Estimation Of Oyster, Crassostrea Virginica, Standing Stock, Larval Production And Advective Loss In Relation To Observed Recruitment In The James River, Virginia

Standing stock and demographic data for oysters, Crassostrea virginica, in the James River, Virginia are used to generate spatial estimates of egg production on a reef-specific basis. Subsequent estimates are made of losses related to density-dependent fertilization, natural mortality in the plankton, advective loss related to estuarine circulation, availability of substrate (both absolute amounts and after occlusion by fouling organisms), limited competency of pediveligers to metamorphose, and post settlement mortality to an age of 4 wk post metamorphosis. Reef-specific egg production is highly variable on a per unit basis within the James. In all reef systems fertilization losses approach two orders of magnitude, in some instances higher than estimated losses to advection over a 21-day development period. The combination of limited substrate availability compounded by substrate fouling suggests that increasing substrate availability at the rime of settlement would strongly facilitate an increase in population size. Final estimates from sequential calculations of surviving juvenile densities agree within one order of magnitude with field observations

Oyster Reef Habitat Restoration : a synopsis and synthesis of approaches; proceedings from the symposium, Williamsburg, Virginia, April 1995

This volume has its origin in a symposium held in Williamsburg, VA in April 1995, though most of the chapters have been significantly revised in the interim. The primary purpose of the symposium was to bring together state fisheries managers involved in fisheries-directed oyster enhancement and research scientists to refine approaches for enhancing oyster populations and to better develop the rationale for restoring reef habitats. We could hardly have anticipated the degree to which this been successful. In the interim between the symposium and the publication of this volume the notion that oyster reefs are valuable habitats, both for oysters and for the other ecosystem services they provide, has been gaining wider acceptance. . . . Table of Contents Introduction and Overview by Mark W. Luckenbach, Roger Mann and James A. Wesson Part I. Historical Perspectives Chapter 1 - The Evolution of the Chesapeake Oyster Reef System During the Holocene Epoch by William J. Hargis, Jr. Chapter 2 - The Morphology and Physical Oceanography of Unexploited Oyster Reefs in North America by Victor S. Kennedy and Lawrence P. Sanford Chapter 3 - Oyster Bottom: Surface Geomorphology and Twentieth Century Changes in the Maryland Chesapeake Bay by Gary F. Smith, Kelly N. Geenhawk and Dorothy L. Jensen Part II. Synopsis of Ongoing Efforts Chapter 4 - Resource Management Programs for the Eastern Oyster, Crassostrea virginica,in the U.S. Gulf of Mexico ...Past, Present and Future by Richard L. Leard, Ronald Dugas and Mark Benigan Chapter 5 - Oyster Habitat Restoration: A Response to Hurricane Andrew by William S. Perret, Ronald Dugas, John Roussel, Charles A. Wilson, and John Supan Chapter 6 - Oyster Restoration in Alabama by Richard K. Wallace, Kenneth Heck and Mark Van Hoose Chapter 7 - A History of Oyster Reef Restoration in North Carolina by Michael D. Marshall, Jeffrey E. French and Stephen W. Shelton Chapter 8 - Oyster Restoration Efforts in Virginia by James Wesson, Roger Mann and Mark Luckenbach Part Ill. Reef Morphology and Function - Questions of Scale Chapter 9 - South Carolina Intertidal Oyster Reef Studies: Design, Sampling and Focus for Evaluating Habitat Value and Function by Loren D. Coen, David M. Knott, Elizabeth L. Wenner, Nancy H. Hadley, Amy H. Ringwood and M. Yvonne Bobo Chapter 10 - Small-scale Patterns of Recruitment on a Constructed Intertidal Reef: The Role of Spatial Refugia by Ian K. Bartol and Roger Mann Chapter 11 - Perspectives on Induced Settlement and Metamorphosis as a Tool for Oyster Reef Enhancement by Stephen Coon and William K. Fitt Chapter 12 - Processes Controlling Local and Regional Patterns of Invertebrate Colonization: Applications to the Design of Artificial Oyster Habitat by Richard W. Osman and Robert B. Whitlatch Chapter 13 - Reefs as Metapopulatons: Approaches for Restoring and Managing Spatially Fragmented Habitats by Robert B. Whitlatch and Richard W. Osman Chapter 14 - Application of Landscape Ecological Principles to Oyster Reef Habitat Restoration by David B. Eggleston Chapter 15 - Use of Oyster Reefs as a Habitat for Epibenthic Fish and Decapods by Martin H. Posey, Troy D. Alphin, Christopher M. Powell and Edward Townsend Chapter 16 - Are Three Dimensional Structure and Healthy Oyster Populations the Keys to an Ecologically Interesting and Important Fish Community? by Denise L. Breitburg Chapter 17 - Materials Processing by Oysters in Patches: Interactive Roles of Current Speed and Seston Composition by Deborah Harsh and Mark W. Luckenbach Chapter 18 - Oyster Reefs as Components in Estuarine Nutrient Cycling: fucidental or Controlling? by Richard F. Dame Part IV. Alternative Substrates Chapter 19 - Use of Dredged Material for Oyster Habitat Creation in Coastal Virginia by Walter I. Priest, III, Janet Nestlerode and Christopher W. Frye Chapter 20 - Alternatives to Clam and Oyster Shell as Cultch for Eastern Oysters by Haywood, E. L., III, T. M. Soniat and R. C. Broadhurst, III Chapter 21 - Dredged Material as a Substrate for Fisheries Habitat Establishment in Coastal Waters by Douglas Clarke, David Meyer, Allison Veishlow and Michael LaCroix Part V. Management Options and Economic Considerations Chapter 22 - Managing Around Oyster Diseases in Maryland and Maryland Oyster Roundtable Strategies by Kennedy T. Paynter Chapter 23 - Chesapeake Bay Oyster Reefs, Their Importance, Destruction and Guidelines for Restoring Them by William J. Hargis, Jr. and Dexter S. Haven Chapter 24 - Economics of Augmentation of Natural Production Using Remote Setting Techniques by John E. Supan, Charles A. Wilson and Kenneth J. Robert

