Showing papers on "Oyster published in 1979"
TL;DR: Current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses, and no significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water andshellfish.
Abstract: The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses.
133 citations
TL;DR: The levels of genetic variation and estimates of genetic similarity and distance were determined for populations of Crassostrea gigas and Saccostrea commercialis and have resulted in some provisional reclassifications.
Abstract: The levels of genetic variation and estimates of genetic similarity and distance were determined for populations of Crassostrea gigas (Thunberg) and Saccostrea commercialis (Iredale and Roughley). The proportion of polymorphic loci in Japanese populations of C. gigas ranged from 0.58 to 0.63, while the individual heterozygosities ranged from 0.20 to 0.22. The proportion of polymorphic loci in Australian populations of S. commercialis ranged from 0.43 to 0.46, the individual heterozygosities from 0.17 to 0.19. The genetic similarity between different geographical populations of both species was approximately 99%. The genetic distance and similarity data derived from this investigation has resulted in some provisional reclassifications. The Portuguese oyster C. angulata (Lamarck) appears to be more appropriately regarded as a recent colonized isolate of C. gigas. The New Zealand oyster S. glomerata (Gould) is considered a subspecies of the eastern Australian rock oyster S. commercialis. The Japanese Kumamoto population of C. gigas warrants reclassification as the non-sibling species C. sikamea.
130 citations
Book•
01 Jan 1979
TL;DR: The structure, physiology and reproduction of oysters, and observations on the larvae of Ostrea edulis and other species of bivalves, are described.
Abstract: Introduction Structure, physiology and reproduction of oysters Tank rearing Hatchery rearing of oyster larvae Observations on the larvae of Ostrea edulis Oyster spat Other species of bivalves The Tal-y-foel oysterage Epilogue.
126 citations
TL;DR: Experimental studies designed to investigate the influence of factors which influence cadmium concentrations, such as regional differences, seasonal fluctuations and salinity in a filter feeding bivalve mollusk, the American oyster, demonstrate that an inducible Cadmium binding protein, similar to metallothiomein, is present in the oyster.
Abstract: A general review of cadmium concentrations in marine organisms and studies of cadmium bioaccumulation is presented. Factors which influence cadmium concentrations, such as regional differences, seasonal fluctuations and salinity, are discussed and species which are likely to accumulate cadmium identified. Experimental studies designed to investigate the influence of some of these factors on cadmium bioaccumulation in a filter feeding bivalve mollusk, the American oyster (Crassostrea virginica), are presented. Field studies of seasonal dynamics of cadmium in oysters indicate patterns which may be correlated with seasonal physiological activity. The bioaccumulation of cadmium following input to estuarine systems by natural phenomena is observed. Cadmium concentrations in oysters collected from regions of different salinity suggest an inverse relationship between cadmium concentration and salinity. Laboratory experiments designed to investigate mechanisms of cadmium accumulation demonstrate that an inducible cadmium binding protein, similar to metallothiomein, is present in the American oyster.
115 citations
TL;DR: A highly anionic protein which is not present in control oysters was found to be present in cadmium-exposed animals after 3 days of treatment and to increase in concentration at succeeding time points.
111 citations
TL;DR: A female milkfish, captured at sea, was injected with two hormonal injections of acetone-dried salmon pituitary powder and human chorionic gonadotropin, plus Vitamin B complex, and produced 128,000 ripe eggs, with the highest larval survival rate obtained from different experimental groups was 46.8%.
86 citations
TL;DR: The author has compiled a schematic diagram which illustrates the possible causes of mass mortality among C. gigas in an eutrophic environment such as Matsushima Bay.
