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Full-Text Articles in Life Sciences

Temporal And Spatial Changes In Fecundity Of Eastern Oysters, Crassostrea Virginica (Gmelin, 1791) In The James River, Virginia, Carrollyn Cox, Roger L. Mann Jan 1992

Temporal And Spatial Changes In Fecundity Of Eastern Oysters, Crassostrea Virginica (Gmelin, 1791) In The James River, Virginia, Carrollyn Cox, Roger L. Mann

VIMS Articles

A~u1t Crass~strea virgi.nic~ ~Gmelin) were examined during the reproductive season of 1986 to determine temporal and spatial vanation m fecundity among md!Vldual female oysters from four reefs in the James River, Virginia. Sex ratio and oyster abu.ndance were. ~so determined to :acilitate ~s~imation of total reproductive output of oyster assemblages. Fecundity was highly vanable, both w1thm and among locations. Vanation was attributed to differences in oyster size, asynchrony and variation in time since pri~r spawning, prevalence of parasites (especially Haplosporidium nelsoni (MSX) and Perkinsus marinus) and differing salinity regimes.


The Effects Of Copper, Cadmium And Zinc On Particle Filtration And Uptake Of Glycine In The Pacific Oyster Crassostrea Gigas, Wenyu Lin, Michael A. Rice, Paul K. Chien Dec 1991

The Effects Of Copper, Cadmium And Zinc On Particle Filtration And Uptake Of Glycine In The Pacific Oyster Crassostrea Gigas, Wenyu Lin, Michael A. Rice, Paul K. Chien

Michael A Rice

1. The filtration rate (volume of water completely cleared of collodial carbon per unit time) by control oysters is 36.60 ml/g hr ± 7.68 (sd).2. Filtration rates decrease with increasing concentrations of Cd2+ and Zn2+.3. In 8–16 mg/l Cu2+, filtration rates are significantly higher than the control, but in Cu2+ concentrations above 32 mg/l, filtration rates are lower than controls.4. Influx of 14C-glycine is characterized by Michaelis-Menten kinetics with Jmax and Kt values of 1.85 ± 0.097 μmol/g hr and 33.7 ± 4.6 μM respectively.5. The uptake rate of glycine from 1 μM solution is 37.79 μmol/g hr.6. In order …