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24 result(s) for "Rotta, Andrea"
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A spatially explicit risk assessment approach: Cetaceans and marine traffic in the Pelagos Sanctuary (Mediterranean Sea)
Spatially explicit risk assessment is an essential component of Marine Spatial Planning (MSP), which provides a comprehensive framework for managing multiple uses of the marine environment, minimizing environmental impacts and conflicts among users. In this study, we assessed the risk of the exposure to high intensity vessel traffic areas for the three most abundant cetacean species (Stenella coeruleoalba, Tursiops truncatus and Balaenoptera physalus) in the southern area of the Pelagos Sanctuary, which is the only pelagic Marine Protected Area (MPA) for marine mammals in the Mediterranean Sea. In particular, we modeled the occurrence of the three cetacean species as a function of habitat variables in June by using hierarchical Bayesian spatial-temporal models. Similarly, we modelled the marine traffic intensity in order to find high risk areas and estimated the potential conflict due to the overlap with the cetacean home ranges. Results identified two main hot-spots of high intensity marine traffic in the area, which partially overlap with the area of presence of the studied species. Our findings emphasize the need for nationally relevant and transboundary planning and management measures for these marine species
Adaptive Response to Gillnets Bycatch in a North Sardinia Mediterranean Shag (Gulosus aristotelis desmarestii) Population
Mediterranean Shag (Gulosus aristotelis desmarestii) is a seabird endemic to the Mediterranean and Black Seas, recently included in the IUCN list of threatened Species. Most of the reproductive colonies are hosted in Sardinia and surrounding islets. Bycatch in fishing nets is one of the most significant threats for this population. Our work aimed to assess alterations in the sex ratio caused by bycatch and to study the adaptive response of the population to a skewed adult sex ratio. The sex ratio of Mediterranean Shags found drowned in the gillnets near the colonies and that of the nestlings of the Corcelli (northeast Sardinia) colony was determined using the sex-linked polymorphism of the gene Chromobox-Helicase-DNA-binding 1. The data of the shags found drowned in gillnets evidenced a high mortality rate (83.3%; p < 0.001) and a larger size of males (35% heavier than females, p < 0.05) compared to females, supporting the theory that heavier individuals are able to forage at great depths. With 64.8% of the nestlings being male, the sex ratio of nestlings was statistically different from parity (p < 0.05). Furthermore, it was related to the brood size. In one- and two-chick broods, 73% and 70% of nestlings, respectively, were males, while in three-chick broods, only 33% were males. Our data identify the higher rate of male shags drowned in gillnets as a factor causing an alteration of the sex ratio in the Mediterranean Shag population. According to the Sex Allocation Theory, an adaptive adjustment of sex made by adult females restores the Mendelian sex ratio in the population.
Ejaculate collection efficiency and post-thaw semen quality in wild-caught Griffon vultures from the Sardinian population
This study aimed to test the feasibility of a programme of semen collection and cryopreservation in Griffon vultures. Four wild-caught individuals kept in captivity because of unrecoverable traumas were used. Semen collection attempts were made twice a week during three consecutive reproductive seasons (December – March) using the abdominal massage method. Ejaculation was successfully induced between late January and late February. Semen collection efficiency was rather low (27.9%) and it did not vary among individuals (p > 0.05). No differences were found in ejaculate volumes (12.5 +/- 9.1 μl), spermatozoa concentration (28.4 +/- 30.9 million cells/ml) and viability (61.3 +/- 13.9%) among the 4 vultures. ATP values differed among the four vultures (p < 0.001); B showed higher nucleotide concentration than both C and D, while it did not differ form A, whose values were higher compared with D. After freezing and thawing, semen in vitro viability, DNA integrity and ATP intracellular concentration were determined. Spermatozoa viability after thawing did not differ among the four individuals (52.6 +/- 5.8 in A, 53.4 +/- 4.6 in B, 50.4 +/- 3.2 in C, 42.5 +/- 2.7 in D), but it decreased significantly compared to fresh semen (p < 0.05). During 4 hrs in vitro culture, spermatozoa collected from B maintained over time a higher viability in vitro when compared to A, C and D. As evaluated by the comet assay method, DNA fragmentation after freezing and thawing did not differ in the 4 vultures. ATP concentration in frozen/thawed semen was significantly lower than in fresh semen (p < 0.0001). This study indicates that semen cryopreservation can be considered as a useful tool in the conservation of Griffon vulture genetic resources, but further studies are needed to optimize this technique.
