The Mediterranean Sea is a biodiversity hotspot but faces a range of direct and indirect anthropogenic pressures
threatening its ecosystems, including intensive coastal urbanization. Growing “marine urbanization”, such as
the construction of commercial and touristic ports and marinas, has led to extensive coastal armoring, with
evidence of marine ecosystems’ disruption. However, recent studies have found that these areas can host
unexpected biodiversity levels, act as nurseries and offer heterogeneous microhabitats.
This preliminary study investigates how coastal infrastructures and different anthropogenic pressure levels
may affect the composition and structure of fish assemblages along the NW coast of Sicily, including port
areas, small marinas and areas under different levels of protection within an MPA.
Sampling was carried out using Baited Remote Underwater Video systems (BRUVs). Univariate and
multivariate analyses, community indices (S, MaxN, LCBD, IndVal) and a habitat quality index, which takes
into account habitat heterogeneity and complexity, were performed.
Results on a single sampling season reveal an unexpected relationship between anthropogenic pressure and
fish assemblages in these coastal environments, with the port of Palermo city showing fish assemblages that
are quite diversified and structured, suggesting that heterogeneity and complexity of artificial habitats might
favor some fish species. Along the anthropogenic gradient, areas at moderate human press and with less
complex and heterogeneous habitats, exerts low diversity but unique species. Less-disturbed and highly
protected areas hosted assemblages of high ecological value, with a balanced presence of species belonging to
different trophic levels and associated with natural substrates.
These results show that fish assemblages do not follow the gradient of anthropogenic pressure in a linear way
but exhibit more complex responses. Both protected and heavily modified by humans environments can
contribute to the mosaic of biodiversity at a meso-scale (100 m-10 km), suggesting the need for integrated
management and perhaps consideration into spatial planning.