Search

This work illustrates the use of geomatics techniques for the documentation of Teatro Massimo in Palermo (Italy), one of the most important and big in Italy and in Europe. The theatre is characterized by a very complex structure and is realized also using innovative solution, studied at the time of the project specifically for this building; for example, an original system was realized for a natural air-conditioning system of the auditorium. Due to his complexity, the documentation of the Teatro Massimo requires studying specific survey solutions for the different parts of the building. In this paper, some studies on two of the most representative parts of the building were described. In particular, a 3D survey of the auditorium was carried out to obtain a first 3D model of the most important internal part; a very accurate monitoring of structure inside the dome of the theatre was also carried out. The survey of the auditorium was realized by a Terrestrial Laser Scanning (TLS), that has allowed the creation of a digital archive of point clouds, showing, however, the some level of criticality due to the complex shapes of building and of architectural details. The work has highlighted that specific strategy to optimize the number of acquisitions needed for the complete documentation of the auditorium. The monitoring of the structure inside the dome was carried out by topographic and photogrammetric techniques. The monitoring was aimed at measuring the displacements of the support devices connecting the iron structure of the dome. The monitoring has allowed to understand and to test the proper functionality of this complex system. Some tests were carried out also by a thermal camera to correlate the displacements of the support devices with the dilatations produced by steel thermal gradients. [ABSTRACT FROM AUTHOR]

Nowadays, 3D documentation of architectural assets is becoming a demanding task for the valorisation of Cultural Heritage especially after a restoration project. The 3D documentation can be used for detailed analysis of specific elements, for monitoring the state of conservation and for valorisation actions. The paper describes the results of the 3D close-range photogrammetry survey of the main portal of the Cathedral of Monreale (Palermo, Italy). The Cathedral is one the most important monumental complexes in Sicily that, for its high historical and artistic importance has been inscribed on UNESCO's World Heritage List since 2015. The main portal of the Cathedral has been recently restored. The restoration work has given the opportunity to evidence small details of the sculptural decorations and to carry out new interpretative analysis of the bas-reliefs. The main purpose of the work is to obtain a detailed 3D model and a high-resolution ortophoto of the entire portal and of some architectural details. The study was used to evaluate the most appropriate technical solutions for the 3D survey and to define the most suitable parameters for image acquisition and data processing. [ABSTRACT FROM AUTHOR]

This paper presents the results of an application of ultrasonic telemetry on white seabream, Diplodus sargus inhabiting an artificial reef (AR) in NW Sicily (western Mediterranean Sea). The objective of the study was to investigate the movement pattern of seabreams, verify their homing behaviour and site fidelity, determine their home range and describe their use of the habitat. Four seabreams were tagged and released, and their movements were recorded with automated and manual acoustic receivers. The spatial and temporal distribution of positional data suggest that the tagged seabreams hide inside the AR during the day, staying out of their shelter at night. The nocturnal movements of the tagged fishes are suggested to be a search for food in the seagrass patches surrounding the ARs. The monitored seabreams showed clear homing behaviour and strong site fidelity. Their home range extended from 0.01 to 0.17 km and included the AR and the surrounding sandy area with seagrass patches. Home range areas increased proportionally to the distance between the refuge on AR and the foraging areas on seagrass patches. The higher activity of seabreams during the night was interpreted as a result of a trade-off between predation risk and foraging needs. [ABSTRACT FROM AUTHOR]

Resource partitioning in two congeneric sparids, pandora Pagellus erythrinus and axillary seabream Pagellus acarne, was investigated using stomach content analysis integrated with data on stable isotopes ( δN and δC). The study was carried out on coastal muddy bottoms in the Gulf of Castellammare (southern Tyrrhenian Sea, western Mediterranean Sea) in seasons (autumn, November 2004; winter, March 2005; spring, early June 2005), at depths between 50 and 100 m. Stomach content analysis suggested low trophic niche overlap between the two species. Pagellus erythrinus mainly preyed on strictly benthic organisms (polychaetes, brachyuran crabs and benthic crustaceans). Although it consumed benthic prey, P. acarne preferred suprabenthic prey such as peracarid crustaceans from the benthic boundary layer a few metres above the bottom. The two species showed different isotopic values, with P. erythrinus exhibiting higher δN and more enriched δC than P. acarne, in accordance with its marked benthic behaviour and high predation on carnivore polychaetes. Significant temporal variability in both diet and isotopic values caused trophic differences between the two species. The autumn and winter diet differed from the spring diet and the trophic levels of both species increased from autumn and winter to spring, in accordance with variations in food availability and changes in prey δN and δC. These temporal variations may be linked to an increase in energy requirements for reproduction, together with the differing availability of preferred prey throughout the year. Significantly, lower δC was recorded in fishes collected in winter (March), suggesting the influence of river inputs as a source of particulate organic matter in this zone after the flooding season. In conclusion, these sympatric congeneric fish species displayed clear food partitioning throughout the temporal scale analysed. [ABSTRACT FROM AUTHOR]

