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Showing papers on "Oyster published in 1990"


Journal ArticleDOI
01 Feb 1990-Genetics
TL;DR: The results are consistent with the hypothesis that historical vicariant events, in conjunction with contemporary environmental influences on gene flow, can result in genetic discontinuities in continuously distributed species with high dispersal capability.
Abstract: Restriction site variation in mitochondrial DNA (mtDNA) of the American oyster (Crassostrea virginica) was surveyed in continuously distributed populations sampled from the Gulf of St. Lawrence, Canada, to Brownsville, Texas. mtDNA clonal diversity was high, with 82 different haplotypes revealed among 212 oysters with 13 endonucleases. The mtDNA clones grouped into two distinct genetic arrays (estimated to differ by about 2.6% in nucleotide sequence) that characterized oysters collected north vs. south of a region on the Atlantic mid-coast of Florida. The population genetic "break" in mtDNA contrasts with previous reports of near uniformity of nuclear (allozyme) allele frequencies throughout the range of the species, but agrees closely with the magnitude and pattern of mtDNA differentiation reported in other estuarine species in the southeastern United States. This concordance of mtDNA phylogenetic pattern across independently evolving species provides strong evidence for vicariant biogeographic processes in initiating intraspecific population structure. The post-Miocene ecological history of the region suggests that reduced precipitation levels in an enlarged Floridian peninsula may have created discontinuities in suitable estuarine habitat for oysters during glacial periods, and that today such population separations are maintained by the combined influence of ecological gradients and oceanic currents on larval dispersal. The results are consistent with the hypothesis that historical vicariant events, in conjunction with contemporary environmental influences on gene flow, can result in genetic discontinuities in continuously distributed species with high dispersal capability.

336 citations


Journal ArticleDOI
TL;DR: Oyster and seawater samples were collected seasonally from May 1984 through April 1985 from shellfish-growing areas in Washington, California, Texas, Louisiana, Alabama, Florida, South Carolina, Virginia, and Rhode Island which had been designated as approved or prohibited by the National Shellfish Sanitation Program.
Abstract: Oyster and seawater samples were collected seasonally from May 1984 through April 1985 from shellfish-growing areas in Washington, California, Texas, Louisiana, Alabama, Florida, South Carolina, Virginia, and Rhode Island which had been designated as approved or prohibited by the National Shellfish Sanitation Program. Fecal coliforms counts, aerobic plate counts, and Vibrio parahaemolyticus densities were determined for the samples. Mean V. parahaemolyticus density was more than 100 times greater in oysters than in water, whereas density of fecal coliforms was approximately 10 times higher in oysters. Seasonal and geographical distributions of V. parahaemolyticus were related to water temperature, with highest densities in samples collected in the spring and the summer along the Gulf coast. The synthetic DNA probe for thermostable direct hemolysin hybridized with 2 of 50 isolates, 1 of which was positive by the Kanagawa test.

244 citations


Book ChapterDOI
01 Jul 1990
TL;DR: An interactive proof editor closely based on the Cornell NuPRL system, but implemented in Prolog, which allows the system to be used as a program synthesis environment, since a theorem can be regarded as a speciication which is realised by its extract term.
Abstract: O Y S T ER Hor88] is an interactive proof editor closely based on the Cornell NuPRL system, but implemented in Prolog. The object-level logic is a version of Martin-LL of type theory (a higher order constructive logic including induction) in a sequent-calculus formulation. Proofs are constructed in a top-down fashion by application of the rules of inference. Notational deenitions and libraries of theorems are supported. The tactic language for the system is Prolog. Predicates describing properties of a proof under construction are available to the user, who may also include arbitrary Prolog in tactics. Soundness of the system is ensured by the use of an abstract data type of proofs: partial proofs can only be altered by application of the primitive proof rules. Tactics can be combined using system deened tacticals. Prolog pattern-matching and backtracking in tactics have proved useful in the automation of proof search. Since the object-level logic is constructive, terms of an enlarged-calculus can be computed from complete proofs, and these so-called ex tr act terms can then be executed by application on appropriate inputs. This allows the system to be used as a program synthesis environment, since a theorem can be regarded as a speciication which is realised by its extract term. The system is written in some 2000 lines of Prolog, making it considerably more compact than the original NuPRL system, while the speed of the two systems is comparable.

