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Chapter 23

Chesapeake Oyster Reefs, Their Importance,Destruction and Guidelines for Restoring Them

byWilliam J. Hargis, Jr. and Dexter S. Haven

Professors Emeritus of the School of Marine Scienceand the Virginia Institute of Marine Science of the College of William and Mary in Virginia

AbstractThe eastern oyster, Crassostrea virginica (Gmelin), can live any place in coastal marine and estua-

rine waters of the North American east coast offering suitable setting and survival opportunities. Itoccurs singly or in small clumps scattered widely but thrives best in colonial aggregations which, likethose of tropical corals, are truly reefs. The massive self-renewing oyster reefs (“whole banks andbeds”) reported by early Chesapeake observers have yielded much. Without readily accessible oysterreefs the first English colonists of Jamestown might have starved. Without them the rich oyster indus-tries of later years could never have developed. But oyster reefs benefitted the oysters that built andmaintained them as well as the humans using them.

The oyster reefs of the Chesapeake region, including those on Seaside, developed during some7,000-6,000 years of Bay evolution during the current (Holocene) Epoch. Until about 200 years ago reefoyster populations were able to maintain themselves and their reef habitats and withstand the inroads ofbiological enemies, other natural hazards and increasing harvests. By the late 1800s, Chesapeake publicmarket oyster harvests had peaked and total market harvests and the oyster populations which providedthem were in decline.

Continued overharvesting had done more than reduce harvestable populations. It had reducedbroodstock fecundity and the genetic qualities of the various Chesapeake subpopulations as well. Fur-ther, it had diminished natural shell replacement due to excessive removal of shell-producing oysters andtheir shells, causing reef destruction. Additionally, removal of shells for landfill, road building, con-struction, chemical production, soil conditioning and poultry grit hastened that destruction. The syner-gistic cycle of population reduction and habitat destruction accelerated. Today many formerly-produc-tive reefs are mere remnants (or totally obliterated—even eliminated) and Chesapeake public (aided orunaided) market oyster production is far less than one percent of its maximum.

If the trend of decline of self-sustaining natural oyster production is to be reversed, public oysterreefs must be restored. Proven guidelines exist. Such factors as location, geometry and materials havebeen naturally tested over time. The features which developed during the millennia of successful naturaloyster reef evolutionary trial-and-error should be employed in well-planned reef-restoration activities.Where improvement is possible it should be done.

An effective reef restoration program will benefit not only the oyster resource, the public owners, theindustry and consumers but the Bay’s ecology and finfishermen as well. Active oyster reefs harbor many

Reprinted from-Oyster Reef Habitat Restoration: A synopsis and Synthesis of ApproachesEdited by M. W. Luckenbach, R. Mann and J. A. Wesson • 1999 • Virginia Institute of Marine Science Press , Gloucester Point, VA.

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epifaunal and infaunal organisms, increasing overall estuarine productivity and diversity. Further, theyattract finfishes and other browsers and predators. Sportfishing charts identify many formerly-produc-tive oyster reefs as fishing spots. This is no accident! More importantly, better utilization of H. L.Mencken’s immense “protein factory” and restoration of such filtering and cleansing capabilities of reefoyster populations and their associates as may occur will benefit all Chesapeake citizens and othersregion- and nation-wide.

Introduction

Review of numerous reports on details ofoyster production by earlier students of oysterecology and the oyster industry of the Chesa-peake Region, and elsewhere (i.e. Winslow1881, 1882 and 1884; Baylor 1894, Stevenson1894, Moore 1910, Loosanoff 1932, Marshall1954), and the recent studies and conclusions ofDeAlteris (1988), Hargis and Haven (1988a andb), Hargis and Haven (1995), Newell (1988) andRothschild et al. (1994), has resulted in ourrecent realization of the great importance ofviable reefs to the past and future natural pro-duction of oysters. These and other studiesshow that brood-stock reduction and impairmentof genetic quality by over a century of adverseselection and destruction of the preferred naturalhabitat of C. virginica, the reefs, have been theprimary, long-term factors in the tremendousdecline in the natural, self-renewing productionand harvest of market and seed oysters in theChesapeake system.

As a consequence, Hargis and Haven (un-published reports) have urged in several publicforums since early 1991 the rebuilding, orreplacement, of oyster reefs as a measure inrestoring the population levels and viability ofC. virginica and the industry dependent thereonon the public or natural oyster grounds. Weagain recommend this restorative action. Doingso, whether by passive (simple recuperativeclosure) or active (actual replenishment byshells and/or seed, plus significant recuperativeclosure) restoration or by new construction (alsoaided by closure), will require careful planning,site selection and design. Below we developand support these conclusions and offer someguidelines for restoration.

Brief History of Oyster Reefsin the Chesapeake

When English settlers reached the Chesa-peake in 1607 they found hundreds of massive,medium-sized and small upthrusting (mostcommon in the Bay, itself) and fringing (mostcommon in the lagoons and embayments of theEastern Shore) oyster reefs. The heights orcrests of many ebbed dry, or nearly so, at lowwater (Wharton 1957). Harvesting oystersrequired little effort. One had only to wade,pole, paddle, row or sail to the nearest exposedreef and hand-pick, rake or shovel a sack full,canoe full or boatload.

As time passed and demand and harvestsincreased, reef elevation and extent diminishedand rake and tong handles (tongs are reallyopposed rakes, operating in scissor-like fashion)had to be lengthened. The harvesting efficien-cies, effective depth range and, incidentally,destructive capabilities of tongs were increasedwith the introduction of mechanically—and laterhydraulically, operated patent tongs (Haven etal. 1978).

Dredges (or their lesser relatives, scrapes),which enabled the taking of more oysters moreefficiently than with rakes or tongs—and fromdeeper-lying populations, were brought intoservice. Reef elevation declined ever morerapidly as live oysters (with their shells) andassociated empty shells were removed by tongsand dredges. Then, dredge and patent tongcables and hand tong handles were elongatedeven further. Removal of living oysters andshells increased and the cycle intensified.

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Oyster reefs declined still further in height, basedimensions, volume and surface area. Thoughthe base extent of each was undoubtedly in-creased for a time as the uppermost or outermostshells and surviving oysters were dragged ontothe surrounding bottom by dredges or knockedover onto or deposited there by tongers (asindicated by Winslow 1891, Stevenson 1894,Moore 1910), it, too, eventually shrank asfurther harvesting and shell removal, over-sedimentation and sinking occurred and thattemporary harvest-related advantage was lost.The process continued throughout each harvestyear, decade after decade over two centuries orso.

In early times there were no closed seasonsand sailing dredge boats remained over the reefsuntil their holds and decks were filled. Oftenbuy-boats or “runners” emptied the dredge boatswhile the latter were still over the oyster bedsenabling uninterrupted dredging and reductionof populations, and reefs, proceeded relentlessly.Continuous harvesting by tongs (ordinary andpatent) did the same, only more slowly (per tongor per tong boat).

Besides taking living oysters for foodmarkets, harvesters have removed shells fromthe reefs for direct use or transformation intoshell by-products. In Colonial times crushedshells were employed in mortar, which oftenincluded recognizable shell fragments. Manyshells were used to “sweeten” the soil and buildwalkways. Later huge numbers of whole shells,some with meats still in them, were employed inlandfills and in the building of roads, alleys andwalkways. For example, much of the city ofCrisfield, Maryland was built on shell-filledwetlands and many, probably most, cities, townsand counties of tidewater Maryland and Virginiahad oyster shell road beds, roadways and alleys.Shells were also used as ballast for railroadtrack construction. The total used for thesepurposes is unknown—probably unknowable.

We are somewhat better informed about thequantities used as ground- or burnt-lime orground into poultry grit in recent times. Large-scale demand for these shell by-products had

developed in the 1800s. By the early 1900’sfactories producing them had sprung up allaround the coasts of the United States. In 1921the U.S. Bureau of Fisheries reported 54 shell-processing plants nationwide. Of them themajority (29 or 53.7%) were in the ChesapeakeBay region; 18 in Maryland and 11 in Virginia(U.S. Department of Commerce Report for1922). The Department of Commerce beganreporting details of production of oyster shellbyproducts in the United States in 1920. It, orthe Department of Interior continued to do sountil around 1945. Though production of shellbyproducts had begun long before 1920 andcontinued after 1945, reporting of annual pro-duction state-by-state began in 1920 and contin-ued, with at least one interruption, until 1943.Despite certain variations in the details theycontained one can derive useful informationfrom these reports. Briefly, from 1920 to 1944the two Chesapeake Bay states are reported tohave produced over 2,770,000 tons of shellbyproducts. Of them at least 1,555,000 tonswere in the form of poultry grit, with at least1,215,000 tons as ground and/or burnt lime(Reports of the U.S. Department of Commercefor 1921 through 1939: Reports of the U.S.Department of Interior for 1939 through 1945).We have no ready conversion factors to allowdetermination of the number of bushels of wholeshell required in preparing the tonnage of eachtype of by-product. Obviously, it was great—greater for the fine-grained lime products thanfor the much coarser grit.

Even after the flattening of reefs occurred,either through removals of live oysters for use asseed, “soup” or market oysters or throughincidental and purposeful shell removal, theremaining shells have not escaped use. Large-scale mining activities employing heavy dredg-ing equipment have taken shells from recent reeffoundations as well as from remaining oldersub-bottom reef deposits since World War II.For example, ancient and recent reef strata weremined by a commercial shell-dredging company(Radcliffe Materials, Inc.) in the lower JamesRiver estuary downriver of the current seed beds

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in the 1960’s with the Virginia Marine ResourceCommission (VMRC) receiving 1/3 of theharvest as the public’s share of the shell (Havenet al. 1978, DeAlteris 1988). During 6 years(1963 through 1968) this activity produced atotal of about 39 million bu of so-called “ex-tinct” or “ancient reef” oyster shells. This large-scale commercial mining of shells in Virginiawas halted by VMRC, with the urging andconcurrence of the Virginia Institute of MarineScience (VIMS), when the mining companyrequested use of more accessible and morerecent shell deposits.

In Maryland, buried reef shell has beencommercially mined for about 30 years byLangenfelder and Son, Inc. for landfill, limemanufacture and other commercial uses and tobe sold as cultch for Maryland’s Oyster Reple-tion Program. Virginia has purchasedLangenfelder-produced shells for the samepurpose from time to time as have other statesand private parties. According to sources withinthe Maryland Department of Natural Resourcessome 5 to 7 million bushels were mined annu-ally. Thus, a total of as many as 150 to 200million bushels of shells, or more, have beentaken to date. Mining of shells from “ancient”and recent oyster reef deposits continues inMaryland, apparently at about the same rate.In both states (especially Virginia) many shells,originally from oysters set and grown on publicbottoms and all nurtured by primary and sec-ondary productivity of public waters, have beenemployed by private planters to firm their leased(private) grounds for subsequent planting ofseed oysters.

