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VIMS Articles

2004

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Articles 1 - 29 of 29

Full-Text Articles in Life Sciences

Dinitrogen Fixation And Release Of Ammonium And Dissolved Organic Nitrogen By Trichodesmium Ims101, Mr Mulholland, Da Bronk, Dg Capone Nov 2004

Dinitrogen Fixation And Release Of Ammonium And Dissolved Organic Nitrogen By Trichodesmium Ims101, Mr Mulholland, Da Bronk, Dg Capone

VIMS Articles

Two methods used to measure dinitrogen (N-2) fixation (acetylene reduction and N-15(2) uptake) often result in different N-2 fixation rates. Part of the discrepancy may arise from the observation that Trichodesmium can release a fraction of their recently fixed N-2 as dissolved organic nitrogen (DON) and/or ammonium (NH4+). To resolve outstanding issues regarding N-2 fixation and the production of dissolved combined nitrogen (N) by Trichodesmium, we conducted a comprehensive analysis of N-2 fixation and the production of DON and NH4+ in cultures of Trichodesmium IMS101. We performed N-15(2) uptake experiments in parallel with acetylene (C2H2) reduction assays ...


Real-Time Pcr For Detection And Quantification Of The Protistan Parasite Perkinsus Marinus In Environmental Waters, Corinne Audemard, Kimberly S. Reece, Em Burreson Nov 2004

Real-Time Pcr For Detection And Quantification Of The Protistan Parasite Perkinsus Marinus In Environmental Waters, Corinne Audemard, Kimberly S. Reece, Em Burreson

VIMS Articles

The protistan parasite Perkinsus marinus is a severe pathogen of the oyster Crassostrea virginica along the east coast of the United States. Very few data have been collected, however, on the abundance of the parasite in environmental waters, limiting our understanding of P. marinus transmission dynamics. Real-time PCR assays with SybrGreen I as a label for detection were developed in this study for quantification of P. marinus in environmental waters with P. marinus species-specific primers and of Perkinsus spp. with Perkinsus genus-specific primers. Detection of DNA concentrations as low as the equivalent of 3.3 x 10(-2) cell per ...


Parasitism In Species Of Bathymodiolus (Bivalvia : Mytilidae) Mussels From Deep-Sea Seep And Hydrothermal Vents, Me Ward, Jeffrey D. Shields, Cl Van Dover Nov 2004

Parasitism In Species Of Bathymodiolus (Bivalvia : Mytilidae) Mussels From Deep-Sea Seep And Hydrothermal Vents, Me Ward, Jeffrey D. Shields, Cl Van Dover

VIMS Articles

Bivalve species, especially mussels, are biomass dominants in many deep-sea chemosynthetic ecosystems. As in shallow-water environments, parasites are likely to be important factors in the population dynamics of bivalve communities in chemosynthetic ecosystems, but there has been little study of parasitism in deep-sea seep or vent molluscs. In this study, Parasite types, diversity, prevalence, infection density and non-infectious indicators of stress or disease as related to host age, reproductive condition, and endosymbiont density were assessed in mussels (Bathmodiolus heckerae) from 2 seep sites and mussels (B. puteoserpentis) from 2 vent sites. We identified 10 microbial or parasitic agents in histological ...


Ultrastructure Of Mycobacterium Marinum Granuloma In Striped Bass Morone Saxatilis, Dt Gauthier, Wolfgang K. Vogelbein, Ca Ottinger Oct 2004

Ultrastructure Of Mycobacterium Marinum Granuloma In Striped Bass Morone Saxatilis, Dt Gauthier, Wolfgang K. Vogelbein, Ca Ottinger

VIMS Articles

An emerging epizootic of mycobacteriosis currently threatens striped bass Morone saxatilis populations in Chesapeake Bay, USA. Several species of mycobacteria, including Mycobacterium marinum, species resembling AT. avium, All. gordonae, M. peregrinum, M. scrofulaceum and M. terrae, and the new species M. shottsii have been isolated from diseased and healthy bass. In this study, we describe the ultrastructure of developing M. marinum granulomas in experimentally infected bass over a period of 45 wk. The primary host response to injected mycobacteria was formation of large macrophage aggregations containing phagocytosed bacilli. AT marinum were always contained within phagosomes. Close association of lysosomes with ...


