University of Maryland Extension

Bottom Culture

The traditional method of oyster production is bottom culture using a Submerged Land Lease (SLL) granted by the State of Maryland.  This creates a landlord/tenant relationship between the grower and the State, allowing the leaseholder to grow oysters using methods that mimic a natural oyster reef.

Shell placed on lease to form a base for

planting seed oysters

The bottom is prepared with oyster shell or another base material so that it is above the bottom.  Spat set on shell can be spread on the area and the base keeps the spat or small oysters from sinking into the bottom and smothering.  It is important to choose the location of the SLL carefully.  If the area has too much soft sediment it will require a great deal of shell to create the base.  Base material, especially oyster shell, is hard to obtain and getting more expensive as demand increases.

Seed should be checked periodically and broken apart
for better growth

In areas where there is a history of frequent natural spat production the shell may get a “set” fairly regularly.  If so, the grower may wish to only supplement this with hatchery seed to ensure an annual rate of production or to grow certain animals such as triploid for summer harvest.  Bottom culture provides a lower cost production method to water column culture but must be managed like any other aquaculture crop.  Spat on shell helps protect young oysters from many predators but as the young oysters grow, they must be worked with harvest gear and broken apart to create oysters with better shape and size.  Leaving them on the shell throughout their growing cycle will result in oysters that have less marketability due to remaining in clumps and being considered less desirable.

Bottom Culture Cost Analysis Publication

(PDF Document)

Bottom Culture Cost Analysis Spreadsheet

(Excel Document)

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