The total number of shells taken from thereefs and bottoms of the Chesapeake system andemployed for the various uses described abovewill never be known. All shells applied to usesother than public reef repletion programs were(and are) essentially removed from any possibil-ity of employment in efforts at replenishment ofnatural reefs by state management agencies. Allshells originating from public reefs and disposedof elsewhere contributed to destruction of thosereefs and reef-fields!

Realization of possible problems associatedwith oyster (and shell) harvesting and reefdestruction, and their possible ecological andeconomic significance developed during the late18th or early 19th century, albeit slowly andfitfully. Dredging was banned early on (1811—Va. and 1820—Md.) but later restored by bothstates. For most of this century dredging ofmarket and seed oysters has been banned fromVirginia’s public reefs (Hargis and Haven 1995).Eventually efforts were made by both Chesa-peake states to reduce the rate of shell removal,small oyster removal and destruction and reefreduction through requiring the culling ofmarket-oyster catches on the grounds whencethey came (Ingersoll 1881, Stevenson 1894,Yates 1913, Kennedy and Breisch 1983). Un-fortunately, in situ culling was avoided whereverpossible by many, probably most, harvesters,and public management agencies were largelyunable to effectively enforce cull laws andregulations. Even closures or gear restrictionswere often violated.

In 1924, Maryland began a program of reefreplenishment, or repletion, by planting shell onthe diminishing natural oyster beds. Virginia’spublic reef shell-planting program began in1928. Later, both states planted seed on publicreefs as well, though shell plantings have alwayspredominated (Haven et al. 1978). These effortsat public reef rehabilitation (for consideredcarefully that is what they really were, thoughtrue rehabilitation was rarely accomplished—probably never) failed to halt the long-termdecline of reefs and their living populations.The reason they failed is simple. Instead ofbeing closed to harvest after replenishment(either with shell or seed, or both) for sufficienttime to allow restorative or even recuperativerebuilding of their oyster populations or of thereef structure, itself, the “repleted” beds werequickly opened. Without known exceptions,they were rapidly harvested. Repleted publicoyster grounds came to be operated (essentially)as “put-and-take” fisheries in both Chesapeakestates. Since monies developed from non-industry sources, including state General Funds,

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were often employed, the repletion programs(shell and/or seed planting) have been, in largemeasure, public subsidies to harvesters. Ulti-mately, these reef-improvement efforts were notenough and in some cases, accelerated bysedimentation, predation, disease and effects oftoxicants (all of which must be factored intomanagement decisions and allocations), produc-tion on the public grounds plummeted, due—primarily—to continued habitat destruction andpopulation reduction. Additionally, manynatural public reefs were allowed to be reducedwithout regular replenishment efforts. Neitherstate could afford to attempt to maintain all ofits dwindling or already barren public reefs!

That oyster reefs have been overharvestedand mined away (reduced in height, volume andsurface area volume) can be documented notonly by records of reduced harvests of marketand seed oysters from the Chesapeake’s manyonce very productive public reefs and reeffields, but by other reliable means. Alreadymentioned are early reports that many reefsreached upward into the intertidal zone inColonial times (Wharton 1957 and others).

Though well over half century of harvestinghad already destroyed many, some reefs contin-ued emergent in the market and seed oysterareas of the James River into Civil War times.As late as 1871-73, soundings made by the U.S.Coast Survey (USCS 1872 & 1874) showed anumber of reefs breaking the surface at meanlow water. Some were extensive. For example,the emergent portion of Long Shoal Reef in theJames River seed area near Point of ShoalsLight was over a mile-and-a half long (USCS1872 and 1874). (See Hargis, Chapter 1, thisvolume.) Certain of these emergent reefspersisted into the 20th century.

Marshall (1954) surveyed elevations ofseveral oyster reefs in the lower James Riverand compared his depth data with those shownon older hydrographic charts. After allowing forchanges in sea level he reported a loss in eleva-tion of about 30 cm (12 in.) in about 90 years.This finding of declining reef height was rein-forced by Hargis (1966) who confirmed reef

height reductions and other geomorphologicalchanges by harvesters after a large-scale VIMSstudy of the James estuary. Later, DeAlteris(1988), comparing old and recent hydrographiccharts, estimated an elevation reduction of 1.2 to1.8 m (4 to 6 ft.) at Wreck Shoal in the JamesRiver seed area (upriver from the market oysterarea that Marshall had studied) over the 130years preceding his field work. Unquestionablythe reefs in the James River have been severelyreduced by harvesting and shell mining.The same has happened elsewhere in the Bay.Bailey (1941), who studied oysters of the YorkRiver for the Virginia Fisheries Laboratory(predecessor of the Virginia Institute of MarineScience), wrote:

“Oysters have in the course of their longevolutionary period evolved as reef animals....Prior to 1880 good oyster rocks (bottoms) werecommon in the York River. They were the resultsof generation after generation of oyster shellssettling on top of the previous crop, until finallythe “oyster bars” were exposed at low tide.Those the results of natural conditions, but notfor long.”

“By 1900 the oystermen had tonged up mostof the oysters and had failed to return anyappreciable amount of the shells. They sold theshells as well as the meats. The shells wereground and sold as chicken grit or burned intolime.”

“No better proof of this lowering or eventotal removal of the oyster rocks can be pre-sented than the examination and comparison ofa York River Coast and Geodetic Chart of 1858with a recent one.1 “Bare at low water” is thenotation on the 1858 chart at Pages RockLighthouse. Today the reading at the same spotshows a depth of three feet and the bottom issoft mud.”

Clearly, destruction of Chesapeake oysterreefs has resulted from oyster harvesting andshell mining activities. Equally clearly, reef

1In 1858 the organization was officially titled the U. S.Coast Survey. It did not become the U.S. Coast andGeodetic Survey until the late 1870s or early 1880s.

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destruction in the Chesapeake system hasresulted in reduction of self-renewing oysterpopulations and in declining market oysterproduction among other adverse effects!

Location of Oyster Reefs inVirginia - Their Sizes, Shapesand Associated Bottom Types

We are most familiar with and have accessto considerable information on the reefs of thelower Chesapeake, especially those of the JamesRiver which, of those in Virginia’s waters, havebeen studied most. Consequently, we empha-size them here; however, the same principles,results and conclusions derived from study ofthe James can be applied to oyster reefs through-out the Chesapeake!

The James estuary is similar in essentialgeomorphological and hydrological features toMaryland’s upper Bay northward of the mouthof the Patuxent River as well as to the estuary ofthe Potomac River. The estuarine areas of allthree systems are affected significantly byfreshwater inflow from extensive piedmont andmontane watersheds. (Annually, theSusquehanna River normally contributes about49% of all riverine freshwater entering the Bay,the Potomac about 18% and the James about16%, or about 83% all together—Figure 1.Obviously, all of the rest of the rivers and creeksaround the Bay contribute relatively little fresh-water—about 17% of average annual inflow.)The normal freshwater inflow patterns of theupper Bay and of the Potomac and James estuar-ies and their effects on the hydrographic andecological aspects of those systems are similar.The same is true of their hydrographic andecological responses to abnormal precipitationin their upper watersheds. Hence, their freshetsand salinity advances and retreats and otherfreshwater-inflow-affected dynamics are similar.Historically, all three of these mesohalineestuarine areas have produced many market (andseed) oysters on extensive reefs and reef fields.Undoubtedly, common favorable ecological

factors have contributed to their successes.Today natural market oyster production in allthree is markedly reduced to less than onepercent of former maxima (Hargis and Haven,1995).

Some of the Bay’s “natural”, or public,oyster reefs were first investigated systemati-cally by Lt. Francis Winslow USN, then work-ing for the U.S. Coast and Geodetic Survey.Winslow (1882) examined reefs in both Mary-land and Virginia and did the earliest such workin the James River. Winslow’s surveys, espe-cially those of Tangier and Pocomoke Sounds,established reef contours and provided somepopulation-relevant information.

The locations of Virginia’s natural oysterreefs were identified in 1892-93 by Lt. JohnBowen Baylor, USN, also with the Coast andGeodetic Survey. This survey identified andplotted the borders of areas within which oystersand oyster reefs had occurred historically ac-cording to the collective memories of the par-ticipating watermen, many of whom wereCommissioners (Baylor 1894). Unfortunately, itdid not carefully examine the condition of thereefs within these areas or establish the size (i.e.height, basal area, slope, or surface area) of thethen-surviving reefs or the nature of the bottomsaround them (Haven et al. 1981). It is reportedthat the Baylor boundaries included at least 391known, named reefs and large areas of unpro-ductive bottom. The official public oystergrounds of Virginia were legally established in1892 by Acts of Assembly. Actual legal bound-aries were based on Baylor’s survey results.They have been resurveyed since 1894 andoccasionally augmented by General Assemblyaction. At present, some 243,000 acres areofficially designated as public grounds (alsocalled Baylor grounds) in Virginia. About199,000 acres are within the Chesapeake sys-tem. Some 43,000 to 44,000 are on Seaside ofthe Eastern Shore (Figure 2).

Surveys conducted during the years 1906-1912 established the numbers, boundaries andnames of the public grounds in each oyster-producing county of Maryland, see Yates 1913.

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Figure 1 . The Chesapeake Bay Drainage System Showing the Average Annual Freshwater Inflows of the Three MajorDrainage Basins . The Susquehanna, Potomac, and James Drainage Basins, comprising most of the overall drainage areaand contributing most of the Bay's riverine freshwater, are clearly identified.

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In all, this extensive survey covered 741 namedreefs in 11 counties bordering Maryland’sChesapeake. Most occurred in the areas whichStevenson had outlined in 1894 (Figure 3). But,Yate’s surveys involved more than areal out-lines. They actually determined availability ofoysters and bottom types as well as the areasand locations of the reefs. The surveys of Yateswere used to establish the official (legislativelyestablished) public oyster beds of Maryland.

It is known that the natural oyster reefs inboth states had been extensively reduced byharvesting activities long before either of thesetwo official surveys (i.e. Baylor, 1894; Yates,1913) was conducted (Ingersoll 1881, Stevenson1894, Hargis and Haven 1995).

