418 results on '"Shumway, Sandra E."'
Search Results
202. Osmotic Balance in a Marine Pulmonate,Amphibola crenata
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Shumway, Sandra E., primary and Freeman, R. F. H., additional
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- 1984
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203. Oxygen consumption and feeding rates of the sabellid polychaete, Myxicola infundibulum (Renier)
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Shumway, Sandra E, primary, Bogdanowicz, Christine, additional, and Dean, David, additional
- Published
- 1988
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204. Physiological effects of Protogonyaulax tamarensis on cardiac activity in bivalve molluscs
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Gainey, Louis F., primary and Shumway, Sandra E., additional
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- 1988
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205. In MemoriamRobert R. L. GuillardFebruary 5, 1921-September 25, 2016.
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Shumway, Sandra E. and Wikfors, Gary H.
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- 2017
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206. ROBERT GUILLARD (1921-2016).
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Shumway, Sandra E. and Wikfors, Gary H.
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SCIENTISTS - Abstract
An obituary is presented for scientist Robert Guillard.
- Published
- 2016
207. Commentary on Formatting manuscripts for journal submission - an author's editor's view.
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Shumway, Sandra E.
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MANUSCRIPTS , *SCIENCE publishing , *SCIENCE journalism , *SCIENCE writers , *SCIENTIFIC literature - Published
- 2017
208. Selective Capture and Ingestion of Particles by Suspension-Feeding Bivalve Molluscs: A Review
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Rosa, Maria, Ward, J. Evan, and Shumway, Sandra E.
- Published
- 2018
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209. Preface from First Edition.
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Shumway, Sandra E.
- Abstract
A preface of the book "Scallops: Biology, Ecology and Aquaculture," Second Edition, edited by Sandra E. Shumway and G. Jay Parsons is presented.
- Published
- 2006
210. Preface.
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Shumway, Sandra E. and Parsons, G. Jay
- Abstract
A preface of the book "Scallops: Biology, Ecology and Aquaculture," Second Edition, edited by Sandra E. Shumway and G. Jay Parsons is presented.
- Published
- 2006
211. Effects of Surface Properties on Particle Capture by Two Species of Suspension-Feeding Bivalve Molluscs
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Rosa, Maria, Ward, J. Evan, Frink, Ashley, and Shumway, Sandra E.
- Published
- 2017
- Full Text
- View/download PDF
212. In Memoriam Robert R. L. Guillard February 5, 1921–September 25, 2016
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Shumway, Sandra E. and Wikfors, Gary H.
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- 2017
- Full Text
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213. The relationship between microplastics in eastern oysters (Crassostrea virginica) and surrounding environmental compartments in Long Island Sound.
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Mladinich, Kayla, Holohan, Bridget A., Shumway, Sandra E., and Ward, J. Evan
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PLASTIC marine debris , *AMERICAN oyster , *MICROPLASTICS , *BIODEGRADABLE plastics , *POLYETHYLENE terephthalate , *TERRITORIAL waters , *INFRARED spectroscopy - Abstract
Microplastics (MP, <5 mm) are found in coastal waters across various environmental compartments (biota, water, marine snow, sediment). The eastern oyster (Crassostrea virginica) is a commercially important species that ingests MP; however, oysters are discriminant suspension feeders that do not consume all particles to which they are exposed. This study explored the relationship between MP in oysters on a recreational oyster bed and the surrounding environmental compartments in Long Island Sound (LIS; USA). The quantity and types of MP in oysters, water, marine snow, and sediment samples were determined. Precautions were taken to minimize and monitor MP contamination in the field and laboratory to improve the quality of data collected. Microplastics were isolated from samples via chemical digestion, and any suspected particles were identified using micro-Fourier transform infrared spectroscopy. A total of 86 MP were identified out of 885 suspected particles across environmental media. The highest MP count in an individual oyster was nine, indicating low concentrations of MP in oysters and the surrounding environment. Few polymers, except polyethylene terephthalate, were shared between oysters and the surrounding environmental compartments. Sediments contained the highest number of MP across all environmental compartments (42 total). These data aid in determining the types of MP (polymer composition, shape, size) to which oysters are exposed and identified those ingested. The low numbers of MP recorded, coupled with the lack of alignment of polymers between oysters and their surrounding environment, demonstrates further that oysters are a poor bioindicator species for MP pollution. • Oysters are selective suspension feeders that do not consume all the particles they are exposed to. • Concentrations and polymers were explored and compared across oysters, water, marine snow, sediment on a recreational bed. • Microplastic concentrations are low and the polymers in oysters do not align with those in the surrounding environment. • These data indicates that oysters are a poor bioindicator species for microplastics pollution. [ABSTRACT FROM AUTHOR]
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- 2023
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214. IN DEFENSE OF SCHOLARLY PUBLICATIONS - LOOKING BACK BEFORE LURCHING FORWARD.
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SHUMWAY, SANDRA E.
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HISTORICAL literature ,PUBLICATIONS ,INFORMATION resources ,FEDERAL aid to research ,SCIENCE publishing - Abstract
The article presents the author's insights about the importance and significance of historical literature for scholarly publications, to prevent from wasting of time and research funds. Topics discussed include the scientific research, the poor literature research and knowledge and the concerns about the guidance for accessibility of scientific journals.
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- 2017
215. Debasing the Currency of Science: The Growing Menace of Predatory Open Access Journals
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Beninger, Peter G., Beall, Jeffrey, and Shumway, Sandra E.
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- 2016
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216. Mortality Assessment of Atlantic Sea Scallops (Placopecten magellanicus) from Gray-Meat Disease
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Levesque, Megan M., Inglis, Susan D., Shumway, Sandra E., and Stokesbury, Kevin D. E.
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- 2016
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217. 17: Bay Scallop and Calico Scallop Fisheries, Culture and Enhancement in Eastern North America: 17.1 INTRODUCTION.
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Blake, Norman J. and Shumway, Sandra E.
- Abstract
Chapter 17 of the book "Scallops: Biology, Ecology and Aquaculture," Second Edition, edited by Sandra E. Shumway and G. Jay Parsons is presented. It deals with the interest in all aspects of scallop biology and ecology. Moreover, it provides a comprehensive overview of the biology, ecology and aquaculture for scallop species worldwide. It focuses on efforts in presenting discussions regarding the need for a comprehensive treatise and researches on scallops.
- Published
- 2006
218. 7: Physiology: Energy Acquisition and Utilisation: 7.1 INTRODUCTION.
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MacDonald, Bruce A., Bricelj, V. Monica, and Shumway, Sandra E.
