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2 M. Angiolillo et al. / Marine Pollution Bulletin xxx (2015) xxx–xxx
1995), raising concerns regarding threats to the conservation of the
rich Mediterranean biodiversity (Coll et al., 2010).
Among the sources of marine pollution, litter is an ecological
and social concern and an increasing issue worldwide (Galil
et al., 1995; Galgani et al., 2000; Bauer et al., 2008; UNEP, 2009).
Marine debris is defined as a solid or persistent material of human
origin either discarded or abandoned in the marine and coastal
environment (National Academy of Sciences, 1975). It represents
a significant and persistent threat to wildlife due to its low biode-
gradability and its potential to be ingested by or to entangle mar-
ine organisms (Laist, 1987, 1997; Bavestrello et al., 1997;
Yoshikawa and Asoh, 2004; Lee et al., 2006; Bo et al., 2014). More-
over, it can serve as means of transport and habitat for alien spe-
cies, altering the natural community composition (Katsanevakis
et al., 2007)
Since the 1970s, several studies have faced the problem of deb-
ris in marine environments (Galgani et al., 1996; Matsuoka et al.,
2005; Katsanevakis et al., 2007; Spengler and Costa, 2008; UNEP,
2009; Keller et al., 2010). In particular, beach and floating litter
has been recognized as an important social problem due to its
esthetic impact and its influence on public health (Hess et al.,
1999; UNEP, 2009). Whereas, little information is available regard-
ing the composition and distribution of submerged marine debris
and its influence on the benthic organisms (Galgani et al., 2000;
Spengler and Costa, 2008; Watters et al., 2010; Miyake et al.,
2011). Once settled on the seabed, marine debris alters the habitat
by providing a previously absent hard substrate that organisms can
eventually cover. Moreover, the debris covering the sediment pre-
vents gas exchange and interferes with life on the seabed (UNEP,
2009). Finally, lost fishing gears, such as lines and nets, and
anchors may cause direct physical damage to benthic organisms
(Donohue et al., 2001; Yoshikawa and Asoh, 2004; Bauer et al.,
2008; Heifetz et al., 2009; Bo et al., 2013, 2014), since abrasive
actions cause the progressive removal of tissues from sessile
organisms (Bavestrello et al., 1997).
Various methods have been employed to quantify marine debris
on the sea floor and the ones currently used in deep sea environ-
ments include: bottom trawlers, sonar, submersibles and ROVs
(Spengler and Costa, 2008). In particular, submersibles and ROVs
have been used to investigate benthic litter on the continental
slope and the abyssal plain (Galgani et al., 1996, 2000; Freese,
2001; Fosså et al., 2002; Heifetz et al., 2009; Watters et al., 2010;
Miyake et al., 2011; Mordecai et al., 2011; Bergmann and Klages,
2012; Fabri et al., 2014). Visual data, in form of videos and pictures, ates a basin-scale cyclonic gyre transporting offshore the land run-
have been demonstrated to be useful in obtaining quantitative data
on deep-sea litter; even if debris cannot be directly inspected and
measured (Spengler and Costa, 2008; Watters et al., 2010). The
most important feature of these methods is that they can be effec-
tively applied to all sea bottom types, including complex rocky
habitats, where some debris (especially fishing gears) may be
found in abundance (Watters et al., 2010). Moreover, these meth-
ods do not cause any impact on the explored environments;
whereas the bottom trawling gear method can affect the seafloor
(Gage et al., 2005).
In the last decade, there has been an increased interest from the
scientific communities on how commercial fisheries and the pres-
ence of debris have affected the sea bottom. However, the majority
of studies have investigated the impact of mobile gears, such as
trawls and dredges, on soft bottom community structure (e.g.
