsandhumaninteractions Since the protection of the Danish harbour seals in 1977 several seal reserves have been established, and the Danish harbour seal population has increased from around 2000 to approximately 16000 individuals. At the same time human activity in the marine environment has increased, both in terms of commercial and recreational use, and calls for a thorough evaluation of current management and its data basis is needed. Specifi cally, in order to manage the Danish harbour seals properly more detailed information on the current abundance and reproduction, as well as detailed information on harbour seal move- ments, and the importance of the interactions between harbour seals and human activities, such as fi sheries and disturbance activities is needed. The six papers included in the present PhD thesis starts out by providing an overview of the status of the Danish har- bour seal populations (Paper I), where after examinations of management-related issues are addressed: the harbour seal – cormorant – fi shery interactions in Limfjord (Paper II), the eff ects of constructional activity from an off shore wind farm on harbour seal haul-out numbers in the Rødsand seal reserve (Paper III), the eff ectiveness of current regulati- ons in the Anholt seal reserve to protect harbour seals from disturbances (Paper IV and V), and the seasonal move- ments of harbour seal in Kattegat (Paper VI). Based on the fi ndings in the PhD, several suggestions to improve the current management of the Danish harbour seals are given. HARBOUR SEALS AND HUMAN INTERACTIONS IN DANISH WATERS PhD thesis 2011 Signe May Andersen AARHUS UNIVERSTY ISBN: 978-87-92825-05-6 AU DEPARTMENT OF BIOSCIENCE HARBOUR SEALS AND HUMAN INTERACTIONS IN DANISH WATERS PhD thesis 2011 Signe May Andersen AARHUS AU UNIVERSITY DEPARTMENT OF BIOSCIENCE Data sheet Title: Harbour seals and human interactions in Danish waters Subtitle: PhD thesis Author: Signe May Andersen Institute: Institute of Biology, University of Southern Denmark and Aarhus University, Department of Bioscience Publisher: Aarhus University - Denmark URL: http://www.dmu.au.dk Year of publication: 2011 Editing completed: 9 September 2011 PhD supervisors: Dr. Lee A. Miller, Institute of Biology, University of Southern Denmark, Denmark Dr. Jonas Teilmann, Aarhus University, Department of Bioscience, Denmark Assessment committee: Dr. Magnus Wahlberg Dr. Lars Bejder Dr. Susanna Blackwell Please cite as: Andersen, S.M. 2011. Harbour seals and human interactions in Danish waters. PhD thesis. Institute of Biology, University of Southern Denmark and Department of Bioscience, Aarhus University, Denmark. 130 pp. Reproduction permitted provided the source is explicitly acknowledged Abstract: Since the protection of the Danish harbour seals in 1977 several seal reserves have been established, and the Danish harbour seal population has increased from around 2000 to approximately 16000 individuals. At the same time human activity in the marine environ- ment has increased, both in terms of commercial and recreational use, and calls for a thor- ough evaluation of current management and its data basis is needed. Specifi cally, in order to manage the Danish harbour seals properly more detailed information on the current abundance and reproduction, as well as detailed information on harbour seal movements, and the importance of the interactions between harbour seals and human activities, such as fi sheries and disturbance activities is needed. The six papers included in the present PhD thesis starts out by providing an overview of the status of the Danish harbour seal populations (Paper I), where after examinations of management-related issues are addressed: the harbour seal – cormorant – fi shery interac- tions in Limfjord (Paper II), the eff ects of constructional activity from an off shore wind farm on harbour seal haul-out numbers in the Rødsand seal reserve (Paper III), the eff ectiveness of current regulations in the Anholt seal reserve to protect harbour seals from disturbances (Paper IV and V), and the seasonal movements of harbour seal in Kattegat (Paper VI). Based on the fi ndings in the PhD, several suggestions to improve the current management of the Danish harbour seals are given. Keywords: Anthropogenic disturbance; conservation; dietary overlap; harbour seal; harbour seal – cormorant – fi shery interactions; Phoca vitulina; seal reserve; status; telemetry; wildlife- management Layout: Tinna Christensen Drawings: Signe May Andersen Cover photo: Niels Martin Schmidt ISBN: 978-87-92825-05-6 Number of pages: 130 Printed by: Rosendahls – Schultz Grafi sk a/s Circulation: 100 Supplementary notes: The thesis will be defended in public at The University of Southern Denmark, Odense, on 27 October 2011. Content 1 Current status and conservation of harbour seals in danish waters 10 1.1 Protection of harbour seals 10 1.2 Assessment of the conservation status of harbour seals in Denmark 