Estuaries and Coasts

, Volume 40, Issue 3, pp 880–888 | Cite as

Early Post-Settlement Growth in Wild Eastern Oyster (Crassostrea virginica Gemlin 1791) Populations

Article

Abstract

Management and restoration of wild oyster populations with the ecosystem services they provide require detailed understanding of oyster population dynamics, including temporally and spatially varying growth. Much of the existing literature documenting growth rates for eastern oysters (Crassostrea virginica) reports growth for large, protected, and/or hatchery-spawned oysters. By following growth of wild oysters set on planted clamshells in Delaware Bay, we document early growth (within the first year) of 21 wild oyster cohorts settling over 8 years and assess the importance of interannual variability in temperature and salinity. In general, oysters follow a linear growth trajectory in the first year of life, interspersed by periods of little to no growth in the colder months. Wild oysters settling in the Delaware Bay mid-salinity region reach a size between 27 and 33 mm in their first year and tend to reach greater shell heights at 1 year of age in higher salinity years and at temperatures averaging 23 °C. Multi-year, population-level estimates of wild growth such as these are important for understanding changes in restored and managed oyster populations, and resulting ecosystem services, under naturally variable conditions.

Keywords

Crassostrea virginica Early life history Post-metamorphic growth Spat 

Introduction

Oysters are a keystone ecological species. A number of direct and indirect ecosystem services are generated by the oysters themselves such as water filtration (Fulford et al. 2007; zu Ermgassen et al. 2013), benthic-pelagic coupling (Newell 2004), nutrient cycling (Fulford et al. 2010; Kellogg et al. 2013), and via their provision of hard substrate, including juvenile fish habitat (Harding and Mann 2001; Lehnert and Allen 2002; Peterson et al. 2003; Taylor and Bushek 2008), sediment stabilization (Piazza et al. 2005; Scyphers et al. 2011), and wave energy dissipation (Pinsky et al. 2013). Management of wild oyster populations with the ecosystem services they provide requires an understanding of their dynamics which, in turn, requires a basic understanding of oyster demography and growth in response to temporally and spatially varying environmental conditions (Casas et al. 2015).

The overall ecological impact of an oyster population can be modulated by abundance and size structure of the population because these population characteristics are directly linked to the ecological services provided. For example, filtration rate and shell size change ontogenically (Winter 1978; Harding 2007), and a greater overall biomass is able to filter a greater volume of water and provide more shell habitat. Thus, the dynamics of size, age, and abundance of a population determines the ecological impact of that population in the ecosystem. As a result, understanding growth is important for linking population dynamics with the ecological role of bivalve populations.

In addition to the ecological importance of the eastern oyster (Crassostrea virginica), the US fishery for this species is economically important. In 2010, an estimated 18.2 million pounds (8.26 million kg) of meats, valued at US $76.2 million, were landed (Lowther 2011). In Delaware Bay, the commercial oyster harvest is primarily conducted via dredge fishery with recently stable landings of between approximately 75,000 to 90,000 bushels annually (1 NJ bushel = 35 L and yields about five pounds [2.27 kg] of meat) (Ashton-Alcox et al. 2015). Like many, C. virginica stocks along the Atlantic and Gulf coasts of the USA; Delaware Bay oyster stocks suffer large disease losses, adding to the complexity of management in the species. Clear definition of early growth is important for identification of year classes for use in fishery and population management models (Hilborn and Walters 1992) and for linking population dynamics with the ecological role of that population (Andersen et al. 2013).

Extensive literature exists documenting growth rates for eastern oysters; however, many of these growth studies were performed with large (>50 mm) individual (unattached) oysters in trays or other containers (Kraeuter et al. 2007). Trays can cause growth rates to be skewed high because (1) they provide protection from predation, which can lead to higher growth rates in oysters (Walne and Davies 1977), and (2) growth in trays is faster than that on bottom (Kraeuter et al. 2007). Likewise, the use of larger oysters misses growth during the first year immediately following settlement, a critical stage in sessile benthic species that controls subsequent population dynamics (Keough and Downes 1982; Hunt and Scheibling 1997). Growth rates of these early size classes can vary annually and spatially and are influenced by a number of factors such as temperature, salinity, and food availability (Shumway 1996). The salinity gradient present in estuaries creates a corresponding gradient in oyster growth such that oysters in the upper estuary areas (low salinity) typically grow slower than those in the higher salinity regions of an estuary (Kraeuter et al. 2007). Interannual variability in environmental conditions such as temperature and salinity likely influences early growth rates similarly.