Assessing the effects of different management scenarios on the conservation of small island vulture populations
Although the population of Griffon Vulture Gyps fulvus is significantly increasing in Europe, in Italy the species is still on the Red List as ‘Critically Endangered’, with the last natural population persisting on the island of Sardinia. Several episodes of poisoning hampered the success of conservation actions implemented in the years 1987–1995. In 2005 there were estimated to be only 31–32 territorial pairs, with the population occupying the territories of Alghero and Bosa. We used a long-term dataset of reproductive records from the Sardinian Griffon Vulture populations to run a population viability analysis (PVA) to evaluate the extinction risk using the Vortex simulation software. The model estimated the probability of extinction over the next five generations (estimated generation time: 11 years, simulation time used: 55 years) as 96.4% for the Alghero population, and near-zero for the Bosa population. We used sensitivity analyses to understand how uncertainty about parameter values affect model outcomes. Population projections were evaluated under different management scenarios tackling the main threats (poisoning and human disturbance) and implementing conservation actions (supplementary feeding and restocking). Our results showed that population size is a critical factor in affecting the projections of population dynamics of Griffon Vultures. Sensitivity analyses highlighted the importance of poisoning events to population persistence and showed that juvenile and adult mortality rates had a secondary impact on population viability. The only conservation measure effective in significantly increasing stochastic growth rates in the Alghero population, whose initial population was set at five individuals, was the complete removal of poisoning events. When targeting the Bosa population (initial population size 94 individuals), supplementary feeding, mitigation of the risk of poisoning episodes, restocking, and mitigation of human disturbance in the reproductive sites significantly increased stochastic growth rate. A cost-effectiveness analysis should be performed to prioritise interventions.
Effects of vessel traffic on relative abundance and behaviour of cetaceans: the case of the bottlenose dolphins in the Archipelago de La Maddalena, north-western Mediterranean sea
Many studies have shown that vessel traffic has both long- and short-term negative effects on marine mammals. Although there has been a great expansion of recreational vessel traffic in the Mediterranean Sea in recent decades, few studies focused on this problem. Here, Bayesian models were used to explore the influence of vessel traffic on behaviour and relative abundance patterns of bottlenose dolphin in the Archipelago de La Maddalena (Italy), a coastal area included within the Pelagos Sanctuary. Results showed that season, moon phase and presence of calves had an effect on the number of adult dolphins per sighting, and that there were differences in occurrence in the sub-areas. On the contrary, the number of vessels was negatively related to the number of adult dolphins and their mean dive intervals. In particular, when more than three recreational boats were present in the area, dolphins surfaced more frequently per unit time and behaviours such as feeding and socializing were not detected. On the contrary, longer mean dive was found when fishing boats were present. Our results provide additional support for the need to consider disturbance such as vessel traffic in management plans for cetacean conservation.
FIRST GAMMAHERPESVIRUS DETECTION IN A FREE-LIVING MEDITERRANEAN BOTTLENOSE DOLPHIN
Recently, herpes viruses have been detected in different cetacean species from the Atlantic and in Mediterranean striped dolphins (Stenella coeruleoalba). While pathogens such as cetacean morbillivirus have been widely studied following recent epizootics, herpesvirus (HV) distribution and pathogenic effects in cetaceans are still understudied. This study reports the first molecular identification of a Gammaherpesvirus in the genital mucosa of a free-living Mediterranean bottlenose dolphin (Tursiops truncatus) stranded off the coast of central Italy. Sequenced herpesviral PCR product was closely related to other HVs recently isolated in the genital mucosa of various cetacean species.
Assessing foraging tradition in wild bottlenose dolphins (Tursiops truncatus)
This study was part of the Tursiops Project of the Dolphin Research Centre of Caprera, La Maddalena. Financial and logistical support was provided by the Centro Turistico Studentesco and by the National Park of the Arcipelago di La Maddalena.
