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On the Ecology of Rorqual Whales (Balaenopteridae) in Irish Waters Using Intrinsic Markers

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On the Ecology of Rorqual Whales (Balaenopteridae) in Irish Waters Using Intrinsic Markers On the Ecology of Rorqual Whales (Balaenopteridae) in Irish Waters using Intrinsic Markers PhD Thesis Conor Gerard Ryan BSc. (jiQll£lZoology Submitted for fulfillment of Doctorate of Philosophy Galway-Mayo Institute of Technology Supervised by: Dr Ian O'Connor, Dr Simon Berrow, Dr David McGrath (Galway-Mayo Institute of Technology] and Dr Brendan McHugh (Marine Institute] Submitted to the Higher Education and Training Awards Council October 2012 An Leabharlann GMIT J151728 b l W W X J151728 © Inter-Research (Chapters 2 and 6, pending acceptance) © Wiley-Blackwell (Chapter 3) © Society for Marine Mammalogy (Chapter 4 pending acceptance) © Society for Marine Mammalogy (Chapter 5) No Copyright on Chapters 1 and 7 Author: Conor Gerard Ryan Title: On the Ecology of Rorqual Whales (Balaenopteridae) in Irish Waters using Intrinsic M arkers Abstract: Despite repeated calls for an ecosystem-based approach to the management of marine resources, little information exists on the ecosystem role and requirements of top predators such as baleen whales in Irish waters. Considering that they are long-lived and highly migratory, baleen whales such as rorquals (Family Balaenopteridae] are potentially useful bio-monitors of anthropogenic environmental change. However, their use as environmental indicators is precluded by an insufficient understanding of their basic ecology. Following centuries of whaling and other emerging threats to their survival including pollution, bycatch and ship-strikes, the conservation status of most rorqual species is difficult to assess due to a shortfall in our knowledge. This thesis aims to facilitate more informed management decision-making and the implementation of more effective conservation measures by bridging key gaps in our knowledge. Pertinent questions on feeding and migration ecology are addressed using intrinsic m arkers, i.e. chemicals whose stable properties ensure they move through biotic systems and are detectable in tissues. Intrinsic markers include naturally occurring [e.g. stable isotopes, DNA, trace elements] and anthropogenic compounds (e.g persistent organic pollutants or POPs]. In Chapter 1, current knowledge on the ecology of blue [Balaenoptera musculus], fin (R physalus), humpback (Megaptera novaengliae] and minke whales (R acutorostrata] in Irish waters is reviewed. In chapter 2, stable isotope analysis of baleen from these four species is used to approximate the ecological niche and thus to examine resource partitioning. Chapter 3 is a methodological precursor to Chapter 4 where stable isotope Bayesian mixing models are used to investigate the preferred diet of fin and humpback whales in the Celtic Sea. In Chapter 3, unpredictable effects of pre- analytical lipid-extraction of skin and blubber biopsies were found for both 513C and <515N values. Chapter 5 is a methodological chapter, concluding that the amount of lipid remaining in blubber biopsies is not representative of blubber in situ. This finding was relevant to Chapter 6 which used POP concentrations to investigate elements of population structure of humpback whales in the North Atlantic. Chapter 7 discusses how the key findings such as the diet preferences of Celtic Sea fin whales (Euphausiids such as Meganyctiphanes norvegica and Nyctiphanes couchii, and year-0 sprat [Sprattus sprattus] and herring (Clupea harengusj) and humpback whales (chiefly sprat and herring) may be used to facilitate an informed ecosystem-based approach to fisheries management. GMIT i wrrrraigi n n w ninnm w> «>■ i w m-writi so MUHfir-iimiNsnTVfEWirafio^niinMrr M gnninw nifttw r«yniiw I hereby certify that this material, which I now submit for assessment on the programme of study leading to the award of PhD is entirely my own work and has not been taken from the work of others save and to the extent that such work has been cited and acknowledged within the text of my work. Signed: ID No. G00267618 iv Acknowledgements To Simon Berrow, Brendan McHugh, Ian O'Connor and David McGrath, thanks for having the faith in me to carry out this thoroughly rewarding work. Without your faith in my ability, this thesis would not have been achievable. To Brendan in particular, your encouragement and guidance was beyond the call of duty, for which I am very thankful. I am very grateful for the opportunity to pursue what truly has been my passion since I was a young child. Thanks to my parents Liz and Richie, brothers Cian and John and my sister Amy who nurtured this passion - they are responsible for my first ever encounter with a whale - a fin whale that stranded at Ballyheigue, Co. Kerry in 1994 (IRBp94001, Table 1, Chapter 2!). The floods of curious questions that entered my mind