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Individual study: Ecological value of submerged breakwaters for habitat enhancement on a residential scale

Published source details

Scyphers S.B., Powers S.P. & Heck K.L. (2015) Ecological value of submerged breakwaters for habitat enhancement on a residential scale. Environmental Management, 55, 383-391


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Create artificial reefs of different 3-D structure and material used Subtidal Benthic Invertebrate Conservation

A replicated, controlled study in 2008–2010 of four artificial breakwaters in northwest Mobile Bay, Gulf of Mexico, Alabama, USA (Scyphers et al. 2015) found that breakwaters made of bags of oyster shells recruited more oysters and ribbed mussels, but did not have different species richness and abundance of small mobile animal species (invertebrates and fish combined, referred to as “nekton”), compared to “ReefBall” breakwaters, during the two years following deployment. More eastern oysters Crassostrea virginica were recorded on shell breakwaters (20 in total) than on ReefBall breakwaters (2) throughout the study period (data not statistically tested). On average across the study period, significantly more ribbed mussels Geukensia demissa were recorded on shell breakwaters (>2,500/m2) than on ReefBall breakwaters (14/m2). Across the study period, shell and ReefBall breakwaters had similar nekton species richness (shell: 2.3; ReefBall: 2.2 species/m2) and abundance (shell: 0.46; ReefBall: 0.46 individual/m2). Four artificial breakwaters made of either bags of clean oyster shells (2,000 bags/breakwater) or ReefBall modules (three rows of 41 modules/breakwater), acting as artificial reefs, were created in May 2008 along an eroding shoreline in Mobile Bay (60 m from, and parallel to, the shore; 0.75m depth). On three occasions in 2008–2010, nine modules/ReefBall breakwater and nine bags/shell breakwater were sampled. The surface area of each modules and the content of each bag were examined for live oysters and mussels. Between May 2008 and November 2009, nekton was surveyed on each side of all breakwaters using a bag seine (6.25 mm mesh) deployed over 12.5 m. All organisms were identified and counted.

(Summarised by Anaëlle Lemasson)

Create artificial reefs Subtidal Benthic Invertebrate Conservation

A replicated, site comparison study in 2008–2009 of six sites in northwest Mobile Bay, Gulf of Mexico, Alabama, USA (Scyphers et al. 2015) found that artificial breakwaters had more small mobile animal species (invertebrates and fish combined, referred to as “nekton”), but similar overall nekton abundance compared to adjacent mudflats 1.5 years after deployment. Artificial breakwaters had more species of nekton (2.2–2.3 species/m2) compared to adjacent mudflats (1.3 species/m2). However, breakwaters did not have statistically higher nekton abundance (0.5 individual/m2) compared to mudflats (0.1 individual/m2). Four artificial breakwaters made of either bagged oyster shells or concrete domes, acting as artificial reefs, were deployed in May 2008 along an eroding shoreline in Mobile Bay (60 m from, and parallel to the shore; 0.75 m depth). Between May 2008 and November 2009, nekton was surveyed at each breakwater and at two adjacent natural mudflats. During each survey, a bag seine (6.25 mm mesh) was deployed over 12.5 m on each side of the breakwaters and twice in the mudflats. All individuals were identified and counted.

(Summarised by Anaëlle Lemasson)