Showing papers on "Oyster published in 1983"
288 citations
TL;DR: The study revealed that the migration of planktonic oyster larvae is predominantly in a westerly direction along the Gulf of Mexico and that gene flow appears to be disrupted in the region of the Laguna Madre.
Abstract: An examination by protein-gel electrophoresis of 19 different geographical populations of the American oyster Crassostrea virginica (Gmelin) was conducted along the Atlantic coast and the Gulf of Mexico. Estimates were made of levels of genetic variation and similarity among the populations based on 32 structural loci. The percentage of loci polymorphic ranged from 46.9 to 65.6% along the Atlantic coast while the estimate ranged from 54.8% to 68.8% on the Gulf of Mexico. The percentage of loci heterozygous ranged from 18.6 to 23.6% along the Atlantic coast and from 20.0 to 25.4% in the Gulf of Mexico. The genetic similarities between all contiguous populations from Cape Cod, Massachusetts to Corpus Christi, Texas were estimated as 99%, while the same estimate between Corpus Christi and Brownsville, Texas was computed as 93%, indicating a major transition in genetic structure for the Brownsville population of the Laguna Madre. The study revealed that the migration of planktonic oyster larvae is predominantly in a westerly direction along the Gulf of Mexico and that gene flow appears to be disrupted in the region of the Laguna Madre. Evidence has been presented for single gene selection at the Lap-2 and Pgi loci in the form of macrogeographical clines in allele frequencies with changing environmental conditions.
188 citations
TL;DR: Kinetic studies showed that both species have a Kt value of 3-4 µM, indicating that bivalve larvae have amino acid transport mechanisms that function efficiently in natural sea water, which is similar to those reported for adult bivalves.
Abstract: The rates of uptake and metabolism of 14C-labeled glycine and alanine from sea water into larval oysters, Crassostrea gigas (Thunberg) and mussels, Mytilus edulis L. were determined. Kinetic studies showed that both species have a Kt value of 3-4 µM, indicating that bivalve larvae have amino acid transport mechanisms that function efficiently in natural sea water. The Kt values for larvae are similar to those reported for adult bivalves. However, larvae take up dissolved amino acids at approximately ten times the rate reported for adult bivalves on a gram dry weight basis. This difference in uptake capacity presumably reflects the greater absorptive surface area to volume ratio of a larva. Rates of metabolism of absorbed amino acids by larvae were also rapid. Following a 100 min exposure, oyster larvae incorporated 47% of the glycine into protein and 38% was produced as CO2. In comparison to adults, larval bivalves have a more rapid weight-specific uptake and faster rate of utilizing absorbed amino acids....
106 citations
TL;DR: A morphological study demonstrates the intracellular development of the etiologic agent and the cytopathological consequences for host cells, and the effects of the disease on oyster populations.
103 citations
TL;DR: It is recommended that an evaluation of natural populations as outlined in this study is a necessary prerequisite to achieve the formation of a closed breeding unit with a broad genetic base for domestication and selection.
Abstract: Phenotypic differences were observed among pure population matings and crosses grown in two natural environments for the following characters: larval shell length, juvenile and adult shell length, ...
76 citations
TL;DR: The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.
Abstract: Tests with naturally-occurring sediments are rare and sediment testing methodology is not standardized. The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.
73 citations
TL;DR: The degree of heterozygosity as determined by electrophoretic analysis of three or four polymorphic loci correlates positively with survival in age groups of the American oyster (Crassostrea virginica) collected as spat from two different natural populations.
Abstract: The degree of heterozygosity as determined by electrophoretic analysis of three or four polymorphic loci correlates positively with survival in age groups of the American oyster (Crassostrea virginica) collected as spat from two different natural populations. The phenomenon is shown to operate in ages from 2 weeks (post-settlement) to 3 years and appears to be general in populations of marine molluscs. The most likely explanation for this result is that heterozygosity improves survival through its effect on growth (heterozygotes grow faster). The effects of individual loci on viability are independent of each other. A direct involvement of the enzyme polymorphisms is the most probable genetic interpretation of the data, but associative overdominance cannot be excluded.
