Ocean sciences Abstract In this study, we analyzed the bioconcentration of Cd, Cr, Cu, Pb, Ni, and Zn in the soft tissue of transplanted oysters in two sites in the Potengi estuary for six months. Native oysters collected before and after the transplantation experiment provided the background for statistical analyses. Cd, Cr, and Ni showed a strong inverse correlation with oyster weight in both sites. Transplantation upstream of the estuary presented increasing concentrations of Zn, Cu, and Pb and condition index CI and decreasing trends for Cd and Ni, whereas Cr oscillated significantly.
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Genera , See text. The Ostreidae, the true oysters, include most species of molluscs commonly consumed as oysters. Pearl oysters are not true oysters, and belong to the order Pteriida. Like scallops , true oysters have a central adductor muscle , which means the shell has a characteristic central scar marking its point of attachment. The shell tends to be irregular as a result of attaching to a substrate. Both oviparous egg-bearing and larviparous larvae-bearing species are known within Ostreidae.
Both types are hermaphrodites. However, the larviparous species show a pattern of alternating sex within each individual, whereas the oviparous species are simultaneous hermaphrodites , producing either female or male gametes according to circumstances. Members of genus Ostrea generally live continually immersed and are quite flat, with roundish shells. They differ from most bivalves by having shells completely made up of calcite , but with internal muscle scars of aragonitic composition.
They fare best in somewhat oligotrophic water. They brood their fertilized eggs for various proportions of the period from fertilization to hatching. Members of genera Saccostrea , Magallana , and Crassostrea generally live in the intertidal zone , broadcast sperm and eggs into the sea, and can thrive in eutrophic water.
One of the most commonly cultivated oysters is the Pacific oyster , which is ideally suited for cultivation in seawater ponds. Genera and species[ edit ].
PLoS One. Published online Feb Received Oct 31; Accepted Jan This article has been cited by other articles in PMC. Abstract Hemocytes are the first line of defense of the immune system in invertebrates, but despite their important role and enormous potential for the study of gene-environment relationships, research has been impeded by a lack of consensus on their classification. Here we used flow cytometry combined with histological procedures, histochemical reactions and transmission electron microscopy to characterize the hemocytes from the oyster Crassostrea rhizophorae.
Crassostrea rhizophorae (Guilding, 1828)