The purpose of this study is to examine early post-settlement growth rates for wild eastern oysters and test how settlement timing, temperature, and salinity influence early growth. The extent of the spatial and temporal replication in this study allowed a unique and robust characterization of the interannual and environmental variability on early oyster growth under natural, unmanipulated conditions.

Methods

Shell Plants

Oyster habitat enhancement via shell planting has been done in the Delaware Bay to improve oyster recruitment and help sustain native oyster beds since the 1960s (Babb et al. 2008; Ashton-Alcox et al. 2015). Oyster shell was initially used, but clamshell from Spisula solidissima and Arctica islandica shucking houses is now typically used in Delaware Bay shell planting programs. It is a substrate that is effective for catching oyster set (Nestlerode et al. 2007; Ashton-Alcox et al. 2015) but is not naturally found within the bay. Enhancement locations are selected annually based on existing or historic oyster setting patterns, reef habitats, and the most recent oyster stock monitoring data. A barge is used to transport shell, and seawater pumps are used to spray that shell overboard onto selected enhancement locations prior to settlement (late June through early July annually). Because the Spisula and Arctica clamshell used is not naturally found within the oyster beds, we used the planted shell as a means to identify the oyster cohort that settled on planted grids and follow that cohort’s growth through time. This study annually tracked growth of naturally recruited oysters on 21 different subtidal shell plant enhancement sites within the central portion of the oyster resource in the Delaware estuary between 2005 and 2013 (Fig. 1).
Fig. 1

Map of Delaware Bay, showing all shell plant sites (2005–2013). Each shell planting location is indicated by a circle with fill of the circle coded for the year of the planting. Gray lines show 2-m depth contours

Sampling Spat and Juveniles

Sampling at each shell plant site began approximately 8 weeks following planting and continued monthly during the growing seasons (May to September) for 2 years after planting or until it was difficult to distinguish the first cohort to settle on the planted shell from subsequently settled oysters. Samples were taken by dredge with a maximum of five tows at each plant site each month. Shell height (longest dimension from hinge to growing edge) was measured for a maximum of 100 randomly selected live oysters attached to planted clamshell at each site each month. Only yearlings and spat attached to planted shell were measured; oysters that set on any substrate other than planted shell were excluded from the survey. Cohorts with fewer than 20 individuals (observations) per sample were excluded from further analysis.

Calculation of Growth

Oyster growth was calculated for the first cohort of oysters that settled at each of the shell plants. We calculated early growth in two ways. The first was to estimate the shell height of each cohort at 1 year of age (365 days since settlement). When a measurement was not available exactly on day 365, the average shell height of a cohort was interpolated linearly between the two average cohort height measurements bounding day 365. The second growth estimate was a calculation of the time required for each cohort to grow to 20 mm, the size defined as the transition from “spat” to “juvenile oyster” for purposes of the Delaware Bay annual oyster stock assessment (Aston-Alcox et al. 2015). The number of days required for each cohort to attain an average shell height of 20 mm was estimated by linear interpolation between the two observations of average cohort shell height that bounded 20 mm. For example, if the average shell height was 15 mm on day 40 and 25 mm on day 70, it would be assumed that the cohort reached 20 mm at day 55. Finally, each of the cohorts was characterized as early or late settlers. If the cohort reached 20 mm before day 200, it was considered an early settling cohort; if it reached 20 mm on or after day 200, it was considered a late settling cohort. This distinction was necessary because cohorts setting later in the year are smaller (<20 mm) at the time that they enter the period of almost no growth through their first winter resulting in a slower initial growth rate.

Temperature and Salinity

Bottom water temperature and salinity at each sample site was recorded using a YSI® Model 30 handheld meter during each sampling event. For each cohort, temperature and salinity measurements were averaged over the monthly measurements made, while the cohort was tracked during growing seasons (May to September).

Analysis

Average shell size was calculated for each cohort, and differences in calculated growth metrics (days to reach 20 mm and shell height at 1 year) between early and late settling cohorts were compared using analysis of variance (ANOVA). The relationship between environmental variables (average temperature and salinity) and each of the calculated growth metrics was evaluated using generalized linear modeling (GLM, R Development Team 2007) to find the best fit model using Akaike’s information criterion (AIC; Akaike 1974).