The Structure and SpecialEcological Features of

An Oyster ReefNo one, to our knowledge has “dissected”

an unharvested, upthrusting natural Chesapeakeoyster reef to determine its detailed structure.However, De Alteris (1988) examined thestructure and age of the once-important WreckShoal reef in 1986 and 1987. Unfortunately, bythen Wreck Shoal had been largely destroyed.

It is possible to make some inferences fromearly charts and descriptions such as thoseprepared by the U.S. Coast Survey for the Jamesestuary in 1871, ’72, and ’73 (USCS 1872 and1874). (See Hargis 1998, Chapter 1, this vol-ume.) As well, past field observations in theChesapeake, and reports therefrom providesome information about reef morphology(Winslow, 1882, Stevenson 1894, Moore 1910,Loosanoff 1932, Haven et al. 1981, Haven andWhitcomb 1983 and 1989, DeAlteris 1988, andWhitcomb and Haven 1987).

Figure 3. General Distribution of Oyster Reefs and ReefFields in Maryland's Chesapeake Bay System, early1890s. (Modified from Stevenson, 1894)

Figure 2. The Public Oyster Grounds of Virginia.Black areas outline and contain the natural (publicor"Baylor") oyster reefs and reef fields of Virginia at thetime of the Baylor Surveys of 1892 and 1893 as modifiedby later official additions. (Modified from Haven et al,1978)

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We have attempted a diagrammatic “recon-struction” of an idealized unharvested reef inFigure 4. Consisting of two main above-bottomcomponents, the “core” and the “veneer”, theentire reef rests on a foundation of shells, shellfragments, and other persistent materials embed-ded in a matrix of sand-mud or silt. The coreconsists of depositional materials such as shell,shell fragments, sand, silt or clays in variousproportions. The veneer consists mostly ofliving oysters, shells of recently-dead oysters,biological associates and persistent depositionalmaterials. This whole structure rests typicallyon old shoreline and adjacent upland featuresexisting prior to Holocene sea level flooding inthe particular section of the estuary in which thereef was developed (Hargis, Chapter 1, thisvolume).

The masses of shell in the underlying core ofan “undisturbed” successful living reef keptgrowing vertically and horizontally by accretionas successive generations of oysters set, grew,reproduced and died, leaving their shells behind.Eventually these shells were themselves over-lain by new ones deposited as the oysters in theveneer died and by living oysters as the reefgrew upward and outward. Of course, manyindividuals of each age group died of variouscauses, including disease undoubtedly (allanimals and plants harbor parasites and have

diseases), before maturing but enough survivedto perpetuate themselves and contribute togrowing populations and reefs. Or so it wentuntil excessive seed and market oyster harvest-ing and shell mining upset the progression.

The interstices between shells and shellfragments provide places where sedimentparticles and reef wastes from upper levels maybe sequestered even though the residence timetherein of some of this material may be more orless temporary. Undoubtedly some is trans-ferred, transformed, and even consumed bybiological and chemical processes in the in-terim. A certain residue probably remainssequestered as long as the core remains undis-turbed. Particulate material dropping away fromreef “heights” can also settle onto the adjacentestuary bottom or be swept away from the reefby currents. Thereby, portions of the exposedouter surfaces of the veneer of the reefs, them-selves, remain relatively clean of particulates.At the same time increasing reef elevation,bolstered by the shell being continually added tothe core, and by new spatfall and growth in theveneer keeps the living oysters away from thebottom (the sediment-water interface) eventhough the surrounding sediment layer andassociated nephalic layer may, themselves,thicken. Consequently, stresses exerted onliving reef oysters by proximity to the bottom(bottom effects) are lessened and survivalenhanced. Further, infective materials releasedby living, moribund or dead animals are morelikely to drop or be carried away from otheroysters living on the heights (or in the upperlayers) of the reef’s veneer than they would on aflat bed, or even on a low, bottom-hugging“lump”.

The reef topography also increases theoverall surface area significantly (as intestinalrugae and villi do in the guts of in higher verte-brates) available to setting and growing oysters.Consequently, chances of successful setting onsuitably clean, exposed surfaces are improved.

Hidu (1969) and others have shown that thepresence of living oysters enhances spatfall.The presence of living oysters in the veneershould, therefore, improve setting.

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Base Shells, Shell Fragm ents,and Detritus on O riginal Holocene Cultch

Figure 4. Diagram of an "Upthrusting" ChesapeakeOyster Reef, the Oyster's (a communal animal) "Favored"Habitat. (Details of the early post-Wisconsinan, "originalHolocene Cultch" Base are hypothetical. To ourknowledge, no one has carefully “dissected” the sub-bottom portion of an upthrusting reef.)

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While general patterns of estuarine salinityare dominated by fluvial freshwater input andsalty water intrusions from down- estuary and/orthe nearby ocean, it is highly likely that signifi-cant local rainfall events and temperaturechanges affect the oysters on the crests andupper elevations of the reefs. Most probablythere are (or were) vertical differences in salinityand temperature related to local weather phe-nomena as well as normal estuarine stratifica-tion on the upthrusting reefs of the Chesapeake.Likely, these micro-environmental variations are(or were) sufficient to affect survival of theoysters. This possibility deserves further scien-tific attention.

Upthrusting reefs also interdict and modifysurrounding currents. Undoubtedly a largegroup of upthrusting oyster reefs (hereaftercalled a reef field) exerts considerable influenceupon local current patterns and other hydro-graphic and geological features (Hargis,Chapter 1, this volume).

Taken together, paleontological, archaeo-logical, historical, geological and ecologicalevidence shows that oysters set, survive andgrow better on elevated reefs with substantial“cores” of oyster shells and “cinders”, and othersuitable substrate, and healthy “veneers” ofliving oysters than on beds near or on the bot-tom. Spatfall is better, growth is faster, preda-tion effects are lower and disease-related effectsreduced. Oysters lying flat on the bottom orpartially submerged in the bottom do not farenearly as well. Relative successes of “off-bottom culture” efforts employing man-madestructures to maintain the living oysters off ofthe bottom in disease- and predation-prone areasconfirm this.

Oyster reefs benefit other biota as well.Hundreds of micro-organism and small macro-organism species colonize them using oystershell surfaces and interstices and wastes andthose of other reef-associated invertebrates forsupport, shelter and sustenance. The oyster reefbiocoenose (Moebius 1883) includes organismsof many life styles and food web levels. At-tached and infaunal sessile plants and animalsabound as does associated nekton. In the Chesa-

peake several finfishes (oyster toadfish,skilletfish, gobies, blennies and others) areamong the regular inhabitants and the wholereef attracts many other grazers, browsers andpredators. Though this aspect is generallyignored, it is highly likely that the oyster-reefbiocoenose was the most prominent one in theChesapeake system!

On reefs which have been heavily worked(overworked) live oysters mixed with shell andshell fragments and some organic matter andinorganic sand, silt or clays form a flat, hardcrust up to 15 to 46 cm (6-18 in.) thick on theless-solid estuary floor. Typically a mixture ofoyster shell and shell fragments (“cinder”)embedded in a stiff matrix of sand-mud and siltlies below (Table 1). These latter substances(i.e. sand, silt or clay) may often form 50% ofthe total mix, and sometimes more (Haven et al.1981, DeAlteris 1988). Oyster reefs usuallyextend below the surface sediment as shown inthe Gulf of Mexico by Bouma (1976) and in theChesapeake Bay by DeAlteris (1988) and byNichols, Johnson and Peebles (1991). In theWreck Shoal area of the James River the foun-dations of extant oyster reefs may extend intothe bottom 6 m (19.7 ft) or more. Still olderburied shell reefs associated with the changes insea level during earlier interglacial oceanictransgressions may lie beneath the foundationlayers of some recent reefs.

In summary, it is evident that reefs, nature’soff-bottom culture “devices”, have been impor-tant to the survival and natural renewal of C.virginica. If they were not, oyster populationswould not have survived and produced so wellon the many reefs that they “built” during theevolution of the current (Holocene) Chesapeake.Without those reefs and their accumulatedpopulations the valuable public oyster fisheriesof the Bay states would never have developed.Wherever natural reefs have been destroyed bynatural forces or human activities (or both)along the Atlantic or Gulf coasts, economicallysignificant natural (unaided) production ofoysters has declined—even disappeared. Over-all estuarine productivity has been reduced andfinfish have declined as well.

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Decline in Chesapeake OysterPopulations Related to

Overharvesting andConcomitant Reef

Destruction and Vice-VersaHargis and Haven (1995) established that

both Maryland and Virginia natural (or public)oyster populations have been overharvested overthe last 150 years or more. Many others, includ-ing Ingersoll 1881, Winslow 1882, Brooks 1891and 1905, Stevenson 1894, Baylor 1894, Moore1910, Yates 1913, Loosanoff 1932, Bailey 1941,Kennedy and Breisch 1983 and Rothschild et al.1994, have concluded likewise. The relation-ship between harvesting effort and the Chesa-peake oyster population decline is simple anddirect. When more living adult (or any othersought-after age- or size-class) animals areremoved from any population than nature (aided

or unaided) can replace, overharvesting is takingplace and the demise of the overall (or target)population (economically or even ecologically)is inevitable as long as the process continues.When any population’s genetic strength isreduced by continuous adverse selection, theirability to survive environmental adversity,including disease, is weakened. When theessential habitat is destroyed in the process thepopulation decline occurs faster and the likeli-hood of its self-restoration is seriously dimin-ished. These are immutable and implacable“laws of nature”. Their violation endangers theeconomic utility of those natural resources andmay ultimately destroy the resource as well.Human wishes, political solutions (compro-mises), harvesting goals and management planswhich are not consistent with these natural lawsare irrelevant and doomed to failure! Thequestion becomes not whether the resource willdecline and the fishery will fail—but merelywhen.

Hard-Rock Sand-Shell Mud-ShellParameter Mean S.D. Mean S.D. Mean S.D.

