Melanie

Annu. Rev. Ecol. Syst. 1999. 30:515–38 Copyright c 1999 by Annual Reviews. All rights reserved

HISTORICAL EXTINCTIONS IN THE SEA
James T. Carlton
Maritime Studies Program, Williams College—Mystic Seaport, P.O. Box 6000, 75 Greenmanville Avenue, Mystic, Connecticut 06355; e-mail: jcarlton@williams.edu
Annu. Rev. Ecol. Syst. 1999.30:515-538. Downloaded from arjournals.annualreviews.org byINECOL - Instituto de Ecologia, A.C. on 02/22/10. For personal use only.

Jonathan B. Geller

Moss Landing Marine Laboratories, P.O. Box 450, Moss Landing, California 95039; e-mail: geller@mlml.calstate.edu

Marjorie L. Reaka-Kudla Elliott A. Norse

Department of Zoology, University of Maryland, College Park, Maryland 20742; e-mail: mr9@umail.umd.edu

Marine Conservation Biology Institute,15806 NE 47th Court, Redmond, Washington 98052; e-mail: enorse@u.washington.edu

Key Words extinction, endangered, threatened “The Frail Ocean”

Monday, June 3, 1844 (Date when the last Great Auks were seen alive, on the island of Eldey, Iceland )

INTRODUCTION

Communities of organisms can change over historical (ecological) time in three ways: Species can be deleted (extinctions), added(invasions), or can change in relative abundance. In marine environments, while the latter two types of alterations are increasingly recognized (if not extensively studied), extinctions in historical time have received little recognition. This lack of attention to marine extinctions stands in striking contrast to the comparatively advanced recognition of the existence of extinctions, particularlyof larger organisms, in terrestrial communities (7). Extinctions in historical time have been referred to as neoextinctions, and prehistoric extinctions as paleoextinctions (19), a distinction we follow here. Baillie & Groombridge (7) treat historical extinctions as those occurring in the past 400
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—Wesley Marx, 1967 (79)

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CARLTON ET ALAnnu. Rev. Ecol. Syst. 1999.30:515-538. Downloaded from arjournals.annualreviews.org by INECOL - Instituto de Ecologia, A.C. on 02/22/10. For personal use only.

years or less. Ehrlich et al (37) noted examples of birds that had become extinct “since 1776,” noting that they had “chosen 1776 as our cutoff point somewhat arbitrarily, but reliable reports from before that point are few, museumspecimens are rare, and documented extinctions are rarer still” (if this cutoff were to be extended beyond birds, it would not include the extinction of the Steller’s Sea Cow, Hydrodamalis gigas, last observed in 1768). We review the record of neoextinctions in the ocean and discuss these in terms of both temporal and spatial patterns. We further review the possible extent of underestimation of marineneoextinctions. Finally, we attempt to set the importance of what we do know about marine extinctions into a larger framework of the vulnerability of marine organisms to global deletion. It is important to understand the diversity and number of extinctions in the oceans for a variety of reasons. At a general level, an understanding of marine extinctions provides a measure of the scale ofsusceptibility of the seas to human perturbations and alterations. More specifically, determining which species have become extinct can serve as a harbinger of further loss in particular habitats, providing both a rationale and an opportunity for increased protection of species guilds and habitats that may be most at risk. Knowledge of which species have regionally or globally disappeared is critical inunderstanding modern-day community and ecosystem structure and function. Energy flow, predator-prey networks, indirect interactions, and a host of other processes may change dramatically with the removal of a species—removals that have, by and large, preceded scientific study. Knowing which species were removed from communities in historical times is the sine qua non of understanding prealtered...