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Fate and legacy of an invasion: extinct and extant populations of the soft-shell clam (Mya arenaria) in Grays Harbor (Washington)

2000; Wiley; Volume: 10; Issue: 4 Linguagem: Inglês

10.1002/1099-0755(200007/08)10

1099-0755

Ra�l Palacios, David A. Armstrong, J.M. Orensanz,

Marine and fisheries research

Aquatic Conservation: Marine and Freshwater EcosystemsVolume 10, Issue 4 p. 279-303 Research Article Fate and legacy of an invasion: extinct and extant populations of the soft-shell clam (Mya arenaria) in Grays Harbor (Washington) Raúl Palacios, Raúl Palacios ROSTLAC, UNESCO, Montevideo, Uruguay and PEDECIBA, Área Biología, Montevideo, UruguaySearch for more papers by this authorDavid A. Armstrong, David A. Armstrong School of Fisheries, University of Washington, Seattle, USASearch for more papers by this authorJ. (lobo) Orensanz, Corresponding Author J. (lobo) Orensanz School of Fisheries, University of Washington, Seattle, USASchool of Fisheries, University of Washington, PO Box 537980, WA 98195, USASearch for more papers by this author Raúl Palacios, Raúl Palacios ROSTLAC, UNESCO, Montevideo, Uruguay and PEDECIBA, Área Biología, Montevideo, UruguaySearch for more papers by this authorDavid A. Armstrong, David A. Armstrong School of Fisheries, University of Washington, Seattle, USASearch for more papers by this authorJ. (lobo) Orensanz, Corresponding Author J. (lobo) Orensanz School of Fisheries, University of Washington, Seattle, USASchool of Fisheries, University of Washington, PO Box 537980, WA 98195, USASearch for more papers by this author First published: 17 July 2000 https://doi.org/10.1002/1099-0755(200007/08)10:4 3.0.CO;2-ICitations: 26AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract 1. The soft-shell clam, Mya arenaria, was intentionally introduced to Washington State during the mid-1870s. Presently, extensive shell deposits cover parts of the intertidal flats of Grays Harbor, an estuarine ecosystem that has received much attention because of its role as nursery ground for Dungeness crab (Cancer magister), a commercially significant species. 2. Preliminary observations revealed that shells in the deposits belonged to clams that were much larger than extant conspecifics. Shell deposits and extant populations have spatially disjoint distributions; few individuals are found living within the deposits. The purpose of our study was to determine the cause of the different size characteristics between extinct and extant clams, when and how the deposits originated, and why the extant population does not prosper in what appears to be prime habitat. 3. We (i) surveyed extant populations and shell deposits, (ii) followed the extant population through periodic sampling over a 3-year period, (iii) investigated growth and survival in extant and extinct populations, (iv) experimentally manipulated growth conditions, and (v) searched archival sources for information about the origin of the deposits. 4. We conclude that extinct clams grew faster and lived longer, apparently because they occupied the best habitats available. Archival records suggest that the population expanded rapidly during the period around 20 years after its introduction, but was decimated between 1895 and 1897 by a mass-mortality episode that resulted in the formation of the deposits. The population since then has never rebounded in its prime habitat, in spite of potential settlers being regularly available. 5. Dungeness crab larvae settle preferentially in the shell deposits, where the abundance of 0+ age juveniles is orders of magnitude higher than in the adjacent flats. We hypothesize that predation by juvenile crabs limits clam recruitment. 6. The introduction of Mya to Grays Harbor during the 1870s has had long-lasting effects, which persist a century after their once large populations were decimated by a mass-mortality event. Copyright © 2000 John Wiley & Sons, Ltd. Citing Literature Volume10, Issue4July/August 2000Pages 279-303 RelatedInformation