- Abstract
Chapter 7 of the book "Scallops: Biology, Ecology and Aquaculture," Second Edition, edited by Sandra E. Shumway and G. Jay Parsons is presented. It deals with the interest in all aspects of scallop biology and ecology. Moreover, it provides a comprehensive overview of the biology, ecology and aquaculture for scallop species worldwide. It focuses on efforts in presenting discussions regarding the need for a comprehensive treatise and researches on scallops.
- Published
- 2006
219. Honored Life Member.
- Author
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Harding, Juliana, Soniat, Thomas, and Shumway, Sandra E.
- Abstract
The article profiles marine ecologists Roger Mann. He took Bachelor of Science in Marine Ecology at the University of East Anglia in 1972. He is a recognized leader in the field of sound scientific reasoning for the management, conservation, and restoration of estuarine, coastal, oceanic, and marine resources in which his work with Dr. Peter Walne on flat oysters and pacific oysters got a high standard in quantitative examination of oyster physiological ecology in field and laboratory studies.
- Published
- 2009
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220. SCALLOPS AND ALGAL TOXINS REVISITED.
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Shumway, Sandra E.
- Abstract
The article presents the abstract of the research entitled "Scallops and Algal Toxins Revisited."
- Published
- 2006
221. In Memoriam: George R. Abbe 1943–2013
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Kreeger, Danielle, Shumway, Sandra E., and Hixson, J
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- 2014
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222. Observations of Feeding in the Common Atlantic Slippersnail Crepidula fornicata L., with Special Reference to the “Mucus Net”
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Shumway, Sandra E., Ward, J. Evan, Heupel, Eric, Holohan, Bridget A., Heupel, Johann, Heupel, Tamara, and Padilla, Dianna K.
- Published
- 2014
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223. Enhancing Shellfish Safety in Alaska through Monitoring of Harmful Algae and Their Toxins
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Trainer, Vera L., Sullivan, Kate, Eberhart, Bich-Thuy Le, Shuler, Andrew, Hignutt, Emanuel, Kiser, John, Eckert, Ginny L., Shumway, Sandra E., and Morton, Steve L.
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- 2014
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224. Seasonal Patterns of Ascidian Settlement at an Aquaculture Facility in the Damariscotta River, Maine
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Bullard, Stephan G., Davis, Christopher V., and Shumway, Sandra E.
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- 2013
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225. Honored Life Member Roger L. Mann
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Harding, Juliana, Soniat, Thomas, and Shumway, Sandra E.
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- 2009
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226. DIVERSE FEEDING RESPONSES OF FIVE SPECIES OF BIVALVE MOLLUSC WHEN EXPOSED TO THREE SPECIES OF HARMFUL ALGAE
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HÉGARET, HÉLÈNE, WIKFORS, GARY H., and SHUMWAY, SANDRA E.
- Published
- 2007
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227. A FIBER OPTIC SENSOR FOR HIGH RESOLUTION MEASUREMENT AND CONTINUOUS MONITORING OF VALVE GAPE IN BIVALVE MOLLUSCS
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FRANK, DANA M., HAMILTON, JOHN F., EVAN WARD, J., and SHUMWAY, SANDRA E.
- Published
- 2007
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228. A Fishy Story Promoting a False Dichotomy to Policy-Makers: It Is Not Freshwater vs. Marine Aquaculture.
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Costa-Pierce, Barry Antonio, Bockus, Abigail B., Buck, Bela H., van den Burg, Sander W. K., Chopin, Thierry, Ferreira, Joao G., Goseberg, Nils, Heasman, Kevin G., Johansen, Johan, Shumway, Sandra E., Sims, Neil A., and Tacon, Albert G. J.
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MARICULTURE , *OCEAN zoning , *FISH farming , *FRESH water , *NONGOVERNMENTAL organizations , *SUSTAINABILITY - Abstract
A recent publication by Belton et al. raises points for policy-makers and scientists to consider with respect to the future of aquaculture making recommendations on policies and investments in systems and areas of the world where aquaculture can contribute most. Belton et al. take an 'us versus them' approach separating aquaculture by economics, livelihood choices, and water salinity. They conclude "that marine finfish aquaculture in offshore environments will confront economic, biophysical, and technological limitations that hinder its growth and prevent it from contributing significantly to global food and nutrition security." They argue that land-based freshwater aquaculture is a more favorable production strategy than ocean/marine aquaculture; they disagree with government and non-governmental organizations spatial planning efforts that add new aquaculture to existing ocean uses; they advocate for open commons for wild fisheries as opposed to aquaculture; and they oppose 'open ocean' aquaculture and other types of industrial, capital-intensive, 'carnivorous' fish aquaculture. They discredit marine aquaculture rather than explain how all aquaculture sectors are significantly more efficient and sustainable for the future of food than nearly all land-based animal protein alternatives. As an interdisciplinary group of scientists who work in marine aquaculture, we disagree with both the biased analyses and the advocacy presented by Belton et al. Marine aquaculture is growing and is already making a significant contribution to economies and peoples worldwide. None of the concerns Belton et al. raise are new, but their stark statement that farming fish in the sea cannot 'nourish the world' misses the mark, and policy-makers would be wrong to follow their misinformed recommendations. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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229. Osmotic balance in a marine pulmonate, Amphibola crenata
- Author
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Shumway, Sandra E. and Freeman, R. F. H.
- Published
- 1984
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230. Modulation of pumping rate by two species of marine bivalve molluscs in response to neurotransmitters: Comparison of in vitro and in vivo results.
- Author
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Frank, Dana M., Deaton, Lewis, Shumway, Sandra E., Holohan, Bridget A., and Ward, J. Evan
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BIVALVES , *NEUROTRANSMITTERS , *IN vitro studies , *IN vitro toxicity testing , *SEROTONIN antagonists , *DOPAMINE agonists , *HYDRAULICS , *PHYSIOLOGY - Abstract
Most studies regarding the neuroanatomy and neurophysiology of molluscan ctenidia have focused on isolated ctenidial tissue preparations. This study investigated how bivalve molluscs modulate their feeding rates by examining the effects of a variety of neurotransmitters, including serotonin, dopamine, and the dopamine agonist apomorphine on both isolated ctenidial tissue and in intact members of two commercially important bivalve species: the blue mussel, Mytilus edulis ; and the bay scallop Argopecten irradians . In particular, we examined the effect of changes in: 1) beat of the lateral cilia ( in vitro ), 2) distance between ctenidial filaments and/or plicae ( in vivo ), and 3) diameter of the siphonal openings ( in vivo ) on alteration of bulk water flow through the mantle cavity. Important differences were found between isolated tissue and whole animals, and between species. Drugs that stimulated ciliary beat in vitro did not increase water processing rate in vivo . None of the treatments increased water flow through the mantle cavity of intact animals. Results suggest that A. irradians was primarily modulating lateral ciliary activity, while M. edulis appeared to have a number of ways to control water processing activity, signifying that the two species may have different compensatory and regulatory mechanisms controlling feeding activity. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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231. A multi-phylum study of grazer-induced paralytic shellfish toxin production in the dinoflagellate Alexandrium fundyense: A new perspective on control of algal toxicity.