218 citations


Journal ArticleDOI
TL;DR: Average per locus allele-frequency variances between the progenitor and derived hatchery populations are normally distributed after appropriate transformation, indicating that divergence of hatchery stocks from Dabob Bay population owes to random genetic drift.

206 citations


Journal ArticleDOI
TL;DR: Veliger larvae of the oysterCrassostrea gigas responded to unknown dissolved chemical inducers found in supernatants of cultures of the bacteria Alteromonas colwelliana and Vibrio cholerae, suggesting that competence to respond to bacterial supernatant is divided into two phases: behavioral competence followed by morphogenetic competence.
Abstract: Veliger larvae of the oysterCrassostrea gigas (Thunberg) responded to unknown dissolved chemical inducers found in supernatants of cultures of the bacteriaAlteromonas colwelliana andVibrio cholerae. The response, which was similar to that seen when larvae were exposed to the neurotransmitter precursor L-3,4-dihydroxyphenylalanine (L-DOPA), consisted of an initial settlement phase of swimming with the foot extended and crawling on the substrate. Subsequently larvae attached to the substrate and metamorphosed. The percentage of veligers metamorphosing following inducation of settlement behavior was higher in a group of older larvae, a response similar to that seen with L-DOPA, suggesting that competence to respond to bacterial supernatants is divided into two phases: behavioral competence followed by morphogenetic competence. Following size exclusion chromatography, the molecular weight of the peak containing the activity which induced settlement behavior was determined to be ≤ 300 daltons. Autoclaved Marine Broth, which induced low levels of settlement behavior also contained this low molecular weight active peak, suggesting that an oyster settlement inducer is also present in this medium.

144 citations


Journal ArticleDOI
TL;DR: Chlorinated pesticides and PCBs were analyzed in more than 590 oyster and sediment samples collected during 1986 and 1987, the first 2 years of the NOAA's Status and Trends Mussel Watch Program established to monitor the current status and temporal trends of these contaminants in the Gulf of Mexico.

115 citations


Journal ArticleDOI
TL;DR: Calculations show that detrital complexes in the natural environment may provide a significant contribution to an oyster’s C demand and estimate that freeliving bacteria may be capable of supplying up to -9.5% of the total C requirements of oysters in their natural habitat.
Abstract: Unattached, cellulolytic bacteria isolated from a salt marsh were cultured on [LSN]ammonium sulfate and [‘Qglucose and fed to the American oyster Crassostrea virginica. Oysters were able to digest and assimilate bacterial C with an assimilation efficiency of 52.5%. We estimate that freeliving bacteria may be capable of supplying up to -9.5% of the total C requirements of oysters in their natural habitat. Cellulolytic bacteria were also cultured on 14C-labeled refractory Spartina alternlyora particles as the sole C source and [rSN]ammonium sulfate as a source of N. These labeled bacteria, together with the S. a/terniforu, were fed to the oysters. The refractory C from these detrital complexes was assimilated by the oysters with an efficiency of 10.3%. It was significantly (P = 0.0007) greater than the assimilation efficiency of 2.7% measured in a previous study for oysters feeding on the refractory S. alterniflora substrate alone. This result provides direct experimental evidence that cellulolytic bacteria in the environment can contribute to the transfer of C from refractory detritus to an ecologically important suspension-feeding macroinvertebrate. We calculated that C. virginica, when fed detrital complexes, assimilated bacterial N with an efhciency of 57.2% but that assimilation of total N present in the detrital complexes was only 3.4%. We speculate that this low assimilation efficiency was due to most (94%) of the N being in the form of condensation products such as humic geopolymers and extracellular polymeric substances secreted by bacteria which could not be digested and absorbed by the oysters. Calculations show that detrital complexes in the natural environment may provide a significant contribution to an oyster’s C demand. The magnitude of this contribution can increase from 1.3 to 60% as both absolute bacterial abundance and proportion of bacteria attached to detrital particles increase, raising the oysters’ efficiency of filtration for these substrates.