Abstract: Matsushima Bay, one of the richest oyster-culture areas in Japan, is subject to heavy artificial eutrophication, mainly from the inflow of city and factory sewages. The physiological activity in the oyster Crassostrea gigas in hanging cultures (i.e., suspended in wire-mesh cages) in this embayment declines markedly with progressive development of the gonads; this decline in activity coincides with eutrophication-induced accumulation of fatty material in the epithelia of the digestive organs; the oyster is thereby forced to depend on these accumulated fats for respiratory substrates in order to maintain its increased physiological needs. However, the fats are inefficient energy sources for the oyster and hence, during each spawning season, 50% mortality occurs. In addition, such phenomena as overmaturation of the gonad and disturbance of the lipid and steroid metabolism seem to accelerate this mass mortality. On the basis of the results, the author has compiled a schematic diagram which illustrates the possible causes of mass mortality among C. gigas in an eutrophic environment such as Matsushima Bay.
85 citations
TL;DR: The estimated levels of genetic variation are reported for 6 Crassostrea and 3 Saccostrea species and a new sibling species from the Philippines has been identified by means of protein electrophoresis.
Abstract: The estimated levels of genetic variation are reported for 6 Crassostrea and 3 Saccostrea species. The estimates are based on examination of 25 to 34 genetic loci. The average heterozygosities ranged from 6 to 22% for the Crassostrea species and from 17 to 19% for the Saccostrea species. A new sibling species (S. manilai) from the Philippines has been identified by means of protein electrophoresis. The genetic similarity and distance between species has been computed for each genus. Also, a pairwise comparison of loci and a dendrogram of the phylogenetic relationship of species has been constructed from the two genera. Some of the taxonomic levels during oyster speciation have been computed from the data of the electrophoretic study of the two lineages. The possibilities of oyster superspecies (e. g. C. gigas, C. virginica and S. cucullata) are discussed based on our population genetic study.
80 citations
TL;DR: A filterable agent, designated 13p2 was isolated from homogenized juvenile oyster tissue inoculated on to bluegill fry (BF-2) cell cultures, suggesting the virus belonged to the family Reoviridae, and may be an undescribed virus.
Abstract: Summary
A filterable agent, designated 13p2 was isolated from homogenized juvenile oyster tissue inoculated on to bluegill fry (BF-2) cell cultures. The oysters were from a hatchery on Long Island Sound, New York. Successive passages resulted in progressive cytopathic effects (c.p.e.) consisting of discrete plaques containing large syncytia seen within 2 to 3 days in cultures held at 15 °C. The agent was concentrated from supernatant fluids by ultracentrifugation. Negative stained preparations examined by electron microscopy revealed icosahedral particles with a mean diam. of 79 nm.
Virus replication in tissue culture occurred at both 15 and 23 °C. Susceptible fish cells in addition to the BF-2 included brown bullhead, Atlantic salmon, guppy embryo and walleye fry lines. Limited c.p.e. occurred in Atlantic salmon heart cells while rainbow trout gonad, rainbow trout spleen and fathead minnow cells were refractory to cytopathic changes.
Biochemical and physical characteristics suggested the 13p2 virus belonged to the family Reoviridae. The possibility that this virus is a known reovirus, present only as a contaminant, was ruled out on the basis of serological results and failure of avian or mammalian cells to support its growth. The 13p2 agent may be an undescribed virus. Further investigations concerning the identity of this virus and its capabilities as a pathogen in fish and shellfish are under way.
70 citations
TL;DR: The response of embryos and larvae of the American oyster to copper at various salinity-temperature regimes was studied in the laboratory using response surface methods and factorial analysis and indicated that salinity had the greatest effect on the embryos, but temperature had as great an effect as that of salinity at 20 ppb copper.
