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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
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 …
Settlement Patterns Of Crassostrea Virginica (Gmelin, 1791) Larvae In Relation To Tidal Zonation, G. Curtis Roegner, Roger L. Mann
Settlement Patterns Of Crassostrea Virginica (Gmelin, 1791) Larvae In Relation To Tidal Zonation, G. Curtis Roegner, Roger L. Mann
VIMS Articles
Experiments were conducted to determine the settlement distribution of the oyster Crassostrea virginica (Gmelin) in relation to tidal zonation in an area where adult populations are largely confined to the intertidal zone. Hatchery-reared pediveliger larvae were interned in PVC tubes positioned at known tidal heights. The influence of non-tidal factors was limited: mesh covering the ends of the tubes prevented loss of larvae to dispersal or predation, the settling substrate was not colonized by competitors, and the effects of light and horizontal currents were minimized. Settlement was found to occur throughout the intertidal zone but predominated at the bottom of …
Effect Of Decreasing Oxygen Tension Of Swimming Rate Of Crassostrea Virginica (Gmelin, 1791) Larvae, Roger L. Mann, Julia S. Rainer
Effect Of Decreasing Oxygen Tension Of Swimming Rate Of Crassostrea Virginica (Gmelin, 1791) Larvae, Roger L. Mann, Julia S. Rainer
VIMS Articles
Four sizes of Crassostrea virginica Gmelin larvae (mean lengths 76.8, 118.1, 139.7 and 290.2 [Lm) were exposed to ·stepwise decreases in oxygen concentration from I 00% saturation (5 .38 mill at 22°C and 22 ppt salinity) to as low as 10% saturation and their swimming rates (net vertical movement per unit time) were recorded at each oxygen concentration. No cessation of swimming was observed and in only two conditions, that of 76.8 [Lm larvae at 10% saturation and 290.2 j.Lm larvae at 21% saturation, was swimming rate significantly lower than that of the same size larvae at full saturation.