67 citations
TL;DR: Diseases causing high mortality occurred in a hatchery for rearing juvenile oysters, C. gigas, at Bicheno, Tasmania, during 1980, and was the first report of pathogenic marine bacteria in an Australian shellfish hatchery.
Abstract: Diseases causing high mortality occurred in a hatchery for rearing juvenile oysters, C. gigas, at Bicheno, Tasmania, during 1980. Outbreaks of the disease characteristically showed three peaks: in 7-10-day- old larvae, in older larvae several days before setting, and in spat 1-2 weeks after setting. Various marine bacteria were cultivated from inactive larvae and other hatchery specimens, and the predominant strains were identified. When given to normal young larvae at doses of 1 × 105-5 × 105 or 1 × 10-5-5 × 107 bacteria (total dose), seven strains (five strains of Vibrio, two strains of Alteromonas) caused fatal infections in most animals. This is the first report of pathogenic marine bacteria in an Australian shellfish hatchery.
58 citations
01 Jan 1983
TL;DR: The habitat suitability index (HSI) model presented in this report on Gulf of Mexi co stocks of the Ameri can oyster is intended for use in environmental impact assessment and habitat management as mentioned in this paper.
Abstract: PREFACE The habitat suitability index (HSI) model presented in this report on Gulf of Mexi co stocks of the Ameri can oyster is intended for use in envi ronmenta1 impact assessment and habitat management. The model was developed from a review and synthesis of existing information based on methodology prescribed by the U.S. Fish and Wildlife Service (1981) and is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 (optimal suitable habitat). Assumptions used to transform habitat use information in the HSI model and guidelines for model applications, including techniques for measuring the model variables, are described. The HSI model presented herein is a hypothesis of species-habitat re l at i onshi ps, not statements of proven cause-and-effect re 1ati onships. The model has not been-field-tested, but it has been applied to six hypothetical sets of data that are presented and di scussed. For thi s reason, the U. S. Fish and Wildlife Service (FWS) encourages model users to convey comments and suggestions that may increase the utility and effectiveness of this habitat-based approach to fish and wildlife planning. Please send any comments or suggestions that you may have on the American oyster HSI model to:
58 citations
TL;DR: Although fecal coliform and total bacterial counts did not correlate with those for vibrios in fresh oysters, strong correlations were observed in oysters stored for 7 days, suggesting that these indicators may be useful in monitoring oyster quality when meats are stored for a limited time as shellstock.
Abstract: The effects of storage on the microbial load in two commercially important species of shellfish were examined. Oysters (Crassostrea virginica) were stored as shellstock, shucked meats, and fully processed meats at four temperatures for up to 21 days, and clams (Mercenaria campechiensis) were stored only as shellstock. The concentrations of most microbiological groups of organisms increased with the duration and temperature of storage in both shellfish species, although the increases were significantly lower in claims. Concentrations of Vibrio cholerae rose by approximately 1 log in oysters stored as shellstock after 7 days at 2 degrees C, and Lac+ vibrios increased 2 logs at 8 degrees C. Total counts of bacteria, fungi, coliforms, fecal streptococci, Aeromonas hydrophila, and clostridia were significantly higher in shucked oysters than in those stored as shellstock. Fecal coliforms were statistically the same, but V. cholerae, Vibrio parahaemolyticus, and the Lac+ vibrios were higher in oysters stored as shellstock. The concentrations of all microbial groups were higher in fully processed oysters than in shucked meats, with the exception of the vibrios, which showed no significant difference among the treatments. The results showed that although traditional methods of storing shellfish resulted in an overall increase in the microbial load, vibrio levels increased only in oysters stored as shellstock. Although fecal coliform and total bacterial counts did not correlate with those for vibrios in fresh oysters, strong correlations were observed in oysters stored for 7 days, suggesting that these indicators may be useful in monitoring oyster quality when meats are stored for a limited time as shellstock.
56 citations
TL;DR: It is clearly demonstrated that cigarette smoking had a more pronounced and significant effect on whole blood cadmium levels than the intake of Cadmium via oysters.
