DOC PREVIEW
MIT 12 000 - Historical Overfishing

This preview shows page 1-2-3-4 out of 11 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 11 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 11 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 11 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 11 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 11 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

DOI: 10.1126/science.1059199 , 629 (2001); 293Science et al.Jeremy B. C. Jackson,Coastal EcosystemsHistorical Overfishing and the Recent Collapse of www.sciencemag.org (this information is current as of September 4, 2007 ):The following resources related to this article are available online at http://www.sciencemag.org/cgi/content/full/293/5530/629version of this article at: including high-resolution figures, can be found in the onlineUpdated information and services, http://www.sciencemag.org/cgi/content/full/293/5530/629/DC1 can be found at: Supporting Online Materialfound at: can berelated to this articleA list of selected additional articles on the Science Web sites http://www.sciencemag.org/cgi/content/full/293/5530/629#related-content http://www.sciencemag.org/cgi/content/full/293/5530/629#otherarticles, 16 of which can be accessed for free: cites 62 articlesThis article 625 article(s) on the ISI Web of Science. cited byThis article has been http://www.sciencemag.org/cgi/content/full/293/5530/629#otherarticles 57 articles hosted by HighWire Press; see: cited byThis article has been http://www.sciencemag.org/cgi/collection/ecologyEcology : subject collectionsThis article appears in the following http://www.sciencemag.org/about/permissions.dtl in whole or in part can be found at: this articlepermission to reproduce of this article or about obtaining reprintsInformation about obtaining registered trademark of AAAS. is aScience2001 by the American Association for the Advancement of Science; all rights reserved. The title CopyrightAmerican Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005. (print ISSN 0036-8075; online ISSN 1095-9203) is published weekly, except the last week in December, by theScience on September 4, 2007 www.sciencemag.orgDownloaded fromHistorical Overfishing and the RecentCollapse of Coastal EcosystemsJeremy B. C. Jackson,1,2* Michael X. Kirby,3Wolfgang H. Berger,1Karen A. Bjorndal,4Louis W. Botsford,5Bruce J. Bourque,6Roger H. Bradbury,7Richard Cooke,2Jon Erlandson,8James A. Estes,9Terence P. Hughes,10Susan Kidwell,11Carina B. Lange,1Hunter S. Lenihan,12John M. Pandolfi,13Charles H. Peterson,12Robert S. Steneck,14Mia J. Tegner,1† Robert R. Warner15Ecological extinction caused by overfishing precedes all other pervasivehuman disturbance to coastal ecosystems, including pollution, degrada-tion of water quality, and anthropogenic climate change. Historical abun-dances of large consumer species were fantastically large in comparisonwith recent observations. Paleoecological, archaeological, and historicaldata show that time lags of decades to centuries occurred between theonset of overfishing and consequent changes in ecological communities,because unfished species of similar trophic level assumed the ecologicalroles of overfished species until they too were overfished or died ofepidemic diseases related to overcrowding. Retrospective data not onlyhelp to clarify underlying causes and rates of ecological change, but theyalso demonstrate achievable goals for restoration and management ofcoastal ecosystems that could not even be contemplated based on thelimited perspective of recent observations alone.Few modern ecological studies take into ac-count the former natural abundances of largemarine vertebrates. There are dozens of placesin the Caribbean named after large sea turtleswhose adult populations now number in thetens of thousands rather than the tens of mil-lions of a few centuries ago (1, 2). Whales,manatees, dugongs, sea cows, monk seals, croc-odiles, codfish, jewfish, swordfish, sharks, andrays are other large marine vertebrates that arenow functionally or entirely extinct in mostcoastal ecosystems (3–10). Place names foroysters, pearls, and conches conjure up otherecological ghosts of marine invertebrates thatwere once so abundant as to pose hazards tonavigation (11), but are witnessed now only bymassive garbage heaps of empty shells.Such ghosts represent a far more profoundproblem for ecological understanding andmanagement than currently realized. Evi-dence from retrospective records stronglysuggests that major structural and functionalchanges due to overfishing (12) occurredworldwide in coastal marine ecosystems overmany centuries. Severe overfishing drivesspecies to ecological extinction because over-fished populations no longer interact signifi-cantly with other species in the community(5). Overfishing and ecological extinctionpredate and precondition modern ecologicalinvestigations and the collapse of marine eco-systems in recent times, raising the possibil-ity that many more marine ecosystems maybe vulnerable to collapse in the near future.Importance of Historical DataMost ecological research is based on local fieldstudies lasting only a few years and conductedsometime after the 1950s without longer termhistorical perspective (1, 8, 13). Such observa-tions fail to encompass the life-spans of manyecologically important species (13, 14) and crit-ically important environmental disturbancessuch as extreme cyclones or ENSO (El Nin˜o–Southern Oscillation) events (8), as well aslonger term cycles or shifts in oceanographicregimes and productivity (15–17). To help ad-dress this problem, we describe ecosystemstructure predating modern ecological studiesusing well-dated time series based on biological(18, 19), biogeochemical (20, 21), physical(22), and historical (23) proxies that are infor-mative over a variety of spatial scales and bio-geographic realms (24). Although proxies varyin precision and clarity of the signals they mea-sure, the use of multiple proxies that give thesame ecological signal greatly increases confi-dence in results. Precision in age dating variesfrom centuries to a single year, season, or eventin the exceptional case of varved sediments, icecores, and written historical records (25). Pre-cision decreases with the amount of biologicalor physical disturbance to the sediment ana-lyzed (26).We exploited data from many disciplinesthat span the period over which anthropogen-ic changes may have occurred. Because ourhypothesis is that humans have been disturb-ing marine ecosystems since they firstlearned how to fish, our time periods need tobegin well before the human occupation orEuropean colonization of a coastal region.Broadly, our data fall into four categories andtime periods:1) Paleoecological records from marinesediments from about 125,000 years ago tothe present, coinciding


View Full Document

MIT 12 000 - Historical Overfishing

Documents in this Course
Load more
Download Historical Overfishing
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Historical Overfishing and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Historical Overfishing 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?