- Author
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Senft-Batoh, Christina D., Dam, Hans G., Shumway, Sandra E., and Wikfors, Gary H.
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PARALYTIC shellfish poisoning , *DINOFLAGELLATES , *ALEXANDRIUM , *ALGAL toxins , *BOTRYLLOIDES violaceus , *BIOLOGICAL assay , *KAIROMONES - Abstract
The present study surveyed grazer-induced stimulation of paralytic shellfish toxin (PST) production by the marine dinoflagellate Alexandrium fundyense. The survey included species, known to graze upon A. fundyense , from five phyla: the protists, Polykrikos kofoidii (Dinoflagellata) and Tiarina fusus (Ciliophora), the bivalve molluscs Mytilus edulis and Mya arenaria (Mollusca), the ascidians, Molgula manhattensis and Botrylloides violaceus (Chordata), and the copepod, Eurytemora herdmani (Arthropoda). Direct (grazers in contact with cells of A. fundyense ) and indirect (grazers not in contact with cells of A. fundyense ) induction assays were carried out with protists and copepods. Only indirect assays were carried out with molluscs and ascidians. Indirect assays also tested whether induction of PST production occurred via kairomones or feeding-related cues. All metazoan grazers induced PST production. By contrast, neither of the two species of protistan grazer induced PST production. Direct and indirect inductions of PST production were evident for the copepod, with direct induction being significantly higher than indirect induction. Effects upon PST production by phylum, species (nested within phylum), and interactions of phylum by diet, and species by diet, were evident. When induction of PST production occurred, a kairomone effect was apparent, except for M. edulis . Similarly, feeding-related cues were evident, except for E. herdmani . An asymptotic relationship between the magnitude of indirect induction of PST production and total cell ingestion by the grazers suggests a saturation response of grazer-induced PST production. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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232. Influence of predator-prey evolutionary history, chemical alarm-cues, and feeding selection on induction of toxin production in a marine dinoflagellate.
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Senft ‐ Batoh, Christina D., Dam, Hans G., Shumway, Sandra E., Wikfors, Gary H., and Schlichting, Carl D.
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PREDATION , *ALEXANDRIUM , *ACARTIA hudsonica , *PHYTOTOXINS , *KAIROMONES , *EVOLUTION research - Abstract
The dinoflagellate, Alexandrium fundyense, produces paralytic shellfish toxins and co-occurs with populations of the copepod, Acartia hudsonica, from Maine, but not New Jersey. The hypothesis that history of co-occurrence between predator and prey effects the ability of prey to recognize and respond to predators with increased toxin production was tested for this copepod-alga interaction. When A. fundyense was exposed to waterborne cues released by copepods from Maine (indirect exposure) that were either starved or fed toxic cells, cell toxin quota increased by 35% compared to unexposed controls. The induced response was significantly less for cells exposed to waterborne cues of copepods from New Jersey, and induction (20%) was only elicited by this population when fed toxic cells. These results suggest that A. fundyense responded to a kairomone from copepods from Maine, but required a feeding cue from copepods from New Jersey. An increase of approximately 300% in cell toxin quota, however, occurred when cells were directly exposed to grazing, and was independent of copepod population. Evolutionary history, therefore, had no apparent effect when induction was underlain by feeding cues. In assays with a mixture of toxic and nontoxic cells, selection for the latter was evident, and also independent of copepod population. Selectivity for nontoxic cells, however, could not account for changes in cell toxin content in the mixture experiments. When A. fundyense was exposed to extracts of toxic or nontoxic Alexandrium, toxin production increased significantly (23%), suggesting modest induction by an alga-to-alga alarm signal. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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233. Accumulation of paralytic shellfish toxins by surfclams, Spisula solidissima (Dillwyn, 1897) in the Gulf of Maine: seasonal changes, distribution between tissues, and notes on feeding habits
- Author
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Selvin, Rhonda, Shumway, Sandra E., Cembella, Allan D., and Sherman, Sally A.
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ECONOMIC seasonal variations - Published
- 1994
234. Juvenile and yearling growth of Atlantic surfclams Spisula solidissima (Dillwyn, 1817) in Maine
- Author
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Shumway, Sandra E., Scully, Kevin C., and Davis, Christopher V.
- Abstract
With the recent emergence of a shellfish aquaculture industry in Maine, the development of alternative species would provide mariculturists some flexibility and stability by diversifying their product line and opening up coastal environments unsuitable to the oysters and mussels currently being cultivated. The Atlantic surfclam, Spisula solidissima, occurs naturally in Maine, and although it has not been commercially exploited, this mactrid clam may provide growers with a profitable new product line. What is not known is how well this species will grow in a culture setting throughout Maine's diverse marine environment. The goal of this study was to assess the growth and survival of two age/size classes of Atlantic surfclams under a variety of growing conditions. Juvenile (3-mm) and yearling (23-mm) surfclams were reared for one growing season in floating screened trays and intertidalsediments, respectively, at six study sites along the coast of Maine. After 4 mo of growth, mean size differences of juveniles among the six growing sites were significant. Juveniles reared at the upper Damariscotta River site grew the fastest (8.9 mm. shell length [SL] among the six sites. In comparison, those grown in Mud Hole Cove had the slowest growth (5.5 mm SL). Yearling surfclams at both planting densities grew the fastest in the Mud Hole Cove plot (40 mm SL) compared with the slowest growing sibling cohorts in the Deer Isle plot (27 mm SL). Similar trends among plots were observed with respect to both wet and dry weight gain. Surfclams reared in low-density treatments tended to grow faster than the high-density cohorts, although the means were not significantly different at any of the study plots. The optimal nursery sites for juvenile growth were different from the most productive areas for yearling growth, suggesting that growers may want to choose separate areas for different culture phases. This study is the first to document rates of growth and survival of Atlantic surfclam [ABSTRACT FROM AUTHOR]
- Published
- 1997
235. Physicochemical surface properties of microalgae and their combined effects on particle selection by suspension-feeding bivalve molluscs.
- Author
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Rosa, Maria, Ward, J. Evan, Holohan, Bridget A., Shumway, Sandra E., and Wikfors, Gary H.