Infection Dynamics Of Marteilia Refringens In Flat Oyster Ostrea Edulis And Copepod Paracartia Grani In A Claire Pond Of Marennes-Oleron Bay, Corinne Audemard, Mc Sajus, Et Al Oct 2004

Infection Dynamics Of Marteilia Refringens In Flat Oyster Ostrea Edulis And Copepod Paracartia Grani In A Claire Pond Of Marennes-Oleron Bay, Corinne Audemard, Mc Sajus, Et Al

VIMS Articles

The protozoan parasite Marteilia refringens has been partly responsible for the severe decrease in the production of the European flat oyster Ostrea edulis Linnaeus in France since the 1970s. The calanoid copepod Paracartia grani Sars was recently found to be a host for M refringens in French shallow-water oyster ponds ('claires'). This study reconsidered M refringens transmission dynamics in the light of this finding, taking into account not only oyster infection dynamics and environmental factors but also data concerning the copepod host. P. grani population dynamics in the claire under study revealed that this species is the dominant planktonic copepod ...


Allee Effects Driven By Predation, J Gascoigne, Rom Lipcius Sep 2004

Allee Effects Driven By Predation, J Gascoigne, Rom Lipcius

VIMS Articles

No abstract provided.


Isolation And Characterization Of Mycobacteria From Striped Bass Morone Saxatilis From The Chesapeake Bay, Mw Rhodes, H Kator, I Kaattari, D Gautier, Wolfgang K. Vogelbein, Ca Ottinger Sep 2004

Isolation And Characterization Of Mycobacteria From Striped Bass Morone Saxatilis From The Chesapeake Bay, Mw Rhodes, H Kator, I Kaattari, D Gautier, Wolfgang K. Vogelbein, Ca Ottinger

VIMS Articles

Mycobacteriosis in striped bass Morone saxatilis of Chesapeake Bay, USA, was first diagnosed in 1997 based on the presence of granulomatous inflammation and acid-fast bacteria in skin and spleen. To confirm histopathology, bacteriological detection and identification of mycobacteria were begun using splenic tissue from fish with and without skin ulcerations. On the basis of initial studies using a variety of selective and nonselective media, decontamination, homogenization and incubation conditions, a simple and quantitative recovery method using aseptic necropsy of splenic tissue was developed. Optimal recovery was obtained by spread-plating homogenates on Middlebrook 7H10 agar with incubation for 3 mo at ...


Light Dependence Of [H-3]Leucine Incorporation In The Oligotrophic North Pacific Ocean, Mj Church, Hw Ducklow, Da Karl Jul 2004

Light Dependence Of [H-3]Leucine Incorporation In The Oligotrophic North Pacific Ocean, Mj Church, Hw Ducklow, Da Karl

VIMS Articles

The influence of irradiance on bacterial incorporation of [H-3] leucine was evaluated at Station ALOHA in the oligotrophic North Pacific subtropical gyre. Six experiments were conducted on three cruises to Station ALOHA to examine how [H-3]leucine incorporation varied as a function of irradiance. Two experiments were also conducted to assess the photoautotrophic response to irradiance (based on photosynthetic uptake of [C-14] bicarbonate) in both the upper and lower photic zones. Rates of [H-3]leucine incorporation responded to irradiance in a photosynthesis-like manner, increasing sharply at low light and then saturating and sometimes declining with increasing light intensity. The influence ...


Microsatellite Marker Development And Analysis In The Eastern Oyster (Crassostrea Virginica): Confirmation Of Null Alleles And Non-Mendelian Segregation Ratios, Kimberly S. Reece, Wl Ribeiro, Pm Gaffney, Ryan Carnegie, Standish K. Allen Jr. Jul 2004

Microsatellite Marker Development And Analysis In The Eastern Oyster (Crassostrea Virginica): Confirmation Of Null Alleles And Non-Mendelian Segregation Ratios, Kimberly S. Reece, Wl Ribeiro, Pm Gaffney, Ryan Carnegie, Standish K. Allen Jr.