Abstract: The response of embryos and larvae of the American oyster,Crassostrea virginica, to copper at various salinity-temperature regimes was studied in the laboratory using response surface methods and factorial analysis. The experimental design was a 3 x 3 x 4 factorial experiment using temperatures of 20, 25, and 30°C, and salinities of 17.5, 22.5, and 27.5 ‰ It was carried out at copper concentrations of 0, 5, 10, and 20 ppb for the embryos and 0, 30, 60, and 90 ppb for the larvae. Statistical analysis indicated that salinity had the greatest effect on the embryos at 0, 5, and 10 ppb copper, but temperature had as great an effect as that of salinity at 20 ppb copper. The capacity of the embryos to adapt to the temperaturesalinity changes was impaired when exposed to 20 ppb copper, as indicated by the shifting of the response center. Temperature had the greatest effect on the larvae when exposed to 30, 60, and 90 ppb copper. The interaction between temperature and salinity was significant only at the higher levels of qopper. Low levels of copper may produce intolerable stress upon the recruitment of oyster embryos during periods of persistently low salinities and low or high temperatures.
65 citations
01 Jan 1979
TL;DR: Preliminary studies have been undertaken to test the indicator ability of the rock oyster Saccostrea glomerata for monitoring the trace metals cadmium, copper, iron and zinc, and application of POLYDIV statistical analysis to these data has aided their interpretation and confirmed the relationship between known areas of contamination and elevated metal levels in S.glomerata.
Abstract: An urgent need for a sub-tropical and tropical indicator organism for use in the biological monitoring of pollutants is recognised. To this end, preliminary studies have been undertaken to test the indicator ability of the rock oyster Saccostrea glomerata (=Crassostrea glomerata Gould) for monitoring the trace metals cadmium, copper, iron and zinc. A survey of these trace metals in rock oysters from 54 sites in Hong Kong waters revealed elevated levels of metals in several areas. Profiles of metal abundance in S. glomerata agreed substantially with the distribution of industrial and domestic discharges in Hong Kong, and also with patterns of contamination found in studies of the Pacific oyster Crassostrea gigas and of sediments. Application of POLYDIV statistical analysis to these data has aided their interpretation and confirmed the relationship between known areas of contamination and elevated metal levels in S. glomerata. This oyster, which exhibits an unusually great capacity to accumulate a range of elements from the ambient environment, thus appears to be a reliable indicator organism, and may be of great value in global monitoring studies.
TL;DR: It was ascertained quantitatively that oyster hemocytes are attracted to live E. coli, B. megaterium, and M. varians but not to heat-killed bacteria, and the chemoattractant is some molecule emitted by living vegetative cells of certain Gram-positive as well as Gramnegative bacteria.
TL;DR: Larvae resulting from fertilization of fresh eggs with 39-day-old cryopreserved spermatozoa appeared normal after 11 days and fertilized 92% of approximately the same number of eggs from the same females.
01 Jan 1979
TL;DR: Three major diseases of oysters have been monitored in Virginia estuaries for 2-3 decades and transmission of the diseases and life cycles are still important objectives after 18 years of studies.
Abstract: Three major diseases of oysters have been monitored in Virginia estuaries for 2-3 decades. Dermocystidium marinum, causing a warm-season wasting disease, was discovered in Virginia in 1950 and continues actively to kill oysters where beds or populations are found in highsalinity waters (>15%0). This disease spreads by close proximity ofdying oysters to other oysters, hence each isolated bed must be sampled in early fall annually to document activity of the pathogen. Control involves avoiding infected seed oysters, cleaning beds of all oysters after harvest, and isolation of new beds. A new pathogen, Minchinia nelsoni (MSX), caused catastrophic oyster mortalities in 1959-60, and oyster planting ceased thereafter in a large area of highsalinity (>15%o) waters in lower Chesapeake Bay. A third pathogen, Minchinia costalis (Sea Side Organism or SSO), was found almost simultaneously on Seaside of Virginia in high-salinity waters ( >30 %o). January-February 1979 ported Jots of disease-free oysters in legged trays on natural oyster beds. Disease-free oysters were obtained from low-salinity waters « 15 %0) in the James River seed area of Virginia. Legged trays lined with I-inch mesh hardware netting prevented smothering and predation which were the major interfering problems on natural bottoms. In 1959, a disease caused by Minchinia costalis, a pathogen closely related to M. nelsoni, was discovered on Seaside of Eastern Shore, Virginia, in high-salinity waters (Andrews et aI., 1962). This disease has a well-defined seasonal pattern of activity, and the J. D. Andrews is with the Virginia Institute of Marine Science and School of Marine Science, The College of William and Mary, Gloucester Point, VA 23062. This paper is Contribution No. 898 of the Virginia Institute of Marine Science. Both these haplosporidan parasites kill native susceptible oysters