An Introduction to Culturing Oysters in Virginia

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							              An Introduction to Culturing
                  Oysters in Virginia

                                              Mark W. Luckenbach,
                                               Francis X. O’Beirn
                                                  Jake Taylor1




                                            School of Marine Science
                                       Virginia Institute of Marine Science
                                          College of William and Mary

                                                              1999
1
    Present address: Conservation and Repletion Division, Virginia Marine Resources Commission, Newport News, Virginia.
                                 Acknowledgments


The ideas expressed here are the product of work conducted by the staff of the Virginia
Institute of Marine Science Aquaculture Program, largely since 1989. Mike Castagna con-
ceived of and initiated the program. Administrative support under the VIMS Dean and
Director Frank O. Perkins and his successors Dennis L. Taylor and L. Donelson Wright have
allowed the program to continue. Armistead Williams first pointed us in the right direction
and Linwood Holton, former governor of Virginia and President of Virginia’s Center for
Innovative Technology (CIT), provided not only the financial support of his agency, but
needed encouragement and enthusiasm for our program over the years. Funding support for
the program has come from state funds, Virginia’s Center for Innovative Technology,
NOAA’s National Coastal Resources Research and Development Institute and the National
Marine Fisheries Service. The Tidewater Oyster Gardeners Association contributed to the
printing costs of this brochure. We are especially indebted to Wanda Cohen and Kay
Stubblefield for editorial and production assistance, and to Sylvia Motley and Eileen Horne
for printing.




                           To obtain a copy of this report contact:


              Nancy Lewis                                        Wanda Cohen
   Virginia Institute of Marine Science               Virginia Institute of Marine Science
        Eastern Shore Laboratory                              Publications Center
        Wachapreague, VA 23480                            Gloucester Point, VA 23062
          Fax: (757) 787-5831                                Fax: (804) 684-7573
         Phone: (757) 787-5816                              Phone: (804)684-7011
        email: nlewis@vims.edu                            email: wcohen@vims.edu




                                              2
Preface
        This document is intended to respond to a growing demand for information on
intensive, off-bottom aquaculture of the eastern oyster, Crassostrea virginica, in Virginia and
neighboring coastal states. Over the past few years the number of individuals involved in
intensive oyster aquaculture in Virginia has increased dramatically, and we now estimate that
over 2000 separate off-bottom oyster culture operations are underway within the coastal
waters of Virginia. Individuals involved in this activity include non-commercial gardeners,
traditional watermen and members of the well-established hard clam aquaculture industry. In
addition to growing oysters for personal consumption and marketing, an increasing number
of individuals are participating in the activity to supply oysters for environmental restoration
projects.
        This publication represents an attempt to fulfill the need for an introduction to
culturing oysters. The approach described here reflects a strategy which we have been
developing and refining over the past 10 years. It is neither complete nor exclusive. It is
directed towards the culture of C. virginica in areas where the common oyster diseases
Dermo and MSX (caused by the pathogens Perkinsus marinus and Haplosporidium nelsoni,
respectively) are endemic and it includes information for both commercial aquaculturists and
non-commercial gardeners. This publication is revised from a 1997 edition and contains new
information about the status of selective breeding programs, regulations in Virginia related to
oyster aquaculture and non-indigenous oyster species. We have also attempted in this revision
to provide a listing of more reference materials for individuals interested in further reading.
As in the past, our experiences are drawn largely from work in Virginia, but the general
strategy should be applicable in many locations from southern New Jersey south along the
U.S. Atlantic coast.
        It is never quite the right time for a publication of this type. Refinements in
techniques and new lessons learned from failures are ongoing. Nevertheless, we offer this in
the hope that it will provide an outline of the major components of culturing oysters in the
region.