85 citations


Journal ArticleDOI
TL;DR: Multiple regression analysis indicates that the food pathway may predominate in copper accumulation by green oysters, and the total uptake of copper per oyster is an exponential function of exposure time for the first 2 weeks with an accumulation rate of 214 ppm Cu/day and then levels off.

83 citations


Journal ArticleDOI
TL;DR: Oyster larvae exposed to solutions of NH4Cl exhibit stereotypical settlement behavior similar to that which normally precedes cementation and metamorphosis, suggesting that NH3 acts by increasing intracellular pH.
Abstract: Oyster larvae exposed to solutions of NH4Cl exhibit stereotypical settlement behavior similar to that which normally precedes cementation and metamorpho- sis. Un-ionized ammonia is the active chemical species. At pH = 8.0, the threshold concentration of NH4Cl (pH = 8.0) for newly competent larvae is 2.5 mM; maximum activity is at 7.9 mM, corresponding to calculated NH3 concentrations of 100 pA4 and 3 10 PUM, respectively. In- duction of settlement behavior is rapid, with >90% of larvae exposed to 310 pA4 NH3 responding within less than 5 min. After 15 to 30 min, larvae become habituated to NH3 and resume swimming so that the percent exhib- iting settlement behavior after 30 min is < 10%. Other weak bases, such as methylamine and trimethylamine, induce similar behavior suggesting that NH3 acts by in- creasing intracellular pH. Evidence that NH3 and L-3,4- dihyrodxyphenylalanine (L-DOPA) induce settlement behavior through different mechanisms is presented. Ammonia may be a natural environmental cue that promotes oyster settlement behavior and, ultimately, recruitment.

79 citations


Journal ArticleDOI
TL;DR: It is postulated that sand bottoms may provide more suitable resuspension environments than mud due to lower suspended loads over coarse sediments, and the relationship of oyster growth to gross changes in sediment chlorophyll showed a similar parabolic trend.
Abstract: Field experiments withOstrea edulis L. were conducted to examine the effects of resuspension on subtidal oyster growth in a small cove in malifax County, Nova Scotia. Removable racks with strips of fixed juvenile oysters were placed at 4 and 30 cm above a coarse sandy bottom (2 m depth). Summer growth was assessed weekly for 7 wk (July to August 1985) using silhouette images to follow individual change in shell area, a correlate of change in wet weight. Daily measurements of temperature, erosion/deposition (buried plate depth) and sediment chlorophyll suggested that sediment transport partially controlled the standing stock of benthic microalgae. Relative oyster growth per week was positively correlated with temperature. In addition, relative growth initially increased as the transport regime went from erosional to depositional (maximum growth near zero net transport) but growth rate declined with continued deposition. The relationship of oyster growth to gross changes in sediment chlorophyll showed a similar parabolic trend. The shape of these curves is similar to those obtained in published laboratory feeding experiments, which suggest beneficial effects of resuspension as a bivalve food supplement, but inhibition at higher levels due to decreased ingestion or dilution of food with inorganics. It is postulated that sand bottoms may provide more suitable resuspension environments than mud due to lower suspended loads over coarse sediments. Resuspension may be a valuable supplement to water column production as food for cultured bivalves, a factor of value in grow-out site selection.

