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Several aspects of the relationships between VME indicator taxa and associated fauna have been previously explored mainly on rocky habitat respect the soft bottom. However, the soft bottom hosts many VMEs indicator taxa for which the ecological role remained still unexplored. This habitat hosts many associated species, a lot of them also of commercial value making this habitat more vulnerable to fishing pressure. The present study investigates the variables that shape the distribution of associated fauna and their relationship with VME indicator species in the deep soft bottom of the Mediterranean Sea. Analyzing 74 ROV (Remotely Operated Vehicle) transects, VMEs indicator taxa and fish and crustacean density were extracted and analyzed together with environmental, morphological and anthropogenic variables. Through Redundancy Analysis (RDA), our findings reveal a clear relationship between several fish and crustacean species of commercial value and VME indicator taxa, like Isidella elongata and Pennatuloidea. By applying multivariate statistical approaches to an integrative dataset, the study provides a community-level perspective on the factors shaping fish and crustacean assemblages in potentially vulnerable habitats. The result highlights the necessity to better investigate the relationship among deep sea species in a wide prospectives to give powerful data for their conservation.

A Mediterranean \"roche du large\" ecosystem, represented by four rocky shoals, located a few miles apart on a muddy bottom at 70-130 m depth in the gulf of St. Eufemia (Calabria, South Tyrrhenian Sea), was studied by means of Remotely Operated Vehicle (ROV) photo imaging. The shoals host highly diversified coral communities, mainly composed of arborescent colonies of gorgonians (Callogorgia verticillata, Paramuricea clavata, Paramuricea macrospina, Bebryce mollis, Villogorgia bebrycoides, Corallium rubrum, and Leptogorgia sarmentosa), and antipatharians (Antipathella subpinnata, Antipathes dichotoma and Parantipathes larix). The coral colonies reach high densities (up to ca. 17 colonies m(-2)) and large sizes, such as the over 1.5 m wide antipatharian colonies. We hypothesized that the abundance and composition of the coral assemblages differed significantly among the rocky shoals and with respect to the surrounding soft bottoms. Various environmental variables were tested as possible explanatory factors of the observed differences. Moreover, due to their off-coast localization, we report here that these unique ecosystems are potentially subjected to a strong pressure from the local fishing activities, which were tentatively characterized. The recorded coral β-diversity among the shoals supports the hypothesis that these habitats behave like small oases of hard substrata interspersed in a muddy bottom. Because of their intrinsic beauty and rarity and their biological and ecological value, we stress the need of specific actions aimed at the urgent protection of these oases of biodiversity.

The sea star Hymenodiscus coronata is the only Mediterranean representative of the deep-sea order Brisingida. In the North-eastern Atlantic Ocean, this species is known to create dense aggregations, while, in the Mediterranean basin, it is generally reported as scattered individuals. Through the analysis of the video footage obtained from an extensive ROV campaign carried out in the northern Strait of Sicily in 2021, over 2850 specimens were counted. The specimens, observed between 310 m and 714 m depth, showed a large variability in size and number of arms. It was noted that 17% of the specimens displayed the peculiar “sail position”, with all the arms extended vertically in the water column, possibly increasing the filtration rate. Almost the totality of the individuals was noted on soft bottoms, in accordance with the ecological preferences of the species. The density of H. coronata in each site varied between 0.01 and 0.81 individuals m−2, with the highest densities reported in sites characterized by large muddy areas among rocky outcrops and turbulent hydrodynamic conditions. Although the trawling areas exploited in 2021 did not seem to interfere with the presence of H. coronata in the study area, a precautionary approach should be assumed to protect the largest ever reported Mediterranean aggregation of this poorly known species.

Cold-water corals (CWCs) are bioengineering species that can increase habitat heterogeneity and improve the deep sea’s biological diversity and ecosystem functioning. Knowledge of their distribution provides a critical baseline for assessing the effect of natural and anthropogenic impacts on these important deep-sea habitats. The aims of this study are: i) provide new data on the spatial distribution of six CWCs species in the Strait of Sicily, ii) describe the principal environmental and anthropogenic variables that play a role in shaping their distribution, iii) identify hotspots in which individuals belonging to the various species co-occur. Presence-only data of six CWCs species, ten environmental variables (depth, slope, rugosity, aspect, flowdir, temperature, salinity, north bottom current, east bottom current, chlorophyll-a), and one variable relating to bottom trawling effort (Automatic Information System – AIS) were used to predict the suitable habitats. We used Maximum Entropy modelling (MaxEnt) approach and used the AUC (area under the receiver operating characteristic curve) and TSS (true skill statistics) to evaluate the model performance. The results showed excellent AUC, TSS and AUC’s standard deviation mean values for all six species. The validation show high predictive performance. MaxEnt identified slope, depth, and rugosity as the most important predictors, showing the highest percentage contribution for all six species considered. Throughout the study area, highlyinterspecific persistent density hotspot of CWCs co-occurrence were discovered, with a total extension of 4.05 km 2 where all species co-occur. Although studies on the effect of environmental and anthropogenic factors that impact the distribution of these species of conservation interest remain scarce, the results of this study offer useful guidance for decision-makers to develop necessary conservation measures.