Water Depth (ft) 11.9 0.9 11.9 0.6 17.0 1.8 (m) 3.6 3.6 5.2

Volume ofExposed Cultch (qt) 5.0 2.8 2.0 1.2 2.5 1.4 (l) 4.7 1.9 2.3

Total Number of 74.4 22.8 90.9 30.8 24.9 12.7Live Oysters

Volume ofLive Oysters (qt) 5.3 1.4 4.9 1.2 3.1 1.3 (1) 5.0 4.6 2.9

Number of 8.3 4.5 6.5 3.6 4.4 3.1Oyster Boxes1

Sediment, 39.4 6.2 34.0 7.4 8.1 8.7Percent Gravel1

Sediment, 38.0 6.1 41.6 7.2 25.5 6.2Percent Sand

Sediment, 22.5 5.0 23.8 5.4 66.5 7.9Percent Silt-Clay

1 Gravel consisted mostly of shell fragments.

TABLE 1. Subenvironment sediment sample made in the vicinity of Wreck Shoals, James River, Va. (Means and standarddeviations) (From De Alteris 1988)

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The “first” rule of responsible renewable-resource management is: The essential habitatmust be preserved. The “second” is: the essen-tial survival-related features of the target popu-lations must be preserved. The “third” is:harvests must be limited to available “sur-pluses”. Determination of “available surpluses”must consider all applicable negative ecologicalfactors such as diseases, predators, adversewater quality, poor spawning and poor settingyears, etc! The surplus available for harvestingin any harvest period is that which remains afterthese and other adverse factors have beenconsidered: That and no more! Because of thenatural uncertainties involved in the quantitativeaffects of thees processes, the approach todetermining “available surpluses” must beconservative!

Responsibility forPreservation and Restorationof Public Oyster Populations

and Their HabitatsOysters of the Chesapeake and their natural

habitats belong to all of the people of Virginia.They are truly part of the common wealth asformer Governor Harry F. Byrd wrote in 1928(Hargis and Haven 1995). As with other “com-mon-property” resources their effective manage-ment is a responsibility and function of govern-ment. Regulation of their use and condition is,therefore, not an unjustified or unreasonableimposition by government upon private rights ofharvesters and other users but a necessity topreserve the common-property resource and itsfuture social and economic benefits. Publicmanagers may allow socioeconomic use butmust also preserve the people’s (and posterity’s)long-term socioeconomic interests in the re-source. Where they do not do so the interests ofthe present and future owners are damaged, andthe public managers are derelict. Prevention ofabuse of common property resources should be

6.6 ft19.7 ft52.2 ft

DeepWater Shoals

Horse

Head

Wreck

Shoal

Point ofShoals

White Shoal

Nans

emon

d Ri

dge

Figure 5. James River Estuary Chart Showing General Bathymetry, Location of Public Seed Oyster Beds and NamedFeatures Referred to in Text. Inset shows location of James relative to Chesapeake Bay.

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the state’s ultimate management goal: Whereabuse has already occurred, restoration of thatresource must be a priority!

As state governments undertake to restorenatural oyster production on the public oystergrounds of the Chesapeake they must restore theoyster’s “favored” habitats - the reefs. In doingso they would do well to emulate nature’s reefsas closely as possible, including height andother dimensional features. Nature has been“experimenting” with C. virginica and its reefsalong the western North Atlantic coast for some18 million years or more under all of the variedecological, geological, meteorological condi-tions that have transpired, through interglacialand glacial periods and in both estuarine andmarine environments. On such reefs, underpressures of competition, predation and disease,C. virginica has survived for millennia.

Scientists talk much of experimentation, andthere is room for reef experiments for specialpurposes. But “nature” has already accom-

plished the basic experimentation on reefs assuitable natural habitats for C. virginica. Wecan, and should, make use of her efforts andresults!

The remainder of our paper is directed attechnical aspects relevant to the Chesapeakeoyster reefs and their oyster populations.

Ecological Conditions UnderWhich Oyster Reefs Originate

and SurviveLarge oyster populations, as exemplified by

living oyster reefs, develop and persist onlywhere and when ecological conditions arefavorable. For example, large (economicallysignificant) oyster populations occur naturally inlocations where biogeological and hydrographicfeatures favor them. Such features include:

1. Salinity range from about 5‰ to full-strength or undiluted seawater—32-35‰.Within this salinity range, areas experi-encing salinities averaging between (5‰to 20‰) are probably most suitable foroyster survival. In contrast, many com-mon oyster predators , such as the oysterdrilling snails, Urosalpinx cinerea andEupleura caudata,and parasites [includ-ing Perkinsus marinus (Dermo) andHaplosporidium nelsoni (MSX)] do bestin salinities averaging higher than 15‰.On the other end of the salinity spectrumfrequent and prolonged freshwater condi-tions (0.5-5.0‰) mitigate against accu-mulation of living oysters and develop-ment of significant reefs. Frequentexposure to prolonged freshets increasesmortality, depending on water tempera-tures, and results in (relatively) morerapid rates of reef shell deposition andbuild-up, but at the same time populationsof living oysters are generally smaller andtheir growth (including shell growth) isslower. This is illustrated by oyster reefsin the James seed area (i.e. Wreck Shoaland above—Figures 5 and 6) where

Figure 6. Distribution and Base Outlines of Oyster Reefsand Reef Fields in Upper Reaches of the EstuarinePortion of the James River in the Early 1980s. Areashown encompasses all of the James River "seed oysterarea" as identified by Moore (1910). The bottom typesexisting in the 1980s are identified -- see key to symbols.(Modified from Haven and Whitcomb, 1983).

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oysters become fewer and reefs fewer andsmaller (relative to age) as one progressesupriver to the area around the HorseheadReefs and especially around and aboveMulberry Point, i.e. the Deepwater Shoalsarea. The same would apply to the lowersalinity reaches of the Potomac and theupper Chesapeake and its tributaries.Low salinity, or upper estuarine areas arenot good candidates for “commercial” (asopposed to experimental) reef restoration.

2. Depth range from mid-intertidal to about8 m (26.2 ft), sometimes more, but mostlybetween 2.5-5.5 m (8.2-18 ft);

3. Oxygen levels of from about 20% satura-tion to saturation. Mature, healthy oys-ters are able to close-up and surviveunder low oxygen conditions as they canin very low salinity water, but only forrelatively short periods of time. Pro-longed anoxia leads to the developmentof H

2S in the water which is quickly

lethal;4. A relatively sheltered area, protected

against excessive wave action yet appro-priately exposed to water movementswhich permit and/or facilitate setting,feeding, cleansing and reproduction;

5. Levels of natural predation low enoughto permit accumulation of sexuallymature oysters of an appropriate sexualmix of mature oysters;

6. Levels of mortality (related to disease andother natural or man-made causes) lowenough to permit survival, adaptation andaccumulation of favorable geneticallytransmissible characteristics;

7. Levels of competition from other filter-feeders low enough to permit the same asin 6.

8. Production of viable larvae in numberssufficient to maintain the endemic oysterpopulations and the reef habitat, and meetthe demands of environmental pressures,including adverse ecological factors suchas sedimentation, diseases, competitorsand predators, including man.

9. A hydrographic circulation pattern whichretains, preferably gathers as well, matur-ing oyster larvae in the vicinity of the reefor reef field and, optimally, carries oysterlarvae from nearby and distant oysterpopulations to that reef during the seasonof active setting;

10.Current patterns and velocities sufficientto prevent or reduce the rate of accumula-tion of fine sand, mud and/or silt, ondeveloping reefs and of infective materi-als (particles), feces, and pseudofeces orother organic materials on or around theliving oysters, and;

11.Sufficient elevation to provide the advan-tages of height and vertical differences indistribution of water of varying salinity.

Surveys Relevant to ReefRehabilitation Activities

Moore (1910), using surveying gear, achain-drag and oyster tongs, delineated theactual outlines and acreage of oyster reefs in theJames River. He also established the outlinesand acreage of various bottom types and thedensity of oysters (in terms of economicallyharvestable quantities available) on the fourtypes of bottom he identified. Unfortunately,reef elevations and contours were not reported.

The first truly comprehensive investigationof Virginia’s public oyster bottoms was madeduring the period from 1978 to 1981 by DexterS. Haven and his colleagues of VIMS. Thisthree and a half year study employed electronicpositioning gear (Hastings Raydist©) and arecording fathometer to establish depth con-tours, plus a sonic bottom drag to locate andoutline reefs (in 2 dimensions, 3 with thefathometer) and to secure data on bottom types.Standardized patent tong samples were used toestimate oyster and shell density and furtheridentify bottom constituents. The data wereused to prepare a series of charts and tablespresenting basal outlines of existing oyster reefs,acreages of various types of bottoms, estimates

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Figure 7. Distribution and Base Outlines of Oyster Reefsand Reef Fields in Lower Reaches of the EstuarinePortion of the James River above Newport News Point inthe Early 1980s. Area shown encompasses most of theJames River "market oyster area" as identified by Moore(1910). The bottom types present in the 1980s areidentified -- see key to symbols. (Modified from Havenand Whitcomb, 1983).

of living oysters and shells, setting potentials,and occurrences of diseases and predators.Most of the study was published in an extensiveseries of reports (Haven et al. 1978, Haven et al.1981, Haven and Whitcomb 1983 and 1989 andWhitcomb and Haven 1987).

These documents, particularly Haven et al.1981, provide information relative to reeflocation, condition and other data needed to planand conduct reef restoration programs in Vir-ginia. Almost all tributary and Bay bottoms andthose of the lagoons and embayments of theSeaside of the Eastern Shore were sampled anddescribed. Until data even more accurate andcomprehensive are available the results ofHaven et al. (1981) must be employed to pro-vide the basis for such work in Virginia andshould not be ignored! Their conscientious usein developing reef rehabilitation programs isvital!

Specifically, these charts and tables showed:1. Areas of thick, hard bottom with living

oysters and shells;2. Bottoms less firm than those mentioned

above (1) but with a firm crust of liveoysters and shell fragments (“cinder”) in amatrix consisting largely of sandy sedi-ments;

3. The same as (2) but with a firm matrix ofdense sand, silt and clay;

4. Sandy bottoms containing few to nooysters or shells;

5. Mud bottoms containing few to no oys-ters or shell, and,

6. Buried shell 6-12 inches below thebottom, i.e. overlain by sand-mud or othersedimentary material.

A study in 1985 in the James River seedarea utilizing patent tongs confirmed the validityof the designation of bottom types by Haven etal. 1981 and their location in a small section ofthe Wreck Shoal area (DeAlteris, 1988). It alsoshowed that sand or silt-clay may form over50% of the substrate matrix even on active orproducing Hard Rock (Reef) bottoms, i.e. thosewhich continue to produce oysters despitehaving been severely reduced by harvesting andbeing merely “bumps” on the bottom (Table 1).

