Thursday, 4:30–5:30 pm
18 February 2010
School of Aquatic & Fishery Sciences
102 Fishery Sciences (auditorium)
1122 NE Boat Street (map)
University of Washington
Reception follows each talk

Julia BaumJulia Baum

Joint NCEAS Postdoctoral Associate and Marine Science and Technology Foundation Fellow, UCSB

In hot water: Consequences of escalating shark exploitation

Abstract

Sharks are iconic oceanic predators. Exploitation of these fishes - both as bycatch and as direct targets - has increased significantly globally in recent decades. In particular, the shark fin trade has escalated rapidly, and shark fins are now among the most highly valued marine commodities. The life history traits (slow growth, late age at sexual maturity) of many shark species render them highly vulnerable to overexploitation. This vulnerability, coupled with intense exploitation and limited fisheries regulations in most regions, heightens the need to understand how shark populations are changing and the broader ecosystem effects of depleting these species. Yet data to examine these questions is scarce. I will present current global assessments for sharks and an evaluation of the global knowledge base for shark fisheries assessment and management. I will then provide examples of how non-traditional data types may be used to assess changes in abundance for these data-poor species, and present evidence for significant declines in populations of apex predatory sharks as well as the controversy surrounding this research. Finally, I will explore the evidence for cascading effects of shark declines and discuss potential mechanisms by which the loss of these and other apex predators could alter the resilience of marine ecosystems.

Bio

Julia Baum's most significant research contributions have been investigating how community structure, biodiversity, and ecosystem resilience vary across extreme disturbance gradients, using Pacific coral reefs as a focal system. Additionally she demonstrated ecosystem consequences of overexploiting sharks and provided some of the first evidence for trophic cascades in the ocean.

She also conducted the first rigorous analyses demonstrating significant declines in Northwest Atlantic large pelagic sharks, and shifting baselines for these species over the past fifty years.

Julia transferred to Dalhousie University to work with Ransom Myers, after a brief stint as a Masters student at UBC, where she completed her M.Sc. (2002) and PhD (2007) in Biology.

Julia has just completed a two-year postdoc at Scripps Institution of Oceanography where she was a David H. Smith Conservation Research Fellow (www.smithfellows.org) and an NSERC Postdoctoral Fellow. In January she will be starting a postdoc at NCEAS, UCSB as a joint NCEAS Postdoctoral Associate and Marine Science and Technology Foundation Fellow.

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