                                               3
Historical Perspective                                  During the past few decades oyster
                                                    populations in Virginia have been particu-
    It is now clear that a prominent feature
                                                    larly hard hit by the sustained presence of
of the Chesapeake Bay, and other estuaries
                                                    two parasite-induced diseases (MSX
along the U.S. Atlantic coast, were large,
                                                    [caused by Haplosporidium nelsoni] and
structurally complex oyster reefs.1,2 These
                                                    Dermo [caused by Perkinsus marinus]).
reef environments not only provided
                                                    These protozoan parasites have been found
critical habitat for the survival and growth
                                                    at record high levels in recent years;
of oysters,3-5 but it is becoming increas-
                                                    Dermo has now spread to all public oyster
ingly clear that they were important habitat
                                                    beds in Virginia and accounts for 70 to
for other commercial and non-commercial
                                                    90% mortality in most.13 Clearly the
species.6-9 Additionally, the oysters and
                                                    presence of these diseases present major
other suspension feeders on these reefs
                                                    challenges to current efforts to restore wild
likely affected water quality, phytoplank-
                                                    populations of oysters and develop oyster
ton abundance and food web structure
                                                    aquaculture.
within the Bay and similar estuaries.10-12
Critical features of these reefs included
3-dimensional relief above the seabed,              Diseases
interstitial space within the fabric of the             Contrary to popular accounts these
reef surface and multiple year classes              diseases are not caused by viruses, but
(>10) of oysters.                                   rather by single-celled protozoa. The
    The demise of Virginia’s oyster fishery         causative agent of MSX is
has been over 100 years in the making.              Haplosporidium nelsoni; Dermo results
The initiation of this decline had as much          from infections by Perkinsus marinus.
to do with the development of the steam             Neither parasite is harmful to humans and
canning process in the 1870’s as it did with        no threat is posed by consuming shellfish
pollution and disease. This process made            infected with either parasite. P. marinus is
possible the wholesale over exploitation            endemic to the area and Dermo disease has
which ultimately led to reduction of                likely afflicted oyster populations for a
populations below those capable of coping           long time,14 but the origin of H. nelsoni is
with natural threats or sustaining a fishery.       less certain.
The virtual elimination of natural oyster               Both parasites thrive in salinities above
reef habitat and alteration of population           15‰ and exhibit lowered virulence at
structure to include only a few year classes        lower salinities. Below about 10‰
fundamentally changed the nature of the             H. nelsoni is eliminated from its host,
resource.                                           while P. marinus persists at lower salini-
                                                    ties but does not reach pathogenic intensi-
                                                4
ties. Transporting of oysters infected with         been the focus of several researchers who
P. marinus from low salinity to higher              have identified variations in disease
salinity (above 15‰) will generally                 susceptibility in natural populations.18,19
result in rapid disease progression.15-17           The widely used practice of using large,
    New infections of both H. nelsoni and           old (and presumably, therefore, disease
P. marinus generally occur during warmer            resistant) field-collected animals as brood
months with the peak period for new                 stock by some hatcheries is representative
Dermo infections generally occurring in             of this strategy. Problems with this ap-
August and early September in Virginia.14           proach include the unverified nature of
MSX infections can arise from May                   disease exposure among the brood stock
through September, yet the life cycle of H.         and the uncertainty of resistance to both
nelsoni and the mode of infection remain            of the major diseases.
unknown. Although observed levels of the                Selective breeding programs begin
parasites in oyster tissues are reduced in          with natural variation among wild popula-
the wintertime, infections are not elimi-           tions and select for desired traits. For the
nated by current “normal” wintertime                eastern oyster, development of dual resis-
temperatures.14 The pathology of MSX                tance to both Perkinsus marinus (Dermo)
infections can be confined to local out-            and Haplosporidium nelsoni (MSX) has
breaks resulting in fast acting and high            been the priority. The most successful of
mortality events. Dermo infections tend to          these efforts was initiated at Rutgers
be more chronic and result in high cumula-          University over 35 years ago. Selected
tive mortality, the levels of which can rival       lines of oysters were developed with a
that of MSX.                                        high degree of resistance to MSX.20
                                                    These stocks initially proved to be highly
Disease Resistance and                              susceptible to Dermo and slow growing,21
Selective Breeding Programs                         but subsequent selection efforts have made
                                                    significant improvements in both of these
    There is an abiding hope by many that
                                                    areas. The current oyster breeding pro-
a disease resistant oyster will someday be
                                                    gram, known as CROSBreed (Cooperative
available for both aquaculture and restora-
                                                    Regional Oyster Selective Breeding
tion of wild stocks. Research related to
                                                    program), is a multi-state cooperative
this goal has generally followed three
                                                    effort to further develop and test these
lines: (1) the search for natural strains of
                                                    oyster lines. Currently, under the direction
the native oyster which exhibit some
                                                    of the Aquaculture Genetics and Breeding
disease tolerance; (2) selective breeding
                                                    Technology Center (ABC) at VIMS, this
programs; and (3) investigations with non-
                                                    program has developed a hardy strain of
indigenous oyster species. The first has
                                                5
oyster which exhibits good growth rates             requiring a comprehensive management
and reduced susceptibility to both MSX              approach as described below.
and Dermo in low to moderate salinities                 One final avenue for acquiring a
(approximately 10-25‰). However, the                disease resistant oyster that has received
performance of this strain of oysters in            attention in recent years is the use of non-
higher salinity has not yet been estab-             indigenous or exotic oyster species. Exist-
lished. CROSBreed oysters have been                 ing data suggest that at least two other
distributed to commercial hatcheries, and           oyster species, the Pacific oyster
seed from these lines may be purchased              (Crassostrea gigas) and the Suminoe
from these hatcheries. As discussed below           oyster (Crassostrea ariakensis) are less
in the section on Purchasing Seed and               susceptible to Dermo and MSX than our
Materials, it is not advisable to publish a         native oyster. It is beyond the scope of this
fixed list of seed suppliers which sell this        publication to discuss all of the ecological
or any other strain–it would likely be out          and legal issues surrounding the importa-
of date by the time the ink was dry. Rather,        tion and use of a non-indigenous species.
we provide in the Appendix a list of                We note, however, that it is illegal to
contacts within VIMS and other organiza-            introduce a non-indigenous species into
tions which should between them be                  Virginia coastal waters without approval
knowledgeable about seed availability in            of the Commissioner of Fisheries and
any given year.                                     similar requirements apply in other coastal
    It is important to note that selective          states. Given the uncertain state of our
breeding is an ongoing process and that             current knowledge of the ecological and
even as one generation of CROSBreed                 economic consequences of introducing an
oysters has been distributed to hatcheries,         exotic oyster species, we think it unlikely
another generation is being developed and           that such an action will be approved in the
tested. We fully expect that no one strain          near term. New technologies, currently
of oyster will meet all needs and that some         under development in the VIMS ABC,
day, as Dr. Standish Allen, Director of the         may facilitate the production of reproduc-
ABC notes, “you will be able to purchase            tively sterile exotic oyster species and
your oyster seed from a catalog, selecting          speed approval of their use in aquaculture.
the seed most appropriate for your envi-            Presently, however, the native oyster is the
ronment and farming practice.” Selective            only game in town. Fortunately, by follow-
breeding programs are, however, unlikely            ing the few simple steps in the strategy
to develop the “perfect oyster” and dis-            outlined below it is generally possible to
eases likely will remain a significant issue,       culture the native oyster to market size,
                                                    even in disease endemic waters.

                                                6
Overview of the Strategy                                  Managing around disease - The
                                                     second component of our strategy for
    Growing native oysters in the presence
                                                     culturing oysters is to manage around the
of these diseases requires an integrated
                                                     diseases. One approach is to grow oysters
strategy which emphasizes (1) brood stock
                                                     in low salinity sites. Below 10‰
selection, (2) management around disease
                                                     Haplosporidium nelsoni does not persist
and (3) rapid growth to harvest size. All
                                                     and, while Perkinsus marinus can survive
too often attempts to culture oysters have
                                                     at these salinities, it does not cause mortal-
focused on just one of these components to
                                                     ity. Raising oysters throughout the entire
the exclusion of others; for instance, the
                                                     growing cycle in low salinity can be an
development of a “super” disease resistant
                                                     effective means of avoiding disease, but it
oyster or a particular containment system
                                                     results in a very watery tasting oyster
for holding oysters off the bottom.
                                                     which is generally regarded as less desir-
    Brood stock selection - The foregoing
section discussed the importance of brood            able. Moreover, oysters grown at some low
stock selection programs and described               salinity sites are at risk of mortality from
one such program (CROSBreed). We                     freshets.
stress again that, while disease tolerant                 A temporal approach to managing
oyster lines have been developed, it is              around diseases, particularly Dermo, can
unlikely that a fully disease resistant oyster       be effective. June through early September
will ever be realized. A more realistic              is the period within Virginia during which
scenario is that continuing small improve-           new infections of P. marinus generally
ments in the disease tolerance of oyster             occur and existing infections intensify.14
stocks will enhance the success of inte-             By avoiding exposure to the pathogen
grated approaches to oyster culture.                 during the early stage of seed production,
    The most important point for the oyster          it is possible to limit oysters to a single
culturists with respect to brood stock               disease exposure period (summer) during
selection is to ensure that seed is pur-             the culture cycle. As noted above, this
chased from a hatchery which has used the            level of exposure to P. marinus is gener-
best available brood stocks, by which we             ally not sufficient to cause mortality in
mean oysters with a proven record of good            hardy oyster stocks. Seed producers may
growth and survival in disease endemic               dramatically reduce the risk of P. marinus
areas. As the evaluation of wild stocks              exposure by spawning oysters in late June
from different regions and breeding pro-             to early August (so that the seed do not go
grams progress, we expect that the best              into overboard nurseries until the major
                                                     disease threat has passed).
available stocks will change and, as noted
above, may become site specific.
                                                 7
Box 1