Haven and his colleagues (1981) evaluatedabout 203,405 acres of the state’s approximately243,000 acres of public (Baylor) bottoms,including both Seaside and Bayside of theEastern Shore (Figure 2) . They showed that inthe James River (Figures 5, 6, and 7), whichencompassed about 25,152 acres of all publicbottoms, a lesser but still substantial acreage(16,245 acres or 64.6%, i.e. 1 to 3, below) of itwas suitable for growing oysters. These can becategorized as follows:

1. Hard Oyster Rock, generally with liveoyster and some profile; 4,310 acres

2. Shell-Oysters - Mud; 7,487 acres3. Shell-Oysters - Sand; 4,448 acres4, Sand - few or no oysters; 1,540 acres5. Buried shell; 420 acres6. Soft Mud or Channel Areas 6,947 acres

25,152 acres

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Unfortunately only a small amount (about3,000-4,000 acres) continues to produce appre-ciable quantities of seed and very few (5,178 Va.bu. in 1993-94) market oysters. In the JamesRiver seed area market oysters were defined asthose at least 2 1/2 inches in shell length in1986-87. In early 1994 it was restored to 3". Inthe James River seed area size limits mean verylittle in terms of population protection andconservation because oysters called “seed” canbe any size. Additionally, for many years smallindividuals from the “market” oyster area of theJames were harvested for use in the making ofoyster soup. Such oysters were called “soups.”Soup oysters could be any size but buyerspreferred small ones. With such variations in thesizes allowed to be harvested, it is obvious thatsize limits actually meant very little in theJames!

If the primary objective of reef rehabilitationor rebuilding activity is to increase naturalproduction (self-reproducing populations) ofoysters and restore reef structure as quickly andeffectively as possible, as it should be, the reefsin the Hard Oyster Rock category (No. 1 above)should receive the most effort. Even if expenseis a concern, rehabilitating this category of reefshould receive more (and more effective) man-agement efforts since they are in the best condi-tion to rehabilitate themselves with or withoutaddition of shell or seed (more rapidly withboth, clearly), but—given adequate respitefrom harvesting pressures. The implications ofthis last condition are obvious: To rehabilitateactive or inactive reefs most quickly, harvestingpressures must be reduced severely—preferablyeliminated, for a significant period of time!Rehabilitation of reefs without closing them andleaving them closed until they achieve signifi-cant rebuilding will be wasteful. Even afterrebuilding is accomplished and production reefsare opened, harvest levels must be strictlycontrolled!

Categories 2 or 3 reefs are older depletedones and are good candidates for reef rebuildingefforts as well. Reefs of these three categories(1, 2 and 3) are sufficiently numerous and

extensive that “barren” bottoms need not beconsidered—except for special purposes. Fur-ther, category 1, 2 and 3 reefs are sufficientlywidespread to provide suitable “platforms” forrebuilding efforts in every part of Virginia’s Bayand its tributaries where oysters once flourished.The same is probably true of Maryland’s watersexcept where shell mining has removed toomuch sub-bottom shell.

Sizes and Shapes of OysterReefs in the James River

As stated above, the survey by Haven et al.(1981) determined size, bottom types and waterdepths of Virginia’s Baylor bottoms. All sur-veyed were charted and the charts deposited inthe VIMS library. Those occurring in the JamesRiver above Newport News Point are shown inFigures 5, 6 and 7.

The Hard Oyster Rock areas (reefs) shownin black in those figures are most often irregularin shape. Many are elongated, presumably onsites of old elevated river bank or river bedtopography or along prevailing bottom currents,or along the long axis of the river. Many aresituated at right angles to the long axis of theriver (i.e. to the prevailing bottom tidal cur-rents). The long axes of many are arrangedacross-river, perhaps reflecting the water massmovements driven by the west to east, wind-driven cross-river currents occurring during thesetting season and/or topographic features of thebottom. (Obviously, both the location andorientation of cultch and the prevailing currentshave affected the locations and shapes of thereefs.) Some were a mile (6.4 km) or more inlength and 1,000 feet (305 m), or more, wide.[The crests of a large number of them are knownto have breached the water’s surface at meanlow water: Some in the not so distant past(Hargis, Chapter 1, this volume.)] Many, how-ever, are much smaller and are often called“lumps” by watermen.

The Haven et al. (1981) study measured thearea of discrete Hard Rock Reefs surviving inthe James River (Table 2) and elsewhere in

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Table 2. Location, Acreage and Percent Total of Hard Oyster Rock (Reef) Areas (Category 1) in the James River by Sections

A. Deep Water Shoals to Mulberry Point — Total - 37.7 acres

1. 0 to 20 acres 100.0 %

B. Mulberry Point to Point of Shoals — Total 1750.2 acres

1. <20 acres 4.6 %2. 20.1 - 100 acres 10.8 %3. >100 acres 84.6 %

C. Point of Shoals to White Shoals — Total 1355.9 acres

1. <20 acres 27.1 %2. 20.1 - 10 acres 30.5 %3. >100 acres 42.4 %

D. White Shoals to Fishing Point — Total 1031.4 acres

1. <20 acres 10.9 %2. 20.1 - 100 acres 17.6 %3. >100 acres 71.5 %

E. Fishing Point to Nansemond Ridge — Total 135.1 acres

1. <20 acres 44.62. 20.1 - 100 acres 55.4

Virginia’s tidal waters at the time of the surveys.These data showed about 4,310 acres of HardOyster Reefs in the entire James estuary, i.e.above and below Wreck Shoal. These areaswere locations where more extensive reefsexisted prior to being subjected to intensiveexploitation. Areas classed as Shell-OysterSand and Shell-Oyster-Mud were reefs whichare gradually being covered with sediments afterhaving been harvested and mined away.

The Vertical Elevation of“Hard Rock” Bottoms in

the James RiverFathometer traces of bottom depths were

made during the study of Haven et al. (1981).Significantly, these traces showed that most ofthe “tops” of the hard reef areas in the upperJames around Burwell Bay were at least 0.6 m(2 ft) below the water surface at MLW. Further

downriver in the important Wreck Shoal areathe tops of most reef areas were about 2.4 m(7.9 ft) below MLW. A few areas of reef stillshowed the classic “peak” or emergent ridgeformation as presented in Figure 4 and in earlyU. S. Coast Survey (USCS) charts, but mostshowed gradually sloping configurations withlittle elevation above the surrounding bottom.No oyster-bearing reef crests breached thesurface at any normal low tide. This indicatesclearly that the natural oyster reefs in the JamesRiver, as elsewhere, have been largely “planed”away by over two centuries of harvest by rakeand dredge (very early) and tong.. Few “reefs”with significant elevation remain. Most surviv-ing “reefs” are “footprints” only. Shell-oyster-mud and shell-oyster-sand beds showed noappreciable elevation above the surroundingbottom (Haven and Whitcomb 1983).

Review of the studies of Haven and hisassociates and others discloses clearly that the

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condition of the natural oyster reefs of the“former” James River seed area (i.e. WreckShoals and upriver) is serious! Very littleremains of the numerous upthrusting reefsreported in the early 17th century and surveyedand charted over two centuries years later in1871, ’72 and ’73 by the USCS that haveyielded seed and market oysters for over 200years. This finding was surprising! Haven andhis colleagues expected to find many reefs withgreater elevations in the most productive reeffields of the James River seed area. Consider-ing the poor condition of the oyster reefs of theJames, it is no surprise that populations of smallseed-sized (and market oyster yields) are so low!Nor is it a surprise that surviving populationsand setting are so sparse.

The reefs in the lower James below WreckShoal (Figures 5 and 7), shown as a marketoyster area in the text and charts of Moore(1910), are in worse shape. In fact, most hadbeen significantly reduced before Moore actu-ally made his survey in 1909.

For the James River oyster reef fields torecover as quickly as possible (or even to sur-vive) it is important that the destruction of thestructure of existing reefs be halted and that thereefs, themselves, be augmented and/or restored.The oyster’s favored habitat must be restored sothat self-renewing populations can be rebuiltand/or assisted to rebuild themselves to neartheir former levels!

The need for this is obvious. Today mostpublic market oyster production in Virginiacomes from the James River “seed beds” as ithas in the past. If that is to continue, rebuildingis essential. In the past and today most privateoyster production originated on the same seedbeds, as it does today. For example, in the earlyand mid-1950s private oyster planters wereharvesting as many as 2-3 million bushels ofmarket oysters from their rented grounds annu-ally. In fact, from 1930 on, and probably before,about 80 to 85% of the seed oysters forVirginia’s large private market oyster production(which reached levels of as much as 70-80% ofthe total state market production) came from the

public reefs in the James estuary. If the reefsaround the Burwell Bay seed area continue to bedepleted and the reef “footprints” becomecovered over with sediments their present andfuture utility as a source of seed will be de-stroyed. Consequently, the likelihood of recov-ery of the Virginia’s private oyster (C. virginica)planting industry to former levels will be re-duced severely—probably eliminated. Silt-covered reef remnants can produce few oysters.

Restoration (Enhancement) ofOyster Reefs (In the James)

and Their ManagementRebuilding oyster reefs in the James River,

or elsewhere in the Chesapeake (or on Seaside),should only be attempted if sound plans andprocedures for doing so are fully adopted by theentire decision-making apparatus of the manage-ment agency (ies) responsible in both states.Money spent on poorly-planned or “half-hearted” attempts is largely wasted. Further-more, for most rapid Bay-wide recovery, bothstates must develop clear plans and proceduresfor future maintenance. We urged reef restora-tion in several public forums in 1991! Thereaf-ter we recommended establishment of a systemof sanctuary broodstock reefs (SBR) and satel-lite production reefs (SPR), Figure 8. Thisrecommendation is reiterated—forcefully!Since then some reef restoration has beenundertaken in both Maryland and Virginia. Thetrend is encouraging. A few of these projectsappear to be showing some positive results.Unfortunately, many, probably most, will failbecause of faulty planning, poor placement,inadequate construction and maintenance and/orineffective post-construction management.Some watermen in both Bay states continue toresist effective oyster management. In fact, somewho oppose reef construction actually serve oncommittees to select sites and other details ofreef construction!