Results

The timing, location, environmental conditions, and growth of each cohort in this study are summarized in Table 1. Growth was relatively linear within each growing season during the first 2 years after settlement for each cohort (Fig. 2). On average, it took the cohorts 243 days to reach 20 mm (minimum of 82 days to maximum of 365 days). In 1 year, the cohorts grew to an average of 29.1 mm shell height with average size at 1 year ranging from a minimum of 20.0 mm to a maximum of 37.3 mm.
Table 1

Summary information about each shell plant used in this study

Locations shown in Fig. 1. Row shading denotes different years

Fig. 2

Average (±95% confidence interval) shell heights of oyster cohorts at each sampling event in units of days since settlement. Lines connect the growth of each individual cohort. Panels contain cohorts that set in a given year, as labeled

Growth differed among early and late settling cohorts (Fig. 3). Early settling cohorts grew to the 20-mm spat transition size in significantly less time than late settling cohorts (p ≪ 0.0001, d.f. = 15, t = −12.4). On average, it took early settling cohorts 112 days to reach the 20-mm spat transition size, whereas late settling cohorts took an average of 309 days (Fig. 3a). At 1 year after settlement, early settling cohorts were significantly larger (p = 0.006, d.f. = 13, t = 3.23) on average by 5.8 mm, than late settlers (Fig. 3b).
Fig. 3

Average number of days for early and late settling cohorts to reach the spat transition size of 20 mm (a) and the average shell height of early (n = 7) and late (n = 14) settling cohorts at 1 year after settlement (b). Error bars represent 95% confidence interval

Weak relationships exist among environmental drivers (temperature and salinity) and the time required for each cohort to reach the 20-mm spat transition cutoff (Fig. 4a, b). The time to reach 20 mm was more strongly governed by settlement timing (early vs. late) than by environmental conditions; however, the size at 1 year showed significant relationships with environmental drivers. Cohorts that experienced higher salinity during their first year of growth reached a larger average shell height in that year (p = 0.001, n = 20, F = 14.4; Fig. 4c). Cohorts that experienced average temperatures between 22.5 and 23.5 °C achieved greater average shell heights after 1 year of growth compared to those that experienced lower or higher average temperatures (p = 0.045, n = 20, F = 3.7; Fig. 4d).
Fig. 4

Relationships between environmental drivers and growth estimates. Black circles mark cohorts characterized as late settlers; gray circles mark those characterized as early settlers. Linear regression line is plotted for the relationship between salinity and both growth estimates (a, c), with the gray band showing the 95% confidence interval. A second-order polynomial fit shows the best fit relationship between temperature and size at 1 year (d), with gray band showing the 95% confidence interval

Both the time it took a cohort to reach 20 mm and the cohort shell height at 1 year were best predicted by the following model:
$$ \mathrm{Growth}=\mathrm{Bed}+\mathrm{Salinity}+\mathrm{Temperature}+\mathrm{Settlement}+\mathrm{Bed}\times \mathrm{Salinity}+\mathrm{Bed}\times \mathrm{Temperature}+\mathrm{Salinity}\times \mathrm{Temperature}+\mathrm{Salinity}\times \mathrm{Settlement}+\mathrm{Temperature}\times \mathrm{Settlement}+\mathrm{Bed}\times \mathrm{Salinity}\times \mathrm{Temperature}+\mathrm{Salinity}\times \mathrm{Temperature}\times \mathrm{Settlement} $$

This indicates that the early growth of a given cohort is governed by a number of factors including location within the bay (bed), environmental conditions of a given year (temperature and salinity), and the timing of settlement, as well as interactions among those factors.