F a ll S eed
1 F all Þ 1 W inter Þ 1 Sp ring Þ 1 S um m er Þ 2 F all Þ 2 W inter Þ 2 S p rin g Þ 2 S u m m er
 st            st               st                      st                      nd                           nd                     nd                  nd

  go od               p oor           good                   poo r               goo d                              p oor                 go od            poo r
 g ro w th          g ro w th        gro w th              gro w th             gro w th                          g row th               g ro w th        gro w th
                                                      d isea se ex p o su re                                                                      d isease exp o sure
                                                                                H a rv e st                                                H arv est

S p rin g S eed
1 S p rin g Þ 1 S u m m e r Þ 1 F a ll Þ 1 W inte r Þ 2 S p ring Þ 2 S u m m e r
  st            st             st         st           nd           nd

  g o od                poor                g o od                    p o or                    g o od                          poor
 g ro w th            g ro w th            g row th                 g ro w th                  g ro w th                      g row th
                d isease exp osure                                                                                           d isease exp o sure
                                                                                            H a rv e st


    Over the past 10 years we have advo-                                             harvestable size prior to succumbing to
cated a strategy whereby oyster culturists                                           disease. Among the many examples of
purchase fall seed. That is, oyster seed                                             successful oyster culture in Virginia over
spawned in July or even early August and                                             the past 10 years, have been several cases
moved to nursery facilities when the threat                                          of alternative approaches to the fall seed
of disease exposure is reduced. This                                                 strategy. Spring seed, spawned as early as
strategy maximizes the number of growing
seasons prior to reaching two disease                                                 Box 2. Idealized growth curve for
                                                                                      cultured oysters using fall seed. Middle
exposure seasons (see Box 1). We define
                                                                                      line represents average growth at a good
growing seasons as the fall (September -                                              growing site; upper and lower lines
November) and spring (March - May)                                                    represent excellent and poor sites,
periods during which oysters in Virginia                                              respectively, within the expected range.
generally experience the greatest growth                                                        100
and disease exposure seasons as June
through August. Each of these periods are,                                                                  80
                                                                                        Shell length (mm)




however, approximations and variations
are observed both spatially and temporally.                                                                 60
    The use of fall seed is predicated on
achieving very rapid growth during the                                                                      40
first fall season (see Box 2). In our experi-
ence, failure to achieve this results in                                                                    20
small oysters (less than 35 mm) entering
the winter months and a much reduced                                                                         0
                                                                                                                 Aug Dec Apr Aug Dec Apr
likelihood that oysters will reach

                                                                           8
March, has successfully been used by
                                                     Box 3 Highlights of the strategy:
numerous growers. While this approach
                                                     • Purchase disease-free seed produced
provides for fewer growing seasons prior               from the best available brood stock
to two disease exposure seasons (see Box             • Select a good growing site
1), it does avert the risks posed entering           • Protect oysters from predators with
the winter with small oysters. We have                 appropriate meshes
                                                     • Keep meshes clean and unobstructed
generally observed this strategy to work at          • Harvest oysters as soon as they are
sites where very high growth rates are                 large enough
achieved, such as the high salinity envi-
ronments of the Atlantic side of the East-          floats. The principal behind this approach
ern Shore, permitting growth to harvest             is that both the quantity and quality of the
size in 14 months or less. Further, some            food available to the oyster is improved
individuals have had success growing                when suspended in the water column.
oysters which were spawned during May               Unfortunately, there are no strict guide-
or June and placed in the field during July.        lines with respect to the best position in
Successful use of these summer seed                 the water column to place the oysters.
would appear to require a culture site with         Often raising the oysters as little as 6
only modest disease exposure risk. For the          inches above the bottom is sufficient to
oyster culturist it is most important to            reduce the amount of suspended sediments
ensure that the seed you purchase is                which they must filter and improve their
disease free at the time of the purchase            growth rates, but performance is very site
and that they were produced from the best           specific and depends on the bottom type,
available brood stocks.                             water depth and food availability. Place-
    A final aspect of temporal disease              ment of oysters in racks or bags in the
management is to harvest oysters before             intertidal can have advantages which
they enter their second summer when P.              include access to oysters, fouling control
marinus infections are likely to intensify          and predator protection; however, ex-
and the oysters succumb to Dermo. It is             tended exposure reduces the feeding time
better to eat a 2½ inch oyster in April than        available for oysters and reduces growth
to wait a few months for it to grow larger          rates. If intertidal culture sites are used,
and lose it to disease.                             oysters should be placed in the low inter-
Grow them fast! - The third component of            tidal to reduce exposure to extremes of
the strategy is rapid growth to harvest size.       heat and cold.
This has generally been achieved in off-                The quantity and quality of food
bottom culture, in which oysters are                available to oysters can vary considerably
suspended above the bottom in bags or               between locations and is a function both of

                                                9
the hydrodynamics at a site and the abun-           the most desirable for everyone. Recently
dance of phytoplankton in the water. At             a number of different modifications of this
present the best approach for an oyster             system has become commercially avail-
grower with access to more than one site is         able.
to experiment with different areas to                   The important features of any system
determine the site which affords the best           for maintaining oysters in off-bottom
growth. Others confined to a single loca-           culture are (1) adequate predator protec-
tion may have to evaluate different seed            tion, (2) minimal flow obstruction, (3)
stocks and handling strategies in order to          ease of maintenance and handling, and (4)
maximize oyster growth and survival.                low cost. Additionally, it may be neces-
    Oyster growth rates are also dependent          sary, depending upon location, to consider
upon salinity. Below 10‰ oyster growth              the impediments of navigation or aesthet-
rates are generally reduced compared to             ics associated with the structures.
higher salinities; some stocks show inter-          Taylor Float
mediate growth rates at salinities between              The Taylor float, so called because
10 - 20‰ and highest growth rates at high           much of the design and original testing
salinities, but that may be a function of           was done by Jake Taylor, is constructed of
heritage. As noted above, we expect that            4 inch diameter PVC pipe and galvanized
oyster seed bred for selected salinity              wire (Box 4). The float is approximately 2
regimes may be available in the near                ft x 8 ft x 1 ft deep and is of sufficient size
future.                                             to grow 1,500 to 2,000 oysters to market
                                                    size. Lightweight, schedule 20 PVC drain
Containment Systems                                 pipe works as well as the more expensive
                                                    schedule 40 pipe. Sizes of the pipe and
    A wide range of options are available
                                                    the number of fittings are shown in Box 4.
for maintaining oysters off the bottom,
                                                    The mesh cage of the float is generally
each combining advantages and disadvan-
                                                    constructed of 1 inch square, double-
tages. Published methods include the use
                                                    dipped, 16 gauge galvanized hardware
of fixed racks, floats and suspended
                                                    cloth, cut and folded as shown in the
bags—e.g. the flexible belt22 and the chub
                                                    figure. The plastic-coated form of this wire
ladder system.23 No single method will
                                                    generally sells for about 20% more than
work for everyone and no single method
                                                    the un-coated, but that is more than offset
guarantees success. Each grower must
                                                    by an extended life, especially in high
consider characteristics of the growing site
                                                    salinity sites. The wire cage is then at-
and his or her handling capabilities. We
                                                    tached to the PVC float using 14.25"
describe a particular containment system
                                                    cable ties.
below, but do not mean to imply that it is
                                               10
 Box 4. Schematic of Taylor float construction and approximate materials cost.




