Biomass and shell weight estimator with increasing oyster size. The purpose is to provide quantit... more Biomass and shell weight estimator with increasing oyster size. The purpose is to provide quantitative relationships between shell length (SL, mm), dry meat weight (DMW, g), and dry shell weight (DSW, g) from a range of locations in the Virginia Chesapeake Bay.
The progression of diseases caused by the oyster parasites Perkinsus marinus and Haplosporidium n... more The progression of diseases caused by the oyster parasites Perkinsus marinus and Haplosporidium nelsoni were evaluated by periodic sampling (May 1994-December 1995) of eastern oysters Crassostrea virginica on an artificial reef located in the Piankatank ...
Growth, tolerance of Perkinsus marinus, and gametogenesis of diploid and triploid Eastern oysters... more Growth, tolerance of Perkinsus marinus, and gametogenesis of diploid and triploid Eastern oysters, Crassostrea virginica (Gmelin, 1791) were compared in the York River, Virginia between June 1989 and November 1990. Triploid oysters had significantly greater mean shell height (P ,a;; 0.02) and whole weight (P ,a;; 0.005) than diploid oysters throughout the study period. In November 1990, triploids had significantly greater mean dry tissue weight (P ,a;; 0.006) than diploids. On average, triploid oysters reached commercial size (63.5 mm) 5 months before diploid oysters. Diploid and triploid groups became similarly infected with P. marinus during summer 1990. Prevalences reached 96% with moderate and heavy intensities in both groups in October 1990. Gonadal development in triploids was significantly reduced (P ,a;; 0.02) compared to development in diploids. While diploid oysters completed a normal gametogenic cycle, gametogenesis in triploid male oysters was arrested prior to gamete ma...
Oyster population density (total number of right valves of all sizes counted per 50 L) from the H... more Oyster population density (total number of right valves of all sizes counted per 50 L) from the Holland Point (HP) Pleistocene reef.
A number of techniques have been reported to estimate condition index in oysters and other bivalv... more A number of techniques have been reported to estimate condition index in oysters and other bivalve molluscs. We report and compare condition index, estimated by three different methods, for oysters collected from a single reef in the James River, Virginia over a four week period in the summer of 1987. Two indices express condition as a ratio of dry meat weight to shell cavity volume, but differ in methods of estimating shell cavity volume. A third method expresses condition as a ratio of dry meat weight to dry shell weight. Within the size range 36-96 mm length there is no effect of size on index values. We suggest that indices based on both shell cavity vqlume and shell weight have utility in reflecting biochemical or nutritive status; however, intercalibration is difficult and comparisons of data from different authors and locations limited in scope.
Reproductive activity of oysters, Crassostrea virginica(Gmelin, 1791) in the James River, Virgini... more Reproductive activity of oysters, Crassostrea virginica(Gmelin, 1791) in the James River, Virginia, during 1987-1988. R Mann, JS Rainer, R Morales-Alamo Journal of Shellfish Research 13:11, 157-164, 1994. Reproductive activity ...
Biomass and shell weight estimator with increasing oyster size. The purpose is to provide quantit... more Biomass and shell weight estimator with increasing oyster size. The purpose is to provide quantitative relationships between shell length (SL, mm), dry meat weight (DMW, g), and dry shell weight (DSW, g) from a range of locations in the Virginia Chesapeake Bay.
The progression of diseases caused by the oyster parasites Perkinsus marinus and Haplosporidium n... more The progression of diseases caused by the oyster parasites Perkinsus marinus and Haplosporidium nelsoni were evaluated by periodic sampling (May 1994-December 1995) of eastern oysters Crassostrea virginica on an artificial reef located in the Piankatank ...
Growth, tolerance of Perkinsus marinus, and gametogenesis of diploid and triploid Eastern oysters... more Growth, tolerance of Perkinsus marinus, and gametogenesis of diploid and triploid Eastern oysters, Crassostrea virginica (Gmelin, 1791) were compared in the York River, Virginia between June 1989 and November 1990. Triploid oysters had significantly greater mean shell height (P ,a;; 0.02) and whole weight (P ,a;; 0.005) than diploid oysters throughout the study period. In November 1990, triploids had significantly greater mean dry tissue weight (P ,a;; 0.006) than diploids. On average, triploid oysters reached commercial size (63.5 mm) 5 months before diploid oysters. Diploid and triploid groups became similarly infected with P. marinus during summer 1990. Prevalences reached 96% with moderate and heavy intensities in both groups in October 1990. Gonadal development in triploids was significantly reduced (P ,a;; 0.02) compared to development in diploids. While diploid oysters completed a normal gametogenic cycle, gametogenesis in triploid male oysters was arrested prior to gamete ma...
Oyster population density (total number of right valves of all sizes counted per 50 L) from the H... more Oyster population density (total number of right valves of all sizes counted per 50 L) from the Holland Point (HP) Pleistocene reef.
A number of techniques have been reported to estimate condition index in oysters and other bivalv... more A number of techniques have been reported to estimate condition index in oysters and other bivalve molluscs. We report and compare condition index, estimated by three different methods, for oysters collected from a single reef in the James River, Virginia over a four week period in the summer of 1987. Two indices express condition as a ratio of dry meat weight to shell cavity volume, but differ in methods of estimating shell cavity volume. A third method expresses condition as a ratio of dry meat weight to dry shell weight. Within the size range 36-96 mm length there is no effect of size on index values. We suggest that indices based on both shell cavity vqlume and shell weight have utility in reflecting biochemical or nutritive status; however, intercalibration is difficult and comparisons of data from different authors and locations limited in scope.
Reproductive activity of oysters, Crassostrea virginica(Gmelin, 1791) in the James River, Virgini... more Reproductive activity of oysters, Crassostrea virginica(Gmelin, 1791) in the James River, Virginia, during 1987-1988. R Mann, JS Rainer, R Morales-Alamo Journal of Shellfish Research 13:11, 157-164, 1994. Reproductive activity ...
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