at rates of 20-50 percent annually. Strains resistant to MSX were selected from survivors by laboratory breeding. SSO appears to be an endemic pathogen that causes confined periods ofinfection and mortality. Sporulation and infection occur regularly each May-June associated with oyster deaths. A long incubation period of8 months with hidden or subclinical infections characterizes the disease. SSO is confined to high-salinity waters along the seacoast from Cape Henry to Long Island Sound. MSX is a highly infectious pathogen that appears to be new by importation or advent ofa virulent strain. Infections occur during 5 warm months (June-October) and deaths occur throughout the year. Direct transmission has not been achieved in the laboratory for either haplosporidan. Transmission of the diseases and life cycles are still important objectives after 18 years of studies. pathogen achieves sporulation regularly in May-June each year (Andrews and Castagna, 1978). The life cycles of these two haplosporidans are obscure, and artificial infections have not been achieved. A comparison of epizootiological traits is made for clues to sources of infection which are a persistent mystery. Hypotheses on timing of activities and infective sources are derived from these comparisons. Studies of the two diseases in Chincoteague Bay were made by Couch and
TL;DR: It is suggested that oxidation by-products formed during chlorination or ozonization of power plant cooling waters may have adverse effects upon the growth of marine invertebrates, such as C. virginica, during their delicate larval stages.
TL;DR: The data suggest that when a pathogenic bacterium is present the potential for disease is much greater in non-UV-treated sea water.
TL;DR: Evidence is presented showing that Thais can kill oysters without mechanical injury, presumbly by some paralytic material, and that snails taken from low-salinity water survived transfer to still lower salinities or lived longer even in lethally low salinity water than those coming from higher salinITIES.
Abstract: Original work was carried on at the U.S. Bureau of Fisheries Laboratory on Apdachicoh Bay from August 1935 to April 1936. Since then observations have been made in Texas, Louisiana and Mississippi. Five papers on specific aspects of the biology of the animal have been written since on this and other predatory gastropods. Here all commentaries are drawn together and unpublished matter is presented. The name Thais haemastoma is used because separations based upon the rugosity of the shells do not hold up. Perfectly smooth and very rugose specimens are found in the same bays, with various shell characteristics being related to various oyster reefs on which they grow. Radular movement is by the band-over-pulley method suggested by Husley (1853), Herrick (1906) Gunter (1936) and Carriker (1943). Evidence is presented showing that Thais can kill oysters without mechanical injury, presumbly by some paralytic material. About one-third of the oysters are opened by large Thais without any boring whatsoever. Smaller Thais are more prone to bore complete holes into the shell cavity of the prey. In Apalachicola Bay large Thais may eat one oyster about every 8 days and it was calculated that on St. Vincent’s Bar 24 million adult oysters could be killed in a year. The resting gonads consist of a thin layer of tissue on the body over the liver and they are lavender-grey in the males and yellowish-orange in the females. They begin to thicken in January and the color intensifies. Egg laying takes place from April to July on the Gulf coast. No young or small Thais were seen in Apalachicola Bay probably because of heavy freshwater drainage in the springs of 1934 and 1935. Several hundred Thais were measured and each month the length frequency mode was at 80.0 mm. The largest known specimen of Thais, a Louisiana specimen, was 103 mm long. A heavy kill of Thais took place in the spring of 1935 and no adults survived in Apalachicola Bay ezcept on Hiles’ Bar near Indian Pass, which is close to the ocean. The Thais seemed to perish when salinity dropped to 9 / o ~ and stayed that way for several weeks. Both oysters and mussels survived at salinities lower than Thais could withstand. Thais shells are extremely hard and are difficult to break with a hammer. Nevertheless, they are cracked by stone crabs. They are also invaded by commensals such as the boring clam Diplothyra smithii, the annelid worm Polydora websteri, and the boring sponge Cliona. In Louisiana a so-called conch line was established by St. Amant (1938)owhen it was found that adult conchs did not get much beyond the areain Barataria Bay where the salinity fell to around 20 loo. This was confirmed later by J. G. Mackin and Gunter at about 18O/oo, but has not been published. It has also been found that baby %onchs are found landward of this line. It was found by experiments that conchs were generally killed by water registering 9 /OO salinity and, additionally, that snails taken from low-salinity water survived transfer to still lower salinities or lived longer even in lethally low salinities than those coming from higher salinities. Attempts to trap conchs on oyster beds were unsuccessful because no baits more attractive than the surrounding oysters and mussels could be found. The conchs’ activity stopped at temperatures of 10°C and below.
