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The absence of sharks from abyssal regions of the world's oceans

Priede, Imants G.; Froese, Rainer; Bailey, David M.; Bergstad, Odd Aksel; Collins, Martin A.; Dyb, Jan Erik; Henriques, Camila; Jones, Emma G.; King, Nicola. 2006 The absence of sharks from abyssal regions of the world's oceans. Proceedings of the Royal Society of London, B, 273 (1592). 1435-1441. 10.1098/rspb.2005.3461

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Abstract/Summary

The oceanic abyss (depths greater than 3000 m), one of the largest environments on the planet, is characterized by absence of solar light, high pressures and remoteness from surface food supply necessitating special molecular, physiological, behavioural and ecological adaptations of organisms that live there. Sampling by trawl, baited hooks and cameras we show that the Chondrichthyes (sharks, rays and chimaeras) are absent from, or very rare in this region. Analysis of a global data set shows a trend of rapid disappearance of chondrichthyan species with depth when compared with bony fishes. Sharks, apparently well adapted to life at high pressures are conspicuous on slopes down to 2000 m including scavenging at food falls such as dead whales. We propose that they are excluded from the abyss by high-energy demand, including an oil-rich liver for buoyancy, which cannot be sustained in extreme oligotrophic conditions. Sharks are apparently confined to ca 30% of the total ocean and distribution of many species is fragmented around sea mounts, ocean ridges and ocean margins. All populations are therefore within reach of human fisheries, and there is no hidden reserve of chondrichthyan biomass or biodiversity in the deep sea. Sharks may be more vulnerable to over-exploitation than previously thought.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1098/rspb.2005.3461
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > DISCOVERY 2010 - Integrating Southern Ocean Ecosystems into the Earth System
ISSN: 0962-8452
Format Availability: Electronic, Print
Additional Information. Not used in RCUK Gateway to Research.: Full text not available from this repository
Additional Keywords: Sharks ; Distribution ; Deep-sea
NORA Subject Terms: Zoology
Date made live: 20 Aug 2007 09:06
URI: http://nora.nerc.ac.uk/id/eprint/103

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