VIMS Articles

Eighteen microsatellite markers were developed for the Crassostrea virginica nuclear genome, including di-, tri-, and tetranucleotide microsatellite repeat regions that included perfect, imperfect, and compound repeat sequences. A reference panel with DNA from the parents and four progeny of 10 full-sib families was used for a preliminary confirmation of polymorphism at these loci and indications of null alleles. Null alleles were discovered at three loci; in two instances, primer redesign enabled their amplification. Two to five representative alleles from each locus were sequenced to ensure that the targeted loci were amplifying. The sequence analysis revealed not only variation in the ...


A New Pathogenic Virus In The Caribbean Spiny Lobster Panulirus Argus From The Florida Keys, Jeffrey D. Shields, Dc Behringer May 2004

A New Pathogenic Virus In The Caribbean Spiny Lobster Panulirus Argus From The Florida Keys, Jeffrey D. Shields, Dc Behringer

VIMS Articles

A pathogenic virus was diagnosed from juvenile Caribbean spiny lobsters Panulirus argus from the Florida Keys. Moribund lobsters had characteristically milky hemolymph that did not clot. Altered hyalinocytes and semigranulocytes, but not granulocytes, were observed with light microscopy. Infected hemocytes had emarginated, condensed chromatin, hypertrophied nuclei and faint eosinophilic Cowdry-type-A inclusions. In some cases, infected cells were observed in soft connective tissues. With electron microscopy, unenveloped, nonoccluded, icosahedral virions (182 +/- 9 nm SD) were diffusely spread around the inner periphery of the nuclear envelope. Virions also occurred in loose aggregates in the cytoplasm or were free in the hemolymph. Assembly ...


Particle-Associated Flagellates: Swimming Patterns, Colonization Rates, And Grazing On Attached Bacteria, T Kiorboe, Hp Grossart, H Ploug, K Tang, B Auer Apr 2004

Particle-Associated Flagellates: Swimming Patterns, Colonization Rates, And Grazing On Attached Bacteria, T Kiorboe, Hp Grossart, H Ploug, K Tang, B Auer

VIMS Articles

Some pelagic flagellates colonize particles, such as marine snow, where they graze on bacteria and thus impact the dynamics of the attached microbial communities. Particle colonization is governed by motility. Swimming patterns of 2 particle-associated flagellates, Bodo designis and Spumella sp., are very different, the former swimming slowly in an erratic, random pattern, and the latter faster and along smooth helixes of variable amplitude and frequency. At spatial scales exceeding ca. 50 mum, the motility of B. designis can be described as a random walk and modeled as diffusion. Spumella sp. shows directional persistence of the helical axes up to ...


Perkinsus Mediterraneus N. Sp., A Protistan Parasite Of The European Flat Oyster Ostrea Edulis From The Balearic Islands, Mediterranean Sea, Sm Casas, A Grau, K S. Reece, Et Al Mar 2004

Perkinsus Mediterraneus N. Sp., A Protistan Parasite Of The European Flat Oyster Ostrea Edulis From The Balearic Islands, Mediterranean Sea, Sm Casas, A Grau, K S. Reece, Et Al

VIMS Articles

A new species, Perkinsus mediterraneus, a protistan parasite of the European oyster Ostrea edulis (L.), farmed along the coast of the Balearic Islands, Mediterranean Sea, is described. Morphological examinations with light and transmission electron microscopy, DNA sequence-analysis and enlargement in Ray's fluid thioglycollate medium (RFTM) confirmed that this parasite belongs to the genus Perkinsus. Specific morphological and genetic characteristics indicated that it should be considered a new species in the genus, Sequencing of the small subunit ribosomal (ssu rRNA) gene confirmed that the parasite belongs to the genus Perkinsus, and sequences of the internal transcribed spacer (ITS) were distinct ...