Discussion

Monitoring growth rates of wild spat is difficult due to the inability to identify when settlement occurs and difficulties in marking and tracking specific cohorts. Here, we used a unique approach for tracking the early growth of oyster cohorts under a variety of environmental condition over a number of years. By following the size of oysters settling on planted clamshells, we were able to monitor and compare growth of 21 oyster cohorts over the first 2 years after settlement and assess the importance of interannual variability in temperature and salinity in early growth. In general, oysters in the Delaware Bay follow a relatively linear growth trajectory in the first year of life, interspersed by periods of little to no growth in the colder months, and tend to reach greater heights at 1 year in higher average salinity and at temperatures averaging 23 °C. Faster growing cohorts will achieve greater biomass and shell surface area in a shorter period of time, thereby providing more filtration capacity and shell habitat in a shorter period of time relative to slower growing cohorts, all else being equal (i.e., abundance and mortality). The factors that were important in determining early growth rates included timing of settlement, temperature, salinity, and location within the bay. Success of oyster restoration efforts and of sustainable management of wild oyster populations requires a basic understanding of variability in early growth and the role of factors that influence it (Paynter et al. 2010; Casas et al. 2015).

In general, our population-based estimates of growth to 1 year are lower than many of those previously published (Fig. 5). Harding (2007) observed a strain of C. virginica that grew to a size of 50 mm at 1 year of age, much larger than the 29 mm observed on average in wild Delaware Bay oysters. Likewise, Paynter et al. (2010) documented growth rates of 27 different plantings of hatchery-raised oysters in Maryland, where size at 1 year post-planting varied from 50 to 70 mm. The conditions experienced by the oysters may explain this discrepancy. Harding’s (2007) oysters were grown in higher salinity (∼19) than those in this study (Table 1). Oysters in both Harding (2007) and Paynter et al. (2010) were spawned and reared in laboratory conditions before planting, whereas the oysters in this study were wild set and experienced natural, uncontrolled conditions from settlement. Gunther (1951) reports on C. virginica growth in the Gulf of Mexico from settlement on an oil platform through to 1 year under natural conditions. In his limited survey of three individual oysters, the oysters attained a size of 61–94 mm in their first year. This is much faster than we observed in the Delaware Bay over multiple locations and years, likely because water temperatures in the Gulf of Mexico are sufficient for oysters to grow year-round, whereas oysters in the Delaware Bay experience growth limitation during the winter months after settlement. The summary of first-year oyster growth rates under field conditions reported in the literature (Fig. 5) illustrates a possible trend in early growth with latitude, showing faster early growth in southern locations compared to northern locations; however, many of the reported growth rates come from experiments where oysters are held in trays or off-bottom, which are known to differ from natural on-bottom growth rates (Kraeuter et al. 2007). The rates we have calculated in this study are important for understanding population-level changes in oysters and resulting ecosystem services under naturally variable conditions in the Delaware Bay.
Fig. 5

Published reports of Crassostrea virginica early growth rates by latitude. Data shown here are restricted to those studies reporting growth to 1 year after spat settlement (reported growth intervals range from 12 to 18 months after settlement) under non-laboratory conditions. Where specific latitudes are not reported, latitude was estimated from published maps using Google Earth. Outlined circle indicates growth estimated in this study. Marker shape denote the experimental deployment method, marker color indicates the temperature range reported. Growth observations for oysters on “Bottom” are from Shaw (1962), Moore (1899), Hofstetter (1963), Paynter et al. (2010), and this study. Reports of growth from “Tray” experiments come from Mann and Evans (2004) (tray on bottom in cages), Menzel and Hopkins (1951, 1955), Paynter and Dimichele (1990) (suspended trays), and Menzel (1955) (stacked trays). “Raft” observations were reported in Shaw (1962), “Line from surface” observations from Shaw (1963), and “Other” comes from Gunter (1951) (oysters set on a piling)

Growth differences on the individual level can have a pronounced effect on the description of the growth of a group, and ignoring this individual variability can result in biased estimates of the mean parameter values. The effect of individual variability is particularly important when interpreting growth increment data and can result in overestimates of the mean height at age of a cohort (Sainsbury 1980). Nonetheless, on a population level, early growth in oysters appears to follow a linear pattern rather than a more commonly used saturation function such as a von Bertalanffy model (Fabens 1965). Lester et al. (2004) argue that fish exhibit differences in somatic growth before and after maturity with prereproductive growth best modeled as a linear function and a von Bertalanffy function more appropriate after maturity. Our data suggests that oysters may also show this pattern in prereproductive growth.

