13 research outputs found

    Unexpected Records of Newborn and Young Sharks in Ligurian and North Tyrrhenian Seas (North-Western Mediterranean Basin)

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    Between 2007 and 2022, 112 specimens of newborn and young pelagic sharks were recorded in the waters of Tuscany Region, in the South Ligurian–North Tyrrhenian Seas (north-western Mediterranean basin). The sharks belonged to the Carcharhinus plumbeus (n = 14), Prionace glauca (n = 66), Isurus oxyrinchus (n = 16), Mobula mobular (n = 5) Alopias vulpinus (n = 7) and Hexanchus griseus (n = 4) species. Each animal was correctly identified thanks to the photographs or videos collected. All specimens were incidentally captured with set nets in inshore shallow waters, except bluntnose six-gill sharks, which were bycatch of deep-water bottom-trawl fishery. Body mass, sex, total length and biometric measurements were recorded in 34 baby sharks following the Mediterranean Large Elasmobranches Monitoring (MEDLEM) protocol. The presence of very evident and often non-healed umbilical scar confirmed that some of the sample specimens were newborn. Further confirmation came from the comparison between the total length observed and the size at birth known for the sampled species as reported in the literature. Some baby sharks were preserved in the Museums of Natural History of Pisa and Florence University collections. The importance of the coastal area studied as a possible shark nursery is discussed

    Strongly structured populations and reproductive habitat fragmentation increase the vulnerability of the Mediterranean starry ray Raja asterias (Elasmobranchii, Rajidae)

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    1. The Mediterranean starry ray (Raja asterias) populations within the Mediterranean Sea are susceptible to high rates of bycatch in the multispecies trawl fisheries. Understanding its population structure and identifying critical habitats are crucial for assessing species vulnerability and setting the groundwork for specific management measures to prevent population decline. 2. To assess the population structure of R. asterias in the Mediterranean, the genetic variation in nine population samples at one mitochondrial marker and eight nuclear microsatellite loci was analysed. Moreover, 172 egg cases collected in the Strait of Sicily were identified at species level using integrated molecular and morphological approaches. 3. Genetic analyses revealed that the Mediterranean starry ray comprises three distinct units inhabiting the western, the central-western, and the central-eastern areas of the Mediterranean. An admixture zone occurs in the Strait of Sicily and the Ionian Sea, where individuals of the central-western and central-eastern population units intermingle. 4. The joint morphometric–genetic analyses of rajid egg cases confirmed the presence of more than one species in the admixture area, with a predominance of egg cases laid by R. asterias. DNA barcoding revealed that egg cases and embryos of R. asterias shared several haplotypes with adult individuals from the centralwestern and central-eastern Mediterranean Sea, revealing that females of both populations laid numerous eggs in this area. 5. According to these findings, detailed taxonomic determination of egg cases, when combined with seasonal migration studies, could improve the capability to identify important spawning or nursery areas for the Mediterranean starry ray, particularly in those admixture zones relevant to maintaining genetic diversity. 6. Finally, these new insights should be considered to update the Action Plan for the Conservation of Cartilaginous Fishes in the Mediterranean Sea with effective measures to reduce the impact of skate bycatch in trawling and safeguard egg cases in nursery areas

    Biomaterials and implants for orbital floor repair

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    Towards an ideal biomaterial for vitreous replacement: historical overview and future trends

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    Materials Used for Reconstruction After Orbital Floor Fracture

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    Advances in biotechnology continue to introduce new materials for reconstruction of orbital floor fractures. Which material is best fit for orbital floor reconstruction has been a controversial topic. Individual surgeon preferences have been supported by inconsistent inconclusive data. The purpose of this study was to assess and analyze published evidence supporting various materials used for orbital floor reconstruction and to develop a decision-making algorithm for clinical application. A systematic literature review was performed from which 48 studies were selected after primary and secondary screening based on set inclusion and exclusion criteria. This cumulatively included 3475 separate orbital floor reconstructions. Results revealed risk and benefit profiles for all materials. Autologous calvarial bone grafts, porous polyethylene, and polydioxanone (PDS) were most widely used for orbital floor reconstruction. Increased infection rates were reported with polyglactin 910/PDS composites and silastic rubber. Ocular motility was reduced most with lyophilized dura and PDS. Preoperative and postoperative rates for diplopia and enophthalmos varied among the materials. In conclusion, our results revealed continued inadequate evidence to exclusively support the use of any one biomaterial/implant for orbital floor reconstruction. Results have served to create a decision-making algorithm for clinical application. Our authors propose certain parameters for future studies seeking to demonstrate a comparison between 2 or more materials for orbital floor reconstruction

    Preliminary considerations of the status of elasmobranchs in the Italian waters

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    Few stock assessments of elasmobranchs have been conducted in the Mediterranean due to the lack of available detailed and precise information. In recent years, in the Mediterranean Sea a major concern on the status of this group does exist and consequently scientists and managers have paid a major attention on the collection of data of fisheries in which they are involved as by-catch, on the impact of different fishing techniques, and on management issues aiming at reducing undesired removals. Information on landings for the more important species is now available in some Mediterranean countries but time series are still too short. Data on age structure of catches is often partial and does not regard all the fisheries in which the species are involved making difficult the reconstruction of the demographic structure of the commercial catches. So far such difficulties made almost impossible the use of age-based analytical models or surplus production models for stock assessment. Recently, stock assessments using simple approaches suitable for data poor stocks were performed for Raja asterias and Raja clavata, Scyliorhinus canicula and Galeus melastomus in the GFCM-GSA9. R. asterias is caught especially by trawlers fleet segments targeting flat fish (15-100 m of depth). R. clavata and S. canicula are in general part of the by-catch of a fishery operating at deeper waters (about 100-200 m) mainly targeting Parapenaeus longirostris, Eledone cirrhosa and Merluccius merluccius. G. melastomus is mainly found in the depth range 200-1200 m and is exclusively caught with bottom trawlers. It constitutes an important by-catch fraction of the Nephrops norvegicus fishery (250-500 m of depth) and the deep-sea shrimps fishery
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