Mycobacterium-Inducible Nramp In Striped Bass (Morone Saxatilis), Erin J. Burge, David T. Gauthier, Christopher A. Ottinger, Peter A. Van Veld Mar 2004

Mycobacterium-Inducible Nramp In Striped Bass (Morone Saxatilis), Erin J. Burge, David T. Gauthier, Christopher A. Ottinger, Peter A. Van Veld

VIMS Articles

In mammals, the natural resistance-associated macrophage protein 1 gene, Nramp1, plays a major role in resistance to mycobacterial infections. Chesapeake Bay striped bass (Morone saxatilis) is currently experiencing an epizootic of mycobacteriosis that threatens the health of this ecologically and economically important species. In the present study, we characterized an Nramp gene in this species and obtained evidence that there is induction following Mycobacterium exposure. The striped bass Nramp gene (MsNramp) and a 554-amino-acid sequence contain all the signal features of the Nramp family, including a topology of 12 transmembrane domains (TM), the transport protein-specific binding-protein-dependent transport system inner membrane ...


Seed Production From The Mixed Mating System Of Chesapeake Bay (Usa) Eelgrass (Zostera Marina; Zosteraceae), Jm Rhode, Je Duffy Feb 2004

Seed Production From The Mixed Mating System Of Chesapeake Bay (Usa) Eelgrass (Zostera Marina; Zosteraceae), Jm Rhode, Je Duffy

VIMS Articles

In monoecious plants, gametes can be exchanged in three ways: among unrelated genets (outbreeding), with close relatives (inbreeding), or within individuals (geitonogamous selling). These different mating systems may have consequences for population demography and fitness. The experiment presented herein used artificial crosses to examine the mating system of Chesapeake Bay, Virginia, USA eelgrass (Zostera marina L; Zosteraceae), a bisexual submerged aquatic plant that can outbreed, inbreed, and self. Genetic data indicate severe heterozygosity deficiencies and patchy genotype distribution in these beds, suggesting that plants therein reproduce primarily by vegetative propagation, autogamy, or geitonogamy. To clarify eelgrass reproductive strategies, flowers from ...


Perkiasus Sp Infection Risk For Manila Clams, Venerupis Philippinarum (A. Adams And Reeve, 1850) On The Pacific Coast Of North And Central America, Ra Elston, Cf Dungan, Tr Meyers, Kimberly S. Reece Jan 2004

Perkiasus Sp Infection Risk For Manila Clams, Venerupis Philippinarum (A. Adams And Reeve, 1850) On The Pacific Coast Of North And Central America, Ra Elston, Cf Dungan, Tr Meyers, Kimberly S. Reece

VIMS Articles

Manila clams (Venerupis philippinarum, A. Adams and Reeve 1850) are an important aquaculture species on the west coast of North America and are also cultured in Europe, Asia, and other locations. Clams cultured on the west coast of North America are free of Perkinsus sp. infections, while clams from certain Asian and European sources are infected. Infection in Korean Manila clams is reportedly associated with high morbidity and mortality. We evaluated the health status of readily accessible Manila clam juveniles from Korea that were proposed for importation into Mexican waters where they would increase in size, and then be shipped ...


Evidence Of Shark Predation And Scavenging On Fishes Equipped With Pop-Up Satellite Archival Tags, David Kerstetter, Jeffery J. Polovina, John Graves Jan 2004

Evidence Of Shark Predation And Scavenging On Fishes Equipped With Pop-Up Satellite Archival Tags, David Kerstetter, Jeffery J. Polovina, John Graves

VIMS Articles

No abstract provided.


Conserving Populations At Low Abundance: Delayed Functional Maturity And Allee Effects In Reproductive Behaviour Of The Queen Conch Strombus Gigas, J Gascoigne, Rom Lipcius Jan 2004

Conserving Populations At Low Abundance: Delayed Functional Maturity And Allee Effects In Reproductive Behaviour Of The Queen Conch Strombus Gigas, J Gascoigne, Rom Lipcius

VIMS Articles

Effectiveness of conservation measures for diminished populations depends on the mechanism producing low abundance. In queen conch, which is heavily exploited, reproductive activity is depressed where conch density is low, which may be due to the Allee effect, poor habitat quality, or delayed functional maturity. To determine the mechanism underlying impaired reproduction in shallow seagrass beds, mature conch were translocated from 'source' sites with high and low, ambient conch density (similar to1000 and similar to20 conch ha(-1), respectively), and kept at high density in enclosures within high- and low-density 'host' sites. We monitored reproductive activity, and modelled conch population ...