To assist in reef rehabilitation we haveprepared a list of factors to be employed asguidelines. The features which a reef rebuilding

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SPR

SPR

SPR

SPRSPR

SPR

SPR

SPR

SPR

SPR

SatelliteProduction

Reef(SPR)

SatelliteProduction

Reef(SPR)

BroodstockPreservation

andSpawning

Reef(Sanctuary

Broodstock Reef--SBR)

Direction of

PrevailingTidal

Currents

FLOOD

EBB

SPR

SPR

Figure 8. Diagram of a Two-Tier System of Reef (ReefField) Restoration Involving Preservation of Broodstockand Spawning Populations and Market or Seed OysterProduction.“[Idealized—Actual configurations may haveto differ depending on geomorphological, hydrographicand other important ecological characteristics of thelocality in which reefs (or reef fields) are to be restored orbuilt.]

program designed to produce oysters for harvestshould incorporate are:

1) First priority should be given to identifi-cation and rapid rebuilding of reefsdesignated as broodstock sanctuaryareas, which we have called SanctuaryReefs (SR) or Sanctuary BroodstockReefs (SBR). Harvesting should not beallowed on sanctuary broodstock reefs!

2) These reefs will be the core or centralbuilding blocks of our two-tier reefsystem, or any serious reef rebuildingprogram. A conceptual design of acombination, or two-tiered reef system isshown in Figure 8. It includes one or,

preferably, more sanctuary broodstockreefs (SBR) which must remain closedafter establishment and several surround-ing satellite oyster production reefs(SPR), reefs which, when restored andready, can be opened to “controlled”harvesting. It is important to note that only theessential features [i.e. one, preferablymore, sanctuary (SR) or sanctuarybroodstock reefs (SBR), surrounded byseveral satellite production reefs (SPR)appropriately situated] presented in ourconceptual diagram are critical. Wheregeomorphological or hydrographicconditions around existing or plannedreef fields do not lend themselves to theidealized or diagrammatic geometricarrangement shown in Figure 8 anapproximation would be satisfactory.Where local current patterns suggestdifferent axial alignment(s) of SBRs andSPRs, some rearrangement wouldcertainly be in order.

3) Reefs designated as satellite oysterproduction reefs (SPR) must be closeduntil natural production of oysters hasreturned. When the satellite productionreefs (SPR) are opened to commercial orrecreational harvest the quantities avail-able for annual harvest (quotas) shouldbe carefully limited to the ability ofthose SPR reefs to sustain those harvestsand, at the same time, maintain them-selves. If prolonged rebuilding of theSPR reefs is intended, annual harvestquotas must be even more restricted. Inmost instances continual rebuilding ofSPRs would be desirable in the long run.In every case, managers should beconservative in setting harvestingquotas. Enough animals should be lefton the reef to allow for changes in ratesof survival brought about by variationsin adverse environmental conditions.

Unfortunately, the fishery manage-ment agencies, including legislatorswhenever they have interfered with

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other features by native C. virginica by allowingforces of natural selection to act on unharvested,self-reproducing populations of naturally-produced oysters or those from “laboratory-enhanced” populations; 3) Restoration of thefiltering, sequestering and transformationcapacities of massive oyster populations onrevitalized upthrusting oyster reefs, strategicallyplaced as natural pollution reduction measures,and; 4) Restoration of oyster reef-associatedcommunities once so prevalent in the Chesa-peake. Oyster reefs are natural fishing reefs(often clearly identified as such on charts in-tended for use by sportfishermen) which attractand help support desirable finfish. Enhancementof recreational and commercial fin fishing willbe a significant bonus of reef restoration. (Actu-ally, efforts, funds and expenditures designed toconstruct “finfishing” and/or “ecological im-provement”, or “filtering” reefs, can be adaptedto development of sanctuary and even economicproduction oyster reefs and double- or triple-purpose reefs will result, enhancing ecologicaland economic benefits and allowing sharing ofcosts between objectives.) Also, increasedwater clarity, if such results from the filteringactivities of active reef oysters and/or otherfilter-feeding reef associates, should enhancephytoplankton production and recovery ofsubmerged aquatic vegetation (SAV) in areasinfluenced by reefs or reef fields and reduceother undesirable effects of excessive sedimen-tation. Both would be valuable bonuses ofoyster reef reconstruction. Yet another benefit ofwell-situated, properly-designed and constructedoyster reefs would be stabilization of affectedlee shores. Further, restoration of reef popula-tions may result in reduction of deleteriousmicro-organisms by increased filtration ofwaters in their zones of influence.

rational closure decisions, in both Chesa-peake states, and it is they who areultimately responsible, have consistentlyavoided (even actively and mistakenlyresisted) adoption of management planswhich actually limit oyster harvests frompublic reefs to biologically reasonablelevels. Even on reefs being “replen-ished” at significant public expense, theyhave not done so! Further, they havenever favored actual closure of anyproducing reefs, even to restore them toformal actual or potential “high” produc-tivity. This is one of the most significantreasons that state management of thepublic oyster resource and the fisherythat exploits it in both Virginia andMaryland has been ineffective! Biologi-cally reasonable and necessary harvestcontrols have never been instituted andenforced!

4) Until truly sound management arrange-ments and practices can be instituted andenforced, extensive reef rebuildingprojects or programs are not to be rec-ommended. Money spent on restoringproduction reefs which are not appropri-ately managed will not achieve long-term restoration of public oyster produc-tivity. At best it will be a gift from thestate treasury, a subsidy, to publicwatermen as it has always been—largely.At worst, it will be a waste, as it hasmost often been. Effective post-reple-tion, post-reconstruction or post-con-struction management is the most impor-tant aspect of any reef restoration pro-gram!

There are valid purposes for reef restorationother than for development of sanctuary reefs orrebuilding or enhancement of commercial,subsistence or recreational harvests of seed andmarket oysters. These are: 1) Restoration ofbroodstock levels, and as the oysters mature, ofan appropriate sexual mix; 2) Genetic enhance-ment, i.e. development of desirable characteris-tics such as disease resistance, rapid-growth or

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Technical Aspects of ReefRebuilding Which Can Be

RecommendedSufficient information now exists to allow

planning for and design of reef restorationactivities and pursuit of actual rebuilding orrestoration of effective reefs. As we havesuggested, all that is required is to emulatenature as closely as possible in the placementand “shaping” of reefs. However, technicalaspects pertaining to actual details of reefrestoration activities should be examined delib-erately to see if nature can be improved upon or,where natural materials such as oyster shell forreef “core” rebuilding are not readily or eco-nomically available, to facilitate acquisition andutilization of substitute materials. Further on wewill comment in more detail on them and makerecommendations. (Also, see the several paperson alternate substrates in this volume).

Ideally, it would be excellent if reef restora-tion could be undertaken in every tributary orBay area which formerly held successful andproductive reefs. But, doing so would probablycost more than will be available at times whengovernmental budgets at all levels are appar-ently constrained. Consequently, priority areasmust be chosen. In some measure these can beselected (screened) on the basis of ultimatepurpose of the reefs, i.e. ecological restoration,possible pollution reduction and/or economicrestoration—or even multipurpose fishing reefs.There may be some geographic areas whichfavor one or the other (or several) of theseobjectives. Further, design of reef structure andlayout might be varied to achieve one or more ofthe purposes selected. In many areas of exten-sive and potentially productive public bottomsone design could serve all functions. Selectionof such versatile reef designs should assist injustification, planning, and development ofactual reef rehabilitation or rebuilding projects.

To achieve maximum restoration withminimum cost, effort and time we must take ourcues from nature in making any site selections.Locations at which nature has been most effec-

tive in the past are prime candidates. This canbe established from reliable scientific surveydata. Early hydrographic charts, including boatsheets, incorporating the results of naval andcivilian hydrographic expeditions can be useful.Most valuable will be actual oyster groundsurveys reported by Winslow (1882—Md. andVa.), Baylor (1894—VA), Moore (1910—VA),Yates (1913—MD), Haven et al. (1981), Havenand Whitcomb (1983 and 1989) and Whitcomband Haven 1987—VA) and others. Whenresults of the survey recently conducted by theMaryland Department of Natural Resources(Jordan, personal communication) are finallyprocessed, charted and made available, theyshould be employed for Maryland waters.

Data from objective and carefully doneresearch and management surveys of both statesare of great value and must be employed.Records of such activities as annual oysterground (reef) surveys, spatfall surveys, diseaseand survival surveys and other such informationare important. (If obtained and treated compe-tently these fishery-independent data, coupledwith available objective survey results, are themost valuable.) Reef rebuilding efforts whichfail to incorporate all of the available usefulelements of such sources of information shouldnot be pursued. Funding agencies shoulddemand no less.

In Virginia, preselection of sites for reefrebuilding should be based on Haven et al.1981, and recent data obtained by Mann (per-sonal communication) plus such other relevantsite-specific data as are available. Additionally,once a likely reef area or even a specific reef hasbeen identified the site selected should becarefully surveyed employing the most effectivepositioning and sounding techniques available.Actual probing and positive sampling should beconducted at each site to establish a sound basisfor project design and later performance evalua-tions. Such surveys can be quickly conducted ifconfined to specific sites and pursued vigor-ously. Neither design nor construction shouldbe done without this step.

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From this discussion it should be apparentthat the commonly employed process of selec-tion and design and management by the politicalcommittees or pressure groups of “practical”watermen, or their allies, supporters or apolo-gists, should not be utilized! The process hasnever worked in either Maryland or Virginia! Itwill not work in reef restoration efforts! Experi-enced, competent watermen can and should beinvolved (especially informed and responsibleones) but actual selection of sites, design ormanagement must be controlled by applicabletechnical factors and by persons qualified tointerpret them objectively and scientifically andnot by harvester prejudice and preference. Theoverall interests of the public and its posterity aswell as the users and the resource must berepresented fully and fairly. History has clearlyshown that management decisions based onpolitical popularity or acceptability to industryor on compromise have been wasteful andfruitless! Management efforts of the past 125+years have not achieved desired goals of restora-tion and subsequent continuation of self-renew-ing natural oyster populations and sustainedyields! Most have failed completely (Kennedyand Breisch 1983, Hargis and Haven 1995,Rothschild et al. 1994)). The long-term interestsof the general citizens of both states and theirnatural oyster resources and the potential pro-ductivity thereof have not been well attended bystate managers!

Concerning possible sources of financing forsustained reef programs, each state has under-taken repletion activities for over a half century.Monies devoted to these state programs can andshould be employed in state reef rehabilitationprograms. Funds designed for habitat restora-tion and pollution-control activities can also beapplied. Additionally, monies allocated toresearch and technological development couldjustifiably be used in reef rebuilding programs.Of major importance are careful follow-upstudies of each reconstructed reef. Data, whichmust be collected annually at least (more often ifnecessary), should include oyster density, settingexperience, growth, condition, disease levels,predator levels and mortality. Details of har-

vests and other removals are needed. Knowl-edge of applicable environmental parameters isnecessary!