For the purposes of fishery assessment of the oyster stock in the Delaware Bay, oysters are considered spat, or within their first year, if they are less than 20 mm shell height (Ashton-Alcox et al. 2015). Those that measure greater than 20 mm are no longer considered yearlings. To test the validity of this assumption, a calculation was made for each cohort to determine the average amount of time it took recently settled cohorts of oysters to grow to 20 mm under a variety of conditions, over a number of years, throughout the Delaware Bay. On average, it took the cohorts 243 days to reach 20 mm, placing the average growth to 20 mm within the first year of life. However, the cohorts varied in the amount of time to grow to 20 mm based largely on whether they set early in the season or late. Early settling cohorts reached the spat transition size in 112 days, while the late settling cohorts required more than twice as many days (309) to reach the same average size. This discrepancy occurs because the late settling cohorts enter into the winter period of low growth before they reach 20 mm, and therefore, the winter adds greatly to the time it takes them to reach the spat transition. This has important implications for how young of the year (spat) are interpreted based on height measurements within the first year. It is worth noting here that for any given year in our dataset, cohorts either settled early or late, meaning there are no years during which both categories of settlement timing occur. This limits our ability to discern the influence of settlement timing while holding interannual conditions constant; however, observations from settlement groups distribute equally across the annually varying range of environmental conditions suggesting sufficient coverage of conditions and cohort types.

Despite the vast difference in the time it takes an early settling or late settling cohort to reach 20 mm, the difference in the average size at 1 year of age among these two groups diminishes to about 15%. In the cohorts we observed, late settling cohorts were nearly able to catch up to the size of the early settling cohorts by 1 year of age. Compensatory growth in oysters has been documented in laboratory and hatchery settings, but in those cases, compensatory growth has largely been attributed to release from competition when cohorts are size sorted (Collet et al. 1999). The contrast between early and late settlers in time to 20 mm (>200% difference) and size at 1 year (∼15% difference) observed in our study could result from a reduction in growth of the early settlers due to spawning within their first year. This reproductive effort would require energy to be diverted from growth to reproduction, thereby slowing average growth of the early settlers who had an initial size advantage and resulting in no size difference between early and late settlers at 1 year of age. Details of spawning and reproductive condition of the animals in this study were not assessed, so this possibility cannot be addressed herein.

An important consideration is that the growth rates estimated here use population-based size frequency to follow growth of a cohort. Inaccuracies in growth rate estimates could come from immigration, emigration, and size-dependent mortality. Oysters are sedentary and attached to hard surfaces; therefore, immigration and emigration are negligible. Additionally, in our assessment, we only include oysters that were attached to planted shell material to prevent inclusion of oysters that might have been moved from other locations as those could be attached to a variety or more ubiquitous materials such as oyster shell and rocks. Nonetheless, size-dependent mortality remains an issue for the interpretation of these data. If larger size classes are preferentially lost from a population between sampling events (due to predation for example), estimated growth would be biased low. Likewise, if new small individuals are added to the population between sampling events, growth would be skewed low. To reduce this bias, only those oysters attached to material that was placed in the environment at a known time were measured to prevent us from mixing older and younger settling cohorts in with the target cohort.

Density dependence (e.g., allee effects, competition for food) or food variability may also affect the growth of early settlers. In general, the abundance of oysters baywide is well below the historic high in the long-term time series suggesting that the system is below carrying capacity (Powell et al. 2009). We might expect density-dependent growth effects to manifest in a population at carrying capacity but are unlikely to observe density dependence in a population well below carrying capacity unless allee effects are operating. We did not observe any pattern in early growth relative to adult or spat density, suggesting that density dependence is not a factor for the cohorts we observed (see Munroe (2016) for a similar example in intertidal clams). Although we did not collect data on food resources directly, a separate study (Powell et al. 2012) looked at food at these and a number of other sites in the bay and found that food well exceeded oyster demands. The Delaware Bay estuary system is highly turbid, and the oyster beds observed in this study lie within the region of the estuarine turbidity maximum (McSweeney et al. 2016) with associated high levels of bottom water particulate organic matter and chlorophyll (Hermes and Sikes 2016), suggesting that these oysters may not experience food limitation.

The data provided here, representing broad spatial and temporal replication, allows a robust characterization of the interannual and environmental variability on early oyster growth under natural, unmanipulated conditions. The rates we derive demonstrate that under most circumstances, wild oysters settling in Delaware Bay reach a size between 27 and 33 mm in their first year and that growth is positively influenced by annual salinity conditions. Although these rates are lower than other published rates, the rates may be a reflection of cooler, more northern conditions in Delaware Bay and may be a more realistic reflection of wild population-level growth rates of relevance to restoration and fishery management strategies. Multi-year estimates of wild growth such as these are important for understanding population-level changes in oysters and resulting ecosystem services under naturally variable conditions.