Examination Of Reference Concentration Under Waves And Currents On The Inner Shelf, Guan-Hong Lee, W. Brian Dade, Carl T. Friedrichs, Chris E. Vincent Jan 2004

Examination Of Reference Concentration Under Waves And Currents On The Inner Shelf, Guan-Hong Lee, W. Brian Dade, Carl T. Friedrichs, Chris E. Vincent

VIMS Articles

[ 1] We examine reference concentration using three different data sets of near-bed suspended sediment concentration observed under combined waves and currents. The data include observations made at 15 and 20 m depth off Dounreay, Scotland, UK, and observations obtained at 13 m depth off Duck, North Carolina, USA. These data accommodate different dynamic conditions ( from wave-dominated conditions at Dounreay to wind-driven, current-dominated conditions at Duck) and sediment properties ( median size of bed sediment ranging from 120 to 350 mm). Near-bed concentration profiles to elevations of about 80 cm were obtained using acoustic backscatter sensors with 1 cm resolution. The reference ...


Organisms Associated With Oysters Cultured In Floating Systems In Virginia, Usa, Fx O'Beirn, Pg Ross, Mark Luckenbach Jan 2004

Organisms Associated With Oysters Cultured In Floating Systems In Virginia, Usa, Fx O'Beirn, Pg Ross, Mark Luckenbach

VIMS Articles

The number and abundance of macro-faunal taxa was estimated from six floating structures (floats) used to culture the Eastern oyster (Crassostrea virginica) near Chincoteague Island. Virginia, USA. After a 10-mo grow-out period, all organisms found among and attached to the cultured oysters were counted. The final mean size of oysters was 80.5 (14.7 SD) mm. Overall, 45 species of macrofauna were recorded with the number of species in the floats ranging from 24 to 36. There was no relationship between the number of taxa and the density of oysters in the floats. Total abundances of associated organisms were ...


Plasmablast And Plasma Cell Production And Distribution In Trout Immune Tissues, E S. Bromage, I M. Kaattari, P Zwollo, S L. Kaattari Jan 2004

Plasmablast And Plasma Cell Production And Distribution In Trout Immune Tissues, E S. Bromage, I M. Kaattari, P Zwollo, S L. Kaattari

VIMS Articles

These studies describe the in vitro and ex vivo generation of plasmablasts and plasma cells in trout (Oncorhynchus mykiss) peripheral blood and splenic and anterior kidney tissues. Cells were derived either from naive trout and cultured with the polyclonal activator, Escherichia coli LPS, or from trout that had been immunized with trinitrophenyl-keyhole limpet hemocyanin. Hydroxyurea was used to resolve populations of replicating (plasmablast) and nonreplicating (plasma cell) Ab-secreting cells (ASC). Complete inhibition of Ig secretion was only observed within the PBL. Both anterior kidney and splenic lymphocytes possessed a subset of ASCs that were hydroxyurea resistant. Thus, in vitro production ...


A Comparison Of Dredge And Patent Tongs For Estimation Of Oyster Populations, Roger L. Mann, Melissa Southworth, Jm Harding, J Wesson Jan 2004

A Comparison Of Dredge And Patent Tongs For Estimation Of Oyster Populations, Roger L. Mann, Melissa Southworth, Jm Harding, J Wesson

VIMS Articles

Exploited oyster stocks on public grounds in Virginia waters are subject to regular surveys effected using a traditional oyster dredge and, more recently, patent tongs. Dredges provide semiquantitative data, have been used with consistency over extended periods (decades), and provide data on population trends. Surveys with patent tongs provide absolute quantification (number of individuals per unit area) of oyster stocks but are more labor intensive. Absolute quantification of dredge data is difficult in that dredges accumulate organisms as they move over the bottom, may not sample with constancy throughout a single dredge haul, and may fill before completion of the ...