There is room for construction of experi-mental reefs. Some could even depart some-what from nature’s “tried-and-true” experi-ments. This is not a new concept. Oysterscientists have talked for decades of usingexperimental reefs to enhance the introductionand spread of scientifically-developed, disease-resistant or faster-growing broodstocks intoestuaries with oyster-producing potential(Ruzecki and Hargis 1989). Were broodstockpossessing such desirable genetic featuresavailable it could be “seeded”, or distributed, toexisting, rehabilitated or new reef areas byincluding it among the oyster shells (and liveoysters) of the “veneer” layer. Different geo-metric configurations can be tried as well.

In Virginia the James River estuary has beenthe most successful, long-lived and persistentproducer of seed, soup and market oysters ofany estuary in the Commonwealth. At present,about 3,000-4,000 acres of the former JamesRiver “seed” area (or 1.5% to 2.0%) is the lasteconomically significant oyster producer (mar-ket and seed oysters) of all 199,000 acres ofVirginia’s Chesapeake public beds. Its remain-ing producing reefs should be considered primecandidates as the foundation of reef recoveryefforts. Because the public oyster reefs of theJames have been so productive of market andseed oysters over the years and have actuallybeen the basis of most market oyster productionof private planters, restoration of the area iscritical to the recovery of private plantingactivity using native C. virginica.

Based upon these factors we have recom-mended that reef rehabilitation and enhancementactivities in Virginia be pursued in the JamesRiver “seed” area on a priority basis! This isnot to discourage efforts in other areas such asthe Piankatank or Great Wicomico seed areas orin the Rappahannock, which has been so pro-ductive of market oysters in the past, but theJames should be given highest priority. Politicalpressures to the contrary should be stronglyresisted. Acquisence to them in the past has

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negated effective management of the publicoyster resources of the James!

Similar areas exist in the estuary ofMaryland’s Potomac River and its middleChesapeake and in the lagoons and embaymentsof the Eastern Shores of both states. A largerarea and number of Maryland’s historicallymost-productive public reefs are in generallyecologically favorable situations than those ofVirginia. Therefore, restoration of her publicreefs should be easier and more economical andmore quickly accomplished than those in mostareas of Virginia’s lower Bay.

Aspects of Reef RebuildingWhich Can be Recommended

Today for the James Riverand Similar Estuarine

Reaches of the Potomac andMaryland’s Mid Bay on Both

the Eastern and WesternShores

1. The most rapid and least costly recoveryof reefs can be obtained by employingthose Hard Oyster Reefs that retainsignificant (some) vertical relief and shellvolume, have living young and adultoysters upon them and are known to“catch” spat. Simple closure, adequatelyenforced, is all that is required. Thebetter the shape the selected reef is in[i.e. elevation above the bottom, firm-ness, suitable volume (size) and reliefand similar geomorphological as well asfavorable hydrographic factors] to beginwith, the more rapid the recovery will be.Recovery of such active reefs could behastened by judicial addition of oystershell to the core, i.e. by “lifting” some ofthe living veneer off and replacing it aftercore enhancement, or replacing thedisplaced veneer by addition of livingoysters from elsewhere. [Here we haveattempted to separate the Hard Oyster

Reefs into those with appreciable livingoysters and those without (i.e. HardOyster Reef footprints).] A light “dust-ing” of clean oyster shells (i.e. 2,000 bu.per acre) over the living veneer of HardOyster Reefs each year will enhance setand survival in succeeding years. Of thevarious restorative techniques offeredhere and below, this is the best since itcauses the least destruction to the oystersalready living in the veneer. Closing thereef to harvesting for a period suitable tothe intended function and future of thatreef must follow shelling!

2. Where “living” producing reefs exist,their productivity can be restored andtheir recovery to former (or new) condi-tions and dimensions enhanced by addingnew core materials, preferably cleanoyster shells, to immediately adjacenthard bottoms, thus extending the basalextent of these reefs. Some of the livingoysters in the veneer could be gentlytransferred to the enhanced “core.”

3. On reef rebuilding sites with significantquantities of living oysters (i.e. 500 to1,000 bu per acre) in the “veneer” someof the living oysters could be tonged orgently dredged and moved to other areasor stockpiled overboard nearby forreplacement in the veneer of the reefbeing restored. Thus, possible destructionof living oysters by “smothering” wouldbe reduced or avoided.

However, great care must be exercisedin conducting this phase of the operationto avoid destroying that which is being“saved.” Moving of living oysters, whichmight have to be done twice should thiscourse be decided upon, is usually de-structive of the oysters being moved aswell as those left behind. Perhaps thebest strategy in such a situation is to addonly small quantities of shells and/orseed, but to do so each year for a numberof years.

4. Where appreciable quantities of livingoysters are lacking on existing reefs, reef

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rebuilding in the James, and similarareas, should take place on the “foot-prints” of Hard Oyster Rock as identifiedin Haven et al. 1981.

5. Some “experimental” reefs should berebuilt or established anew in waters withdepths of 1.8-2.4 m (5.9-7.9 ft) atM.L.W. (or greater if funds permit) andshould extend upward into the intertidal.This will permit determination of thedifferences between setting and survival(and of levels of disease and predation) atone vertical level versus another. Pro-vided, of course, that the experimentalreefs are closed and protected and thetime and methods of sampling andmonitoring are adequate. It is extremelylikely that the more-or-less persistentmicrohydroclimatological differencesfound at the different depth levels (orheights) of active three-dimensional reefshave been important to the overall pastsuccesses of those reefs, and will be tothe new or restored reefs.

6. Rebuild some depleted reefs in strategiclocations by reshelling to a depth ofabout 1 foot (30 cm). This will raise thebed slightly above the surroundingbottom and enhance setting and allowcomparing results between activitiesnumbers 5 & 6. This technique shouldbe effective in areas of low sedimentationrates and on reefs with low disease andpredator levels.

7. Where oyster shells are limited in avail-ability reefs with greater vertical heightand volume might be built with “cores”of locally-obtained mollusc shells such assurf clams, ocean scallop or oceanic andestuarine hard clam shells since they aresimilar in chemical and physical compo-sition to oyster shells. However, corescan also be constructed of shale, smallstones or cobbles, crushed rocks, railroadballast stones, ceramics, ceramic andglass fragments (cullet “dulled,” ofcourse) bricks, clean building rubble ofappropriate size, large stones, rocks or

dolmans or even artificial cultch manu-factured from other biologically-neutralmaterials. Whichever is employed, allshould be topped with a veneer of cleanoyster shell at least 15 cm (6.0 in.) thick.It is known that setting occurs on shellsurfaces several inches or more beneaththe outer layer of shells. Survival of spaton “interior” shell is often better than onthat right at the surface because bluecrabs and other such predators cannot getat them readily. The veneer also can be“seeded” with living oysters taken fromsimilar sites to speed rebuilding. Livingoysters apparently encourage setting(Hidu 1969). As indicated above, oysterswith desired special genetic featurescould also be employed in the veneer ifavailable.

8. All reefs (reconstructed, rehabilitated ornew) must be closed to harvest andclosely monitored.

9. Those restored reefs intended for eco-nomic harvests (i.e. Satellite OysterProduction Reefs—SPR, see Figure 8)should not be opened for harvest untilthey are ready, and when they are openedit should be done on an “allowableharvest quota” basis only. When the“allowed” harvest level is reached thereef should be promptly closed andallowed or even assisted to recoverbefore harvesting thereon is permittedagain.

10. Harvest quotas on SPR reefs can beadjusted to accomplish desirable rates ofrebuilding as can further replenishmentefforts and closure times. The quotaconcept could be modified or enhancedby employment of other “limited access”techniques but, whichever is employed,harvests must be restricted to the reefpopulation’s replacement and survivalcapabilities and to plans for eventual reefbuilding.

11.Actual establishment of reefs or reef sitesmust be carefully done by competentpersonnel using accurate positioning

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2 These shells may well be merely “ancient” or old andmany probably are. Use of the term fossil is probablyinappropriate.

equipment. Adequate records of posi-tions, including Loran, Raydist©, or GPSbearings (whichever is employed) andlatitude and longitude are necessary.

12.Any SPR harvests permitted should berecorded accurately as to amount andkind taken (i.e. markets, soups, seeds,etc.) from each specific reef and themanner of and the time required forremoval. Accurate and detailed knowl-edge of harvest location and time andeffort devoted to harvests must be ac-quired in order to allow evaluation ofsuccess or failure of each reef and of thereef-rebuilding program.

13.Where harvesting is allowed after a reefis restored and producing, in situ cullingof shell should be mandatory and strictlyenforced. After shucking of marketoysters, shells should be returned to thepublic reef program.

14.The status of all public reefs should beestablished twice yearly (or more asnecessary) by careful fishery-independentsurveys especially designed for suchmonitoring efforts.

Possible Sources of OysterShells for Cultch

Because their shapes and surface texturewere established by the evolutionary processesof many millennia and are found in nature’ssuccessful “experimental” reefs, clean oystershells (preferably recent; secondarily ancient)are the most desirable of all natural cultchmaterials for “core” construction or enhance-ment. Other suitable materials may be substi-tuted in core construction if necessary, but cleanoyster shells are by far the best material forreconstruction or enhancement of the veneer.For veneer rehabilitation every effort should bedevoted to securing oyster shells. Some dilutionby other suitable materials might be employedto “stretch” shell supplies, but no dilution ispreferable.

Unfortunately, due to their destruction,misuse, misapplication and employment else-where (i.e. private plantings and previous publicrepletion efforts) oyster shells are now scarce.To secure oyster shells for reef enhancement orreplacement programs may require the locationof new sources, recovery of previously-usedshells, use of mined “fossil”2 shell, or in Vir-ginia even by renewed harvesting of shells fromextinct reefs (they are already being mined inMaryland). To assist in the reef rehabilitationefforts we have considered several differentpossible sources of oyster shells and offer thefollowing:

WHERE SHELL MAY BE OBTAINED

1. As late as November 1994 shell could bepurchased from Langenfelder and Son,Inc. in Maryland and barged to the JamesRiver. Cost for 300,000 or more bush-els, delivered to the James River seedarea was then about $0.62/bu. Sincethere are 16.7 bushels per cubic yard, thecost was about $10.35 yd3, according toLangenfelder personnel. Costs wouldhave been higher for delivery to shallowsites since the cost advantages, econo-mies of scale, of shipping in and plantingfrom large, deep-draft barges are lostwhen shallow-water planting is requiredand smaller, shallow-draft barges mustbe used.