TL;DR: In this paper, the authors show evidence of direct epidermal uptake of [3H] glycine from 1 μM solutions in the tissues of larval oysters, Crassostrea gigas, Ostrea edulis, and mussels.
Abstract: Uptake and incorporation of [3H]glycine from 1 μM solutions was observed in the tissues of larval oysters, Crassostrea gigas, Ostrea edulis, and mussels, Mytilus edulis. In all cases, radiolabel first appears in the larva's velum. Following increasing exposure time, label begins to appear in other organs. In newly settled larvae of the oyster, C. gigas, and the scallop, Pecten maximus, uptake occurs via the developing gill buds. All experiments provide evidence of direct epidermal uptake of soluble nutrients without any participation of the digestive tract. Scanning electron micrographs show that there is no bacterial population visible on the surface of the velum that might act as an intermediate step in nutrient transport. These studies on veligers, pediveligers and settled larvae link the phenomenon of larval uptake with the extensive literature on the direct uptake of soluble nutrients by adult bivalves.
TL;DR: Tissue-specific metabolism was monitored in gill, mantle, and adductor muscle of the oyster Crassostrea virginica over a time course of 96 h of anoxia followed by 48’h of recovery from anoxIA to assess the role of anaerobic metabolism and imino acids alanopine and strombine.
Abstract: Tissue-specific metabolism was monitored in gill, mantle, and adductor muscle of the oyster Crassostrea virginica over a time course of 96 h of anoxia followed by 48 h of recovery from anoxia. Succ...
TL;DR: No difference between inbred and outbred treatment was observed for larval shell length and there is evidence of higher larval survivorship coupled with increased homozygosity, which may serve as a basis to explain the heterozygote deficiency present in wild oyster and mussel populations.
TL;DR: The littoral lagoons of the Gulf of Mexico have been investigated to determine the amount of heavy metal pollution as discussed by the authors, and it was found that oysters are able to concentrate metals, mainly Cd and Pb above the maximum permissible limits for edible consumption.
Abstract: The littoral lagoons of the Gulf of Mexico have been investigated to determine the amount of heavy metal pollution. Some lagoons have been contaminated by liquid wastes mainly originating from sugar refining and petrochemical industries, as well as petroleum exploitation and refining. Since mollusks concentrate trace elements, determination of levels of Cd, Cr, Hg, and Pb in oysters (Crassostrea virginica) were measured in some of these lagoons. The results have shown that the concentrations of these metals in lagoon water were below the recommended levels to protect aquatic life, and it was found that oysters are able to concentrate metals, mainly Cd and Pb above the maximum permissible limits for edible consumption.
TL;DR: Newly hatched oyster drills, Urosa!pinx cinerea (Say), that had not eaten prey and had no prior experience in prey detection, were used to screen 25 potential attractants, and odors of intact, living barnacles were most effective, optimally causing upstream migration and retaining detectable activity after 200 fold dilution.
Abstract: Newly hatched oyster drills, Urosa!pinx cinerea (Say), that had not eaten prey and had no prior experience in prey detection, were used to screen 25 potential attractants. Of these, odors of intact, living barnacles, Semibalanus balanoides and Balanus eburneus were most effective, optimally causing upstream migration in over 90% of the snails and retaining detectable activity after 200 fold dilution. The odor of a mixed bryozoan culture evoked a 70% and Sabellaria vulgaris a 30% response, whereas responses to Crassostrea virginica, oyster valves containing Po!ydora web steri, and Trypetesa lampas were low but still significant. Both rheotactic and che motactic factors were involved in the upstream migration. Behavior reminiscent of trail search was observed in homogeneous dilute stimulus solutions. It is argued that the odor stimuli may be discrete molecules.
TL;DR: It is demonstrated that bivalves utilize dissolved organic nutrients throughout their life span, from fertilized egg to adulthood.
TL;DR: V. cholerae is a widely distributed organism in the nutrient-rich warm waters of the Gulf Coast estuaries and was present in the highest concentrations when salinities were 10‰–25‰ and temperatures were 20‡C–35‰.