Materials for 1 Taylor float:                                                                                          Approximate Cost
     [ 10' x 4' double-dipped 16 gauge vinyl coated wire, 1" x 1" squares .................................. 15.90
     [ (2) 10' lengths of 4" schedule 20 gauge PVC pipe. .............................................................. 6.70
     [ (4 ) 4" schedule 20 gauge PVC 90o elbows .......................................................................... 5.00
     [ (20) 14 ¼" black plastic cable ties ....................................................................................... 2.70
     [ 1"x 3"x 8' wood strip for lid ................................................................................................. 1.85
     [ 3' x 8' filter cloth for lid ........................................................................................................ 1.00
     [ Gray PVC glue & PVC cleaner ............................................................................................ 1.00
     [ 24" #8 crab pot line .............................................................................................................. 0.60
     [ ½" stainless steel hog rings ................................................................................................... 0.50
     [ Miscellaneous ....................................................................................................................... 2.00
                                                                                                                             Total $37.25


Some tips for making floats
/ The wire is generally purchased in 100 ft rolls which may actually vary in length by several inches.
Roll out your wire first and measure the total length before cutting. That way if the roll is a little short,
you can spread those missing inches among the cuts and still get 10 floats per roll.


/ Clean and glue the pipe joints well. Water in your pipes can sink the float!




                                                                     11
    It is important to attach zinc bars as           Virginia. One involves using plastic mesh
sacrificial anodes to this mesh to reduce            in the place of galvanized. Plastic has the
corrosion and extend the life of the float.          advantage of not corroding, but is more
Oyster seed which are too small to be                expensive, provides less rigidity and offers
retained within the 1 inch mesh may be               more surface area for fouling. The PVC
placed inside mesh bags (described below)            pipe may, of course, be cut to any size to
which are then placed within the float. As           fit the needs of individual culturists and
the sizes of the oysters increase, the mesh          some non-commercial oyster gardeners
size of the bags should also be increased            have chosen to work with half-sized
and the densities of oysters reduced. Also,          Taylor floats, which are constructed by
a ½ inch mesh liner made of thin plastic             reducing the longest segments of pipe
(sold as bird netting to protect fruit trees)        (shown in Box 4) from 95 inches to 47.5
may be placed within the float and at-               inches.
tached with cable ties. This liner is inex-              Advantages of this containment system
pensive, adding only approximately $1.00             include low materials cost and sturdy
to the cost of a float.                              design. The open mesh of the wire float
    We have investigated several lid                 provides limited surface area for fouling
options for this float including ¼ inch              and permits good water flow. Disadvan-
thick plywood lids, wire mesh, shade cloth           tages include the cumbersome size and
and no lids. Performance of different lid            need for a hoist to retrieve the floats when
options varies with location and opinions            they are full of oysters. Further, in some
about the best type of lid vary between              locations the use of these floats may be
culturists. Lids have been found to be               restricted by navigational or aesthetical
useful in restricting the growth of                  concerns.
macroalgae in the floats and reducing                    Again, we do not wish to imply by
predation by otters and seagulls. However,           presenting designs for the Taylor float here
barnacle and oyster settlement may be                that this is the preferred containment
greater under lids and seagulls roosting             system for all growers. In fact, we expect
(with the associated problem of                      that this system will be replaced in the
elevated fecal coliform bacteria levels)             near future by any number of improved
may be greater on floats with lids. Indi-            designs. For the present, however, we
vidual culturists will need to experiment            receive a large number of requests for the
with the use of lids at their site to deter-         design specifications and this manual is
mine their value.                                    intended in part to meet those requests.
   Several modifications to this basic
design have been used by growers in

                                                12
Constructing the mesh bags and liner:                purchased in small quantities from some
                                                     vendors. Cut 9 ft x 3 ft sections and secure
1/16" mesh bags- Fiberglass window                   it to the inside of the float using cable ties.
screen can be purchased in 4 ft x 100 ft             The liner should extend 6 inches up the
rolls. Cut 18-inch x 24-inch sections and            sides of the float and be secured at the top
sew two panels together with monofila-               with cable ties.
ment line, double stitching along three
sides. After placing oysters in the bag, seal        Box 5. Side view of Taylor float.
by stapling 2 ¾ inch x 18 inch wood strips
together on the open side; adding 2 addi-
tional wood strips along the bottom of the
bag provides additional strength to the
bag.


1/8" mesh bags- Plastic mesh may be
ordered from several aquaculture supply
vendors in flat and tubular forms. The
latter are much better for constructing
bags. The standard dimensions of a roll of           Purchasing Seed and
1/8 inch tubular mesh are 36 inches x 200            Materials
ft. Each roll makes about 100 24-inch x
                                                         The question most commonly posed to
18-inch bags. One end of the bag should
                                                     us is, “Where do I get seed?” Given our
be closed with ½” stainless steel hog rings,
                                                     foregoing discussion of the importance of
and the other end with cable ties.
                                                     using good quality, disease-free seed, this
                                                     is obviously a critically important ques-
3/8" mesh bags- These bags can be
                                                     tion. Unfortunately, it is impractical to
purchased individually from aquaculture
                                                     respond to that question here. Oyster seed
supply companies or rolls of tubular mesh
                                                     are sold by a number of commercial
can be purchased. Each bag measures 40
                                                     hatcheries along the U.S. Atlantic and Gulf
inches x 20 inches. The one open end can
                                                     coasts, but their availability and quality
be closed with cable ties.
                                                     can vary annually. Any list which we
                                                     might provide at the time of this writing
½” liner- Liners are constructed from
                                                     would be quickly out of date and give the
very thin mesh which is sold as bird
                                                     perception of endorsing some hatcheries
netting to protect fruit trees It generally
                                                     and excluding others. Similarly, purchas-
comes in 3000 ft x 14 ft rolls, but may be
                                                     ing materials to construct floats or other
                                                13
containment systems can be done through              culturists and gardeners start with the
a number of sources.                                 larger seed.
    The Virginia Shellfish Growers Asso-                 1. Obtain required permit (see section
ciation, a trade group which represents                     on Regulations below).
many of the shellfish culturists in the                  2. Securely moor floats in the water.
Commonwealth, counts among its mem-                      3. Place 15 - 20 mm seed oysters in
bers most of the shellfish hatchery opera-                  3/8" mesh bags at a density not
tors. You can contact them to get more                      exceeding 2500 oysters/bag and
information about seed supplies from their                  place no more than 2 bags/Taylor
members. Further, the private, non-profit                   float. [Numbers will vary in other
Chesapeake Bay Foundation is actively                       floats]. The best time to initiate this
involved in working with oyster culturists                  step is in late September after the
in Virginia and Maryland, often coordinat-                  greatest threat of P. marinus infec-
ing seed purchases and holding float                        tion has passed. Remember to
construction workshops. Finally, in Vir-                    start with disease-free seed from
ginia there are a number of oyster garden-                  good brood stock.
ing clubs which have been organized to                    4. After 2 - 6 weeks, depending upon
facilitate information exchange, as well as                  growth rates, remove oysters from
seed and materials purchases. The appen-                     the bags and place into a float with
dix provides contacts or initial points of                   ½" mesh lining. Densities within
inquiry for contacting each of these                         the float should not exceed 2000
groups.                                                      animals. Alternatively, some
                                                             growers prefer to keep oysters in
Procedures                                                   @- inch mesh bags throughout
    We recognize that there can be more                      the culture cycle. If this is done,
than a single approach to culturing oysters                  densities should be reduced to
in this region, but offer this basic sequence                approximately 600 oysters/bag
of steps as a starting point. The steps and                  and 2 - 3 bags/float.
                                                         5. Over the next 6 - 18 months main-
the oyster densities are given for oyster
                                                            tain the oysters and floats in good
culture using the Taylor float, because we
are most familiar with this system, but the                 condition (see below) and harvest
basic approach can be followed using                        oysters as soon as they are large
other systems. Modifications based upon                     enough to eat! The oysters will
                                                            grow at varying rates and leaving
using smaller seed are outlined below in
                                                            large oysters within the float will
Box 6. We recommend that beginning
                                                            slow the growth of the remaining

