Oyster breakwater reefs promote adjacent mudflat stability and salt marsh growth in a monsoon dominated subtropical coast

Chowdhury et al (2019) Scientific Reports

Three self-sustaining breakwater oyster reefs were established on an eroding mudflat on Kutubdia Island, Bangladesh. Over four seasons, it was found that the 0.6m-high reefs attenuated wave energy by 95-100% when water levels were up to around 0.5m, whilst wave energy was partially dissipated with water levels of 0.5-1.0m depending on water level and wave height. Sediment accumulated on the landward side of the reefs, with erosion levels 54% lower than control sites. The attenuation of waves and reduction in erosion is also thought to explain the expansion of coastal salt marshes, which further stabilised adjacent sediment. This study provides evidence that constructed oyster reefs can provide sustainable protection against coastal erosion, requiring less maintenance than earthen embankments and providing benefits for coastal biodiversity and fisheries. Direct article link.