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Oyster population maintenance and growth require a sufficient larval supply competent for metamorphosis and settlement. Larval performance, in terms of growth, development, survival, and metamorphic success, determines the capacity for a larval cohort to effectively settle and establish into an existing population. Exogenous factors influencing larval development include temperature, salinity, food quantity, and food quality. A sufficient diet, composed of balanced protein, lipids, and carbohydrates to meet larval nutritional demands, is required to promote successful metamorphosis. To evaluate the influence of these exogenous factors on oyster settlement potential in Delaware Bay, a well-established biochemically based Crassostrea gigas (Thunberg, 1793) larval model was adapted to simulate Crassostrea virginica (Gmelin, 1791) larval performance under in situ environmental conditions measured during the 2009 to 2011 reproductive seasons at 10 sites across the salinity gradient of Delaware Bay. Variation in the initial egg size and lipid content, and larval food assimilation efficiency was incorporated into the model to represent potential within-cohort phenotypic variability. The middle portion of Delaware Bay along the New Jersey shoreline, bridging the 15-salinity line, generated the most successful larvae each year, whereas the low-salinity reach, on the Delaware side, and Nantuxent Point Reef had more variable success. Survivorship was a function of adequate temperatures and salinities, sufficient food quantity, and favorable food quality defined in part by the protein-to-(lipid-plus-carbohydrate) ratio. Most settlement was predicted by the model to occur between July and September of each year. To validate the model, estimated settlement windows were compared with calculated settlement windows derived from recruitment observations on yearly shell plants. Modeled and recruitment-derived settlement windows agreed well with each other and verified the capacity of the model to accurately forecast in situ larval performance. The oyster larval model, based on measures of lipid, protein, and carbohydrate, successfully passed an important field test, demonstrating the potential of such biochemically based models to reliably evaluate larval performance under real-world conditions. KEY WORDS: Crassostrea virginica, larvae, eastern oyster, performance model, settlement window, biochemical, food, INTRODUCTION Successful oyster population maintenance and growth require a consistent larval supply capable of settlement onto existing beds over time (Coen & Luckenbach 2000, Mann & Powell 2007, Lipcius et [...]

Shell planting to enhance oyster recruitment and habitat in Delaware Bay, NJ was reinitiated in 2005 with 3 y of federal funding. Since then, annual plantings of locally available surf clam and ocean quahog shell have been funded by the oyster fishery. The cured shell is deployed directly onto sites already containing commercially viable numbers of market-sized oysters in areas that are routinely fished sustainably. The locations targeted to receive shell plants vary and are selected to provide the greatest benefit throughout the fished reef tract. Annual sampling that included shell plants from 2005 through 2017 permitted evaluation of their performance. New oysters set and survive preferentially on newly planted shell during the first season and later at the same level as native shell for at least 10 y so that the benefit of once-added shell is retained for over a decade. Recruitment to shell plants enhances 'good' sets and makes a critical difference during years of 'poor' set. Plant substrate, now with oysters of its own, significantly outperforms native substrate in recruitment and survival of oysters in the second and third years postplanting. with enhancement declining exponentially over the first 4 y. An estimated half-life for this decline is just under 1 y. Beyond 3 y. the plant-based substrate continues to perform at least as well as native substrate. Size-frequency analysis shows that first-year oysters on planted substrate are larger than those on native substrate and that this difference carries through the fourth year of a plant. The volume contributed by live and dead oysters on planted substrate increases over the first 5 y until the contribution to the reef from planted substrate volume matches that of native substrate, thus carrying the enhancement forward through time. Annual survey data from the first 4 y of shell plants show that on seven of eight beds, live plus dead oyster density (number m-2) was up to 2.8 X greater on planted sites than on non-planted sites. Change in density averaged positive over time on both planted and non-planted sites but was greater on planted sites. Shell plants on beds in the Delaware Bay fishery provide 3-4 y of enhanced oyster productivity and continue to double the local native substrate productivity as they age, maintaining an active and productive fishery. KEY WORDS: oyster. Delaware Bay. shell plant, substrates, recruitment, enhancement, fishery, INTRODUCTION Shell planting in Delaware Bay to enhance the oyster Crassostrea virginica (Gmelin) fishery has a long history (Nelson 1889, Moore 1911. Woodward & Waller 1932, Nelson 1959. Ford 1997, [...]

ABSTRACT Aquaculture of the northern quahog (=hard clam) Mercenaria mercenaria (Linnaeus, 1758) is widespread in shallow waters of the United States from Cape Cod to the eastern Gulf of Mexico. [...]

ABSTRACT Parasites and pathologies of oysters and mussels were sampled yearly from 1995 to 2010 from the Gulf of Maine to Alaska and the Great Lakes as part of the [...]

ABSTRACT Today, populations of eastern oysters, Crassostrea virginica, are commonly limited by disease mortality. Resistance to MSX disease has developed in a number of cases, but the development of resistance [...]

ABSTRACT We evaluate a 54-y survey time series for the Delaware Bay oyster beds in New Jersey waters to identify the characteristics of regime shifts in oyster populations and the [...]

ABSTRACT Published data indicate that spawning seasons for the Asian oyster Crassostrea ariakensis and the eastern oyster C. virginica overlap. Hybrids can form, but the larvae are not viable. If [...]

ABSTRACT The parasites Perkinsus spp. are relatively easily and inexpensively detected in host tissues, but available methods to detect free-living planktonic stages are technologically complex and expensive. As a result, [...]

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 [...]

Human‐pathogenic marine bacteria in the genus Vibrio proliferate rapidly in shellfish tissues when exposed to warm ambient air conditions, such as during intertidal exposure. However, it remains unclear whether intertidal‐cultured shellfish are inherently associated with elevated Vibrio concentrations. Here we spatially matched eastern oysters (Crassostrea virginica) held in subtidal and intertidal aquaculture systems at six experimental oyster farms along the mid‐Atlantic coast and tested whether intertidal aquaculture elevates concentrations of V. parahaemolyticus, the predominant species associated with seafood‐related gastroenteritis, as well as concentrations of V. parahaemolyticus carrying the tdh and/or trh genes associated with pathogenicity in humans. Across the sites and over time, we found only slight evidence for increasing V. parahaemolyticus concentrations with exposure to ambient air at low tide; however, tdh/trh+ V. parahaemolyticus increased about 1.5‐fold. We also found that total V. parahaemolyticus concentrations and concentrations of tdh/trh+ V. parahaemolyticus did not differ between intertidal‐ and subtidal‐cultured oysters when submerged at high tides. Any changes to V. parahaemolyticus concentrations within oyster tissues, including concentrations of tdh/trh+ V. parahaemolyticus, therefore diminish with the incoming tide. Our results collectively support the existing time‐to‐cooling restrictions that are in place in many state Vibrio control plans, which involve minimizing the amount of time harvested shellfish can be held prior to cooling or refrigeration, but oppose more austere measures such as restricting or prohibiting intertidal harvest entirely. [ABSTRACT FROM AUTHOR]

As the son of a conservation officer for the state of New Jersey and a high school teacher, John Kraeuter learned much about the outside world while growing up. His [...]

Susan Ford began her career in shellfish biology in 1966 as a laboratory technician in the Department of Oyster Culture at Rutgers University under the direction of shellfish pioneer Harold [...]