- Subjects
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MICROALGAE , *FLUORESCEIN isothiocyanate , *SURFACE charges , *DISCRIMINANT analysis , *REGRESSION analysis - Abstract
The capabilities of bivalve molluscs to feed selectively have been well documented, and physicochemical properties of particles have been implicated as possible factors in the selection process. In this study, the surface-property profiles of nine different microalgal species were determined by characterizing the surface charge, wettability (= contact angle), and surface carbohydrate moieties. Three fluorescein isothiocyanate (FITC) conjugated lectins were used to characterize carbohydrate moieties, including concanavalin A (ConA), Pisum sativum agglutinin (PEA), and wheat germ agglutinin (WGA). Distinct surface-property profiles were identified using linear discriminant analysis (DA) and used to design mixed-algal feeding experiments to assess particle selection by the blue mussel Mytilus edulis and the eastern oyster Crassostrea virginica . Results demonstrated preferential ingestion of some algal species over others, with strong rejection of some species (e.g. Pavlova lutheri and Prasinocladus marinus ). These data were then used to develop DA and multiple linear regression models that considered the quantified surface properties and microalgal fates (rejected, ingested, or no selection) to examine determinants of selection. The DA model correctly classified 58% of the selection outcomes in mussels and 57% in oysters. Wettability was the most important factor in predicting selection in mussels, and surface charge was most important for oysters. In the multiple linear regression analyses, lectin affinity and wettability were the strongest predictors of particle selection, explaining ca. 90% of the variability in electivity index for mussels and 94% of the variability for oysters. By characterizing both physical and chemical surface properties of several microalgaeused as food for suspension-feeding bivalves, we demonstrate that multiple surface-property characteristics need to be considered in order to develop meaningful models of particle selection in bivalves. Future research also should take into account species-specific differences in selection. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
236. Effects of field and laboratory exposure to the toxic dinoflagellate Karenia brevis on the reproduction of the eastern oyster, Crassostrea virginica, and subsequent development of offspring.
- Author
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Rolton, Anne, Vignier, Julien, Volety, Aswani K., Pierce, Richard H., Henry, Michael, Shumway, Sandra E., Bricelj, V. Monica, Hégaret, Hélène, and Soudant, Philippe
- Subjects
- *
KARENIA brevis , *AMERICAN oyster , *TOXIC algae , *ALGAL blooms , *OYSTER contamination , *REPRODUCTION - Abstract
Blooms of the brevetoxin-producing dinoflagellate, Karenia brevis , are a recurrent and sometimes devastating phenomenon in the Gulf of Mexico. The eastern oyster, Crassostrea virginica , is exposed regularly to these blooms, yet little is known about the impacts of K. brevis upon this important species. The present study considered the effects of exposure to both a natural bloom and cultured K. brevis on the reproductive development of C. virginica . Oysters had been exposed to a bloom of K. brevis that occurred in Lee County, Florida, from September 2012 through May 2013, during a period of gametogenesis and gamete ripening. Ripe adult oysters were collected from this bloom-exposed site and from a site 200 miles north which was not exposed to any bloom. In addition, responses to two 10-day laboratory exposures of either unripe or ripe adult oysters to whole cells of K. brevis at high bloom concentrations (1000 and 5000 cells mL −1 ) were determined. Both field- and laboratory-exposed adult oysters accumulated PbTx (attaining ∼22 × 10 3 ng g −1 and 922 ng g −1 PbTx-3 equivalents in the laboratory and the field, respectively), and significant mucal, edematous, and inflammatory features, indicative of a defense response, were recorded in adult tissues in direct contact with K. brevis cells. Laboratory-exposed oysters also showed an increase in the total number of circulating hemocytes suggesting that: (1) new hemocytes may be moving to sites of tissue inflammation, or, (2) hemocytes are released into the circulatory system from inflamed tissues where they may be produced. The area of oyster tissue occupied by gonad (representative of reproductive effort) and reactive oxygen species production in the spermatozoa of oysters exposed to the natural bloom of K. brevis were significantly lower compared to oysters that were not exposed to K. brevis . Additionally, following 10-day exposure of ripe oysters, a significant, 46% reduction in the prevalence of individuals with ripe gametes was obtained in the 5000 cells mL −1 K. brevis treatment. Brevetoxin (PbTx) was recorded within the spermatozoa and oocytes of naturally exposed oysters and was estimated to be 18 and 26% of the adult PbTx load, respectively. Larvae derived from gametes containing PbTx showed significantly higher mortalities and attained a smaller larval size for the first 6 days post-fertilization. These negative effects on larval development may be due to the presence of PbTx in the lipid droplets of the oocytes, which is mobilized by the larvae during embryonic and lecithotrophic larval development. Provision of a non-contaminated food source to larvae however, appeared to mitigate the early negative effects of this neonatal PbTx exposure. Results herein show that adult eastern oysters and their offspring are susceptible to exposure to K. brevis. Caution should therefore be exercised when identifying oyster reef restoration areas and in efforts to establish aquaculture in areas prone to red tides. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
237. Examining the physiological plasticity of particle capture by the blue mussel, Mytilus edulis (L.): Confounding factors and potential artifacts with studies utilizing natural seston.
- Author
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Rosa, Maria, Ward, J. Evan, Ouvrard, Melissa, Holohan, Bridget A., Pales Espinosa, Emmanuelle, Shumway, Sandra E., and Allam, Bassem
- Subjects
- *
MYTILUS edulis , *PHENOTYPIC plasticity , *SESTON , *MOLLUSKS , *PARTICULATE matter , *PARTICLE size determination , *PHYSIOLOGY , *FOOD - Abstract
Historically, particle capture efficiency (CE) in suspension-feeding bivalve molluscs has been shown to be strongly dependent on particle size, increasing asymptotically to a maximum of about 100% for particles ca. ≥ 4 μm in diameter. Recent advances in the analysis of the particulate matter of seston have allowed for more precise studies of bivalve feeding under natural conditions. Some studies have reported that the mechanisms associated with particle capture exhibit physiological plasticity, and under certain conditions smaller cells and particles are captured in preference to larger ones. For bivalves, however, there is no mechanistic explanation that would account for such fine-scale control of CE based on size. The current study experimentally assessed the seasonal control of CE by the blue mussel, Mytilus edulis , employing a flow-through system to examine particle capture of natural seston. The natural particle field was analyzed using two different types of particle analyzers, the LISST-100X and the Coulter Multisizer IIe. Mussels were simultaneously delivered synthetic microspheres of defined diameter (2–45 μm) to control for the effects of seasonal differences in the size and shape of natural particles. The capture of microspheres was quantified by means of flow cytometry (FCM), and results cross-checked with the Multisizer. Additionally, gene expression of a mucosal lectin (MeML) associated with the feeding organs of mussels was examined as a biomarker for physiological response to seasonal changes in the particle-food supply. Results demonstrated that for microspheres ≥ 4 μm CE of mussels was always near 100%, and did not change seasonally. In contrast, there was an apparent seasonal shift in CE of natural particles, with particles 17-to-35 μm in equivalent spherical diameter (ESD) occasionally being captured at lower efficiencies than particles 4-to-15 μm in ESD (e.g., during September and December). No relationship between MeML expression and seasonal CE was found. These findings call into question the physiological plasticity of CE in mussels and alternative hypotheses are presented. We suggest that the purported changes in CE are not a consequence of behavioral or physiological responses of mussels, but rather a result of one or more of the following confounding factors; 1) instrument artifacts that can arise as a result of the way in which laser and electronic particle counters calculate ESD to estimate particle size; 2) disaggregation of flocculent material collected from control chambers; 3) post-capture escape of highly motile phytoplankton cells from the infrabranchial camber; 4) qualitative factors of the particles that could affect capture; or 5) mathematical happenstance of calculating CE on particle-size classes that contain widely different numbers of particles. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
238. Susceptibility of gametes and embryos of the eastern oyster, Crassostrea virginica, to Karenia brevis and its toxins.