A Review Of Recent Information On The Haplosporidia, With Special Reference To Haplosporidium Nelsoni (Msx Disease), E M. Burreson, S E. Ford Jan 2004

A Review Of Recent Information On The Haplosporidia, With Special Reference To Haplosporidium Nelsoni (Msx Disease), E M. Burreson, S E. Ford

VIMS Articles

The current status of the Haplosporidia is reviewed as well as recent information on Haplosporidium nelsoni, the causative agent of MSX disease in oysters. Recent molecular phylogenetic analyses with greatly increased taxon sampling support monophyly of the Haplosporidia and hypothesize placement of the group as sister taxon to the phylum Cercozoa. Oyster pathogens in the genus Bonamia should be considered haplosporidians based on molecular sequence data. Thus, the group contains 4 genera: Uropsoridium, Haplosporidium, Bonamia and Minchinia. Molecular phylogenetic analyses support monophyly of Urosporidium, Bonamia and Minchinia, but Haplosporidium forms a paraphyletic clade. Reports of haplosporidia worldwide are reviewed. Molecular ...


Allee Effects In Marine Systems, J Gascoigne, Rom Lipcius Jan 2004

Allee Effects In Marine Systems, J Gascoigne, Rom Lipcius

VIMS Articles

The fitness or population growth rate of populations with Allee effects increases with increasing population size or density up to a certain threshold. Allee effects are possible in marine populations, as they are less open than has been assumed and may have a metapopulation structure. We modelled the population consequences of Allee effects and show that increases in mortality interact with critical Allee thresholds, such that an Allee effect with no population consequences at low mortality can drive a population to extinction when mortality is increased. In heavily fished species, populations with strong Allee effects go extinct at lower levels ...


Production Of Chromophoric Dissolved Organic Matter (Cdom) In The Open Ocean By Zooplankton And The Colonial Cyanobacterium Trichodesmium Spp., Deborah K. Steinberg, Nb Nelson, Ca Carlson, Ac Prusak Jan 2004

Production Of Chromophoric Dissolved Organic Matter (Cdom) In The Open Ocean By Zooplankton And The Colonial Cyanobacterium Trichodesmium Spp., Deborah K. Steinberg, Nb Nelson, Ca Carlson, Ac Prusak

VIMS Articles

Chromophoric (or colored) dissolved organic matter (CDOM) has been identified as a major determinant of the optical properties of oligotrophic oceans. The factors controlling distribution of CDOM far from the direct influence of land are not well known, as CDOM abundance and distribution does not directly correlate with phytoplankton productivity or biomass, or with dissolved organic matter (DOM) concentration. As part of a larger study of the dynamics of CDOM in the open ocean, we investigated direct release from plankton as a factor contributing to distribution patterns of CDOM. We measured the production of CDOM by zooplankton (copepods, euphausiids, amphipods ...


Supplementation Of Perkinsus Marinus Cultures With Host Plasma Or Tissue Homogenate Enhances Their Infectivity, Cg Earnhart, Ma Vogelbein, Gd Brown, Ks Reece, Sl Kaattari Jan 2004

Supplementation Of Perkinsus Marinus Cultures With Host Plasma Or Tissue Homogenate Enhances Their Infectivity, Cg Earnhart, Ma Vogelbein, Gd Brown, Ks Reece, Sl Kaattari

VIMS Articles

The protozoan oyster parasite Perkinsus marinas can be cultured in vitro in a variety of media; however, this has been associated with a rapid attenuation of infectivity. Supplementation of defined media with products of P. marinus-susceptible (Crassostrea virginica) and -tolerant (Crassostrea gigas, Crassostrea ariakensis) oysters alters proliferation and protease expression profiles and induces differentiation into morphological forms typically seen in vivo. It was not known if attenuation could be reversed by host extract supplementation. To investigate correlations among these changes as well as their association with infectivity, the effects of medium supplementation with tissue homogenates from both susceptible and tolerant ...