TL;DR: Although several cell types were observed, actively motile, granular amoebocytes predominated and no mitotic cells were observed even following exposure to a variety of mitogens.
Abstract: Explant and monolayer cell cultures were initiated from oyster heart and embryonic tissue and maintained for periods of a few days to 6 mo depending on the type of tissue and the culture medium. A pH of 7.0–7.3 and a temperature of 20 °C were optimum. Vertebrate cell culture media prepared in a marine saline and supplemented with fetal bovine serum and protein digests provided a suitable basal medium. Supplementation of the basal medium with oyster hemolymph or extracts of oyster tissue markedly prolonged cell maintenance. Explant cultures of heart tissue with the subsequent outward migration of individual cells were most easily initiated and maintained for periods up to 6 mo. Although several cell types were observed, actively motile, granular amoebocytes predominated. No mitotic cells were observed even following exposure to a variety of mitogens. Cultures initiated from disaggregated larvae did yield actively dividing cells. Key words: oyster, cell culture, amoebocytes
TL;DR: This study was an attempt to establish under laboratory conditions whether treated oysters would depurate accumulated cadmium and copper when returned to cleaner waters containing natural concentrations of these metals.
Abstract: This study was an attempt to establish under laboratory conditions whether treated oysters would depurate accumulated cadmium and copper when returned to cleaner waters containing natural concentrations of these metals. In addition, an attempt was made to determine if cadmium accumulation would promote copper loss in the oyster.
TL;DR: American oysters, Crassostrea virginica, and hard clams, Mercenaria mercenaria, were experimentally contaminated with Escherichia coli, Salmonella typhimurium, and Shigella flexneri either by intracardial injection or via the natural route of ingestion.
Abstract: American oysters, Crassostrea virginica, and hard clams, Mercenaria mercenaria, were experimentally contaminated with Escherichia coli, Salmonella typhimurium, and Shigella flexneri either by intracardial injection or via the natural route of ingestion. Bacterial inactivation in the hemolymph was monitored for 72 h after exposure to these enteric pathogens at 20 and 6 degrees C. At 6 degrees C, both mean bacterial uptake by ingestion and subsequent clearance was singificantly lower that at 20 degrees C. However, substantial bacterial clearance from the hemolymph occurred for both shellfish at each temperature. At 20 degrees C, viable bacteria were no longer detectable after 24 h in hemolymph of either clams or oysters after exposure to contaminated water containing 4 x 10(3) bacteria per ml.
TL;DR: The relationship between larval setting order and subsequent spat growth in the American oyster was analyzed and spat that metamorphosed during the first 3 days of the setting period were significantly reduced.
DOI•
01 Jan 1979
TL;DR: This paper aims to provide a history of the cownose Ray in Lower Chesapeake Bay and some of the mechanisms that led to its decline in the 1960s and 1970s.