                                                14
       ones. {Note: This suggestion is               vary between sites and between seasons
       made with Virginia growers in mind.           and years at individual sites. Regular
       Other states may have regulations             inspection of the floats and bags is re-
       regarding minimum harvest sizes               quired to judge when cleaning is needed.*
       for aquacultured oysters. In all                  The principal cause of fouling is
       cases growers should abide by                 marine organisms which settle from the
       Health Department regulations                 plankton and attach to the floats, bags and
       regarding the certification of their          oysters. Most of these organisms can be
       growing waters.}                              removed by washing with water (fresh or
   Box 6 provides a summary of the steps             salt) and scrubbing with a stiff brush.
involved, including those for starting with          High pressure washing is sometimes
small seed.                                          required to remove firmly attached organ-
                                                     isms, but care must be taken when using
 Box 6. Number and size of mesh bags                 high pressure washers not to damage small
 and oysters used in a Taylor float.                 oysters.
 2500 2-3 mm oysters/ 1/16" mesh bags; 2                 In some locations the settlement of
 bags/float for approximately 2-4 weeks              barnacles, mussels and even oysters onto
 2500 6-12 mm oysters/ 1/8" mesh bag; 2 bags/        the floats can be a particular problem,
 float for approximately 2-4 weeks                   since these organisms are not easily
 2500 15-20 mm oysters/ 3/8" mesh bag; 1 bag/        washed off. If detected early enough, these
 float for approximately 2-4 weeks                   animals can be cleaned off using a brine
 1500 -2000 20-50 mm oysters/float with ½”           dip24,25 (described below in the section
 mesh liner for approximately 5-8 mo.                about flatworms). It is especially important
 1500 -2000 50-75 mm oysters/float without           that a brine dip only be used with oysters
 liner for approximately 3-8 mo.                     greater than 5 mm, since smaller oysters
                                                     will suffer mortality from the procedure.25

Maintenance and Care                                 Predators and Other
   Maintaining an oyster garden is a little          Associated Organisms
like caring for a vegetable garden. It is a
                                                         Predators ranging from flatworms to
lot easier if you stay on top of a few
                                                     river otters may be found associated with
relatively simple tasks! Analogous to
                                                     off-bottom cultured oysters, but not all
weeding a tomato patch, the bags and
floats that are holding oysters must be              *If oysters are retained in bags throughout the
cleaned periodically. The frequency with             grow-out period, we recommend that you flip the
                                                     bags every 2-3 weeks to remove excess sediment
which this clean-ing must be done will               and re-distribute the oysters.

                                                15
animals pose a threat to the oysters. Distin-        water another hour before being placed
guishing between those organisms which               back in the float.
eat or otherwise harm oysters and those                 Another treatment is to raise the bags
which do not is important. A complete                above the low water mark so they are
accounting of the organisms associated               exposed to the sun at low tide. This
with cultured oysters is beyond the scope            method should kill the flatworms but not
of this document, but a few common                   the oysters, but is subject to variation in
examples are given below.                            success depending upon weather conditions.
    Flatworms - The oyster leech or oyster               Clam worm - This polychaete worm
flatworm, Stylocus ellipticus (formerly              (Nereis succinea) is usually the most
Eustylochus ellipticus) can be a very                common worm associated with cultured
significant predator on small oysters. In            oysters in the region. It is generally 1 - 3
Virginia S. ellipticus generally invades             cm in length, segmented and has numerous
oysters in late spring or early summer,              small appendages running the length of the
though occasionally late summer infesta-             body on each side. Usually light pink to
tions will occur. This animal is usually no          reddish brown in color, this worm is easily
larger than 25 mm, flat and thin with                spotted crawling across the shells of
irregular margins and it lacks the “centi-           oysters. Fortunately, this animal does not
pede looking” appendages seen on the                 pose a threat to oysters and the oyster
common clam worm. It can be green,                   culturist need not be concerned with them.
yellowish brown, or salmon in color with a               Crabs - There are a variety of crabs
whitish branching intestine that can be              which may be associated with oyster
seen through the skin. Flatworms prey on             cultivation and most should be viewed as
barnacles and small oysters and can be               predators. The blue crab (Callinectes
devastating to a crop of cultured oysters if         sapidus) is a voracious predator on oysters
left untreated.                                      and care should be take to exclude them
    The preferred treatment for flatworm             from the bags and floats. Several species
infestation is a brine dip. The bags with            of mud crabs (Panopeous and related
oysters should be left out of water for              genera) also feed on small oysters. During
about one hour before the dipping to make            mid to late summer in this region several
sure all oysters are closed. A brine solu-           of these crabs, especially the blue crab,
tion is made by dissolving 25 pounds of              settle out of the plankton and into bottom
salt in 10 gallons of estuarine water in a           habitats. At this time the small crabs may
plastic trash can. Each bag is dipped into           pass through meshes as small as ½ inch
the brine solution for five minutes with             and grow rapidly to a size capable of
agitation. The bags are then left out of             consuming oysters. It is important, there-