- Author
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Rolton, Anne, Soudant, Philippe, Vignier, Julien, Pierce, Richard, Henry, Michael, Shumway, Sandra E., Bricelj, V. Monica, and Volety, Aswani K.
- Subjects
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GAMETES , *AMERICAN oyster , *KARENIA brevis , *MARINE toxins , *ALGAL blooms , *COASTS - Abstract
The bivalve mollusc, Crassostrea virginica, is frequently exposed to blooms of Karenia brevis along the west coast of Florida during periods of spawning and early larval development. A continuous 4-day exposure of gametes and 2–4 cell stage embryos of C. virginica to whole-cell and culture filtrate of K. brevis at 500 and 5000 cells mL −1 , was followed by a 4-day ‘recovery’ period. Larval growth, percent of normal, abnormal and dead larvae, and the presence of food in the larval gut were measured throughout the exposure period. Results suggest that negative effects mainly occur during embryogenesis and early development. Damage to feeding apparatus/gut may occur during embryonic development or exposure to toxins may act as a feeding deterrent on non-toxic algae. Following 2-h in vitro exposure of gametes, differences in oocyte and sperm cell parameters were investigated using flow cytometry. The reduced sperm viability in the whole-cell 5000 cells mL −1 treatment suggests the involvement of extracellular brevetoxins (PbTx) and perhaps other harmful, uncharacterized compounds associated with the K. brevis cell membrane. The cumulative effects of reduced sperm viability, fertilization success, embryonic and larval survival, and the near-annual exposure to blooms of K. brevis could cause significant bottlenecks on oyster recruitment. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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239. Prevalence and intensity of pathologies induced by the toxic dinoflagellate, Heterocapsa circularisquama, in the Mediterranean mussel, Mytilus galloprovincialis.
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Basti, Leila, Endo, Makoto, Segawa, Susumu, Shumway, Sandra E., Tanaka, Yuji, and Nagai, Satoshi
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DINOFLAGELLATES , *MYTILUS galloprovincialis , *MUSSELS , *TOXICOLOGY of water pollution , *HEMORRHAGE , *METABOLIC detoxification - Abstract
The harmful dinoflagellate, Heterocapsa circularisquama , has been causing mass mortalities of bivalve molluscs in Japan, at relatively low cell densities. Although several studies have been conducted to determine the toxicity mechanisms, the specific cause of death is still unclear. In a previous study, in our laboratory, it was shown that H . circularisquama (10 3 cells ml −1 ) caused extensive cytotoxicity in the gills of short-neck clams, Ruditapes philippinarum . In the present study, Mediterranean mussels, Mytilus galloprovincialis , were exposed to H . circularisquama at four cell densities (5, 50, 500, 10 3 cells ml −1 ), three temperatures (15, 20, and 25 °C), and three exposure durations (3, 24, and 48 h), and the pathologies in nine organs (gills, labial palps, mantle, hepatopancreas, stomach, intestines, exhalant siphon, adductor muscles, and foot) were assessed. Foot, adductor muscles, and exhalent siphons of mussels were not affected; however, 16 inflammatory (hemocytic infiltration and aggregation, diapedesis, hyperplasia, hypertrophy, edema, melanization, and firbrosis) and degenerative (thrombus, thrombosed edema, cilia matting and exfoliation, epithelial desquamation, atrophy, and necrosis) pathologies were identified in the gills, labial palps, mantle, hepatopancreas, stomach, and intestines. The total prevalence and total intensity of pathology in each individual mussel, and the prevalence and intensity of pathology in each organ increased significantly with increased cell density, exposure duration, and temperature. The prevalence of pathology was the highest in gills, followed by the prevalence in labial palps, mantle, stomach, and intestines. Pathology was least prevalent in the hepatopancreas. The intensity of pathology was the highest in the gills, followed by the labial palps and mantle, the stomach and intestines, and the hepatopancreas. This detailed quantitative histopathological study demonstrates that exposure to H . circularisquama induces a broad cytotoxic effect in six vital organs, even at low density (5 cells ml −1 ) and low temperature (15 °C), but not in muscular organs. Combining cell density, time, and duration of exposure, the organ most affected by the harmful alga was the gill, followed by the labial palps and mantle, the stomach and intestines, and the hepatopancreas. The results of this pathological analysis show that exposure to H . ciruclarisquama severely affects the gills, the labial palps, and mantle thereby interfering with particle clearance and sorting, cleansing, and respiration, but also affects the stomach, intestines, and hepatopancreas, altering the digestive processes and possibly detoxification pathways, if mussels are able to detoxify the toxins of H . circularisquama . In the most severe cases, bivalves would most likely have died as a result of combined severe alterations of the vital functions, failure of tissue repair, and moderate to heavy hemorrhaging in both the external organs and the digestive organs concomitantly with light to moderate alterations in the detoxifying processes. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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240. Effect of Food on Metamorphic Competence in the Model System Crepidula fornicata.
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Padilla, Dianna K., McCann, Michael J., Glenn, Mica McCarty, Hooks, Alexandra P., and Shumway, Sandra E.