Abstract: The distribution ofVibrio cholerae was examined in 2 Florida estuaries, Apalachicola and Tampa Bay.Vibrio cholerae serotype non-01 was the most abundant serotype, being isolated from 45% of the oyster samples, 30% of the sediments, 50% of the waters, and 75% of the blue crabs.Vibrio cholerae serotype 01 was isolated from only one oyster sample. Strong linear correlations betweenV. cholerae and temperature, salinity, or the other physical/chemical parameters measured,Escherichia coli, or fecal coliforms were not observed, but a range of temperatures and salinities appeared relevant to the distribution of the organism. The organism was present in the highest concentrations when salinities were 10‰–25‰ and temperatures were 20‡C–35‡C.In vitro growth curves of 95V. cholerae environmental isolates further supported that 10‰–25‰ was an ideal salinity range for the organisms. The results suggest thatV. cholerae is a widely distributed organism in the nutrient-rich warm waters of the Gulf Coast estuaries.
TL;DR: Hatchery production of this species in winter months may help the development of commercial oyster production in southern Chile which is currently limited by summer spatfall.
TL;DR: Hybridization was achieved between cultured female white-spotted green grouper and wild male red grouper (E. akaara) by using human chorionic gonadotropin to induce maturation and the eggs were fertilized by the dry method as mentioned in this paper.
TL;DR: It is concluded that Cd, Zn and Cu are bound and accumulated differently, and that a general principle of element handling does not seem to be present in the tissues examined.
TL;DR: Spread of a new oyster disease caused by Minchinia nelsoni in lower Chesapeake Bay in 1959–1960 threatened Virginia's James River seed area, but few oysters died from the disease and infections were eliminated by oysters in April-May the following spring.
Abstract: Spread of a new oyster disease caused by Minchinia nelsoni (MSX) in lower Chesapeake Bay in 1959–1960 threatened Virginia's James River seed area. Infections appeared in the lower half of the seed area in 1960 and 1961, but few oysters died from the disease and infections were eliminated by oysters in April-May the following spring. Distribution of the disease in controlled broadly by low salinities that inhibit development of infections and allow oysters to discharge plasmodia. Penetrations of the seed area occurred in dry and wet years, but mortalities occurred only in 1964 and 1980, both years of low precipitation. Little mortality was caused by transplanting infected seed oysters to other rivers because only low-salinity grounds were planted after 1959–1960 when severe mortalities occurred in areas of high salinities. In most years, infections were minimal in the seed area and other estuaries where salinities do not exceed 15–20‰ in late summer and fall. Salinities <10‰ prevailed in most of the seed area when oysters expelled the pathogen in early spring.
TL;DR: The results demonstrate that Cd-accumulation does not alter the total Cu and Zn concentrations in gill tissue, and it is postulated that this response, which may involve the release of metals from amoebocytes into gills tissue, is a generalised stress response of this oyster.
Abstract: Oysters, Ostrea edulis, were exposed to cadmium (0.1 mg l-1) for up to 110 d (in 1982) under laboratory conditions in order to determine the effect of Cd exposure on blood amoebocytes. The results demonstrate that Cd-accumulation does not alter the total Cu and Zn concentrations in gill tissue. There was a decrease in the numbers of metal-containing amoebocytes, and electron microprobe analysis showed that this was largely due to a reduction in numbers of the mixed Cu/Zn-containing cells rather than in Cu-or Zn-containing cells. It is postulated that this response, which may involve the release of metals from amoebocytes into gill tissue, is a generalised stress response of this oyster. No evidence was found for the presence of a specific Cd-containing blood cell or Cd-binding protein in blood cells.
TL;DR: The weight gain data suggest that dissolved protein is not efficiently utilised by Saccostrea commercialis, and whole oyster and underwater shell weight gains decreased as the dietary WPC levels increased.
TL;DR: To determine how "detoxification" mechanisms such as metal-binding proteins and concretions are involved in the intracellular partitioning of trace metals in marine shellfish, the oyster, Crassostrea virginica, and the blue crab were exposed to controlled levels of Trace metals.
