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Ecology of QPX disease in the hard clam Mercenaria mercenaria

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dc.contributor.advisor Allam, Bassem en_US
dc.contributor.author Dahl, Soren en_US
dc.contributor.other Department of Marine and Atmospheric Science en_US
dc.date.accessioned 2017-09-20T16:53:36Z
dc.date.available 2017-09-20T16:53:36Z
dc.date.issued 2015-12-01 en_US
dc.identifier.uri http://hdl.handle.net/11401/77794 en_US
dc.description 77 pgs en_US
dc.description.abstract There is increasing recognition of the role of suspension-feeding bivalves in providing important ecosystem services (e.g., water clarity, benthic-pelagic coupling, and habitat structure) within estuarine systems. Mercenaria mercenaria (aka hard clams, quahogs) are frequently the dominant suspension-feeder in estuarine systems across the US east coast and have had significant commercial fishery importance and a steadily growing mariculture industry. M. mercenaria have generally not had disease problems which contrasts the microbial infections that have plagued oyster fisheries. Quahog Parasite Unknown (QPX) is the first substantial infectious microbial pathogen affecting hard clams across both wild populations and cultured stocks. QPX is identified as a Thraustochytrid, a group of saprophytic protists that are considered to play an important role in detrital organic matter recycling in coastal ecosystems, yet there are some reports of their association with molluscan disease and mortalities. QPX infections can be present in hard clams but without causing overt disease problems. Controlled laboratory experiments and applied field experiments were utilized in an approach to understand the factors that control infection dynamics. Results revealed a significant role of the primary environmental factors of temperature and salinity influencing the balance between the hard clam host and opportunistic pathogen QPX, regulating the resultant disease progression. Counter to most microbial pathogens affecting bivalves, warm temperatures (≥21°C) deter infection progression and promote disease remission. High estuarine salinity (e.g., 30ppt) promotes infection and increases the risk of QPX-related hard clam mortalities. Applied field experiments showed the potential to mitigate disease risk. Areas subject to low salinities and high summer temperatures within an enzootic estuary were utilized to deter infection progression. Reductions of hard clam density also helped reduce disease risk. Clam seed raised from locally sourced wild populations displayed good growth and disease resistance during grow out challenges. The investigations provide fundamental insights for developing management strategies. en_US
dc.description.sponsorship This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree. en_US
dc.format Monograph en_US
dc.format.medium Electronic Resource en_US
dc.language.iso en_US en_US
dc.publisher The Graduate School, Stony Brook University: Stony Brook, NY. en_US
dc.subject.lcsh Biology en_US
dc.subject.other Clam, Disease, Mercenaria, QPX, Salinity, Temperature en_US
dc.title Ecology of QPX disease in the hard clam Mercenaria mercenaria en_US
dc.type Dissertation en_US
dc.mimetype Application/PDF en_US
dc.contributor.committeemember Cerrato, Robert en_US
dc.contributor.committeemember Levinton, Jeffery en_US
dc.contributor.committeemember Meliker, Jaymie en_US
dc.contributor.committeemember Bushek, David en_US

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