73 citations


Journal ArticleDOI
TL;DR: In vitro salinity regulation of oceanic oyster hemocytes to lower salinities was not affected by TBT exposure and salinityregulation of estuarine oyster Hemocytes to higher salinity was retarded only after a salinity change from 12 ppt to 36 ppt.
Abstract: Several defense-related activities of hemocytes from oysters (Crassostrea virginica andC. gigas) were assayedin vitro with different levels of tributyltin (0.4–400 ppb)3 to determine whether defense-related cell mechanisms were affected. Chemiluminescence, a presumptive indicator of phagocytic activity, was reduced with increasing concentrations of tributyltin (TBT) and pre-incubation with TBT appeared to eliminate chemiluminescence. Locomotion of hemocytes was also retarded by TBT, but the ability of the hemocytes to spread to an ameboid shape was not affected.In vitro salinity regulation of oceanic oyster hemocytes to lower salinities was not affected by TBT exposure and salinity regulation of estuarine oyster hemocytes to higher salinities was retarded only after a salinity change from 12 ppt to 36 ppt.

Journal ArticleDOI
TL;DR: Individual (mass) selection for growth rate was carried out in the European oyster Ostrea edulis (Linne) and correlations between the traits were found to be high, and differences in survival were detected between the families of the 2 selected groups.
Abstract: Individual (mass) selection for growth rate was carried out in the European oyster Ostrea edulis (Linne). Oysters from 40 families produced In 1983 were selected on the basis of their live weight after the first growing season. Divergent select~on was applied; the High and Low selected group were mated in pairs according to their rank. Twenty-four families were obtained: 6 Low selected and 18 High selected. A total of 6560 spat were individually tagged and brought to the field for 2 yr. Shell height and live weight after the first and second growing seasons were analyzed. Statistically significant &fferences ( p < 0.05) were found between the offspring of the High and Low selected groups for both traits after both growing seasons. No differences in survival were detected between the fam.ilies of the 2 selected groups. Heritability esbmates for live weight and shell height, after each growing season ranged from h* = 0.112 to 0.243. Genetlc correlations between the traits were found to be high; r, = 0.963 for the first growing season and r, = 0.995 for the second growing season.

Journal ArticleDOI
01 Aug 1990
TL;DR: Generally speaking, with natural reproduction and sowing methods or the rack hanging method, in which the cultivation generally takes place in the littoral zone or on sea bottom, the most prevalent harm is caused by such bottom dwelling predators as drills (murices, naticids), sea st...
Abstract: Generally speaking the “enemies”; of oysters can be divided ecologically into three classes: 1) “parasites”; which live within the body of the oyster and cause harm, 2) “competitors (fouling organisms)”; which occupy the same ecological niche as the oyster and cause harm indirectly by, contesting the available food and living space, 3) “predators”; which feed on the oyster. The sort of harm which can affect oysters differs widely with cultivation technique and habitat conditions. For instance, with the raft hanging method, long line method and other intensive cultivation practices which involve submersion in the sea, the harm from competitors such as Mytilus edulis gcdloprovincialis, tunicates and barnacles is most noticeable. On the other hand, with natural reproduction and sowing methods or the rack hanging method, in which the cultivation generally takes place in the littoral zone or on sea bottom, the most prevalent harm is caused by such bottom dwelling predators as drills (murices, naticids), sea st...

Journal ArticleDOI
TL;DR: Oysters (Crassostrea virginica) from 50 to 69 locations (sites) along the Gulf of Mexico coastline, collected annually in 1986, 1987 and 1988, have been analyzed for 13 trace metals, including most of the metals of concern from an environmental quality perspective.


Journal ArticleDOI
TL;DR: The results strongly suggest that highly localized mass mortalities of oysters in North Inlet have been due to virulent levels of P. marinus mfecbons.
Abstract: Investigation of the prevalence of the protozoan parasite Perkinsus marinus in populations of intertidal oysters (Crassostrea vircjnica) from a South Carolina salt marsh led to the finding of a distinct, 4 phase cycle of infection intensity. The cycle consisted of characteristic quiescent, pre-virulent, virulent and remission stages of infection. For the first time, P. marinus infection intensity in South Carolina oysters was found to have a statistically significant positive correlation with temperature and salinity, and a negative correlation with oyster condition index. Our data also indicated that P. marinus infection in adult oysters from South Carolina is not size dependent. Based on a limited, qualitative h~stopathological of oyster tissue samples, we found no evidence to indicate the presence of Haplosporidium spp. in the North Inlet salt marsh/estuary system. These results strongly suggest that highly localized mass mortalities of oysters in North Inlet have been due to virulent levels of P. marinus mfecbons.

