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

Priede, I.G., Froese, R., Bailey, D.M. , Bergstad, O.A., Collins, M.A., Dyb, J.E., Henriques, C., Jones, E.G. and King, N. (2006) The absence of sharks from abyssal regions of the world's oceans. Proceedings of the Royal Society of London Series B: Biological Sciences, 273(1592), pp. 1435-1441. (doi:10.1098/rspb.2005.3461)

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Publisher's URL: http://dx.doi.org/10.1098/rspb.2005.3461

Abstract

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:Articles
Keywords:chondrichthyes; sharks; deep-sea fishes; abyss; elasmobranches
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bailey, Dr David
Authors: Priede, I.G., Froese, R., Bailey, D.M., Bergstad, O.A., Collins, M.A., Dyb, J.E., Henriques, C., Jones, E.G., and King, N.
Subjects:Q Science > QL Zoology
College/School:College of Medical Veterinary and Life Sciences
Journal Name:Proceedings of the Royal Society of London Series B: Biological Sciences
Publisher:The Royal Society
ISSN:0962-8452
ISSN (Online):1471-2954
Copyright Holders:Copyright © 2006 The Royal Society
First Published:First published in Proceedings of The Royal Society of London Series B: Biological Sciences 273(1592):1435-1441
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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