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The geographic boundaries of many important habitat-building shallow estuarine oyster (Family Ostreidae) species are poorly understood, especially in subtropical and tropical waters. These keystone species often have extensive historical and extant ranges, in part because of their ability to adapt to diverse environmental conditions and the transfer and introduction of a few species worldwide for aquaculture production. In addition, oysters exhibit morphological plasticity additionally confounding species identification and taxonomy. Molecular techniques have led to significant improvements in oyster systematics and taxonomy but have not been applied to oysters from many tropical regions, including the coastal areas of the Indian Ocean such as Bangladesh. Because species' identification based on morphological traits alone, in this case primarily shell characteristics, were inadequate, phylogenetic analyses of mitochondrial cytochrome oxidase subunit I gene fragments was also done to confirm the identity of oyster specimens collected from Bangladesh coastal waters. Phylogenetic analyses of collected oyster samples confirmed the two monophyletic subclades of the Ostreidae family Crassostrea and Saccostrea. and five oyster lineages from the region of Bangladesh were identified: Crassostrea gryphoides, Crassostrea belcheri. Saccostrea cuccullata lineage B. 5. cuccullata lineage F, and Saccostrea mordax. A new addition to the list of Crassostrea species, C belcheri was found in Bangladesh, but C. belcheri, C. gryphoides, and 5. cuccullata are. considered 'common' species in the neighboring states of India and Myanmar indicating a widespread distribution of these species along the entire coast of the Bay of Bengal. However, S. mordax, is a new record for the Bay of Bengal region including the coastal waters of Andaman and Nicobar Islands, and thus extends the geographical distribution of this species. KEY WORDS: Bay of Bengal, shell plasticity, morphology, cytochrome oxidase subunit I (COI). Saccostrea mordax, INTRODUCTION Oysters (Family Ostreidae) are considered keystone species and commonly referred to as 'ecosystem engineers' for their ability to exert a large influence on the ecosystem function in coastal waters [...]

ABSTRACT Reefs and beds formed by oysters such as the Eastern oyster, Crassostrea virginica and the Olympia oyster, Ostrea lurida Carpenter 1864 (†) were dominant features in many estuaries throughout [...]

ABSTRACT The most commonly used methods for measuring the amount of seston removed from the water column (uptake) by populations of suspension-feeding bivalve molluscs involve taking discrete water samples followed [...]

ABSTRACT Oyster shell is the preferred substrate for replanting oyster beds and restoring oyster reefs. If pathogens remain viable in tissues attached to shell, then planting shell may inadvertently serve [...]

Most Atlantic and Gulf coast U.S. states with an oyster fishery have operated some form of oyster reef enhancement program over the past 50 years. Although programs were initially only directed at oyster fisheries augmentation, recent emphasis has shifted to include the restoration of their ecological functions. Furthermore, many of these programs are managed by environmental organizations or state agencies not traditionally involved in fisheries management or research, but rather in ecological restoration, monitoring, and/or environmental education. A simple assessment of shellfish meetings over the past five years, including the inaugural Restore America's Estuaries meeting from which this paper is derived, revealed more than 300 presentations related to oyster restoration, with fewer than 25% focused solely on oyster fishery restoration. Unfortunately, many of those efforts lacked well-defined "success criteria," with progress often judged using fisheries-based metrics such as market-sized (generally 75 mm or 3") oysters. Here we discuss our findings as they relate to the value of alternative restoration metrics and associated success criteria using data from two very different systems and approaches: one conducted in Virginia's lower Chesapeake Bay (Rappahannock River), based on data from a two-year program utilizing subtidally constructed reefs of different reef "scale," and the other a long-term study in South Carolina focusing on intertidal reefs. For each system, we compared newly created reef structures, relating oyster abundance and size to resident species abundance and biodiversity over time. Our results revealed positive correlations between several community descriptors and the size and density of oysters on the reefs. Of the 15 significant (and 5 marginally insignificant) correlations observed out of a total 78 examined across both studies, all but one were positive. The exception was for epifaunal invertebrate diversity vs. oyster biomass on the Rappahannock reefs. Despite these numerous positive correlations, none indicated that market-sized oysters are a prerequisite for supporting an abundant and diverse community. For example, intertidal oyster >75 mm in South Carolina typically make up <10% of all reef oysters, with a maximum of 18%. Finally, until we have a more thorough understanding of the interactions between individual species and the mechanisms linking oyster populations and reef community attributes, we propose that oyster abundance/size structure be used for assessments. Future studies need to develop and evaluate restoration progress using a combination of standardized criteria that can be applied to reef success over a wide geographical range and surrogate or indirect ecological measures (e.g., filtering, habitat use). [ABSTRACT FROM AUTHOR]

Abstract: Blind Pass is an inlet that separates Sanibel and Captiva Islands in southwest Florida but has historically closed and opened by both anthropogenic and natural processes. In July 2010, a dredging project to open the small inlet between the two barrier islands was completed. The objective of this study was to use and supplement ongoing estuary-monitoring programs to examine the responses of water quality, seagrass habitat metrics, and fish assemblages both in the immediate vicinity of the inlet and at broader scales (up to 40km2). As far as we are aware, there are no previous studies with this intensity of sampling, both before and after an inlet opening. Significant increases in salinity and turbidity were observed inside Blind Pass, with significant decreases in CDOM and chlorophyll a, however, the effects were not far-reaching and limited to less than 1.7km from the inlet within Pine Island Sound. Seagrass habitat metrics were expected to respond rapidly after the inlet was opened given the reduced light attenuation. However, there were no changes in shoot densities, species composition, and epiphytic algae within the approximately one-year duration of the study. The reopening of the pass did not substantially change fish assemblage structure, except for those from deeper habitats. Although immediate increases in the abundances of estuarine-dependent species were predicted in shallow habitats post opening, this did not occur. In conclusion, the effects of reopening a relatively small ocean inlet on water quality were apparent in the immediate vicinity of the inlet (within 1.7km), but far-reaching effects on water quality, seagrass metrics, and fish assemblages were not immediately apparent in this well-flushed estuary. If subtle changes in tidal exchange and circulation affect productivity of seagrasses or its fish assemblages at broad scales, it may take several years to reach a steady state. [Copyright &y& Elsevier]