Journal ArticleDOI
01 Aug 1990
TL;DR: The oyster cultivation industry of Hiroshima has a history of nearly 400 years and provides about 70% of the oyster production for the whole of Japan and the number of collector plates used for this purpose each year reaches 200–300 million.
Abstract: The oyster cultivation industry of Hiroshima has a history of nearly 400 years and provides about 70% of the oyster production for the whole of Japan. The favourable location enables all the spat to be produced locally and the number of collector plates used for this purpose each year reaches 200–300 million. The natural system of spat collecting which is operated at Hiroshima is explained here in detail. In the first half, the spawning methods, primary environmental factors, development, early life history, the fundamentals of larval development and ecology, resistance of the larvae to their environment, conditions for attachment of the larvae, larval growth and decline, etc. are discussed in detail. In the second half, the practical and technical facts concerning setting up forecasts of spat production, the appropriate number of collector plates for spat collection, the growth and decline of juvenile attached oysters are presented.

Journal ArticleDOI
TL;DR: Principal component analysis demonstrated that Cd, Ni, Zn, Cu and Mn were more closely associated with mantle and gills, and their accumulation seemed to be highly influenced by oyster metabolic alterations.

Journal ArticleDOI
TL;DR: The major pathway of accumulation in these studies was from dissolved Ag, with oysters reaching soft-tissue concentrations of 4 to 6 μg g −1 (several times that of controls) in 3–4 weeks.
Abstract: Metabolic pathways of silver (Ag) accumulation were examined by exposing hatchery-reared oysters to Ag in a variety of forms including dissolved in water, associated with phytoplankton, and sorbed to sediments. Silver dissolved in water (2 and 5 μg l −1 ) was rapidly accumulated, with oysters reaching soft-tissue concentrations of 4 to 6 μg g −1 (several times that of controls) in 3–4 weeks. Uptake was negligible from suspended sediments as oysters rejected the particles as pseudofeces. Uptake of Ag associated with algal cells was negligible also: virtually all of this Ag passed through the oysters and was eliminated in the feces. Thus, the major pathway of accumulation in these studies was from dissolved Ag.

Journal ArticleDOI
TL;DR: It is proposed that oysters provide refuges from predation (by crustaceans or fish) during high tide, which is an important influence on distribution, abundance and sizes of snails in mangrove swamps.

Journal ArticleDOI
TL;DR: Experiments in the Dutch oyster culture have led to a view of the presumptive life cycle, m which an infectious phase might be involved in the ovarian tissue of O. edulis.

Journal ArticleDOI
TL;DR: Although all three bioassays were reasonably successful in predicting the presence or absence of moderately to severely altered benthic assemblages, considerable differences were found in the ability of the tests to identify only the altered assemblage.
Abstract: Laboratory sediment bioassays and alterations of benthic macroinvertebrate assemblages were evaluated at 43 stations in Commencement Bay, Washington, and at 4 stations in Carr Inlet, Washington (a reference embayment). Three bioassays were evaluated: the amphipod mortality test using Rhepoxynius abronius, the oyster larvae abnormality test using Crassostrea gigas and the Microtox® test using Photobacterium phosphoreum. Alterations of benthic assemblages were determined using numerical classification analysis. Bioassay responses and alterations of benthic assemblages were closely related to chemical contamination, suggesting that most biological effects resulted from chemical toxicity. Although all three bioassays were reasonably successful in predicting the presence or absence of moderately to severely altered benthic assemblages, considerable differences were found in the ability of the tests to identify only the altered assemblages. The Microtox bioassay successfully identified the highest percentage of altered benthic assemblages. By contrast, the oyster larvae abnormality bioassay falsely predicted the lowest percentage of altered assemblages. Tiered application of results of both the Microtox and oyster larvae tests improved the accuracy with which altered assemblages were identified.