                                                16
fore, to regularly inspect floats and bags               Epifauna - Organisms that are found
and remove any crabs.                                attached to hard substrates (including
    In high salinity environments in the             oysters, mesh bags and floats) are known
area hermit crabs (genus Pagurus) are                as epifauna. Many are benign and only
common. Though some of these crabs can               impact the aesthetic appeal of the oysters.
grow to a size capable of eating small               Others may compete with the oysters for
oysters, they generally do not pose a threat         food resources and may cause a reduction
to cultured oysters and can in fact be put to        in water flow (and hence food) through the
beneficial use. Small hermit crabs, those            containment/culture system.
found in shells 1 - 2 cm in length, can be               Barnacles are hard-shelled crustaceans.
added to the inside of 3/8 inch mesh bags            They generally attach in large numbers and
to help control the fouling. They will               can compete with oysters for space and
graze on small animals and plants which              food. They can be eliminated by aerial
settle onto the bag and obstruct water flow.         exposure if identified early enough, but
Do not add hermit crabs to bags with                 large individuals must be physically
smaller seed as they may consume small               removed with a scraper. Care must be
oysters.                                             taken when handling floats or oysters
   Grass shrimp- Often the most common               covered with barnacles as they are abra-
organisms associated with oyster floats are          sive.
small grass shrimp (Paleomonetes pugio                   Sea Squirts (Sea Grapes) are com-
and P. vulgaris). These animals do not               monly found in higher saline waters. They
pose a threat to the oysters and may be              resemble grapes with siphons. They can be
ignored.                                             eliminated by either scraping-off or aerial
     Snails - In high salinity areas oyster          exposure for 1-2 hrs (depending on the air
drills (Urosalpinx cinerea and Eupleura              temperature).
caudata) are major predators on oysters.                 Hydroids are ‘algae-like’ colonial
Fortunately, they are seldom found in off-           animals. They can be found in large
bottom floats or trays and the few which do          numbers particularly on the surface of the
manage to invade a float are easily removed          mesh bags or the float. They can result in
by hand. The common periwinkle (Littorina            reduced flow into the culture structure and
littorea), which is usually observed on the          can be removed by washing with freshwa-
stems of salt marsh cord grass, feeds on             ter allied with scrubbing with a brush.
small fouling organisms. Adding a dozen or           Aerial exposure will also result in them
so periwinkles to the inside of the bags             being dried out and subsequent brushing
containing oysters will reduce the fouling           will remove them.
and help keep meshes cleaner.

                                                17
    Other bivalve species in the form of             growers in other states should check local
mussels and ark shells may settle on or in           regulations). Rapidly grown oysters tend to
the culture systems. They pose no real               have thin shells with a high meat content.
threat unless they are extremely abundant.           We recommend harvesting cultured oys-
Vigilance is the key to determining their            ters at relatively small sizes 2¾ - 3 inches
numbers and whether action is necessary.             in shell length. This reduces crowding in
Mussels can be removed only by picking               the floats and allows the remaining oysters
them from among the oysters and it’s                 to grow faster. Of course, for oyster
easier to remove them when they are                  culturists market demands will place size
small.                                               limits on practical harvest size for oysters.
Mammals - The principal mammalian
threats to cultured oysters are river otters,        Health Concerns
raccoons and humans. The first two are                   Oysters filter large volumes of water
generally excluded with securely fastened            and thus have the capacity to concentrate
lids, fending off the latter often requires          both toxins and human pathogens. Tidal
greater vigilance.                                   waters in Virginia are classified open,
    We are currently preparing a fuller              seasonally restricted or closed to shellfish
description of organisms associated with             harvest by the Virginia Department of
cultured oysters, including a pictorial              Health. It is important to know the desig-
guide, as part of a more detailed handbook           nation of your growing waters and to take
on oyster cultivation which should be                care in consuming shellfish (especially
published in 2000.25 This book will also             raw) from waters of unknown designation.
incorporate more details of predator and             Contact the local office of the Shellfish
fouling control mechanisms.                          Sanitation Program within the Virginia
                                                     Department of Health for more informa-
Harvesting                                           tion about status of water quality in your
    Following the procedures outlined                growing area.
above some oysters should be ready for                   It is possible to relay oysters from
harvest within approximately 12 months               contaminated waters to clean waters prior
(fall of the second year). Oysters should be         to harvest and consumption. However, a
harvested as soon as they are large enough           number of specific restrictions apply.
to consume or be marketed. For the                   Water temperature at the time of the
gardener this is largely a matter of per-            relaying must exceed 50oF (10oC) and a
sonal preference since regulations limiting          minimum of 15 days in the clean water is
harvest size for wild stocks do not pertain          required. Regulations guiding relaying of
to cultured oysters in Virginia (but again           shellfish were originally directed towards
                                                18
relocations of wild stocks and the entire          other than Virginia before making plans to
procedure required oversight by a marine           import oyster seed.
patrol officer of the Virginia Marine                  As noted above, cultured oysters are
Resources Commission. At the time of this          exempted from fisheries management size
writing the Virginia Marine Resources              restrictions; however, regulation 4VAC
Commission (VMRC) and the VA Shell-                20-720-90 requires that “any person
fish Sanitation Program are reviewing              harvesting or attempting to harvest
their required procedures for relaying             oysters...on the seaside of the Eastern
shellfish from contaminated to clean               Shore” must first obtain a harvest permit
waters in an attempt to develop procedures         from the Virginia Marine Resources
more amenable to aquaculturists. Inter-            Commission. The requirement for this
ested growers in Virginia should contact           permit includes aquaculture operations.
their regional office of the Shellfish                 The VMRC has recently developed a
Sanitation Program.                                general permit (#3) which authorizes the
                                                   use of riparian waters for the noncommer-
Regulations                                        cial culture of shellfish. This permit is
                                                   intended to facilitate the development of
    Most states have regulations on the
                                                   noncommercial oyster gardening and is
placement of structures in the water for
                                                   much less cumbersome than previous
aquaculture and on the importation of seed
                                                   permitting requirements. However, certain
from other states. Restrictions have been
                                                   restrictions apply concerning the size and
placed on the importation of hatchery-
                                                   location of the structures and impacts to
reared oyster seed into Virginia and Mary-
                                                   navigation and submerged aquatic vegeta-
land. In Virginia, Marine Resource Com-
                                                   tion. Interested individuals should contact
mission regulation #450-01-0102 requires
                                                   the VMRC to receive a copy of the permit
that the hatchery-reared oyster seed (shell
                                                   application.
height less than 25 mm) be accompanied
by certification from a shellfish patholo-
gist that the seed are disease free. All           Economic Considerations
importation of oyster seed into Maryland           It is not our goal in this brochure to pro-
from northern hatcheries is forbidden due          vide a detailed economic analysis of oyster
to concerns over juvenile oyster mortality         cultivation. However, there are a few
syndrome. Because these regulations are            important economic considerations which
subject to change and new ones may be              we would like to briefly highlight. We
promulgated, it is wise to check with the          begin with a very cursory, “back of the
VMRC or appropriate agency in states               envelop” estimate of the cost of produc-