that day, as I rested my two hands on such a giant animal that once roamed the cold rough seas, continue to challenge me. Thanks to my examiners, Florence Caurant and Deirdre Brophy, for their constructive suggestions which helped to improve the final draft. Thanks to my partner Vivi, who had to put up with frustration, distant haziness and constant change of plans throughout the toil. She continues to be an endless source of encouragement and support, and I'm so glad we got to share such memorable days together in the field. Thanks to Jim Wilson, from whom I contracted a highly infectious love of wildlife and passion for conserving what ought to be enJoyed by generations to come. To his son Peter, equally afflicted by this condition, I am also very grateful - he taught me never to underestimate the inspirational power of conversation over a few pints, whether on Cape Clear or in the Donk’ at home in Cobh. I am indebted to Clive Trueman and Chris Harrod for helping me to take a look from another angle and for helpful discussions about stable isotopes in ecology. To those friendly faces in the Marine Institute, especially Brian O’Boyle, Poppy and Philip - I am grateful for your patience and unending help in the chemistry lab. Thanks to Joanne O'Brien who helped me see the wood from the trees, and for always being available for a chat any hour of the day. Joanne and Simon have v taught me to always to raise the bar higher and Jump at every opportunity. To Per Palsb0ll, Martine Berube and everyone at the conservation genetics labs in Stockholm and Groningen, I am very grateful for the opportunity to work with such great scientists. Obrigado to the Cape Verde humpback research community, namely Pedro Lopez Suarez, Fred Wenzel and Beatrice Jann for welcoming a stranger with open arms, into what is normally a 'competitive field'. It is so refreshing to find like-minded people whose mutual passion for understanding and conserving whales is not blemished by ego or competition. For the encouragement and samples I received from UK-based cetacean community (Rob Deaville, Nick Davison, Collin MacLeod, James Barnett and Paul Jepson), many thanks. Thanks to Richard Sabin for one of the most memorable days of my life, not because I travelled the London Underground with a box of blubber samples at rush hour, but because I was privileged enough to drill baleen samples for a whole day inside the London Natural History Museum cetacean collection in Wimbledon. To Padraig Whooley, Nick Massett, Andrew Malcolm, Mick O'Connell, Paddy Roche, Deirdre Slevin and all those involved in the IWDG sightings and strandings schemes - I am indebted to you for being so generous with your time. Thanks to Ronan Cosgrove, Padraig Whooley and John Coveney for permission to use their photographs. To Commodore Mark Mellett, the Commanding Officers and crews of L.E. Orla and the R.V. Celtic Explorer, to Darren Craig, Colin Barnes, Mick Sheeran, Martin Colfer, Alessandro Pierini and Fien deRaedemaeker: thanks for your skilled navigation and for keeping a cool head during those close approaches to the whales! To my drinking and surfing buddies in Galway (Alessandro Pierini, Bernie O’Neill, Clementine Harma, Fien deRaedemaeker, Paula Haynes, Stephen Comerford, Weibke Schmidt and Marieke Volkenandt)- your companionship through tough times was a saving grace ... the shneaky pints and mid-week surf sessions kept despair at bay! vi Contents Abstract:.......................................................................................................................................ii Declaration...................................................................................................................................iv Acknowledgements.................................................................................................................... v List of Figures..............................................................................................................................xi List of Tables............................................................................................................................. xiv Chapter 1........................................................................................................................................1 General Introduction...................................................................................................................1 1.1. Ecology of Rorquals.........................................................................................................1 1.1.1 Systematics.................................................................................................................1 1.1.2 Life History, Reproduction and Migration..........................................................1 1.1.3 Feeding.........................................................................................................................4
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