MEPS 603:117-133 (2018)  -  DOI: https://doi.org/10.3354/meps12706

Impacts of habitat, predators, recruitment, and disease on soft-shell clams Mya arenaria and stout razor clams Tagelus plebeius in Chesapeake Bay

Cassandra N. Glaspie1,4,*, Rochelle D. Seitz1, Matthew B. Ogburn2, Christopher F. Dungan3, Anson H. Hines2

1Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, Virginia 23062, USA
2Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, Maryland 21037, USA
3Maryland Department of Natural Resources, Cooperative Oxford Laboratory, 904 S. Morris St., Oxford, Maryland 21654, USA
4Present address: Department of Oceanography and Coastal Sciences, Louisiana State University, 3195 Energy, Coast, and Environment Building, Baton Rouge, Louisiana 70803, USA
*Corresponding author:

ABSTRACT: Soft-shell clams Mya arenaria and razor clams Tagelus plebeius in Chesapeake Bay, USA, have declined in numbers since the 1970s, with severe declines since the 1990s. These declines are likely caused by multiple factors, including habitat loss, predation, recruitment limitation, disease, warming, and harvesting. We surveyed Chesapeake Bay to examine influential factors on bivalve populations, focusing on habitat (mud, sand, gravel, shell, or seagrass), predators (crabs, fish, and cownose rays), recruitment, disease, and environment (temperature, salinity, and dissolved oxygen). M. arenaria and T. plebeius were found more often in habitats with complex physical structures (seagrass, shell) than any other habitat. Pulses in bivalve density associated with recruitment were attenuated through the summer and fall when predators are most active, indicating that predators likely influence temporal dynamics in these species. Presence of M. arenaria, which is near the southern extent of its range in Chesapeake Bay, was negatively correlated with water temperature. Recruitment of M. arenaria in the Rhode River, Maryland, declined between 1980 and 2016. Infection by the parasitic protist Perkinsus sp. was associated with stressful environmental conditions, bivalve size, and environmental preferences of Perkinsus sp., but was not associated with bivalve densities. It is likely that habitat loss, predators, and low recruitment are major factors keeping T. plebeius and M. arenaria at low densities in Chesapeake Bay. Persistence at low densities may be facilitated by habitat complexity (presence of physical structures), whereas further reductions in habitats such as seagrass and shell hash could result in local extinction of these important bivalve species.


KEY WORDS: Bivalve · Seagrass · Oyster · Temperature · Climate · Perkinsus chesapeaki


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Cite this article as: Glaspie CN, Seitz RD, Ogburn MB, Dungan CF, Hines AH (2018) Impacts of habitat, predators, recruitment, and disease on soft-shell clams Mya arenaria and stout razor clams Tagelus plebeius in Chesapeake Bay. Mar Ecol Prog Ser 603:117-133. https://doi.org/10.3354/meps12706

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