A Survey of Oyster Resources at Glebe Point in the Great Wicomico River

This survey of oyster resources associated with leased oyster bottom in the Great Wicomico River in the vicinity of Glebe Point (State Rt. 200) was undertaken by the Virginia Institute of Marine Science (VIMS) at the request of the Virginia Department of Transportation (VDOT). The study was designed specifically to assess the present and potential value of the two oyster leases adjacent to the bridge crossing the Great Wicomico River at Glebe Point

Eine Überprüfung der evolutionspsychologischen Erklärung von Eifersucht am Beispiel kroatischer und US-amerikanischer Probanden

Numerous investigators reported results which support the evolutionary theory of sex differences in jealousy. In this study we extend the cross cultural evaluation of jealousy to a comparison between U.S. and Croatian populations. Two alternative forced choice methods were used to assess how upset males and females were in the sexual or emotional infidelity of their mate with either a same sex person (homosexual relationship) or an opposite sex person (heterosexual relationship). A checklist of emotions was also given to the subjects to assess in more detail their feelings about the infidelities. In both the US and Croatia females showed a strong tendency to be upset by the emotional infidelity in the heterosexual case, but a complete reversal to the sexual infidelity in the homosexual case. Males were more upset by the sexual infidelity than females in the heterosexual case, but less upset by the sexual infidelity than the females in the homosexual case. Self reported emotions revealed anger, disgust and sadness to differentiate the feelings of the subjects to the different situations. The Croatian participants reported significantly more emotions than the US participants. The general predictions of the evolutionary account of sex differences in what caused the most distress were supported.Rezultati mnogih istraživanja idu u prilog evolucijskim objašnjenjima spolnih razlika u ljubomori. U ovom smo istraživanju te nalaze proširili međukulturnom usporedbom na hrvatskom i američkom uzorku. Upotrijebljena su dva zadatka prisilnog izbora kako bi se procijenio stupanj uznemirenosti kod muškaraca i žena u slučaju seksualne ili emocionalne nevjere njihova partnera/partnerice, ovisno o tome je li se nevjera dogodila s osobom istoga spola (homoseksualna veza) ili osobom suprotnoga spola (heteroseksualna veza). Kako bismo prikupili detaljnije informacije o osjećajima vezanima uz preljub, ponuđena je i lista emocija. Žene u obje kulture pokazale su veću uznemirenost u slučaju emocionalne nevjere u heteroseksualnom scenariju, ali potpuno suprotan obrazac u homoseksualnom scenariju (tj. veću uznemirenost u slučaju seksualne nevjere). Muškarci su u usporedbi sa ženama pokazali veću uznemirenost u slučaju seksualnoga preljuba u heteroseksualnom scenariju, ali manju uznemirenost u homoseksualnom scenariju. Osjećaji ljutnje, gađenja i tuge različito su se javljali u ove dvije situacije. Hrvatski su sudionici općenito izvještavali o većem broju emocija nego američki. Potvrđena su opća predviđanja evolucijske hipoteze o podrijetlu spolnih razlika u ljubomori.Die Ergebnisse zahlreicher Forschungen verweisen auf die Richtigkeit der Annahme, dass die unterschiedlichen Manifestationen der Eifersucht bei Frauen und Männern entwicklungsgeschichtlich bedingt sind. Die Autoren haben diese Erkenntnis durch einen interkulturalen Vergleich erweitert und das Phänomen der Eifersucht unter Kroaten und US-Amerikanern untersucht. Die Probanden wurden vor zwei Aufgaben gestellt, bei denen sie sich für eine von mehreren angebotenen Lösungen zu entscheiden hatten. Die Forscher wollten ermitteln, inwiefern die Frauen und Männer mit Verstörung auf den angenommenen Fall der sexuellen oder emotionalen Untreue ihrer PartnerInnen reagierten; dabei unterschieden die Befrager zwischen Seitensprüngen mit homosexuellen und Seitensprüngen mit heterosexuellen Partnern. Um detaillierte Informationen zu den Gefühlen des betrogenen Partners zu erhalten, wurde eine Checkliste von Emotionen angeboten. Die Probandinnen beider Kulturkreise bekundeten eine stärkere Verstörung für den Fall, dass ihr Partner bei einem heterosexuellen Seitensprung emotionale Untreue manifestierte; ebenso verstörend fänden sie die körperliche Untreue ihres Partners bei einem homosexuellen Seitensprung. Männer hingegen äußerten eine stärkere Verstimmung, sollte ihre Partnerin ihnen bei einem heterosexuellen Seitensprung untreu werden; weniger beunruhigend fänden sie den Fall homosexueller Untreue. Die Gefühle von Wut, Ekel und Traurigkeit zeigten je nach Szenario einen unterschiedlichen Ausschlag. Insgesamt kann gesagt werden, dass die kroatischen Untersuchungsteilnehmer eine größere Bandbreite an Emotionen an den Tag legten als die amerikanischen. Die allgemeine evolutionspsychologische Hypothese, dass sich Eifersucht bei Frauen und Männern unterschiedlich manifestiert, konnte bestätigt werden

Eine Überprüfung der evolutionspsychologischen Erklärung von Eifersucht am Beispiel kroatischer und US-amerikanischer Probanden

