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102 Gianmarco Ingrosso et al.

negatively affect the associated biodiversity. Since most bioconstructions are
the result of calcification processes, ocean acidification has the potential to
change seascapes dramatically.

4.1.4 Fisheries
Fishing activities have several direct and indirect effects on bioconstructions,
particularly in subtidal habitats, affecting single species (Terro ´n-Sigler, 2016;
Terro ´n-Sigler et al., 2016b) or whole bioconstructions (Cerrano et al., 2001).
A major mechanism of distrurbance consists of direct mechanical damage
caused by fishing gears (Piazzi et al., 2012), whereas indirect effects involve
increase in sediment load due the physical disturbance on the sea bottom
and sediment resuspension, or damage from ghost nets (Fig. 10A). Along
North European coasts, physical damage has been reported to seriously impact
Sabellaria reefs, caused mainly by trawling for shrimps and dredging for oysters
and mussels (Dubois et al., 2002, 2006; Riesen and Riese, 1982).
Both artisanal and recreational fisheries affect coralligenous bio-
constructions, damaging their three-dimensional structure (e.g. both remov-
ing pieces of the biogenic structure and the living tissue of the arborescent
organisms, such as gorgonians) as suggested by the widespread occurrence
of lost fishing lines and ghost nets in these environments (Bavestrello et al.,
1997; Cau et al.,2015a,2017a; Di Camillo et al., 2018). Artisanal and recre-
ational fishing (e.g. long lines) are also the main fishing practices affecting
continental coralligenous animal forests and CWC bioconstructions, as these
fisheries target commercial species gravitating within or around these ecosys-
tems (Angiolillo et al., 2015; Bo et al., 2014, 2015; D’Onghia et al., 2012;
Gori et al., 2017). Bottom trawling, in contrast, only marginally affects these
bioconstructions, due to the protection offered by hard substrates and coral
mounds (Enrichetti et al., 2018; Mastrototaro et al., 2013), which can seri-
ously damage the fishing gear, thereby making such areas less accessible to
trawl fishing activities and providing a natural refuge for the associated fauna
(D’Onghia et al., 2011). Under particular conditions, however, trawling can
cause severe damage, as in the northern Adriatic, where mesophotic biogenic
habitats, due to their flat shape, shallow depth, low relief and high friability, are
threatened by this fishing activity, especially when carried out by methods
such as Rapido gear (Pranovi et al., 2000).

4.1.5 Coastal Development
The functioning of coastal marine habitats depends also on a dynamic bal-
ance between sediment input and export; human activities influence these