                                              19
tion. Using the ranges of cost values in             wild-harvested oysters has varied greatly
Box 7, we compute that the cost of pro-              for the past several years, for product
duction currently ranges between 6.5 and             delivered to Virginia it has generally been
11¢ per oyster and that does not include             in the neighborhood of 8-9¢ an oyster. For
such expenses as maintenance and opera-              the noncommercial oyster gardener this
tion of a vessel, leases, licenses, marketing        cost of production is usually not an issue.
costs and a variety of other legitimate              (After all, those of us with backyard
expenses. In a forthcoming book,26 slated            vegetable gardens seldom are concerned
for publication in the spring 2000, we will          that it is more expensive than buying our
discuss these estimates in more detail.              tomatoes from the grocery store.) For the
Additional discussion of the economics of            commercial oyster culturists, however, this
culturing oysters in the mid-Atlantic                production cost is a critical issue, making
region are provided in publications by               it is necessary to market the oysters as a
Allen & colleagues27 and Lacey &                     high quality product at a premium price.
Thacker.28                                           At the present time, this appears to be
                                                     working well in Virginia where oyster
 Box 7. Rough estimates of production                culturists are generally selling oysters
 costs for oysters cultured using the                between 20 to 45¢ apiece.
 methods described here.
                                                         2 - There is more marginal gain to be
                          Cost/Oyster                made from marketing than from cutting
 Seed                      0.5¢ - 2¢                 production costs. This follows directly
                                                     from the foregoing discussion and our
 Materials                   3¢ - 4¢
                                                     estimates of production costs. Although it
 Labor                       3¢ - 5¢                 is common now to hear commercial oyster
                                                     culturists in Virginia proclaim “we’ve got
                                                     to cut our costs so that we can get our
    In this publication we wish to make              production up,” we believe that this misses
three points about the economics of cultur-          two critical points. First, if our production
ing oysters using the methods which we               cost estimates, which include labor at $8-
have described.                                      10/hr, are reasonable, then the solution to
    1 - It is not cheap! With a production           the labor-intensiveness of the approach is
cost which is probably around 10¢ an                 to hire more labor. The profit margin
oyster, it costs more to produce an oyster           would seem to support this contention.
by this means than the wholesale price for           The second point is that, while improve-
wild-harvested oysters from the Atlantic             ments to the cost of production are surely
and Gulf coasts. Though the price for                possible (perhaps they could be reduced by

                                                20
a nickel per oyster), far greater range for         provide a single set of guidelines as to
improving profit margins exist in the sales         what constitutes an oyster which is too
price. After all, current variation in sales        small to retain. That will vary to some
price is at least 25¢ an oyster.                    degree between different culture sites and
   3 - Seed oysters are cheaper than other          each grower must learn from experience.
production costs. This is an important              Generally, we find that oysters smaller
point for both commercial and noncom-               than the lower curve in Box 3 have limited
mercial oyster culturists. Since it costs           chance of reaching harvest size before
more in materials and labor to grow an              succumbing to disease.
oyster to harvestable size than the price of            Much still remains to be done in
seed, it is a waste of money to retain              improving the economics of oyster cultiva-
oysters too small to reach harvestable              tion and the marketing of cultured eastern
size. In other words, buy more seed                 oysters. At the present time we cannot be
oysters than you need and be liberal in             absolutely certain of the economic viabil-
throwing away slow growers during the               ity of the approach described here. How-
cultivation cycle. We often hear growers            ever, we believe that the fundamentals of
say of their runts “it doesn’t cost me              the approach are sound and that it is either
anything to keep them.” Not true! In                economically profitable or on the verge of
addition to labor and materials costs               being so. Continued improvements in
associated with holding them, they com-             culture practices and marketing techniques
pete for food with your other oysters and           should improve the current economic
slow the growth of all oysters in the               outlook for the practice.
system. Unfortunately, it is not possible to




                                               21
References
1 Hargis, W.J., Jr. 1999. The evolution of the           American Fisheries Society Symposium
  Chesapeake oyster reef system during the               22:438-454.
  Holocene Epoch. pp. 5-23, in: M.W.                  7 Coen, L.D. & M.W. Luckenbach. 2000.
  Luckenbach, R. Mann & J.A. Wesson                      Developing success criteria and goals for
  (eds.), Oyster Reef Habitat Restoration: A             evaluating shellfish habitat restoration:
  Synopsis and Synthesis of Approaches.                  ecological function or resource exploita-
  Virginia Institute of Marine Science Press,            tion? Ecological Engineering (in press).
  Gloucester Point, VA.                               8 Breitburg, D.L. 1999. Are three-dimen-
2 Kennedy, V.S. & L.P. Sanford. 1999.                    sional structure and healthy oyster popula-
  Characteristics of relatively unexploited              tions the keys to an ecologically interesting
  beds of Eastern Oyster, Crassosstrea                   and important fish community? pp. 239-
  virginica, and early restoration programs.             250, in: M.W. Luckenbach, R. Mann &
  pp. 25-46, in: M.W. Luckenbach, R. Mann                J.A. Wesson (eds.), Oyster Reef Habitat
  & J.A. Wesson (eds.), Oyster Reef Habitat              Restoration: A Synopsis and Synthesis of
  Restoration: A Synopsis and Synthesis of               Approaches.Virginia Institute of Marine
  Approaches.Virginia Institute of Marine                Science Press, Gloucester Point, VA.
  Science Press, Gloucester Point, VA.                9 Posey, M.H., T.D. Aplin, C.M. Powell and
3 Lenihan, H.S., C.H. Peterson & J.M. Allen.             E. Townsend. 1999. Oyster reefs as habitat
  1996. Does flow speed also have a direct               for fish and decapods. pp. 229-237, in:
  effect on growth of active suspension                  M.W. Luckenbach, R. Mann & J.A.
  feeders: an experimental test on oysters,              Wesson (eds.), Oyster Reef Habitat Resto-
  Crassostrea virginica (Gmelin) . Limnol.               ration: A Synopsis and Synthesis of
  and Oceanogr.41:1359-1366.                             Approaches.Virginia Institute of Marine
4 Bartol, I., R. Mann & M.W. Luckenbach.                 Science Press, Gloucester Point, VA.
  1999Growth and survival of oysters                  10 Cloern, J.E. 1982. Does the benthos control
  (Crassostrea virginica) on constructed                 phytoplankton biomass in South San
  reefs: effects of tidal elevation and sub-             Francisco Bay? Mar. Ecol. Prog. Ser.
  strate depth. J. Exp. Mar. Biol. Ecol. 237:            9:191-202.
  157-184.                                            11 Cohen, R.R.H., P.V. Dresler, E.J.P. Phillips
5 O’Beirn, F. X., M. W. Luckenbach, J. A.                & R.L. Cory. 1984. The effect of the
  Nestlerode, and G. M. Coates. 2000.                    Asiatic clam, Corbicula fluminea, on
  Towards design criteria in constructed                 phytoplankton of the Potomac River,
  oyster reefs: Oyster recruitment as a                  Maryland. Limnol. and Oceanogr. 29:170-
  function of substrate type and tidal height.           180.
  J. Shellfish Res. (in press).                       12 Newell, R.I.E. 1988. Ecological changes in
6 Coen, L.D., M.W. Luckenbach & D.L.                     Chesapeake Bay: are they the result of
  Breitburg. 1999. The role of oyster reefs as           overharvesting the American oyster,
  essential fish habitat: a review of current            Crassostrea virginica? pp. 536-546,
  knowledge and some new perspectives.                   in:M.P. Lynch & E.C. Krome (eds.) Under-