Kaiser et al., 2000; Freese, 2001; Koslow et al., 2001; Cryer et al.,
2002; Fosså et al., 2002; Maynou and Cartes, 2011; Mangano
et al., 2013) or the effect of ghost fishing (e.g. Matsuoka et al.,
2005; Ayaz et al., 2006; Baeta et al., 2009). While, the impact of lost from the San Pietro Island to the Gulf of Cagliari, while a smaller
fishing gears on sessile organisms are less documented (Bavestrello
et al., 1997; Eno et al., 2001; Freese, 2001; Chiappone et al., 2002,
2005; Asoh et al., 2004; Yoshikawa and Asoh, 2004; Heifetz et al.,
Please cite this article in press as: Angiolillo, M., et al. Distribution and assessment of marine debris in the deep Tyrrhenian Sea (NW Mediterranean Sea,
Italy). Mar. Pollut. Bull. (2015), http://dx.doi.org/10.1016/j.marpolbul.2014.12.044
2009; Bo et al., 2013, 2014), and little research has been focused
on the impact of debris on rocky environments (e.g. Watters
et al., 2010; Mordecai et al., 2011; Fabri et al., 2014).
Although, the Mediterranean basin is considered a particularly
sensitive ecosystem (Bianchi and Morri, 2000; Coll et al., 2010),
at present little is known about the extent of litter, especially in
rocky areas deeper than 100 m (Galgani et al., 1996, 2000; Orejas
et al., 2009; Madurell et al., 2012; Watremez, 2012; Bo et al.,
2013, 2014; Fabri et al., 2014).
The aim of this study is to draw a baseline quantitative picture,
by means of ROV, on the marine debris in three Italian regions
(Tyrrhenian Sea, NW Mediterranean). This work attempts to eval-
uate, through a large number of observations, the occurrence and
abundance of different types of debris and their potential impacts
on benthic fauna. The study has been carried out in a marine area
where there is a high level of tourism, commercial fishing and
coastal urban population with respect to other areas of the Medi-
terranean basin.
2. Material and methods
2.1. Study areas
The data on marine debris were collected during three different
surveys financed respectively by the Italian Ministry for Environ-
ment, Land and Sea (MATTM) and by Sardinian Regional Council
aimed to explore rocky coral assemblages and to study red coral
(Corallium rubrum) deep-dwelling populations. The cruises were
carried out on-board the R/V Astrea of ISPRA along the south Tyr-
rhenian coast (NW Mediterranean Sea, Italy), respectively in
June-July 2010 in Campania and September–October 2011 in Sicily
and Sardinia (Fig. 1).
Along the north coast of Campania six areas were explored
(Fig. 1A), located in the Gulf of Naples and in the Sorrentine Penin-
sula. The Gulf of Naples is a SW oriented coastal embayment with
an average depth of 170 m and a continental shelf with variable
width ranging between 2.5 and 10–15 km offshore (Ribera
d’Alcalà et al., 2004). The seafloor is characterized by a rough mor-
phology, influencing hydrological features of the gulf, character-
ized by both oligotrophic and eutrophic systems and exhibiting a
strong seasonal variability. The outer part of the Gulf of Naples is
more directly influenced by offshore Tyrrhenian oligotrophic
waters (Cianelli et al., 2011), that when move inside the gulf, cre-
off. On the contrary, when the Tyrrhenian current moves south-
eastward, the inner part remains separated forming anticyclonic
gyres (De Maio et al., 1985; Cianelli et al., 2011). This condition
prevents the renovation of the coastal waters, thus favoring stag-
nation and consequently pollution and high sedimentation rate
(De Maio et al., 1985; Cianelli et al., 2011). The Gulf of Naples is
among the most densely inhabited Italian areas and it is heavily
influenced by the land runoff. Along its coasts approximately 30
ports and more than 300 maritime constructions are located
(Uttieri et al., 2011). The intense anthropic pressures determine a
strong impact on the marine ecosystem and its waters present
hydrographic and biological properties reflecting anthropic stress
(Ribera d’Alcalà et al., 1989; Zingone et al., 2010).
In Sardinia, eleven areas located in the southern part of the
island (Fig. 1B), and distributed through the Sardinia Channel and
the Tyrrhenian Sea were explored. The seafloor morphology is dif-
ferent from the south eastern coast westwards; on the western
side, a wide shelf area characterized by volcanic outcrops extends
shelf area (2 km of extension on average) with several canyon
heads occurs along the south eastern shelf margin (Sulli, 2000;