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Center for Coastal Resources Management

Pre-Cast Reef Structures

Oyster Castle
Pre-cast concrete structures currently being used for living shoreline reefs include Oyster Castles® which are inter-locking blocks that can be arranged in different ways.
Reef Ball
Reef Balls are another pre-cast concrete product being used to construct oyster restoration reefs and living shoreline reefs.
Ready Reef
Ready Reef is a pyramid-shaped pre-cast concrete structure being used for living shoreline reefs. Ready Reef

Various manufactured products can be used to create an artificial reef foundation that supports the settlement and growth of shellfish.  Individual units are typically placed close together similar to a stacked shell bag or marsh sill structure. 

Suitable Sites
  • Evidence of healthy native shellfish population in vicinity, e.g. oyster beds &/or ribbed mussels
  • Salinity always above 10 ppt; sites with salinity below 5 ppt are not suitable for growing oysters
  • Water depth at least 1 foot at low tide; intertidal reefs are subject to freezing and winter die-off
  • Firm bottom, not soft mud
  • Suitable access to deploy and remove reef structures is available
Guidelines for Pre-Cast Reef Structures
  • Use marine-safe concrete structures that encourage shellfish to attach or settle
  • Include tidal gaps if the height of a continuous reef exceeds the mean high water elevation and the reef is adjacent to a natural or planted tidal marsh
  • Reef structures should be monitored for shifting and displacement from original permitted location
  • Promptly remove failed or damaged reef structures