TL;DR: Analysis of Cd, Zn and Cu in the New Zealand oyster, Ostrea lutaria, showed that on an average it contained 5.8 ..mu..g Cd per g wet weight, while a significant proportion (32%) of the cytosolic Cd was present in low molecular weight (LMW) protein fractions.
Abstract: Analysis of Cd, Zn and Cu in the New Zealand oyster, Ostrea lutaria, showed that on an average it contained 5.8 ..mu..g Cd, 67 ..mu..g Zn and 14.1 ..mu..g Cu per g wet weight. Within the oyster tissue, the amount of Cd was equally distributed between the particulate and soluable (cytosol) fractions. The distribution of Zn and Cu was different, about 70% and 80% respectively being present in the cytosol. Separation of the Cd-binding ligands in the oyster cytosol on Sephadex G-75 column showed that about 60% of the cytosolic Cd was bound to high molecular weight (HMW) proteins eluted near the void volume. Similarly about 40% of Zn and Cu was also present in the HMW proteins.A significant proportion (32%) of the cytosolic Cd was present in low molecular weight (LMW) protein fractions. The protein was estimated to have a molecular weight in the range 6000 to 12,000 daltons and the protein fraction was defined as the metallothionein fraction. Only a very small amount (<1%) of Zn was associated with the MT fraction to the high concentration of Cu (2.23 ..mu..g Cu/g wet tissue). The LMW fraction of the oyster tissue cytosol had less than 1% of cytosolic Cd,more » but it contained a large proportion of Zn (about 60%) and Cu (about 32%).« less
TL;DR: The results suggest that extremely high environmental Cd levels are necessary to induce a metallothionein-like protein in oysters.
Abstract: In contrast to previous results which examined oysters exposed to artificially high cadmium (Cd) levels, the forms of cadmium occurring in “natural” commercially available oysters were partially characterized. About one-third of the Cd was associated with insoluble material. Of the soluble Cd, about 20% occurred in a high molecular weight protein of 40,000–50,000 daltons. The low molecular weight soluble Cd consisted of at least two different forms,i.e., that associated with amino acids (a small peptide) and inorganic Cd. The small peptide fraction also contained zinc and copper. The forms of Cd in commercial oysters were compared to those occurring in both commercial scallops and artificially cultured oysters. Scallops bind Cd to three soluble proteins, all of which are of higher molecular weight than the small oyster peptide. Oysters cultured in 10 ppb Cd medium contained binding sites similar to commercial oysters except that none of the soluble Cd in the cultured oysters was associated with a high molecular weight protein. The results suggest that extremely high environmental Cd levels are necessary to induce a metallothionein-like protein in oysters. Implications of the results to public health are discussed.
TL;DR: Response of newly hatched, predatory snails to competing chemical cues from co-occurring species of prey were determined in laboratory experiments, and cross-adaptation suggests that inhibition or facilitation of chemotaxis in odor ...
Abstract: Response of newly hatched, predatory snails to competing chemical cues from co-occurring species of prey were determined in laboratory experiments. Egg capsules of Urosalpinx cinerea were collected from an intertidal, vertically zoned community of prey species. The most prevalent prey were barnacles Semibalanus balanoides and Balanus eburneus, oysters Crassostrea virginica, mussels Mytilus edulis, and bryozoans Membranipora tenuis and Schizoporella irrorata. Snail chemotaxis evoked by barnacle odor alone and barnacle odor mixed with odor of either mussels or oysters was assayed in an activity chamber. Mussel odor inhibits chemotaxis to barnacles, but does not evoke chemotaxis itself. Oyster odor inhibits chemotaxis to high concentrations of barnacle odor, but increases chemotaxis to low concentrations of barnacle odor. Chemotaxis to barnacle odor is reduced by 2 h pre-exposure to either barnacle, oyster, or mussel odors. Such cross-adaptation suggests that inhibition or facilitation of chemotaxis in odor ...
TL;DR: A questionnaire on prospective breeding goals in oysters was distributed and 49 replies received from researchers and producers in 18 countries, with significant variation in the scores for some traits for geographical area and oyster species.