Wrecks on the Bottom: Useful, Ecological Sentinels?

Abstract

Wrecks play an important role in enhancing marine biodiversity. SCUBA diving video-samplings were performed on eight wrecks, including seven shipwrecks and a sunken airplane, scattered over 180 km along the Ligurian coastline in the northwestern Mediterranean Sea, in water depths of 30‐65 m. Differences in composition of macrobenthic communities were found to be related to the bottom sedimentology and the composition and geometry of the investigated structures. The iron, flat, and even substrata of shipwrecks were dominated by Bivalvia (Ostrea edulis) and Anthozoa (Corynactis viridis), whereas the aluminum, cage-like structure of the airplane was dominated by massive sponges and bryozoans. Furthermore, abundances of some macrobenthic invertebrates were greater on the wrecks than those observed on natural, rocky substrates. Because of the increasing popularity of use of video and photo digital apparatuses among recreational divers, combined with wreck resistance to corrosion, artificial geometries and available surfaces that facilitate species’ settlement and growth, data from wrecks consisting of images and related metadata (depth, date, water temperature, etc.) could provide a new opportunity for monitoring Mediterranean marine biodiversity.