Lettuce production in a DWC aquaponic system with and without bioflocs compared to a hydroponic system in southern Brazil
Three recirculation systems – aquaponics (Aqua), aquaponics with bioflocs (AquaFloc), and hydroponics (Hydro) – were established to evaluate lettuce production (floating) over 45 days. Juveniles of hybrid tambacus kept in aquaponic tanks were fed commercial feed. Water quality was monitored and vegetable growth was assessed. Metrics of lettuce, such as head diameter, height, fresh matter, dry matter, number of leaves, and chlorophyll concentration, were significantly higher (p < 0.05) in the Hydro system than in the AquaFloc system even after 60 days. The AquaFloc system exhibited 62% fish survival, significantly lower (p < 0.05) ammonia and nitrite concentrations than Hydro, and an absence of nitrate. Electrical conductivity and total dissolved solids concentration were significantly lower (p < 0.05) in AquaFloc than in Hydro, while pH levels were significantly higher (p < 0.05) in both Aqua and AquaFloc, resulting in reduced nutrient availability for plant growth. The Aqua system showed no lettuce growth and experienced complete fish mortality. The fish-to-vegetable ratio used did not meet the nutritional demands of lettuce. Further studies are needed to determine an appropriate fish-to-vegetable ratio that provides sufficient nutrients to plants in aquaponics, along with the maintenance of optimal pH control.
The role of 18FDG–PET imaging in VEXAS syndrome: a multicentric case series and a systematic review of the literature
VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic) syndrome is characterized by heterogeneous clinical manifestations. Due to the inflammatory nature of this condition, 18-FDG–PET (18-fluorodeoxyglucose–positron emission tomography) might be used to diagnose and monitor the disease. However, no data are available about the most common findings of PET imaging in this disease. For this reason, we summarised all the available reports of patients with VEXAS who underwent at least one PET scan and described 8 additional patients’ PET from our centres. Overall, we described 35 patients’ PET findings. All patients were male, with a median age of 70 years. The most frequent hypermetabolic sites on PET scans were the bone marrow (77.1%), lymph nodes (35.3%), lungs (28.6%), spleen and large vessels (22.9%), and cartilage (20%). Six patients underwent a PET scan 2.7 ± 1.5 years before VEXAS diagnosis, showing nonspecific uptake in the bone marrow. Four patients had a follow-up PET scan, showing a decrease or a disappearance of the previously identified hypermetabolic areas. In conclusion, although no specific uptake site has been found for VEXAS syndrome, PET imaging could help detect inflammatory foci that are not clinically evident. In addition, high metabolic activity in bone marrow might precede the clinical onset of the disease, shedding light on the pathogenesis of VEXAS.
Enhancing Antimony Electrowinning from Copper Electrolyte Waste by Coupling Ion-Exchange Membrane and Mechanical Stirring
The availability of antimony is limited, as known mineral reserves are estimated at just 2 million tons. To ensure a stable supply of antimony, it is necessary to find alternatives to its primary production. The regeneration of the ion exchange resin, used in controlling impurities in the copper electrolyte, generates a hydrochloric acid waste stream containing approximately 1 g L −1 Sb. Thus, this work investigated the electrowinning of antimony from a synthetic solution emulating this condition in a single-compartment cell as well as in a membrane cell in static and stirring environment. The results demonstrated that using a cationic membrane and mechanical stirring, as a mechanism to improve mass transfer, led to a significant gain in cathodic efficiency associated with higher antimony recovery rates. The optimal condition was found when a current density of 5 mA cm −2 was imposed for 120 min under stirring, reporting an Sb recovery rate of 80.4% with a cathodic efficiency of 60.9%. Along with the high Sb recovery rate from a copper production byproduct, the proposed electrowinning process avoids generating toxic chlorine gas, highlighting its affinity with circular economy principles and environmental friendliness. The results obtained from this work are an important step towards the development of membrane processes to recover Sb from copper electrorefining waste, which have great application potential.