Numerous investigators reported results which support the evolutionary theory of sex differences in jealousy. In this study we extend the cross cultural evaluation of jealousy to a comparison between U.S. and Croatian populations. Two alternative forced choice methods were used to assess how upset males and females were in the sexual or emotional infidelity of their mate with either a same sex person (homosexual relationship) or an opposite sex person (heterosexual relationship). A checklist of emotions was also given to the subjects to assess in more detail their feelings about the infidelities. In both the US and Croatia females showed a strong tendency to be upset by the emotional infidelity in the heterosexual case, but a complete reversal to the sexual infidelity in the homosexual case. Males were more upset by the sexual infidelity than females in the heterosexual case, but less upset by the sexual infidelity than the females in the homosexual case. Self reported emotions revealed anger, disgust and sadness to differentiate the feelings of the subjects to the different situations. The Croatian participants reported significantly more emotions than the US participants. The general predictions of the evolutionary account of sex differences in what caused the most distress were supported.Rezultati mnogih istraživanja idu u prilog evolucijskim objašnjenjima spolnih razlika u ljubomori. U ovom smo istraživanju te nalaze proširili međukulturnom usporedbom na hrvatskom i američkom uzorku. Upotrijebljena su dva zadatka prisilnog izbora kako bi se procijenio stupanj uznemirenosti kod muškaraca i žena u slučaju seksualne ili emocionalne nevjere njihova partnera/partnerice, ovisno o tome je li se nevjera dogodila s osobom istoga spola (homoseksualna veza) ili osobom suprotnoga spola (heteroseksualna veza). Kako bismo prikupili detaljnije informacije o osjećajima vezanima uz preljub, ponuđena je i lista emocija. Žene u obje kulture pokazale su veću uznemirenost u slučaju emocionalne nevjere u heteroseksualnom scenariju, ali potpuno suprotan obrazac u homoseksualnom scenariju (tj. veću uznemirenost u slučaju seksualne nevjere). Muškarci su u usporedbi sa ženama pokazali veću uznemirenost u slučaju seksualnoga preljuba u heteroseksualnom scenariju, ali manju uznemirenost u homoseksualnom scenariju. Osjećaji ljutnje, gađenja i tuge različito su se javljali u ove dvije situacije. Hrvatski su sudionici općenito izvještavali o većem broju emocija nego američki. Potvrđena su opća predviđanja evolucijske hipoteze o podrijetlu spolnih razlika u ljubomori.Die Ergebnisse zahlreicher Forschungen verweisen auf die Richtigkeit der Annahme, dass die unterschiedlichen Manifestationen der Eifersucht bei Frauen und Männern entwicklungsgeschichtlich bedingt sind. Die Autoren haben diese Erkenntnis durch einen interkulturalen Vergleich erweitert und das Phänomen der Eifersucht unter Kroaten und US-Amerikanern untersucht. Die Probanden wurden vor zwei Aufgaben gestellt, bei denen sie sich für eine von mehreren angebotenen Lösungen zu entscheiden hatten. Die Forscher wollten ermitteln, inwiefern die Frauen und Männer mit Verstörung auf den angenommenen Fall der sexuellen oder emotionalen Untreue ihrer PartnerInnen reagierten; dabei unterschieden die Befrager zwischen Seitensprüngen mit homosexuellen und Seitensprüngen mit heterosexuellen Partnern. Um detaillierte