The Potential for Created Oyster Shell Reefs as a Sustainable Shoreline Protection Strategy in Louisiana

Piazza, B. P., et al., 2005. Restoration Ecology

Original research (primary data)
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Coastal protection remains a global priority. Protection and maintenance of shoreline integrity is often a goal of many coastal protection programs. Typically, shorelines are protected by armoring them with hard, non-native, and nonsustainable materials such as limestone. This study investigated the potential shoreline protection role of created, three-dimensional Eastern oyster (Crassostrea virginica) shell reefs fringing eroding marsh shorelines in Louisiana. Experimental reefs (25 X 1.0 X 0.7 m; intertidal) were created in June 2002 at both high and low wave energy shorelines. Six 25-m study sites (three cultched and three control noncultched) were established at each shoreline in June 2002, for a total of 12 sites. Shoreline retreat was reduced in cultched low-energy shorelines as compared to the control low-energy shorelines (analysis of variance; p < 0.001) but was not significantly different between cultched and noncultched sites in high-energy environments. Spat set increased from 0.5 +/- 0.1 spat/shell in July 2002 to a peak of 9.5 +/- 0.4 spat/shell in October 2002. On average, oyster spat grew at a rate of 0.05 mm/day through the duration of the study. Recruitment and growth rates of oyster spat suggested potential reef sustainability over time. Small fringing reefs may be a useful tool in protecting shorelines in low-energy environments. However, their usefulness may be limited in high-energy environments.

Case studies

Basic information

  • Case ID: INT-112-1
  • Intervention type: Restoration
  • Intervention description:

    Oyster reef restoration - A total of 17.5 m3 of shucked oyster shell (cultch material) was off-loaded at each cultched site, and an experimental reef (25 3 1.0 3 0.7 m) was constructed ... Reefs were built as close to the shoreline as possible. All reefs were placed within 5 m of the shoreline and were intertidal

  • Landscape/sea scape ecosystem management: No
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Coastal erosion  Positive Shoreline advance or retreat (mean monthly retreat in m): Baseline measurements of shoreline position were made at each site immediately after placement of the shell reefs, and transects were visited monthly, at which time shoreline markers were replaced ... Shoreline edge was defined as the farthest waterward extent of the wetland macrophytes. Mean shoreline re- treat rates were calculated at each site based on the trip- licate measures and standardized to 28-day rates for analysis and interpretation.
  • Approach implemented in the field: Yes
  • Specific location:

    Sister (Caillou) Lake in the Terrebonne basin, Terrebonne Parish, Louisiana

  • Country: United States of America
  • Habitat/Biome type: Deltas and estuaries |
  • Issue specific term: Not applicable


  • Notes on intervention effectivness: effectiveness determined by comparing to unrestored control sites (no reef construction) intervention was effective at low energy sites. had no effect on high energy sites (neutral + positive --> coded as positive)
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: Yes
  • Impacts for the ecosystem: No-effect
  • Ecosystem measures: nekton shoreline use
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: