The Shy albatross (Thalassarche cauta): Population trends, environmental and anthropogenic drivers, and the future for management and conservation
Despite recent global conservation efforts, albatrosses remain amongst the most threatened groups of birds. Worldwide, they are affected on land and at sea by a range of processes, particularly fisheries bycatch. In spite of their high conservation profile, albatrosses present challenges for monitor...
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| Format: | Thesis |
| Language: | English |
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2012
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| Online Access: | https://eprints.utas.edu.au/14711/ https://eprints.utas.edu.au/14711/1/front-Alderman-thesis.pdf https://eprints.utas.edu.au/14711/2/whole-alderman-thesis-exc-pub-mat.pdf https://eprints.utas.edu.au/14711/3/whole-alderman-thesis-inc-pub-mat.pdf |
| Summary: | Despite recent global conservation efforts, albatrosses remain amongst the most threatened groups of birds. Worldwide, they are affected on land and at sea by a range of processes, particularly fisheries bycatch. In spite of their high conservation profile, albatrosses present challenges for monitoring and recovery actions because they are long-lived, spend most of their life at sea and return to breed at colonies that are often located on remote, relatively inaccessible islands. This thesis offers a comprehensive assessment of the population status and trends of Australia’s endemic shy albatross, Thalassarche cauta, which breeds exclusively on three Tasmanian offshore islands. The main anthropogenic, physical and environmental processes that influence each of the three breeding populations are examined and the processes that shape key demographic parameters and trends are assessed in four analytical chapters which follow the introductory chapter. Chapter two compiles and analyses available population and demographic data to provide the first comprehensive assessment of the status and trends of the three individual shy albatross colonies and of the species as a whole. This chapter shows that the Albatross Island population has recently stabilised following a period of sustained increase post-harvest and that this change in trajectory appears driven by a decrease in juvenile survival. The small Pedra Branca population is declining, likely due to reduced breeding success associated with the increasing population of Australasian gannets on the island. While trends for Mewstone, the largest breeding population, are unknown, it is shown that birds from this colony have greater exposure to commercial fisheries, are therefore at higher risk of fishing-related mortality and, consequently, survival rates for this population are likely lower than their Albatross Island counterparts. Collectively, these results suggest the current status of the shy albatross is likely to be stable at best and quite possibly decreasing.The ... |
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