                                                 22
   standing the Estuary: Advances in Chesa-           20 Haskin, H.H. & S.E. Ford. 1987. Breeding
   peake Bay Research. Chesapeake Research               for resistance in molluscs. pp. 432-441, in:
   Consortium, Publication 129 CB/TRS 24/                Proceedings of the World Symposium on
   88, Gloucester Point, VA.                             Selection, Hybridization, and Genetic
13 Andrews, J.D. 1988. Epizootiology of the              Engineering in Aquaculture, Vol. II.
   disease caused by the oyster pathogen                 Henenmann, Berlin.
   Perkinsus marinus and its effects on the           21 Burreson, E. M. 1988. Effects of Perkinsus
   oyster industry. Am. Fish Soc. Special Pub.           marinus infection in the eastern oyster,
   18:47-63.                                             Crassostrea virginica (Gmelin, 1791): I.
14 Burreson, E.M & L.M. Ragone Calvo.                    Susceptibility of native and MSX-resistant
   1996. Epizootiology of Perkinsus marinus              stocks. J. Shellfish Res. 10:417-424.
   disease of oysters in Chesapeake Bay, with         22 Creswell, L., D. Vaughn and L. Strumer.
   emphasis on data since 1985. J. Shellfish             1990. Manual for the cultivation of the
   Res. 15:17-34.                                        American Oyster, Crassostrea virginica, in
15 Andrews, J.D. & S.M. Ray. 1988. Manage-               Florida. Florida Department of Agriculture
   ment strategies for control disease caused            and Consumer Services, Tallahassee, FL.
   by Perkinsus marinus. Am. Fish Soc.                23 Kemp, P.S. 1995. “Oyster Chub Ladder
   Special Pub. 18:257-264.                              System”, NC Sea Grant project reports.
16 Ford, S.E. and H.H. Haskin 1988. Manage-           24 MacKenzie, C. L. and L. W. Shearer. 1961.
   mentstrategies for MSX (Haplosporidium                The effects of salt solutions of different
   nelsoni) Disease in Eastern Oysters. Am.              strengths on oyster enemies. Proc. Nat.
   Fish Soc. Special Pub. 18:249-256.                    Shellfish Assoc. 50:97-104.
17 Ford, S.E. 1992. Avoiding the spread of            25 DeBrosse, G. A. and S. K. Allen, Jr. 1993.
   disease in commercial culture of molluscs,            Control of overset on cultured oysters using
   with special reference to Perkinsus marinus           brine solutions. J. Shellfish Res. 12:29-33.
   (Dermo) and Haplosporidium nelsoni                 26 Luckenbach, M.W. & F.X. O’Beirn. (In
   (MSX). J. Shellfish Res. 11:539-546.                  prep) A practical guide to intensive culture
18 Bushek, D. & S.K. Allen, Jr. 1996. Host-              of oysters in the mid-Atlantic, with special
   parasite interactions among broadly                   reference to Virginia.
   distributed populations of eastern oyster          27 Allen, S.K., Jr., L.G. Anderson & D. Jones.
   Crassostrea virginica and the protozoan               Guide to shellfish farm spreadsheet and
   Perkinsus marinus. Mar. Ecol. Prog. Ser.              economic analysis. New Jersey Sea Grant
   139:127-141.                                          College Program Special Publication.
19 Brown, B.L., A.J. Butt, S.W. Shelton and           28 Lacey, P.F. & S.G. Thacker. 1995.
   K.T. Paynter. 1998. Growth and mortality              AquaPlan. Business Planning Software for
   of North Carolina-heritage oysters,                   Coastal Aquaculture. Virginia Sea Grant
   Crassostrea virginica, in North Carolina              College Marine Resource Advisory Series,
   and in Chesapeake Bay. J. Applied Aquac-              No. 62, Gloucester Point, VA.
   ulture 8:25-39.

                                                 23
                                        Appendix I
List of contacts for further information on oyster aquaculture in Virginia and Maryland.


Permits
Virginia Marine Resources Commission (VMRC):
   Habitat Management Division, Mr. Robert Neikirk (757) 247-2252, rneikirk@mrc.state.va.us
   Conservation and Replenishment, Dr. James Wesson (757) 247-2121, jwesson@mrc.state.va.us
Maryland Department of Natural Resources:
   Shellfish Division, Steve Minkkinen (410) 260- 8326


Water Quality
   Virginia Department of Health – Division of Shellfish Sanitation (804) 786-7937
   Maryland Department of the Environment, (800) 633-6101


Extension Support
Virginia Institute of Marine Science (VIMS) - Sea Grant Advisory Services
   Mr. Michael Oesterling, (804) 684-7165, mike@vims.edu
   Mr. Tom Gallivan (also VIMS ABC Program), (757) 787-5575, gallivan@vims.edu
University of Maryland, Sea Grant Extension Program
   Dr. Don Merritt (also Center for Envir. Studies), (410) 221-847 meritt@hpl.umces.edu
   Don Webster, (410) 827-8056, dw16@umail.umd.edu
   Jackie Takacs, (410) 326-7356, takacs@cbl.umces.edu


NGOs
Chesapeake Bay Foundation
   In Virginia: Rob Brumbaugh, (757)-622-1964, rbrumbaough@savethebay.cbf.org
   In Maryland: Bill Goldsborough, bgoldsborough@savethebay.cbf.org
               Stew Harris, (410) 268-8816, sharris@savethebay.cbf.org
Maryland Oyster Recovery Partnership, (410) 269-5570
Virginia Shellfish Growers Association c\o VIMS Marine Advisory Service, (804) 684-7173


Oyster Gardening Organizations
Tidewater Oyster Gardeners Associations, Jackie Partin, (804) 694-4407, jpartin@crosslink.net
Northern Neck Oyster Gardeners, Don Beard, (804) 438-6563, donbeard@rivnet.net
Southside Virginia Oyster Gardeners Association, Cliff Love, (757) 481-6449
Assateague Coastal Trust, Ron Pilling, (410) 629-1538

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