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Crassostrea virginica

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Full-Text Articles in Life Sciences

Recruitment And Growth Of Oysters On Shell Planted At Four Monthly Intervals In The Lower Potomac River, Maryland, Reinaldo Morales-Alamo, Roger L. Mann Jan 1990

Recruitment And Growth Of Oysters On Shell Planted At Four Monthly Intervals In The Lower Potomac River, Maryland, Reinaldo Morales-Alamo, Roger L. Mann

VIMS Articles

Oyster shells were planted on four successive months (May to August 1986) in contiguous plots at Jones Shore Bar in the Potomac River, Maryland, to study the effect of differences in time of cultch planting on settlement and survival of oyster spat. The plots were usually sampled at two-week intervals from time of planting through November, 1986, and once in June, 1987. A massive concentration of the tunicate Molgula manhattensis covered the bottom in all plots within four to six or eight weeks following shell planting. A commercially acceptable number of spat per shell, between 1.8 and 2.2 (approximately equivalent …


Effects Of Inter-Specific Density And Food Supply On Survivorship And Growth Of Newly Settled Benthos, Roman Zajac, Robert B. Whitlatch, Richard W. Osman Aug 1989

Effects Of Inter-Specific Density And Food Supply On Survivorship And Growth Of Newly Settled Benthos, Roman Zajac, Robert B. Whitlatch, Richard W. Osman

Biology and Environmental Science Faculty Publications

Using a laboratory model system comprised of newly settled oysters Crassostrea virginica and established fouling species (Botrylloides sp. initially, and others including Styela clava and Ciona intestinalis as the experiment progressed), we tested how differences in food supply and competitor density may affect post-settlement surivorship and growth of sessile marine invertebrates over a 44 d period. After 15 d, results were mixed but indicated that both food and density conditions affected growth and survivorship significantly, with some suggestion of high food levels ameliorating high density effects However, 44 d after settlement, oysters had reduced survivorship and growth when competitors …


Effects Of Resident Species On Recruitment Into A Community: Larval Settlement Versus Post-Settlement Mortality In The Oyster Crassostrea Virginica, Roman Zajac, Richard W. Osman, Robert B. Whitlatch Jun 1989

Effects Of Resident Species On Recruitment Into A Community: Larval Settlement Versus Post-Settlement Mortality In The Oyster Crassostrea Virginica, Roman Zajac, Richard W. Osman, Robert B. Whitlatch

Biology and Environmental Science Faculty Publications

Laboratory and field experiments revealed that a variety of species of common, sessile invertebrates, including barnacles, ascidians, and bryozoans, affected the settlement and post-settlement abundance of the oyster Crassostrea virginica (Gmelin). While the nature of the effects varied, most species both reduced oyster settlement by covering and removing substrate available for attachment, and increased settlement on adjacent surfaces. The solitary ascidians Ciona intestinalis (L.) and Styela clava (Herdman), were found to be predators of oyster larvae. Post-settlement survivorship and growth were also strongly affected by the presence of sessile species. In most cases the effects were negative and correlated with …


Anatomical Features In Histological Sections Of Crassostrea Virginica (Gmelin, 1791) As An Aid In Management Of Gonad Area For Reproductive Assessment, Reinaldo Morales-Alamo, Roger L. Mann Jan 1989

Anatomical Features In Histological Sections Of Crassostrea Virginica (Gmelin, 1791) As An Aid In Management Of Gonad Area For Reproductive Assessment, Reinaldo Morales-Alamo, Roger L. Mann

VIMS Articles

The relationship between gonad area in transverse histological sections of the American oyster Crassostrea virginica (Gmelin 1790) and body location from which the section was cut was studied in specimens collected from four stations in the James River, Virginia in 1984 and 1986. Gonad area, expressed as percentage of total body area, increases in an antero-posterior direction; this requires use of sections from the same body location in comparisons between oysters. Approximate body locations, identified according to the anatomy and arrangement of the internal organs in the sections, were grouped into five types with similar gonad area percentages. One of …


The Growth Of Cultchless Crassostrea Virginica Spat At Biloxi Bay, Mississippi Using Different Methods Of Culture, John T. Ogle Jan 1989

The Growth Of Cultchless Crassostrea Virginica Spat At Biloxi Bay, Mississippi Using Different Methods Of Culture, John T. Ogle

Gulf and Caribbean Research

Oyster spat produced from the experimental hatchery of the Gulf Coast Research Laboratory at Point Cadet, Biloxi, Mississippi, were grown under a variety of conditions. Recovery of spat planted on adjacent bay bottom was negligible, despite the use of either whole oyster valves, crushed oyster shell or clam shell as a substrate. Negligible growth occurred for spat held in vertical and horizontal water tanks. Growth of spat in horizontal tanks was affected by the density of stocking, with lower densities producing faster growth. Growth in all studies was slower than anticipated and a comparison on growth for spat from a …


Predation On Single Spat Oysters Crassostrea Virginica (Gmelin) By Blue Crabs Callinectes Sapidus Rathbun And Mud Crabs Panopeus Herbstii Milne-Edwards, Robert Bisker, Michael Castagna Jan 1987

Predation On Single Spat Oysters Crassostrea Virginica (Gmelin) By Blue Crabs Callinectes Sapidus Rathbun And Mud Crabs Panopeus Herbstii Milne-Edwards, Robert Bisker, Michael Castagna

VIMS Articles

Single spat oysters Crassostrea virginica of four size classes (3.4-24.6 mm mean shell heights [SH]) were offered to six size classes of blue crabs Ca/linectes sapidus (9.3-85.5 mm mean carapace width [CW]) and five size classes of mud crabs Panopeus herbstii (7.1-34.4 mm mean CW) for 48 hr. Predation rate, recorded as the number of dead oyster spat/crab/day, was directly proportional to crab size and inversely proportional to oyster size. Mud crabs of 34.4 mm CW and blue crabs of 85 .5 mm CW had predation rates of 22.5 and 16.7 spat/crab/day on oyster spat of 24.6 and 24.4 mm …


Survival Of The Oyster Crassostrea Virginica (Gmelin) In The Laboratory Under The Effects Of Oil Drilling Fluids Spilled In The Laguna De Tamiahua, Mexico, Jorge Cabrera Jan 1971

Survival Of The Oyster Crassostrea Virginica (Gmelin) In The Laboratory Under The Effects Of Oil Drilling Fluids Spilled In The Laguna De Tamiahua, Mexico, Jorge Cabrera

Gulf and Caribbean Research

In 1965, 970.12 m3 of oil drilling fluid were spilled in the Laguna de Tamiahua, Mexico. Laboratory experiments were carried out to determine possible effects of this upon the oyster Crassostrea virginica. It was found that drilling fluid reduced the survival of oysters to a significant degree in concentrations above 200 ppm. At turbidities between 200 and 500 ppm, there was 50% survival on the seventh day. Tanino in concentrations between 90 and 170 ppm had a drastic effect upon survival which was 50% between the fourth and fifth days. Bentonita in 110 to 190 ppm resulted in …