Notes

Acknowledgments

We gratefully acknowledge the longstanding cooperation with the New Jersey Department of Environmental Protection and the Delaware Bay Section of the New Jersey Shellfisheries Council, with whom shell-planting efforts are conducted each year. E. McGurk, I. Burt, and J. Gius were integral in data collection and shell plant monitoring. Support for shell planting and monitoring was provided by the state of New Jersey in consultation with the Delaware Bay Section of the Shellfisheries Council and Section 1135 of the USACE Continuing Authorities Program. This work was partially supported by the USDA National Institute of Food and Agriculture Hatch project accession numbers 1002345 and 1009201 through the New Jersey Agricultural Experiment Station, Hatch projects NJ32115 and NJ32114.

References

  1. Akaike, H. 1974. A new look at the statistical model identification. IEEE Trans Automatic Control 19: 716–723.CrossRefGoogle Scholar
  2. Andersen, H., I. Dorresteijn, and J. van der Meer. 2013. Growth and size-dependent loss of newly settled bivalves in tow distant regions of the Wadden Sea. Marine Ecology Progress Series 472: 141–154.CrossRefGoogle Scholar
  3. Ashleigh, Lowther 2011. Fisheries of the United States 2010. National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Current Fishery Statistics No. 2010. Silver Springs, Maryland, USA. 104 pp.Google Scholar
  4. Ashton-Alcox, K., Bushek, D., Morson, J., and Munroe, D. 2015. Report of the 2015 Stock Assessment Workshop: New Jersey Delaware Bay Oyster Beds (17th SAW) February 10–11, 2015. 121 pp.Google Scholar
  5. Babb, R.M., J. Hearon, C. Tomlin, D. Bushek, K. Ashton-Alcox, and E. Powell. 2008. The Delaware Bay oyster (Crassostrea virginica) restoration program. Journal of Shellfish Research 27(4): 987.Google Scholar
  6. Casas, S.M., J. La Peyre, and M.K. La Peyre. 2015. Restoration of oyster reefs in an estuarine lake: population dynamics and shell accretion. Marine Ecology Progress Series 524: 171–184.CrossRefGoogle Scholar
  7. Collet, B., P. Boudry, A. Thebault, S. Heurtebise, B. Morand, and A. Gérard. 1999. Relationship between pre-and post-metamorphic growth in the Pacific oyster Crassostrea gigas (Thunberg). Aquaculture 175(3): 215–226.CrossRefGoogle Scholar
  8. Fabens, A.J. 1965. Properties and fitting of the von Bertalanffy growth curve. Growth 29: 265–289.Google Scholar
  9. Fulford, R.S., D.L. Breitburg, R.I. Newell, W. Kemp, and M. Luckenbach. 2007. Effects of oyster population restoration strategies on phytoplankton biomass in Chesapeake Bay: a flexible modeling approach. Marine Ecology Progress Series 336: 43–61.CrossRefGoogle Scholar
  10. Fulford, R.S., D.L. Breitburg, M. Luckenbach, and R.I.E. Newell. 2010. Evaluating ecosystem response to oyster restoration and nutrient load reduction with a multispecies bioenergetics model. Ecological Applications 20: 915–934.CrossRefGoogle Scholar
  11. Gunther, G. 1951. The west Indian tree oyster on the Louisiana coast, and notes on the growth of three Gulf Coast oysters. Science 111: 516–517.CrossRefGoogle Scholar
  12. Harding, J.M. 2007. Comparison of growth rates between diploid DEBY eastern oysters (Crassostrea virginica, Gmelin 1791), triploid eastern oysters, and triploid Suminoe oysters (C. ariakensis, Fugita 1913). Journal of Shellfish Research 26(4): 961–972.CrossRefGoogle Scholar
  13. Harding, J.A., and R. Mann. 2001. Oyster reefs as fish habitat: opportunistic use of restored reefs by transient fishes. Journal of Shellfish Research 20: 951–959.Google Scholar