Informationen zu den Gefühlen des betrogenen Partners zu erhalten, wurde eine Checkliste von Emotionen angeboten. Die Probandinnen beider Kulturkreise bekundeten eine stärkere Verstörung für den Fall, dass ihr Partner bei einem heterosexuellen Seitensprung emotionale Untreue manifestierte; ebenso verstörend fänden sie die körperliche Untreue ihres Partners bei einem homosexuellen Seitensprung. Männer hingegen äußerten eine stärkere Verstimmung, sollte ihre Partnerin ihnen bei einem heterosexuellen Seitensprung untreu werden; weniger beunruhigend fänden sie den Fall homosexueller Untreue. Die Gefühle von Wut, Ekel und Traurigkeit zeigten je nach Szenario einen unterschiedlichen Ausschlag. Insgesamt kann gesagt werden, dass die kroatischen Untersuchungsteilnehmer eine größere Bandbreite an Emotionen an den Tag legten als die amerikanischen. Die allgemeine evolutionspsychologische Hypothese, dass sich Eifersucht bei Frauen und Männern unterschiedlich manifestiert, konnte bestätigt werden

Oyster (Crassostrea Virginica, Gmelin 1791) Population Dynamics On Public Reefs In The Great Wicomico River, Virginia, USA

We describe oyster population trends in the Great Wicomico River, VA, from 2000 through 2009 using quantitative fishery independent survey data collected using a stratified random design. The seven public reefs examined cover a total of 2.8 X 10(5) m(2) and vary in individual size from 1.36 X 10(4) to 7.16 X 10(4) m(2). The river is functionally divided by a sand spit into upriver and downriver regions. Oyster densities on the upriver reefs were typically an order of magnitude higher than densities on the downriver reefs within the same time period. Throughout the system, the highest observed densities were coincident with high annual recruitment events (2002, 2006). Recruitment events were usually followed by high mortality, with small percentages of the population reaching \u3e= 3 y of age. A predictive stock recruit relationship is absent; rather, population demographics appear to be dominated by periodic high recruitment events. In the absence of seed removal, biomass maxima follow 1-2 y after recruitment maxima. Standing stock for the system varied between 1.56 X 10(6) g and 3.63 X 10(7) g in 2005 and 2006. Year-specific age-at-length relationships were estimated from demographics data. Length demographics were recast as age demographics to estimate mortality. Observed proportional mortality between young of the year and age 2 oysters was approximately 0.88 for the 2006-y class, which is slightly higher than the 0.62-0.71 observed for the 2007-y class. The ability to estimate age specific mortality accurately allows the construction of shell (habitat) budgets for the individual reef systems. The Great Wicomico oyster population appears to be maintained by episodic and extraordinary recruitment in the face of high mortality the latter driven by disease (predominantly Perkinsus marinus) epizootics. The shell resource is modest, equivalent to little more than a monolayer several centimeters thick. Over short timescales (years), the available shell resource oscillates in concert with mortality. The shell accretion rate on upriver reefs is consistently 4-5 times greater than that observed on downriver reefs. Periodic modest shell planting has maintained the habitat base (the shell resource) throughout the system over decadal scales