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CREPIDULA , *CLIMATE change research , *DEVELOPMENTAL biology , *CALYPTRAEIDAE , *METAMORPHOSIS , *BENTHIC animals - Abstract
Food quality and quantity, as well as temperature, are all factors that are expected to affect rates of development, and are likely to be affected by expected climatic change. We tested the effect of a mixed diet versus a single-food diet on metamorphic competence in the emerging model species Crepidula fornicata. We then compared our results with other published studies on this species that examined time to metamorphic competence across a range of food concentrations and rearing temperatures. Ours was the only study to test the effects of single food versus a mixed diet on metamorphic competence for this species. Diet composition did not affect metamorphic competence or survivorship. Comparing results across studies, we found that the shortest time to metamorphic competence was typically found when the food availability per larva was the greatest, independent of rearing temperature. Unfortunately, some published studies did not include important metadata needed for comparison with other studies; these data included larval rearing density, food density, frequency of feeding, and rearing temperature. Mortality rates were not always reported and when reported were often measured in different ways, preventing comparison. Such metadata are essential for comparisons among studies as well as among taxa, and for the determination of generalizable patterns and evolutionary trends. Increased reporting of all such metadata is essential if we are to use scientific studies performed to their fullest potential. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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241. Role of Epicellular Molecules in the Selection of Particles by the Blue Mussel, Mytilus edulis.
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ESPINOSA, EMMANUELLE PALES, HASSAN, DAHLIA, WARD, J. EVAN, SHUMWAY, SANDRA E., and ALLAM, BASSEM
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MYTILUS edulis , *SUSPENSION feeders , *CARBOHYDRATES , *BIVALVES , *MICROSPHERES - Abstract
This study provides evidence that the suspension-feeding blue mussel, Mytilus edulis, uses biochemical cues to recognize its food. We identified lectins in mucus from the gills and labial palps, two pallial organs involved in the feeding process. These compounds were able to agglutinate rabbit and horse erythrocytes (RBC) and several species of marine microalgae representing different families. Additionally, the agglutination of RBC and microalgae was inhibited by several carbohydrates (fetuin, lipopolysaccharide (LPS), and mannose-related residues), suggesting that a suite of lectins may be present in mucus from the gills and labial palps. Results from feeding experiments, using microspheres with tailored surfaces, demonstrated that mussels preferentially ingested microspheres coated with the neoglycoproteins glucosamide-BSA and mannopyranosylphenyl-BSA but rejected in pseudofeces microspheres coated with BSA alone. The positive selection for neoglycoprotein-coated microspheres was inhibited when mussels were pre-incubated in seawater containing a solution of the same neoglycoprotein. Two surface properties of the microspheres, charge and wettability, had little effect on the observed selection process. Our results, along with our previous findings for oysters, suggest a new concept for the mechanism of particle selection in bivalves and perhaps other suspension-feeding organisms. Specifically, the selection of particles involves interactions between epiparticulate carbohydrates and lectins in the mucus produced by feeding organs. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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242. Combined effects of a parasite, QPX, and the harmful-alga, Prorocentrum minimum on northern quahogs, Mercenaria mercenaria
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Hégaret, Hélène, Smolowitz, Roxanna M., Sunila, Inke, Shumway, Sandra E., Alix, Jennifer, Dixon, Mark, and Wikfors, Gary H.
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FISH parasites , *NORTHERN quahog , *THRAUSTOCHYTRIALES , *PARASITIC diseases , *PLANKTON , *FLOW cytometry , *SHELLFISH , *DINOFLAGELLATES - Abstract
Abstract: Northern quahogs, Mercenaria mercenaria (L.), frequently are infected with the parasite Quahog Parasite Unknown (QPX, Labyrintohomorpha, Thraustochytriales), which can cause morbidity and mortality of the quahogs. Possible interactions between this parasitic disease and exposure to the harmful dinoflagellate Prorocentrum minimum in M. mercenaria were studied experimentally. Quahogs from Massachusetts with variable intensity of QPX infection were exposed, under controlled laboratory conditions, to cultured P. minimum added to the natural plankton at a cell density equivalent to a natural bloom. After 5days of exposure, individual clams were diagnosed histologically to assess prevalence and intensity of parasitic infection, as well as other pathological conditions. Further, cellular defense status of clams was evaluated by analyzing hemocyte parameters (morphological and functional) using flow-cytometry. Exposure of quahogs to P. minimum resulted in: a lower percentage of phagocytic hemocytes, higher production of reactive oxygen species (ROS), larger hemocyte size, more-numerous hemocytic aggregates, and increased numbers of hemocytes in gills accompanied by vacuolation and hyperplasia of the water-tubular epithelial cells of the gills. Quahogs had a low prevalence of QPX; by chance, the parasite was present only in quahogs exposed to P. minimum. Thus, the effect of QPX alone on the hemocyte parameters of quahogs could not be assessed in this experiment, but it was possible to assess different responses of infected versus non-infected quahogs to P. minimum. QPX-infected quahogs exposed to P. minimum had repressed percentage of phagocytic hemocytes, consistent with immuno-modulating effect of P. minimum upon several molluscan species, as well as smaller hemocytes and increased hemocyte infiltration throughout the soft tissues. This experiment demonstrates the importance of considering interactive effects of different factors on the immunology and histopathology of bivalve shellfish, and highlights the importance of considering the presence of parasites when bivalves are subjected to harmful-algal blooms. [Copyright &y& Elsevier]
- Published
- 2010
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243. Microalgal Cell Surface Carbohydrates as Recognition Sites for Particle Sorting in Suspension-Feeding Bivalves.
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Espinosa, Emmanuelle Pales, Perrigault, Mickael, Ward, J. Evan, Shumway, Sandra E., and Allam, Bassem
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CARBOHYDRATES , *BIVALVES , *CELL membranes , *LECTINS , *MICROALGAE , *PEAS - Abstract
Cell surface carbohydrates play important roles in cell recognition mechanisms. Recently, we provided evidence that particle selection by suspension-feeding bivalves can be mediated by interactions between carbohydrates associated with the particle surface and lectins present in mucus covering bivalve feeding organs. In this study, we used lectins tagged with fluorescein isothiocyanate (FITC) to characterize carbohydrate moieties on the surface of microalgal species and evaluate the effect of oyster mucus on lectin binding. These analyses revealed that concanavalin A (Con A), one of six lectins tested, bound to Jsoc/irysis sp., while Nitzschia closterium reacted with Pisum sativum agglutinin (PNA) and peanut agglutinin (PEA). The cell surface of Rhodomonas sauna bound with PNA and Con A, and Tetraselmis maculata cell surface was characterized by binding with PNA, PEA, and Con A. Pre-incubation of microalgae with oyster pallial mucus significantly decreased the binding of FITC-labeled lectins, revealing that lectins present in mucus competitively blocked binding sites. This decrease was reversed by washing mucus-coated microalgae with specific carbohydrates. These results were used to design a feeding experiment to evaluate the effect of lectins on sorting of microalgae by oysters. Crassostrea virginica fed with an equal ratio of Con A-labeled Isochrysis sp. and unlabeled Isochrysis sp. produced pseudofeces that were significantly enriched in Con A-labeled Isochrysis sp. and depleted in unlabeled microalgae. Selection occurred even though two physical-chemical surface characteristics of the cells in each treatment did not differ significantly. This work confirms the involvement of carbohydrate-lectin interaction in the particle sorting mechanism in oysters, and provides insights into the carbohydrate specificity of lectins implicated in the selection of microalgal species. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