  14. Hermes, A.L., and E.L. Sikes. 2016. Particulate organic matter higher concentrations, terrestrial sources and losses in bottom waters of the turbidity maximum, Delaware estuary, U.S.a. estuarine. Coastal and Shelf Science 180: 179–189.CrossRefGoogle Scholar
  15. Hilborn, R., and C.J. Walters. 1992. Quantitative fisheries stock assessment: choice, dynamics and uncertainty, 570 p. New York: Chapman and Hall.CrossRefGoogle Scholar
  16. Hofstetter, R.P. 1963. Study of oyster growth and population structure of the public reefs in East Bay, Galveston Bay and Trinity Bay. Texas Game and Fish Commission. Project No. MO-R-4 Sept 1961–1962. 23 pp.Google Scholar
  17. Hunt, H.L., and R.E. Scheibling. 1997. Role of early post-settlement mortality in recruitment of benthic marine invertebrates. Marine Ecology Progress Series 155: 269–301.CrossRefGoogle Scholar
  18. Kellogg, M.L., J.C. Cornwell, M.S. Owens, and K.T. Paynter. 2013. Denitrification and nutrient assimilation on a restored oyster reef. Marine Ecology Progress Series 480: 1–19.CrossRefGoogle Scholar
  19. Keough, M.J., and B.J. Downes. 1982. Recruitment of marine invertebrates: the role of active larval choices and early mortality. Oecologia 54: 348–352.CrossRefGoogle Scholar
  20. Kraeuter, J.N., S. Ford, and M. Cummings. 2007. Oyster growth analysis: a comparison of methods. Journal of Shellfish Research 26: 479–491.CrossRefGoogle Scholar
  21. Lehnert, R.L., and D.M. Allen. 2002. Nekton use of subtidal oyster shell habitat in a southeastern U.S. estuary. Estuaries 25: 1015–1024.CrossRefGoogle Scholar
  22. Lester, N.P., B.J. Shuter, and P.A. Abrams. 2004. Interpreting the von Bertalanffy model of somatic growth in fishes: the cost of reproduction. Proceedings of the Royal Society of London B 271: 1625–1631.CrossRefGoogle Scholar
  23. Mann, R., and D.A. Evans. 2004. Site selection for oyster habitat rehabilitation in the Virginia portion of the Chesapeake Bay: a commentary. Journal of Shellfish Research 23: 41–49.Google Scholar
  24. McSweeney, J.M., R.J. Chant, and C.K. Sommerfield. 2016. Lateral variability of sediment transport in the Delaware estuary. Journal of Geophysical Research: Oceans 121: 725–744.Google Scholar
  25. Menzel, R.W., and S.H. Hopkins. 1951. Report on experiments to test the effects of oil well brine or ‘bleedwater’ on oysters at Lake Barre oil field. Vol. 1. 1–130. Report to Texas A. & M. Research Foundation Project Nine. June 26, 1951Google Scholar
  26. Menzel, R.W., and S.H. Hopkins. 1955. Growth of oysters parasitized by the fungus Dermocystidium marinum and by the trematode Bucephalus cuculus. Journal of Parasitology 41: 333–342.CrossRefGoogle Scholar
  27. Menzel, R.W. 1955. Some phases of the biology of Ostrea equestris Say and a comparison with Crassostrea virginica (Gmelin). Publications of the Institute of Marine Science 4: 69–153.Google Scholar
  28. Moore, H.F. 1899. Report on the oyster beds of Louisiana. Report US Commission of Fisheries. 24: 45–100.Google Scholar
  29. Munroe, D. 2016. Habitat effects on early post-settlement growth of intertidal clams, Venerupis philippinarum (a. Adams & Reeve, 1850). Journal of Molluscan Studies. doi:10.1093/mollus/eyw014.Google Scholar
  30. Nestlerode, J.A., M.W. Luckenbach, and F.X. O’Beirn. 2007. Settlement and survival of the oyster Crassostrea virginica on created oyster reef habitats in Chesapeake Bay. Restoration Ecology 15(2): 273–283.CrossRefGoogle Scholar
  31. Newell, R.I. 2004. Ecosystem influences of natural and cultivated populations of suspension-feeding bivalve molluscs: a review. Journal of Shellfish Research 23: 51–62.Google Scholar