Management Of The Piankatank River, Virginia, In Support Of Oyster (Crassostrea Virginica, Gmelin 1791) Fishery Repletion

The Piankatank River is a trap-type estuary on the western shore of Chesapeake Bay that has been managed for seed oyster production since 1963. Market oyster production in the river is minimal. Repletion efforts include shell planting and seed removal. We describe sequential changes in population demographics and habitat in relation to repletion activities on eight Piankatank River public oyster reefs from 1998 through 2009. Two reef groups (northern and southern) may be distinguished by density (oysters/m(2)), biomass (e dry tissue weight), and shell volume (L/m(2)) data. Age-at-length relationships were estimated from demographic data using a quadratic model. Observed mortality rates were high, and age 3+ oysters were essentially absent. A strong recruitment signal was observed in 1999 and 2002. Between 1998 and 2009, about 30% of the live oysters in the river were harvested as seed, corresponding to similar to 7.5% of the total shell base in an average year. Typically, for every 5 bushels of shell planted, 1 bushel of seed was harvested (20% return). Even with shell planting (similar to 10 L/m(2)/y), the river shell budget showed a deficit with respect to the accretion rate required to balance sea level rise and natural degradation processes. During the study period, the mean river recruit-to-stock ratio was similar to 4. The unusual and consistently high recruit-to-stock ratios suggest that management for modest continuous seed removal may be accomplished without shell planting. Annual stock assessment to identify low recruitment years is recommended as a method to adjust annual seed harvest quotas

Population Studies Of The Native Eastern Oyster, Crassostrea Virginica, (Gmelin, 1791) In The James River, Virginia, Usa

We describe oyster population trends in the James River, VA from 1993 through 2006 using quantitative fishery independent survey data collected using a stratified random design, The 23 reefs contained in the study area cover a total of 2.41 to 4.98 X 10(7) m(2). There is a marked pattern in density of oysters among X 10(7) m(2) and vary in individual size from 1.26 X 10(4) m(2) the reefs: during the Study period a small group of reefs comprising 5.4% of the total a rea consistently contained between 25.7 and 55.5% by number and 35.8 and 54.8% by biomass of the total oyster population. The highest density reefs exhibit, with very few exceptions, mean densities well in excess of 200 oysters m(-2), typically between 300 and 500 m(-2) with a single maximum value of 773 oysters m(-2) in 2002 coincident with the highest annual recruitment observed during the Study period. Recruitment events were usually followed by very high mortality with very small percentages of the population reaching ages \u3e= 3 y of age. A strong stock-recruit relationship is absent; rather population demographics appear to be dominated by periodic high recruitment events. Biomass maxima tended to lag one to two years after recruitment maxima. Standing stock for the total system varied between 1.07 X 10(8) g and 3.31 X 10(8) g (107 and 331 metric tonnes) in 2003 and 2005, respectively as the 2002 recruits grew and suffered mortality. Age-at-length relationships were estimated from demographics: using a July I birth date and a November 1 survey date giving lengths of 37.3 mm at 0.33 y, 58.9 mm at 1.33 y, 80.5 mm at 2.33 y, 102.1 mm at 3.33 y and 123.7 mm at 4.33 y Length demographics were recast as age demographics to estimate annual proportional mortality. Mean proportional mortality values for age 1 oysters range from a low of 0.2-0.4 to a high in excess of 0.7. Age 2 mean proportional mortality values range from a low of 0.41 to a high exceeding 0.75. The proportional mortality for age 3 and 4 y olds generally exceeded mean values of 0.6 with highest values approaching 0.95. In all cases, these values exceeded mortality estimates calculated using traditional box count methods by a considerable margin. The ability to accurately estimate age specific mortality allows the construction of shell (habitat) budgets for the individual reef systems. Shell half-life loss rate estimates in the most productive reefs is between 2 and 3 y and the population is maintained by the continual and extraordinary recruitment in the face of high mortality-the latter driven by disease (predominantly Perkinsus marinus) epizootics. The shell resource, even on the most productive reefs, is modest, equivalent to little more than a monolayer several centimeters thick. Individual reefs demonstrate remarkable stability as either high shell density + high population density associations (high:high) or low shell density + low Population density associations (low:low), even in the face of temporal population and demographic fluctuations associated with disease related mortality. The probability of Manipulating either shell and/or live oyster density to effect the transition of a low:low reef to a high:high reef is considered bleak in the face of extant recruitment and mortality patterns. The primary impediment 10 population expansion or rebuilding is high and uncontrolled mortality rather than a lack of recruitment. Given the large numbers of oysters in low salinity refugia that have the ability to contnually contribute to the larval pool, active selection against disease susceptible oysters on a system wide basis is unlikely

