The first assessment of marine debris in a Site of Community Importance in the north-western Adriatic Sea (Mediterranean Sea) Valentina Melli a , Michela Angiolillo b , Francesca Ronchi a , Simonepietro Canese b , Otello Giovanardi a,d , Stefano Querin c , Tomaso Fortibuoni a,c, ⁎ a Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Loc. Brondolo, 30015 Chioggia, VE, Italy b Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Via Vitaliano Brancati 60, 00145 Rome, RM, Italy c Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/c, 34010 Sgonico, TS, Italy d Consiglio Nazionale delle Ricerche – Istituto di Scienze Marine (CNR-ISMAR), Largo Fiera della Pesca 2, 60125 Ancona, AN, Italy abstract article info Article history: Received 16 August 2016 Received in revised form 3 November 2016 Accepted 10 November 2016 Available online xxxx At present, few studies have investigated the marine litter abundance, composition and distribution on rocky bot- toms due to sampling constraints. We surveyed by means of the ROV imaging technique a system of biogenic rocky outcrops classified as a Site of Community Importance in the Adriatic Sea. A mean density of 3.3 (±1.8) items/100 m 2 was recorded, with a strong dominance of fishing- and aquaculture-related debris, accounting for 69.4% and 18.9% of the total, respectively. The abundance of litter over the rocky bottoms was significantly higher than that on soft substrates, and its spatial distribution proved to be related to hydrographic factors. Lit- ter-fauna interactions were high, with most of the debris (65.7%) entangling or covering benthic organisms, in particular habitat constructors such as the endangered sea sponge Geodia cydonium. Unless appropriate measures are undertaken to address this problem, the abundance of marine litter in the area is likely to increase. © 2016 Elsevier Ltd. All rights reserved. Keywords: Tegnùe Rocky outcrops Marine litter Habitats directive Derelict fishing gear Remotely operated vehicle 1. Introduction Every year, millions of tons of solid waste is estimated to enter ma- rine ecosystems worldwide (UNEP, 2016), making this issue one of the fastest growing threats to the ocean's health. These wastes are de- rived from every type of human activity and, after escaping manage- ment procedures, end up in the environment. Commercial and recreational shipping, fishing activities, aquaculture, river discharge, urban and industrialized areas, legal and illegal dumpsites close to the shoreline, recreational use of the coast and ports are all recognized as important sources of marine litter (Sheavly and Register, 2007). As a re- sult, marine litter has become ubiquitous in the world's oceans, from the shorelines to the deepest areas (Thompson et al., 2009). Great concern has recently been shown for how this huge amount of waste may affect the marine environment; thus, the issue was intro- duced as one of the descriptors of the Marine Strategy Framework Di- rective (MSFD) launched by the European Commission (Directive 2008/56/EC). A reduction in the litter already present in the marine en- vironment and the prevention of further inputs are expected to be achieved by 2020, in conformity with the overall goal of reaching a Good Environmental Status (GES) in European waters. Consequently, it is now of crucial importance to identify the main areas of accumula- tion and the most threatened habitats to define a strategy for limiting the amount of marine litter and restoring natural ecosystems. On the seabed, accumulation occurs in areas of complex geomor- phology and under favourable hydrodynamic conditions (Galgani et al., 2000; Watters et al., 2010). Once settled on the seabed, the debris may alter the surrounding habitats by providing a previously absent hard substrate, potentially covering large portions of the settled com- munities (Saldanha et al., 2003), preventing gas exchange, causing chemical and physical pollution (Brown and Macfadyen, 2007), and in- terfering with life on the seabed (UNEP, 2016). However, despite their vulnerability to marine litter, at present, few hard-bottom environ- ments have been investigated in terms of litter distribution. The main reason for this lack of investigation is the methodology commonly used for litter investigation on the seafloor, i.e., trawl sampling with fishing or research vessels (Galil et al., 1995; Galgani et al., 2000; Moore and Allen, 2000; Pham et al., 2014), which is a technique that is not viable on rocky substrates. Recent studies have addressed this gap in knowledge using visual investigations: scuba divers in shallow coastal and/or coral reef Marine Pollution Bulletin xxx (2016) xxx–xxx ⁎ Corresponding author at: Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Loc. Brondolo, 30015 Chioggia, VE, Italy. E-mail addresses: valentina.melli@isprambiente.it (V. Melli), michela.angiolillo@isprambiente.it (M. Angiolillo), francesca.ronchi@isprambiente.it (F. Ronchi), simonepietro.canese@isprambiente.it (S. Canese), otello.giovanardi@isprambiente.it (O. Giovanardi), squerin@inogs.it (S. Querin), tomaso.fortibuoni@isprambiente.it (T. Fortibuoni). MPB-08165; No of Pages 10 http://dx.doi.org/10.1016/j.marpolbul.2016.11.012 0025-326X/© 2016 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Please cite this article as: Melli, V., et al., The first assessment of marine debris in a Site of Community Importance in the north-western Adriatic Sea (Mediterranean Sea), Marine Pollution Bulletin (2016), http://dx.doi.org/10.1016/j.marpolbul.2016.11.012