  32. Paynter, K.T., V. Politano, H.A. Lane, S.M. Allen, and D. Meritt. 2010. Growth rates and prevalence of Perkinsus marinus in restored oyster populations in Maryland. Journal of Shellfish Research 29(2): 309–317.CrossRefGoogle Scholar
  33. Paynter, K.T., and L. Dimichele. 1990. Growth of tray-cultured oysters (Crassostrea virginica Gmelin) in Chesapeake Bay. Aquaculture 87: 289–297.CrossRefGoogle Scholar
  34. Peterson, C.H., J.H. Grabowski, and S.P. Powers. 2003. Estimated enhancement of fish production resulting from restoring oyster reef habitat: quantitative valuation. Marine Ecology Progress Series 264: 249–264.CrossRefGoogle Scholar
  35. Piazza, B.P., P.D. Banks, and M.K. La Peyre. 2005. The potential for created oyster shell reefs as a sustainable shoreline protection strategy in Louisiana. Restoration Ecology 13: 499–506.CrossRefGoogle Scholar
  36. Pinsky, M.L., G. Guannel, and K.K. Arkema. 2013. Quantifying wave attenuation to inform coastal habitat conservation. Ecosphere 4(8): 1–16.CrossRefGoogle Scholar
  37. Powell, E.N., J.M. Klinck, K.A. Ashton-Alcox, and J.N. Kraeuter. 2009. Multiple stable reference points in oyster populations: biological relationships for the eastern oyster (Crassostrea virginica) in Delaware Bay. Fisheries Bulletin 107: 109–132.Google Scholar
  38. Powell, E.N., D.A. Kreeger, J.M. Morson, D.B. Haidvogel, Z. Wang, R. Thomas, and J.E. Gius. 2012. Oyster food supply in Delaware Bay: estimation from a hydrodynamic model and interaction with the oyster population. Journal of Marine Research 70: 469–503.CrossRefGoogle Scholar
  39. R Development Core Team. 2007. R: A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. ISBN3–900051–07-0, URL: http://www.R-project.org.
  40. Sainsbury, K.J. 1980. Effect of individual variability on the von Bertalanffy growth equation. Canadian Journal of Fisheries and Aquatic Sciences 37: 241–247.CrossRefGoogle Scholar
  41. Scyphers, S.B., S.P. Powers, K.L. Heck, and D. Byron. 2011. Oyster reefs as natural breakwaters mitigate shoreline loss and facilitate fisheries. PloS One 6(8): e22396.CrossRefGoogle Scholar
  42. Shaw, W.N. 1962. Raft culture of oysters in Massachusetts. Fishery Bulletin 61: 481–495.Google Scholar
  43. Shaw, W.N. 1963. Comparison of growth of four strains of oysters raised in Taylors pond, Chatham, mass. Fishery Bulletin 63: 11–17.Google Scholar
  44. Shumway, S.E. 1996. Natural environmental factors. In The eastern oyster Crassostrea virginica, ed. V.S. Kennedy, R.I.E. Newell, and A.F. Eble, 467–513. College Park: Maryland Sea Grant College.Google Scholar
  45. Taylor, J., and D. Bushek. 2008. Intertidal oyster reefs can persist and function in a temperate north American Atlantic estuary. Marine Ecology Progress Series 361: 301–306.CrossRefGoogle Scholar
  46. Walne, P.R., and G. Davies. 1977. The effect of mesh covers on the survival and growth of Crassostrea gigas (Thunberg) grown on the sea bed. Aquaculture 11: 313–321.CrossRefGoogle Scholar
  47. Winter, J.E. 1978. A review on the knowledge of suspension-feeding in lamellibranchiate bivalves, with special reference to artificial aquaculture systems. Aquaculture 13(1): 1–33.CrossRefGoogle Scholar
  48. zu Ermgassen, P.S.E., M.D. Spalding, R.E. Grizzle, and R.D. Brumbaugh. 2013. Quantifying the loss of marine ecosystem services: filtration by the eastern oyster in US estuaries. Estuaries and Coasts 36(1): 36–43.CrossRefGoogle Scholar

Copyright information

© Coastal and Estuarine Research Federation 2016

Authors and Affiliations

  • D Munroe
    • 1
  • S Borsetti
    • 1
  • K Ashton-Alcox
    • 1
  • D Bushek
    • 1
  1. 1.Haskin Shellfish Research LaboratoryRutgers UniversityPort NorrisUSA

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