LOOSE OYSTER SHELL
A traditional method for restoring oyster reefs and protecting marsh shorelines has been to place loose oyster shells on bare marsh sediments . The loose shell facilitates the natural creation of oyster reef development by acting as a substrate for oyster larvae to grow upon ( Virginia Institute of Marine Science [ VIMS ]). It is not resistant to wave actions , but is a great way to attract natural reef building and lessen the damage of wave action to the shorelines . This method is often used to spread and increase existing reefs so they have a higher rate of succession . This also allows for a purpose of recycling dead and used oyster shells .
LOOSE OYSTER SHELL
Site Selection
Recruitment of oyster larvae requires water salinity to be above 15 ppt . Conditions below 15 ppt salinity should be avoided , including areas where freshwater is frequently introduced . Evidence of healthy native shellfish populations in the vicinity ( e . g ., oyster beds and / or ribbed mussels ) is a good indicator for suitable sites . Generally , the selected project area should have an eroding intertidal bank , with the shell application placed in the lower limits of the intertidal range . This is generally between mean lowest low water ( MLLW ) and mean sea level ( MSL ). Intertidal reefs are subject to freezing and winter die-off . Firm soils provide optimal conditions for shell placement .
Materials and Preparation
Sun dried and cleaned oyster shells will be scattered along oyster reefs . It is recommended to quarantine shells for a minimum of 6 months before they may be placed , especially for shells originating outside of South Carolina . Treating oyster shells in this matter avoids the spread of shellfish diseases and the introduction of invasive species into South Carolina waters ( SCDNR , 2019 ).
Installation
Loose oyster shells are distributed on existing oyster reefs and open water using heavy-duty containers . For larger scale efforts , oyster shells can be dispersed from a barge using a pressurized hose .
Figure 33 : ( Left ) Distributing loose shell with pressurized hose , Society for Ecological Restoration ( Right ) Example of restored oyster reef , Jerod Foster , The Nature Conservancy ( 2018 )
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