244. Letter to the Editor: Characterization of Pfiesteria Ichthyocidal Activity.
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Gordon, Andrew S., Marshall, Harold G., Shumway, Sandra E., Coyne, Kathryn J., Lewitus, Alan J., Mallin, Michael A., and Rublee, Parke A.
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LETTERS to the editor , *BIOLOGICAL assay - Abstract
Presents a letter to the editor discussing aquarium bioassays.
- Published
- 2005
- Full Text
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245. Lectins Associated With the Feeding Organs of the Oyster Crassostrea virginica Can Mediate Particle Selection.
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Espinosa, Emmanuelle Pales, Perrigault, Mickael, Ward, J. Evan, Shumway, Sandra E., and Allam, Bassem
- Subjects
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LECTINS , *HEMAGGLUTININ , *CRASSOSTREA , *OYSTERS , *BIVALVES - Abstract
Despite advances in the study of particle selection in suspension-feeding bivalves, the mechanisms upon which bivalves rely to discriminate among particles have not been elucidated. We hypothesized that particle sorting in suspension-feeding bivalves could be based, in part, on a biochemical recognition mechanism mediated by lectins within the mucus that covers the feeding organs. Using Crassostrea virginica, the Eastern oyster, our investigations demonstrated that lectins from oyster mucus can specifically bind several microalgal species as well as different types of red blood cells (RBC), triggering their agglutination. Agglutination of microalgal species and RBC varied with the source of mucus (gills vs. labial palps). Hemagglulination and hemagglutination inhibition assays emphasized that mucus contains several lectins. In feeding experiments, Nitzschia closterium and Tetraselmis maculata were separately incubated with mucus before being fed to oysters. Results showed that pre-treating these microalgae with mucus significantly alters the ability of oysters to sort particles. In another experiment, oysters were fed a mixture of micro-spheres coated with either bovine serum albumin (BSA) or glucosamide-BSA. Results show that oysters preferentially ingest microspheres with bound carbohydrates, highlighting probable interactions between lectins and carbohydrates in the mechanisms of microalgae recognition. This study confirms the presence of lectins in mucus that covers the feeding organs of oysters and suggests a new concept with regard to particle processing by suspension-feeding bivalves: specific interactions between carbohydrates on the surface of particles and Lectins within the mucus mediate the selection and rejection processes. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
246. Immunological responses of the Manila clam (Ruditapes philippinarum) with varying parasite (Perkinsus olseni) burden, during a long-term exposure to the harmful alga, Karenia selliformis, and possible interactions
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da Silva, Patricia Mirella, Hégaret, Hélène, Lambert, Christophe, Wikfors, Gary H., Le Goïc, Nelly, Shumway, Sandra E., and Soudant, Philippe
- Subjects
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MANILA clam , *PARASITES , *BIVALVES , *BLOOD cells - Abstract
Abstract: The present study evaluated the possible effects of a toxic dinoflagellate, Karenia selliformis, upon immunological hemocyte functions of the Manila clam Ruditapes philippinarum, and on the progression of infection by Perkinsus olseni. Clams with variable levels of perkinsosis were exposed for 6 weeks to simulated blooms of cultured the K. selliformis (102 and 103 cellml−1). Samples were collected after 0, 2, 3, and 6 weeks of exposure. The following hemocyte parameters were measured by flow cytometry: percentage of dead cells, cell size and complexity, apoptosis, phagocytosis, and production of reactive oxygen species. Agglutination activities of K. selliformis on horse erythrocytes, serum protein concentration, and condition index of clams were also assessed. The harmful alga K. selliformis caused a significant decrease in hemocyte size and percentage of apoptotic cells. In contrast, P. olseni did not affect clams strongly; the only significant effect was an increase in hemocyte size in heavily infected clams. After 2 and 3 weeks, the prevalence and burden of P. olseni decreased in clams exposed to K. selliformis, but after 6 weeks, and a diminution in K. selliformis cell density in the exposure, this effect disappeared. In vitro tests exposing P. olseni to K. selliformis showed direct algal toxicity to the parasite (increased percentage of dead cells and altered morphology). Initial exposure of P. olseni-infected clams to K. selliformis appeared to modify the host–parasite interaction by causing effects in both organisms. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
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247. Hemocyte responses of Manila clams, Ruditapes philippinarum, with varying parasite, Perkinsus olseni, severity to toxic-algal exposures
- Author
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Hégaret, Hélène, da Silva, Patricia Mirella, Wikfors, Gary H., Lambert, Christophe, De Bettignies, Thibaut, Shumway, Sandra E., and Soudant, Philippe
- Subjects
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AQUATIC resources , *CRYPTOGAMS , *PHYCOLOGY , *PHYTOPLANKTON - Abstract
Abstract: This study assessed the possible combined effects of harmful algae and parasite infection on hemocyte and hemolymph parameters of a bivalve mollusc. Manila clams Ruditapes philippinarum, were exposed for 1 week, under controlled laboratory conditions, to bloom concentrations of two cultured dinoflagellates: Karenia selliformis, and Karenia mikimotoi, with demonstrated, sub-lethal, pathological effects upon these bivalves. Each dinoflagellate treatment was added to a basal diet of Chaetoceros neogracile; controls consisted of clams fed only C. neogracile. Hemocyte characteristics measured with flow-cytometric analyses, and agglutination titer, condition index, and prevalence and intensity of Perkinsus olseni, were assessed for individual clams before and after 3 and 6 days of microalgal exposure. Multifactor analysis of variance tests were conducted to determine possible effects of the harmful algae, time of exposure, and P. olseni intensity, as well as interactions between these three factors, upon each physiological variable measured. There was no relationship between P. olseni intensity and hemolymph measures. Both Karenia species, however, had a significant effect upon hemocyte profiles of the clams, and this effect was dependent upon duration of exposure; 3 days of exposure to the dinoflagellates generally was sufficient to resolve the effects on the clams. K. selliformis had a stronger effect than K. mikimotoi, which was intermediate between K. selliformis and clams fed the non-toxic control, C. neogracile. Total hemocyte counts increased in clams exposed to the harmful algae, while the percentage of dead hemocytes, as well as hemocyte size and complexity, decreased. Furthermore, these immunomodulating effects of K. selliformis were significantly more extreme in clams with a high parasite burden, compared with lightly infected clams. This report is, to our knowledge, the first study assessing the combined effects of harmful algae and parasite infection on a physiological function (hemocyte and hemolymph parameters) of a bivalve mollusc. These findings demonstrate that clams maintain hemocyte function when infected with P. olseni, that the clam immune system responds to harmful or toxic algal exposure, and that this response is modified by parasite infection. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