2. Recent and ancient shell deposits exist inVirginia. In the 1950s large volumes ofshell were mined by a large suctiondredge operated by Radcliffe Materials,Inc. in the lower James River. A studyby VIMS in the late 1980s showed some“relict” shell deposits in other areas(Hobbs 1988). There are undoubtedlyothers. Hobb’s study was purposelylimited; it could be profitably expanded.It is suggested that the VMRC investi-

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gate the possibility of controlled miningof shell for reef rebuilding in Virginia.Shell could be stockpiled on the CraneyIsland Disposal Area or some similar sitefor later use. (Incidentally, no furtheroutward expansion of Craney Islanddisposal area shouild be conductedwithout prior removal of sub-bottomshells where they exist.)

3. Shell planted by the VMRC previouslyin areas currently unproductive might berecovered by VMRC dredge boats (orthose of carefully controlled contractors—perhaps even paid cooperatingwatermen) and used again. Locationswhere shells have been planted areknown to VMRC. Cleansing of suchshells prior to planting would be impor-tant. One or more such boats could beequipped with rotating “washer” drumsto clean the shells. Costs of such anoperation should be investigated, andgear developed if cost-effective. One ofus (Haven) was involved in the designand construction of relevant equipmentin the 1970s. And it is known that otherswere also. Undoubtedly plans survive.It is entirely possible that such equip-ment still exists and that it is little usedand could be acquired inexpensively.

4. In high set areas depleted beds might berestored by using shell currently buriedaround the margins of the reef. Thisshell could be lifted from the sand-mudcover by mechanical revolving steelfingers or tines on the head of a Mary-land-type soft clam harvester. Such amachine was developed by VIMS in1973 to harvest oysters and hard clams(Haven et al. 1979). It could be modi-fied and improved to raise and clean oldburied shell to be redeposited on reefsbeing “shelled”.

5. For compelling socioeconomic reasons,sattelite production restoration reefs(SPR) might be located near isolatedcommunities such as Smith Island in

Maryland and Virginia and TangierIsland in Virginia early on. The inhabit-ants of these locations have very fewchoices in remunerative employment.

Summary and ConclusionsNatural oyster reefs consist of a supportive

“core” of “cultch” --oyster shells, and shellfragments in a matrix of sand, clays or siltsoverlain by a veneer of living oysters and shellsof the “recently” dead. The core of dead oystershells continually renewed by receiving the“mortal remains” of successive populations oflive oysters living in and on the “veneer” consti-tutes the greatest volume by far. The core is thereef’s “framework” and provides (undergirds)the basic height and contours of the reef.

It is the veneer of the shells of living oystersand recently dead ones which “welcomes”maturing eyed-larvae, receives spatfall, andprovides support for the survivors and shelterfrom predators. The living oysters on and inthis veneer encourage the setting of maturelarvae. They also filter particulate matter fromthe water and thereby clarify and cleanse it.Other benefits to living oysters are provided bythe upthrusting reefs. Their elevation enables asizeable portion of the reef’s oyster populationto be above the disturbing influences of theestuary’s bottom thereby reducing the negativeeffects of sedimentation and of exposure to theirown wastes and those of other infauna andepifauna. Also, it is likely that exposure toinfective particles is reduced for those individu-als on the upper levels of the reef. Zonationalmicrohydrological effects resulting from three-dimensional aspects of such reefs may alsoenhance setting, survivability, growth, reproduc-tion and recruitment.

The larger (older) mature living oysters ofthe reef provide the essential genetic buildingblocks which, given time and proper manage-ment, will lead to improvements in such featuresas rapid, robust growth, disease resistance,adaptation to other natural and man-made

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stressors. Further, it is these living oysters ofthe reef’s veneer which provide the most spawnand larvae per individual to the home reef,nearby reefs and others “downstream”. Ofcourse, smaller and younger sexually mature andreproductively active oysters supply gametes aswell.

Rational restoration of existing reefs (i.e.with appropriate elevation), or rebuilding (onold reef “footprints” now at or sufficiently closeto the surface to provide a ready foundation)will restore natural oyster production in Virginiaand Maryland—eventually. Restoration orrebuilding should be based upon the locations ofcurrently active or recent reefs (preferably) orold ones (secondarily) to take advantage ofnature’s past successful experimentations. Theformer dimensions of the historically-productivereefs should be emulated as closely as possibleas should the materials employed.

Actual sites for reef enhancement should beselected by competent oyster biologists, withassistance of other scientific personnel, includ-ing estuarine circulation specialists, hydraulicengineers, geologists, toxicologists, and suchother specialists as may be necessary. Informa-tion from knowledgeable and responsible oysterharvesters should be sought. All availablerelevant information, including past survey andmonitoring data, harvest data, informationrelated to current distribution and abundance ofoysters (including reliable input from harvest-ers) should be employed.

To have a significant reef rehabilitation orreconstruction program the successful “designs”of nature (outcomes of countless evolutionaryexperimentations) should be fully employed, asemphasized above. But, there is room forconsideration of alternate materials and different“designs”, and even alternate sites, where suchmight enhance reef rebuilding or replacementactivities or where the new reef to be built willperform some desirable purpose. For example,some sites in disease-endemic areas might bechosen for development of disease resistance insurviving reef populations. Those sites nowbearing surviving adults should receive priority

(of course, surviving older oysters from suchareas could be used to provide “resistant” youngon reefs being rebuilt in disease endemic areas.)Other places might be selected to enhancefiltering of sediments and pollution control toencourage SAV recovery in a specific site orsites. Still others might be selected to providefishing reefs readily accessible to numbers ofsport fishermen. Also, experimentation withalternate materials in selected sites may bedesirable to improve reef planning, constructionor performance and/or reduce costs. Further, it ishighly likely that deliberately designed reefrestoration configurations should be used tomodify local hydrodynamic features so as toenhance and speed reef rejuvenation.

If rapid (relatively speaking) repopulation isthe primary objective, the initial and basic reefrebuilding effort should be directed at those siteswhich are known to have received “good” setsin the past (and likely could do so again), and/orwhich offer the best chances of survival. Prefer-ence should be given to those with significantpopulations of living oysters. Seeding withappropriate broodstock could enhance reefrehabilitation. In the James River seed area (andsimilar systems elsewhere in the Chesapeake)existing productive reefs are the best such sites!Numerous suitable reef areas exist. In the Jamesestuary of Virginia priority should be given tothose in the Point of Shoals—Swash region, i.e.East and South-East of Mulberry Island (seeFigures 4 and 5). The Wreck Shoal area, and/orsuitable sites nearby, would probably be primelocations for disease-resistance monitoring andexperimentation. (In 1992-93 and 1993-94 bothprevalence and intensity of MSX and Dermodisease declined in these two areas as diddisease-induced mortality.)

Additional studies or surveys may be neces-sary, especially those directed at location of newor more economic sources of oyster shell. Otheractivities should be directed at discovering ordeveloping alternate materials for “core” and thenon-living portion of the veneer. Studies oncosts and availability are needed.

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Past oyster repletion programs, while inef-fective at restoring natural oyster populationsover the long run, do provide information whichwill help future reef restoration and maintenanceefforts. For example, a Maryland study estab-lished that 2,240 Md. bushels of “ancient”oyster shells would cover 1 acre of bottom,about 2.5 cm (1 in) deep and at a cost of $1,388per acre (at the time of that study). Obviously,future shelling efforts or extensive reef rebuild-ing or construction efforts would be enhancedby careful evaluation of the various optionsavailable and of the cost-benefits thereof.

We conclude that restoration of oyster reefs,the “preferred” habitat of our native oyster (C.virginica), on the public oyster grounds of theChesapeake followed by subsequent effectivemanagement (as indicated in detail above) offersthe best hope for restoration of self-renewingnatural oyster populations. (Most likely, otheraggregating crassostreid oysters do best in off-bottom situations as well.) Even in areas whereC. virginica populations are at a very low level,sufficient potential for such renewal exists as tooffer the most likely opportunity for “relativelyrapid” restoration of oyster populations in theBay and on the Eastern Shore, and elsewhere.Surviving, reproductively-capable native oystersoccur in many places in the Bay and its tributar-ies. These resources should be carefullyhusbanded and employed in the public reefrestoration effort in responsible fashion! To beeffective, all reef rebuilding or replenishmentefforts must be accompanied by effective clo-sures—closures adequate to the purposes of therestoration program. Upon an effective reefrenewal program depends the future of theChesapeake (C.virginica) oyster resource andits ecological functions and economic utility.Should Bay “public” oyster populations beallowed to continue their decline into ecologicalinsignificance and economic oblivion the citi-zens of both states, and their posterity willsuffer. And Virginia and Maryland watermenand their posterity will lose access to yet anothereconomically-productive resource. Soft clamand hard clam populations are much reduced in

Maryland and self-renewing, harvestable popu-lations of natural hard clams are destined todrop in Virginia. As well, populations andcommercial catches of many edible finfish aredown Baywide and Chesapeake blue crabpopulations appear threatened. Economicdisappearance of the oyster will seriously reducethe economic opportunities of Chesapeakewatermen. It will also cause the attention ofremaining watermen to be focussed even moreheavily on blue crabs and hard clams and hastentheir economic demise.

As matters now stand, the future of publicwatermen in the Bay is not bright. All of theseself-renewing natural resources of the Chesa-peake must be carefully and realistically re-stored and/or husbanded if watermen and theirlivelihoods and the character, productivity,ecological stability and diversity of the Chesa-peake, itself, are to persist. Both Virginia andMaryland should make strenuous efforts torehabilitate oyster populations by restoring their“favored” habitat, the self-renewing publicreefs.

AcknowledgmentsMrs. Shirley O. Sterling prepared early

manuscripts. Dr. Hargis’ wife, MarciaMcK.Hargis, did later drafts. Mrs. Kay B.Stubblefield and William W. Jenkins preparedthe figures. Ms. Stubblefield readied the manu-script for printing and made the necessarytextual changes. Robert J. Byrne, C. H. Hobbs,III, Gerald H. Johnson, Maynard Nichols and L.Donelson Wright assisted with geologicalconcepts. Mark Luckenbach, Roger Mann andothers have reviewed various drafts as they weredeveloped. To all, our thanks. Any faults offact, interpretation or conclusion must be ours.

This paper was presented orally in 1995;manuscript submitted, August, 1995; revised,October 1996; accepted for publication, October1996.

Contribution Number 1966 of theVirginia Institute of Marine Science.

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