11 2 Harbour seal movement behaviour in Danish waters 14 3 Interactions between harbour seals and humans 15 3.1 Harbour seals as competitors for fi sh 15 3.2 Harbour seals and disturbing activities 16 4 Management implications 19 4.1 Access restrictions in Danish seals reserves 19 4.2 Constructional work 19 4.3 Fisheries 19 5 References cited 20 Paper I 23 Paper II 43 Paper III 57 Paper IV 81 Paper V 97 Paper VI 115 PREFACE This thesis has been submitted to the University of Southern Denmark, Odense, Denmark, in partial fulfi lment of the requirements for the degree of Philosophidae Doctor (PhD). The work has concentrated on harbour seals and their interaction with humans, in terms of fi shery, recreational and constructional activity. The PhD project was motivated by the ongoing confl ict of interest between human activities (commercial and recreational) and the interest of protection, and aims at contributing with information to management of the Danish seal reserves. This PhD thesis consists of four introductory chapters and six scientifi c papers. The six papers included represent the results of the scientifi c work conducted during my PhD study. As this work relates directly to the Danish management of seals, the fi rst introductory chapters introduce the current management of seals in Denmark (chapter I), the movements of harbour seals in Danish waters (chapter II), the interaction between harbour seals and humans (chapter III), while chapter IV summarises the conclusions from the previous chapters and puts them into the context of Danish management of seals. During my PhD study I was enrolled in the PhD School Sense organs, Nerve systems, Behaviour, and Communication (SNAK). My PhD was conducted with fi nancial support from SNAK, the Dean of the Faculty of Science, University of Southern Denmark, and the Department of Bioscience, Aarhus University. Additional fi nancial support was kindly granted by the Aage V. Jensen Charity Foundation, the Danish Outdoor Council, the Danish Nature Agency, Gorenje and Knud Højgaards Fond. PhD thesis by Signe May Andersen 5 ACKNOWLEDGEMENTS I would like to thank my two supervisors, Lee A. Miller, University of Southern Denmark and Jonas Teilmann, Department of Bioscience, Aarhus University, for their help and support during my PhD study. Many thanks also to the co-authors of the included manuscripts for letting me use our joint papers in this thesis. I am very thankful to the former director of research Dr. Jesper Madsen who gave me the opportunity to work on this PhD-project, and put me on this track in the very beginning. I would like to thank the staff at Greenland Institute of Natural Resources, Nuuk, Greenland, for making my stay there very exciting, especially thanks to Nannette, Philip and Aqqalu. The following people have all been extremely helpful in connection with my PhD project and I thank them all: Morten Abildstrøm and Lotte Wissum for their invaluable help during my fi eldwork and for their hospitality, Annette Bombosch, Theis Taarnby Nygaard, my colleagues at the Department of Bioscience, and the personnel from the Danish Maritime Safety Administration for their assistance in the fi eld. Bernhard Fabricius and Kjeld Moser helped with the camera system, but without the help from Jan Nielsen during the many times the camera system posed problems, this setup would have been impossible. Bendt Nielsen has been very hospitable and I am thankful to him for letting me and my fi eld assistants use the light house for observation and the gas house for staying at times when it was not possible to stay at the Fyrgården. I am grateful to Aréns for giving me the opportunity to stay at Fyrgården, a fantastic place to stay and a perfect place to match fi eldwork with family. And thanks to Erik Buchwald and Henrik Lykke Sørensen, Danish Nature Agency, for clarifying the Habitats Directive and the legislation regarding the Danish seal reserves. I would also like to thank my other colleagues at the late Department of Arctic Environment (though you haven’t seen much of me lately), especially my fellow PhD student Susi Edrén for company during the years, and Mikkel Tamstorf and Signe Sveegaard for patiently assisting me with GIS. I am very grateful to Niels Martin Schmidt, Asbjørn, Kalle and Vilma, and the rest of my family, for their continuous support and assistance during my study. I am especially thankful to Asbjørn, Kalle and Vilma for your patience during the last couple of months, and for your company during the many trips to Anholt. Thank you for not accepting this PhD as equal to you, and for showing me the level of understanding appropriate for your age: Kalle and Vilma, now the ADHD and Åh- D, is over. And again, as it cannot be said to often, I am forever indebted to Niels for guiding me through this project. 6 PhD thesis by Signe May Andersen DANSK RESUMÉ Siden fredningen af spættet sæl i Danmark i 1977 er fl ere sælreservater blevet etableret.