Journal ArticleDOI
TL;DR: Oysters from 48 Gulf of Mexico sites were examined for presence and infection intensity of the endoparasite, Perkinsus (= Dermocystidium) marinus as part of NOAA's Status and Trends Mussel Watch Program, suggesting an impact of spawning frequency on uptake and depuration.
Abstract: Oysters from 48 Gulf of Mexico sites were examined for presence and infection intensity of the endoparasite, Perkinsus (= Dermocystidium) marinus (Mackin, Owen and Collier, 1950) as part of NOAA's Status and Trends Mussel Watch Program Prevalence exceeded 75% at 25 sites Infection intensity did not vary with sex or reproductive stage Latitude, total polynuclear aromatic hydrocarbon (PAH) content and industrial and agricultural land use significantly affected the parasite's distribution PAH and pesticide concentrations were latitudinally dependent, suggesting an impact of spawning frequency on uptake and depuration P marinus analysis complements the use of pollutant body burden for determining change in environmental quality because it responds differently than pollutant body burden to the biology and ecology of the oyster

Journal ArticleDOI
TL;DR: Analysis of the concentration of heavy metals in soft tissues of S. iridescens of the Mexican northwest coast, during a period of ten months, allows the authors to suggest the relative importance that the seasonal variation and size of bivalve have in the accumulation of these elements.
Abstract: The oyster Saccrostrea iridescens is a marine species which is geographically distributed from the Gulf of California to the North of Peru. In Mexico and particularly in The Pacific coast, this mollusc is widely utilized for human consumption, having consequently, an important commercial values, though no heavy metal data are available to establish natural background levels. In the present study the analysis of the concentration of heavy metals (Fe, Mn, Ni, Pb, Cu, Co, Cr, Zn and Cd) in soft tissues of S. iridescens of the Mexican northwest coast (a rural uncontaminated site), during a period of ten months, allows the authors to suggest the relative importance that the seasonal variation and size (age) of bivalve have in the accumulation of these elements. Additional, the observed levels have been compared with those in other areas.

Journal ArticleDOI
TL;DR: In this paper, liquid wastes including shell liquor, bled liquor, original liquid and wash water were collected from laboratory and commercial oyster shucking operations and were characterized physically and chemically.
Abstract: Liquid wastes including shell liquor, bled liquor, original liquid and wash water were collected from laboratory and commercial oyster shucking operations and were characterized physically and chemically. These liquid wastes contained 0.01 to 0.36% nonprotein-N components, 0.03 to 0.44% total-N, 0.13 to 1.64% salt and an identical protein profile with molecular weights around 20kD to 25kD as major proteins. Total solids could be used to predict the levels of total-N, nonprotein-N, ash, salt, total suspended solids and COD. Steam-jacketed kettle heating was an easy method to concentrate liquid wastes for production of oyster soup. Chemical, physical and sensory properties of processed oyster soup were analyzed and compared with a commercial product.

Journal ArticleDOI
TL;DR: It is proposed that seasonal variation in oyster lipids was more related to reproductive cycles than to food lipid supply and that peak particulate lipids occurred in November.

Journal ArticleDOI
TL;DR: Oyster, clam, crab, and mussel diets, low in cholesterol and high in n-3 fatty acids, lowered VLDL triglycerides and cholesterol and, except for the mussel diet, LDL and total cholesterol and squid and shrimp diets, did not change the blood lipids.

Journal ArticleDOI
TL;DR: In this paper, the authors used microgrowth structures on the anterior nympha of the hinge area of the shell of the American oyster (Crassostrea virginica) to estimate season of death.

Journal ArticleDOI
TL;DR: Continuous inputs of low concentrations of silver can cause large changes in species composition and species succession in Chesapeake Bay phytoplankton communities maintained in experimental ecosystems and oyster growth was reduced significantly relative to growth of oysters of unaltered communities.

Journal ArticleDOI
TL;DR: In contrast to most reports that environmental stress correlates with an increased ratio of males to females, this work found a three-fold increase in the proportion of females among H. nelsoni -infected oyster compared to uninfected oysters.