This paper is the outcome of the 1st Summer School on Geomorphology, Ecology, and Marine Biology in insular environments, focused on the advanced and multidisciplinary methods for the scientific investigation of marine coastal areas. It was held at Tremiti Islands, a significant laboratory for geomorphological, biological, and ecological studies because of its dynamic interaction between geodiversity and biodiversity, which makes it an ideal place for scientific research and geotourism. Landscape information was collected during field trips, while practical activities were finalized to sampling sediments and data collection of hard bottom assemblages. The map is the result of a multidisciplinary analysis incorporating geomorphological field observations and advanced methods applicable for ecological and environmental research, supported by scientific diving. This work represents a useful tool for the dissemination of environmental knowledge of the area and for understanding the relationships between landscape and natural heritage through modern and environmentally aware tourism.

The development of in situ observational tools has significantly contributed to the study of deep-sea cephalopods and exploration of their habitat in the last decades. In this paper, we report in situ observations of rarely observed deep-sea Mediterranean cephalopods (Chiroteuthis veranyi, Chtenopteryx sicula, and Octopoteuthis sicula). These cephalopods were encountered during a scientific expedition, aimed at characterizing the biodiversity of a deep-sea area in the northern Ionian Sea. Images and video were collected by a remotely operated vehicle (ROV) between 537 and 1248 m. Chromatic, postural, locomotor, and bioluminescent behavioral components were reported for each species. This was the first time that O. sicula was filmed in its habitat and all individuals showed hovering and an arm spread posture with the arm tips exposed, producing an intermittent bioluminescence. Furthermore, our observations on six living specimens of C. sicula represent exceptional events, since this species was only observed once in the eastern Mediterranean in 2012. Overall, five females and a mature male of C. sicula were observed; the male had a large dorsal light organ. Finally, an individual of C. veranyi was observed consuming a large lanternfish (Myctophidae). In the near future, in situ explorations in the Mediterranean should be implemented to shed light on deep-sea cephalopods inhabiting this basin and fill information gaps on the biology, ecology, and behavior of elusive species.

The sea star Hymenodiscus coronata is the only Mediterranean representative of the deep-sea order Brisingida. In the North-eastern Atlantic Ocean, this species is known to create dense aggregations, while, in the Mediterranean basin, it is generally reported as scattered individuals. Through the analysis of the video footage obtained from an extensive ROV campaign carried out in the northern Strait of Sicily in 2021, over 2850 specimens were counted. The specimens, observed between 310 m and 714 m depth, showed a large variability in size and number of arms. It was noted that 17% of the specimens displayed the peculiar “sail position”, with all the arms extended vertically in the water column, possibly increasing the filtration rate. Almost the totality of the individuals was noted on soft bottoms, in accordance with the ecological preferences of the species. The density of H. coronata in each site varied between 0.01 and 0.81 individuals m[sup.−2] , with the highest densities reported in sites characterized by large muddy areas among rocky outcrops and turbulent hydrodynamic conditions. Although the trawling areas exploited in 2021 did not seem to interfere with the presence of H. coronata in the study area, a precautionary approach should be assumed to protect the largest ever reported Mediterranean aggregation of this poorly known species.

Errina aspera is the only species belonging to the family Stylasteridae known from the Mediterranean Sea. The distribution of this species includes the Messina Strait, the Gibraltar Strait and the Atlantic coast of Morocco. In spite of the taxonomic and biogeographical importance of this species, no studies were conducted on its population structure in the Messina Strait. Here we report a study carried out with the aid of a ROV on a horizontal transect 350 m long at a depth comprised between 83 and 105 m where an extremely dense population of this stylasterid (101.4 ± 13.3 m−2) was recorded. The main components of the benthic community other than E. aspera are the coralline alga Lithothamnion philippii and the white zoanthid Epizoanthus sp. The colonies of E. aspera have a height ranging between 1.2 and 18.8 cm (4.1 ± 0.1 cm on average); they generally show a bi-dimensional, fan shaped morphology, but three-dimensional, brush-like specimens are also observed. The size–frequency distribution of the colony height is unimodal with a mode in the classes of 3–5 cm and a long tail of rare large colonies suggesting that the current may act as a limiting factor for the colony growth. The association with the gastropod ovulid Pedicularia sicula is confirmed.

The presence of fin whales in the Mediterranean Sea has been documented since ancient times. In spite of this, reliable information on their ecology and distribution is limited to the north-western part of the basin. Recent genetic studies have demonstrated that Mediterranean fin whales comprise a separate population with very limited gene flow with their North Atlantic co-specifics. Although both published and anecdotal information reports their presence in the south central Mediterranean during winter, there is no information on habitat use. In February 2004, a 14-day boat survey was carried out in the waters surrounding the island of Lampedusa, where fin whales occur at this time of the year. A total of 20 fin whale groups (average group size two animals) were encountered. In each encounter the animals were engaged in surface feeding activity. From plankton samples and underwater video, the prey species was identified as the Euphausiid, Nyctiphanes couchi. The information obtained suggests that this area may be an important winter feeding ground for fin whales. The results represent significant new information on fin whale ecology in the Mediterranean, with associated conservation and management implications.

The occurrence of the candelabrum coral Ellisella paraplexauroides in Italian waters (Sicily Strait, Mediterranean Sea), was documented during a remotely operated vehicle cruise, carried out by ISPRA in May 2010 on-board the RV ‘Astrea’. Five specimens were photographed and sampled from 80 to 94 m depth on the north-east coasts of Pantelleria Island, confirming the distribution of this species in the central Mediterranean Sea. A description of the living colonies and other taxonomic and ecological characteristics is provided.