This paper reports the weight-length relationship (WLR) for thirty-eight fish species from the Gulf of Castellammare (NW Sicily, Mediterranean Sea). A total of 59 870 fish were collected and measured during four seasonal trawl surveys carried out in 2005 at 10 to 200 m depth. The b parameter of the WLRs ranged from 1.79 ( Cepola macrophthalma) to 3.56 ( Conger conger). Significant differences in both a and b values among seasons were detected for eight species. Moreover, the condition factors (as weight-at-length) of Merluccius merluccius and Mullus barbatus were compared in different area/year combinations characterized by the presence or absence of trawling impact. While M. barbatus showed a higher condition factor in trawled areas/years, possibly due to density-dependent factors linked to the increased biomass in the no-trawl area, no such link was detected in M. merluccius. [ABSTRACT FROM AUTHOR]

This study assesses the effects of bottom trawling on the feeding ecology of the scaldfish Arnoglossus laterna, by contrasting diets in an untrawled area and in two trawled areas off northern Sicily (western Mediterranean): the Gulf of Castellammare (which hosts a 200 km2 no-trawl area) and the gulfs of Termini Imerese and Sant'Agata. Scaldfish were collected in May–June 2005 using a commercial otter trawler between 40 and 80 m on muddy bottoms. Our data show that scaldfish is a selective feeder and consumes similar prey items in the three gulfs, although between-site differences in the relative prey abundance in the stomachs were detected. In the three gulfs scaldfish fed mainly on the crab Goneplax rhomboides and on the fish Lesueurigobius suerii, but there was an increase in the consumption of L. suerii and the shrimp Alpheus glaber in the trawled areas. Ontogenetic changes were evident in the diet of scaldfish, with juveniles preying mainly upon suprabenthic species, e.g. mysids and small decapods. While significant differences occurred in the diet of juveniles among all areas due to natural spatial variability, variations in the diet of adults, which feed on benthic prey, occurred between untrawled and trawled areas. These variations were clearly due to trawling disturbance, and no significant difference was detected in the diet of adults between the two trawled areas. On the contrary, the trophic level (δ15N values) of scaldfish did not vary between trawled and untrawled areas and between juveniles and adults. Changes in the source of carbon, as detected by δ13C values, were evident between juveniles and adults, evidencing a shift from a suprabenthic (juveniles) to a benthic (adults) diet. [ABSTRACT FROM PUBLISHER]

Fishing exclusion zones have become a key management tool for habitat protection and species conservation within fisheries. In many instances, where overfishing or habitat destruction is taking place, they are being promoted strongly. For fisheries management, their use is widespread and their popularity growing. It is clear that in some cases marine protected areas may be crucial to sustaining resources. Most research to date has considered the biological or ecological effects of such reserves. However, little real analysis has been published that takes into account the links between the biology and the economics of the fisheries involved, making the economic benefits to fisheries less clear. This paper considers an exclusion zone which was implemented in 1990 in the Gulf of Castellammare, Sicily in the form of a trawl ban, modeling the potential effects of future policy in this area. The success of the trawl ban has far exceeded expectations, and it is simulated that it may be advantageous, under strict conditions, to relax the ban in part for some of the year. [ABSTRACT FROM AUTHOR]

The diet of juvenile bluefin tuna ( Thunnus thynnus) caught 2 to 8 miles off NE Sicily was investigated in order to improve knowledge of the species’ early life history. From 1998 to 2000, 107 specimens ranging from 63 to 495 mm (total length) were fished between July and November. Fishes were caught by trolling line or purse seine in a Fish Aggregating Devices (FADs) area 2 to 8 miles offshore and as by-catch of the purse-seine sardine fishery 2 to 4 miles offshore. Most frequently found items in the T. thynnus stomachs were fishes (84.5%), crustaceans (54.6%) and cephalopods (50.5%). The largest contribution in weight was provided by cephalopods (47.3%) and fishes (46.5%), while the most abundant items were fishes (51%), cephalopods (27.2%) and crustaceans (21.1%). These results suggest that young-of-the-year tuna have an essentially piscivorous diet, although invertebrate prey provide a substantial contribution to the food array. Prey show little relationship with FADs, although one prey species (blue runner, Caranx crysos) is associated with FADs in the Mediterranean. [ABSTRACT FROM AUTHOR]

Describes the rediscovery of the diogenid, Paguristes syrtensis de Saint Laurent, 1971, in a shallow-water Posidonia oceanica Delile bed along the coast of southwest Sicily, Italy. Retention of the color pattern after 15 months of fixation; Morphological characteristics; Habitat preference.