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They were placed there on 19 September 2024 as part of an initiative run by the association Casa dei Pesci.
According to the study published in the MDPI journal titled ‘ Early Biodiversity Responses to Underwater Marble Sculptures Deployed as Artificial Reefs: First Scientific Assessment of a Conservation Initiative in the Northern Tyrrhenian Sea ’, underwater installations were conceived primarily to enhance habitat heterogeneity, support conservation outreach and promote community engagement. What the authors call the “first systematic scientific assessment” of an art-based marine conservation initiative. Mediterranean coastal ecosystems are affected by habitat degradation and loss of structural complexity, according to the authors.
Five marble statues stand on the seabed of the Baia del Cannone, off Talamone in Grosseto, Tuscany, in the Northern Tyrrhenian Sea. Researchers from the University of Siena and partner organisations monitored the site for one year. The pressures they list include climate change, coastal development, pollution, overexploitation and destructive fishing practices. In the Talamone area, additional local pressures include episodes of illegal bottom trawling. Casa dei Pesci, a non-profit association, has deployed concrete anti-trawling blocks along the coast to deter that activity.
The bay already hosted two marble sculptures, deployed at greater depth in 2016. The research was funded by the European Social Fund Plus 2021–2027 under the Giovanisì programme of Regione Toscana, within the project VESPESCA. Each was carved from a marble block with an approximate initial weight of 12 tonnes, according to the study. They were deployed from a pontoon with the help of scuba divers and arranged in two rows, approximately 7 metres from each other. The site lies at 5.5–6.5 metres depth on soft-bottom habitat, selected to be free of Posidonia oceanica meadows. Surveys took place on 19 September 2024, then on 4 March, 19 June, 7 August and 18 October 2025. At each visit, the team laid three 20-metre transects and collected five 50 × 50 cm photoquadrats along each. Fish were counted within 3 metres on either side of every transect line, a surveyed area of 120 square metres per transect. Underwater visibility during the surveys ranged from 3 to 7 metres. The silverside Atherina hepsetus contributed most to the difference between the deployment survey and March 2025, being present at deployment and absent in March. By October 2025, the assemblage was characterised by higher abundances or the appearance of Coris julis, Diplodus vulgaris, Sarpa salpa, Mullus barbatus and Serranus scriba.
A further 22 underwater marble sculptures lie beneath the Rocca di Talamone and in front of the “Bagno delle Donne”, and together these installations form the local underwater museum. The five monitored sculptures are S1, “Cimitero senza nome”; S2, “Guardiano”; S3, “Sigillo”; S4, “Genesi”; and S5, “Porta per gli abissi”. Total fish abundance, species richness and Shannon diversity did not differ significantly among survey dates, according to the study.
Divers also inspected each sculpture for two minutes, covering exposed surfaces and the underside, and recorded the taxa they saw as presence-only data. Assemblage composition did. On the surrounding seabed, photoquadrats showed turf, Caulerpa prolifera, bare substrate and Posidonia oceanica as the dominant components, with limited temporal change. The authors report that the sculptures did not produce detectable short-term changes in the composition of the surrounding benthic cover.
Earlier artistic deployments in the bay were not monitored systematically, so the new work establishes a quantitative ecological baseline.
