Relevance of mytilid shell microtopographies for fouling defence – a global comparison

Prevention of epibiosis is of vital importance for most aquatic organisms, which can have consequences for their ability to invade new areas. Surface microtopography of the shell periostracum has been shown to have antifouling properties for mytilid mussels, and the topography shows regional differences. This article examines whether an optimal shell design exists and evaluates the degree to which shell microstructure is matched with the properties of the local fouling community. Biomimics of four mytilid species from different regional provenances were exposed at eight different sites in both northern and southern hemispheres. Tendencies of the microtopography to both inhibit and facilitate fouling were detected after 3 and 6 weeks of immersion. However, on a global scale, all microtopographies failed to prevent fouling in a consistent manner when exposed to various fouling communities and when decoupled from other shell properties. It is therefore suggested that the recently discovered chemical anti-microfouling properties of the periostracum complement the anti-macrofouling defence offered by shell microtopography. 1Laboratório de Manejo, Ecologia e Conservação Marinha, Instituto Oceanográfico, Universidade de São Paulo, Praça do Oceanográfico, 191, CEP 05508-900, São Paulo - SP, Brazil. 2ARONIA Coastal Zone Research Team, Novia University of Applied Sciences at Åbo akademi, Raserborgvägen 9, Ekenäs, Finland. 3Marine Science and Fisheries Department, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, PO Box 34, 123 Muscat, Sultanate of Oman. 4CEAZA – Centro de Estudios Avancados en Zonas Aridas, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile. 5Maritime Platforms Division, Defence Science & Technology Organisation, 506 Lorimer Street, Fishermans Bend, Vic 3207, Australia. 6Natural England, North East Region, The Quadrant, Newburn Riverside, Newcastle upon Tyne NE15 8NZ, UK.