Susceptibility Of Diploid And Triploid Pacific Oysters, Crassostrea Gigas (Thunberg, 1793) And Eastern Oysters, Crassostrea virginica (Gmelin, 1791), To Perkinsus marinus

The susceptibility of Pacific oysters, Crassostrea gigas, to the oyster parasite Perkinsus marinus was compared with that of eastern oysters, Crassostrea virginica, in two separate experiments. Experiments were conducted in flow-through seawater systems with quarantined effluent. Oysters were challenged by addition of infective P. marinus. In the first experiment, which used only diploid oysters, 40% of C. gigas became infected with P. marinus after 83 days compared to 100% of C. virginica. In the second experiment, which examined susceptibility of diploid and triploid individuals of both species, prevalence was high in all groups after 60 days. In C. virginica, heavy and moderate infection intensities prevailed while C. gigas exhibited only light infections. Cumulative mortality of C. virginica after 150 days was 100% for the diploid group and 97.7% for the triploid group. Cumulative mortality of C. gigas after 150 days was 25 .1 % for the diploid group and 34.3% for the triploid group, but this mortality did not appear to be disease related. Thus, C. gigas was consistently more tolerant of P. marinus than was C. virginica, and triploidy provided no increased disease tolerance for either species

Oyster Planting Protocols To Deter Losses To Cownose Ray Predation

The utility of shell overlays to oyster (Crassostrea virginica) plantings as a cownose ray (Rhinoptera bonasus) predator deterrence mechanism was examined. Typical industry practice of oyster seed planting was followed in an experimental design employing treatment areas of 0.5-1.0 acre (0.2-0.4 hectare). Areas were prepared in the Lower Machodoc Creek, Virginia, by the initial application of shell to insure a stable substrate under planted seed oysters. Seed oysters were planted using standard industry methods. Experimental areas were located, two upstream and two downstream, of a constriction in the Lower Machodoc that dictated differing physical environments in the respective locations with downstream locations being more exposed to northeast wind-driven stresses and, historically, a greater incidence of ray predation. Once oysters were planted, two of the areas, one upstream and one downstream of the aforementioned constriction, were additionally treated with a shell overlay as a predation deterrent. Oyster seed were planted in the experimental plots in February 2012. Market oysters were harvested from the experimental plots in December 2013 and January 2014. Final harvest data demonstrated that shell overlays do not offer additional protection to planted oyster seed with respect to possible cownose ray predation. Evidence of predation in the form of characteristically broken oyster valves were recorded in all treatment areas. Concurrent stomach content analysis of rays captured at the study location and observations of fouling community associated with the cultured oysters taken during the harvest operation indicate broad dietary preferences for rays when such a variety exists in the foraging region. For rays, oysters are not the singular preferred diet item, although localized and intensive feeding on oysters remains an option with a wide foraging range. Areas without overlay demonstrated higher production than those with shell overlay. Shell overlays are not recommended as predator deterrents for cownose rays in large deployments of unprotected oyster seed