248. Toxic dinoflagellates ( Alexandrium fundyense and A. catenella) have minimal apparent effects on oyster hemocytes.
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Hégaret, Hélène, Wikfors, Gary H., Soudant, Philippe, Lambert, Christophe, Shumway, Sandra E., Bérard, Jean Baptiste, and Lassus, Patrick
- Subjects
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DINOFLAGELLATES , *OYSTERS , *PARALYTIC shellfish poisoning , *SAXITOXIN , *PHYTOFLAGELLATES , *BLOOD cells , *PHAGOCYTOSIS , *BIOACTIVE compounds , *MARINE sciences - Abstract
The possible effect of Alexandrium spp. containing paralytic shellfish poisoning (PSP) toxins on the hemocytes of oysters was tested experimentally. In one trial, eastern oysters, Crassostrea virginica Gmelin, were exposed to bloom concentrations of the sympatric dinoflagellate, Alexandrium fundyense Balech, alone and in a mixture with a non-toxic diatom, Thalassiosira weissflogii (Grun) Fryxell et Hasle. Subsequently, another experiment exposed Pacific oysters, Crassostrea gigas Thunberg, to a mixed suspension of the sympatric, toxic species Alexandrium catenella (Whedon et Kofoid) Balech, with T. weissflogii. Measurements of numbers of oyster hemocytes, percentages of different cell types, and functions (phagocytosis, reactive oxygen species (ROS) production, and mortality) were made using flow-cytometry. During and after exposure, almost no significant effects of Alexandrium spp. upon hemocyte numbers, morphology, or functions were detected, despite observations of adductor-muscle paralysis in C. virginica and measured toxin accumulation in C. gigas. The only significant correlation found was between toxin accumulation at one temperature and higher numbers of circulating live and dead hemocytes in C. gigas. The PSP toxins are known to interfere specifically with sodium-channel function; therefore, the finding that the toxins had no effect on measured hemocyte functions suggests that sodium-channel physiology is not important in these hemocyte functions. Finally, because oysters were exposed to the living algae, not purified toxins, there was no evidence of bioactive compounds other than PSP toxins affecting hemocytes in the two species of Alexandrium studied. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
249. Effects of the dinoflagellate Karenia brevis on larval development in three species of bivalve mollusc from Florida
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Leverone, Jay R., Blake, Norman J., Pierce, Richard H., and Shumway, Sandra E.
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MOLLUSCICIDES , *AQUATIC invertebrates , *SHELLFISH fisheries , *DEVELOPMENTAL biology - Abstract
Abstract: The effects of Karenia brevis (Wilson clone) on larval survival and development of the northern quahog, Mercenaria mercenaria, eastern oyster, Crassostrea virginica and bay scallop, Argopecten irradians, were studied in the laboratory. Larvae were exposed to cultures of whole and lysed cells, with mean total brevetoxin concentrations of 53.8 and 68.9μgL−1, respectively. Survival of early (3-day-old) larvae was generally over 85% for all shellfish species at K. brevis densities of 100 cellsml−1 or less, and not significantly different between whole and lysed culture. At 1000 cellsml−1, survival was significantly less in lysed culture than whole culture for both M. mercenaria and C. virginica. Survival of late (7-day-old) larvae in all three species was not significantly affected by K. brevis densities of 1000 cellsml−1 or less. At 5000 cellsml−1, however, survival was reduced to 37%, 26% and 19% for A. irradians, M. mercenaria and C. virginica, respectively. Development of C. virginica and M. mercenaria larvae was protracted at K. brevis densities of 1000 cellsml−1. These results suggest that blooms of K. brevis, and particularly their associated brevetoxins, may have detrimental consequences for Florida''s shellfisheries by disrupting critical larval processes. Special attention should be paid to blooms of K. brevis where these shellfish occur naturally or where aquaculture and restoration activities are either ongoing or planned. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
- View/download PDF
250. Dynamics, Assessment, and Management of Exploited Natural Scallop Populations
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Jose Maria Orensanz, Stephen J. Smith, Ana M. Parma, Shumway, Sandra E., and Parsons, G. Jay
- Subjects
0106 biological sciences ,Ecology ,010604 marine biology & hydrobiology ,SCALLOP FISHERY MANAGEMENT ,Ecología ,Biology ,010603 evolutionary biology ,01 natural sciences ,Ciencias Biológicas ,Fishery ,POPULATION DYNAMICS ,Scallop ,SCALLOP STOCK ASSESSMENT ,SCALLOPS ,CIENCIAS NATURALES Y EXACTAS - Abstract
This chapter reviews advances made in the study of the structure and dynamics of scallop populations and in the development of new approaches for the assessment and management of exploited scallop stocks. Significant progress in the understanding of larval transport and connectivity of scallop populations has been achieved in recent years through the use of coupled biophysical modelling in combination with novel population genetics techniques. The assessment of abundance and distribution of scallops stocks has benefitted from recent technological developments, particularly in the fields of acoustics and underwater photography. These developments have led to mapping scallop distributions in relation to bottom type characterisations obtained from multi-beam sonar data, groundtruthed using conventional in situ sampling, including underwater imagery. Underwater cameras have also become more common, replacing conventional fishing gears used for periodic monitoring surveys. Management has increasingly focused on spatial harvesting strategies that recognise the existence of spatial gradients in scallop productivity, the non-random allocation of fishing effort and the large inter-annual variability that is typical of scallop recruitment. The use of management strategy evaluation methods to design harvest control rules that are suited to the fishery specific characteristics, and monitoring capabilities is a promising area of new development. Concerns about habitat impacts of dredges and trawls used for harvesting scallops have received much scientific attention as the scope of fisheries assessment has expanded beyond the target species to include broader ecological effects of fishing. Fil: Orensanz, Jose Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Parma, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Smith, Stephen J.. Bedford Institute of Oceanography, Fisheries and Oceans; Canadá
- Published
- 2016
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