One-year colonization by zoobenthic species on an eco-friendly artificial reef in the English Channel intertidal zone

Abstract

The RECIF project aims to enhance the use of shellfish by-products, i.e. crushed shells of the queen scallop Aequipecten opercularis, in the development of an eco-friendly material for artificial reefs. The short-term colonization of three different types of artificial structure (blocks made of two rough-surface concretes, each with a different porosity, and blocks of ordinary concrete) is investigated to highlight possible differences between substrate materials and observe the succession of colonizing species. A total of 75 blocks were emplaced in March 2014 and monitored until February 2015 in the intertidal zone of Luc-sur-Mer (Calvados coast on the French side of the English Channel). The abundance and species richness of the whole community were recorded. Analyses show significant temporal differences in species abundance between blocks, but no variations in species richness, while also revealing differences in the settlement of species depending on their position on the blocks, i.e. on the face exposed to the main tidal currents and to the light, or on the other faces. These differences are explained by environmental parameters around the blocks and by larval behaviours. This unique experimental study focuses on all species found on the blocks, showing that it is important to take account of all the fauna to estimate the benthic production and the functional role of such artificial reefs.