Microcell Parasites Of Oysters: Recent Insights And Future Trends, Ryan Carnegie, Nathalie Cochennec-Laureau Jan 2004

Microcell Parasites Of Oysters: Recent Insights And Future Trends, Ryan Carnegie, Nathalie Cochennec-Laureau

VIMS Articles

Our understanding of the microcell oyster parasites of the genera Bonamia and Mikrocwos has expanded 111 recent years with the application of ultrastru ctural and espec ially molecular biological research approaches. Molecular phylogenetic analyses of SSU rRNA genes have united three species, Bonamia ostreae, Bonamia exitiosa, and Mikrocytos (now Bonamia) roughleyi, in a microcell clade within the Haplosporidia, supporting both early and recent ultrastructural observations. Ult rastructural and molecular phylogenetic ev idence has emerged that Mikrocytos mackini, on the other hand, is a unique proti st with unusual adaptations for a parasitic existence. DNA probes and polymerase chain reaction (PCR ...


Perkinsosis In Molluscs: A Review, Antonio Villalba, Kimberly S. Reece, M. Camino Ordas, Sandra M. Casas, Antonio Figueras Jan 2004

Perkinsosis In Molluscs: A Review, Antonio Villalba, Kimberly S. Reece, M. Camino Ordas, Sandra M. Casas, Antonio Figueras

VIMS Articles

The genus Perkinsus includes protistan parasites infecting marine molluscs throughout the world, some of which are associated with mass mortalities. Life cycle involves vegetative proliferation within the host, by which a cell named trophozoite undergoes successive bipartitioning. Other stages have been observed in vitro or in vivo, depending on the species: hypnospore, zoosporangium and zoospore. Molecular taxonomy supports a close affinity between dinoflagellates and Perkinsus spp. Six species of Perkinsus are currently considered valid: P. marinus, P. olseni, P. qugwadi, P. chesapeaki, P. andrewsi and P. mediterraneus. Histology and, above all, incubation of host tissues in Ray’s fluid thioglycollate ...


Decadal Scale Changes In Seasonal Patterns Of Oyster Recruitment In The Virginia Sub Estuaries Of The Chesapeake Bay, Melissa Southworth, Roger L. Mann Jan 2004

Decadal Scale Changes In Seasonal Patterns Of Oyster Recruitment In The Virginia Sub Estuaries Of The Chesapeake Bay, Melissa Southworth, Roger L. Mann

VIMS Articles

Reproductive periodicity of sessile estuarine invertebrates reflects local seasonality of environmental (temperature, salinity) and biologic (food) parameters. Estuaries are ephemeral features in geologic time but considered somewhat constant in the course of recent human history (decadal time scales). Analyses of long-term trends in eastern oyster (Crassostrea virginica) settlement periodicity since 1960 in three major Chesapeake Bay rivers (James, Piankatank and Great Wicomico Rivers) of the Chesapeake Bay show marked changes within the 4-decade time frame. The 50th percentile of cumulative recruitment occurs between day 194 and 250 of the year depending on year and location. Significant coherence in interannual variation ...


Site Selection For Oyster Habitat Rehabilitation In The Virginia Portion Of The Chesapeake Bay: A Commentary, Roger L. Mann, Da Evans Jan 2004

Site Selection For Oyster Habitat Rehabilitation In The Virginia Portion Of The Chesapeake Bay: A Commentary, Roger L. Mann, Da Evans

VIMS Articles

A significant body of knowledge has been generated during the past decade on disease tolerance of the native oyster Crassostrea virginica. A major opportunity to move into a large-scale field application phase of that knowledge has been presented by a 10-y commitment by the U.S. Army Corps of Engineers (ACOE) to a partnership in Virginia focused on widespread restoration of oyster resources for ecological purposes. The partnership involves ACOE, the Virginia Institute of Marine Science (VIMS), the Virginia Marine Resources Commission (VMRC), and the Chesapeake Bay Foundation (CBF). This collaboration will effect a sequenced restoration effort involving site selection ...