More than half of the human population lives on the coast, and the resulting impacts on coastal ecosystems are widespread, including habitat destruction caused by the armoring of shorelines via the construction of seawalls. Despite their purpose to protect property from erosion, these structures degrade habitats for commercially important fish and invertebrates, and ultimately cause erosion of nearby shorelines via deflected wave energy. Despite the drawbacks of these seawalls, property owners and coastal managers often have no practical alternatives.
In order to explore seawall alternatives, MSC postdoctoral researcher Steven Scyphers of the Grabowski Lab, and colleagues, investigated the ecological value of two types of submerged breakwaters, that had been constructed along an eroding shoreline in Mobile Bay, AL as part of a community restoration effort. Results of the study were recently published in the journal Environmental Management.
The monitoring efforts revealed that one type of breakwater composed of bagged oyster shell was preferred by ribbed mussels, but that both the bagged oyster and the Reef BallTM concrete dome breakwaters supported increased juvenile and small fish, compared to control habitats with no breakwaters. These finding suggest that construction of inexpensive, small-scale breakwaters can improve the quality of degraded habitats for ecologically important species such as bivalves and small fishes. Scyphers and colleagues note that the ability of these structures to mitigate erosion and protect shorelines will require additional, longer-term research.
