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.