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Spatial ecology and conservation of sharks, rays, and chimaeras

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Thesis type
(Thesis) Ph.D.
Date created
Patterns of biodiversity provide foundational information that can be used to inform conservation prioritization and action. For example, those places harbouring relatively greater numbers of threatened, endemic, or evolutionary distinct species may intersect with threats and conservation actions such as Marine Protected Areas (MPAs) or sustainable fisheries management. Here, I explore patterns of biodiversity, threat, and finally the conservation actions that, if implemented, could improve the status for the world’s threatened marine species. First, I evaluated the contribution of MPAs and governance ability in protecting the world’s threatened marine biodiversity. I found that 74 of the 338 threatened marine species in the database are neither adequately protected by MPAs nor found in countries with higher governance scores. Second, I focused on Class Chondrichthyes as a case study to evaluate the relationships between national landings trajectories and intrinsic ecosystem sensitivity and extrinsic drivers and threats. I found that global decline in Chondrichthyes landings was associated with overfishing, particularly in small tropical diverse ecosystems, rather than with management improvements. Third, I evaluated the degree to which MPAs protected imperilled endemic Chondrichthyan species. I found that only 12 of 99 imperilled endemics have at least 10% of their range overlapping with one or more strictly protected, no-take MPAs. However, over half of the threatened endemic Chondrichthyans can be protected given strategic MPA creation and fisheries management implementation in just 12 countries. Finally, to consider the conservation of a representation of unique assemblages, I delineated the unique shark and ray zoogeographic and phylogenetic regions. Globally, there are 41 zoogeographic and 12 phylogenetic shark and at least 50 and 28 ray regions, respectively. I suggest these regions be the focus for evaluating whether MPAs are ecologically representative. In conclusion, I incorporated biodiversity gradients, MPAs, fisheries management, and socio-economics to inform and improve conservation outcomes for threatened marine biodiversity.
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This thesis may be printed or downloaded for non-commercial research and scholarly purposes.
Scholarly level
Supervisor or Senior Supervisor
Thesis advisor: Dulvy, Nicholas
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