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Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean

Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS B3H 4J1, Canada.
Science (Impact Factor: 31.48). 03/2007; 315(5820):1846-50. DOI: 10.1126/science.1138657
Source: PubMed

ABSTRACT Impacts of chronic overfishing are evident in population depletions worldwide, yet indirect ecosystem effects induced by predator removal from oceanic food webs remain unpredictable. As abundances of all 11 great sharks that consume other elasmobranchs (rays, skates, and small sharks) fell over the past 35 years, 12 of 14 of these prey species increased in coastal northwest Atlantic ecosystems. Effects of this community restructuring have cascaded downward from the cownose ray, whose enhanced predation on its bay scallop prey was sufficient to terminate a century-long scallop fishery. Analogous top-down effects may be a predictable consequence of eliminating entire functional groups of predators.

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    • "Usually they are large-bodied vertebrates that can move over large areas, thus interacting with different communities. Most importantly, apex predators are pivotal in maintaining ecosystem stability, and their elimination can produce cascading effects throughout entire food webs (Myers et al. 2007; Terborgh et al. 2010; Estes et al. 2011). Accordingly , the extinction of C. megalodon potentially affected the structure and function of ancient ecosystems (Pimiento and Clements 2014). "
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