Abstract: Recommended Citation Merriner, J. V., & Smith, J. W. (1979) A Report to the Oyster Industry of Virginia on the Biology and Management of the Cownose Ray (Rhinoptera bonasus, Mitchill) in Lower Chesapeake Bay. Special Reports in Applied Marine Science and Ocean Engineering (SRAMSOE) No. 216. Virginia Institute of Marine Science, College of William and Mary. http://dx.doi.org/doi:10.21220/m2-s8k3-p957
TL;DR: The effects of heat (cooking) and of frozen storage on the cholesterol content of oyster, blue crab, and shrimp meats was determined in this article, where the effects of cooking and freezing of raw tissue increased the cholesterol levels of both oyster and shrimp.
Abstract: The effects of heat (cooking) and of frozen storage on the cholesterol content of oyster, blue crab, and shrimp meats was determined. Cooking decreased the cholesterol content of crab meat but brought about no significant change in shrimp or oyster meat levels (p > 0.05). Freezing and thawing of raw tissue increased the cholesterol content of oyster and shrimp meat but did not affect the level in crab meat.
Journal Article•
TL;DR: Pontoons made from plastic pipe were tested as an alternative to racks for deepwater culture of the Sydney rock oyster and the growth rate was three times that of oysters on intertidal racks over a 5-month period.
TL;DR: Four large rafts, each costing $ A 543 totally equipped and holding 600 kg of trayed layers of oysters, were sited in New South Wales estuaries during 1977 and 1978 and showed evidence of overspatting, but several husbandry practices are recommended.
01 Jan 1979
TL;DR: Observations made at the time of diagnosis for the presence of infections and information gained through studies of oysters on the bottoms of estuaries and coastal waters are mentioned.
Abstract: The parasite responsible for the disease of the flat oyster, Ostrea edulis has been the object of numerous studies (Comps 1970), (Tige and Morel, 1974, Perkins, 1976) in which most considered the internal cycle of development of the parasite in the oyster, and the parasite's structure, ultrastructure, and systematic position, of which the latter remains debatable. In this paper I mention observations made at the time of diagnosis for the presence of infections and information gained through studies of oysters on the bottoms of estuaries and coastal waters. The research is designed to provide practical solutions to problems facing oyster culture.
Journal Article•
TL;DR: A species of enigmatic amoeba was found front the oysters culcured in Jinhae Bay and the Goje Bay in September-October 1978 and October 1979 and based on their peculiar morphological characters the enigmatic body was a species of parasitic amoEBa.
Abstract: A species of enigmatic amoeba was found front the oysters culcured in Jinhae Bay and the Goje Bay in September-October 1978 and October 1979. Occurrence and the morphological characteristics of the amoeba were studied. Based on their peculiar morphological characters the enigmatic body was a species of parasitic amoeba. The amoebas were morphologically very similar to the amoeboid parasite described by Sawyer(1977). Occurrence of the oysters infected with the amoeboid ranged from zero to . The infection rate did not show any relations to the depth of water where the oysters were suspended. The longest diameter of the amoeba is . The thin outer membrane is lightly stained with eosin and PAS positively. Initially one amoeboid was found in an ovum, and later it propagated to 3 to 4 individuals.
TL;DR: The purpose of the study was to determine the size of Pacific oysters selected and the method used by the Black Oystercatcher to open them.
Abstract: Some authors (Jewett et al. 1953, Guiguet 1955) have claimed that Black Oystercatchers Haematopus bachmani do not, in fact, eat oysters, but there is one recent report of the event (Campbell 1966). Campbell's (1966) description of the technique used by the Black Oystercatcher to open Pacific oysters (Crassostrea gigas) is similar to that described for the European Oystercatcher (H. ostralegus) to open native oysters (Ostrea edulis; Dewar 1922) and that for the American Oystercatcher (H. palliatus) to open Atlantic oysters (C. virginica; Tomkins 1947). This technique involves forcing the bill between the gaping valves of submerged oysters and prying them apart. We observed Black Oystercatchers using a different method of opening Pacific oysters. The purpose of our study was to determine the size of Pacific oysters selected and the method used by the Black Oystercatcher to open them.