1,721,011 research outputs found
Westward range expansion of the Lessepsian migrant Fistularia commersonii (Fistulariidae) in the Mediterranean Sea, with notes on its parasites
No full textOne adult female bluespotted cornetfish Fistularia commersonii was captured near the coast of Arbatax (Sardinia, Italy) in late October 2005. Macroscopic and microscopic analysis of the gonad revealed a postspawning ovary. Several body parts of the damselfish Chromis chromis were found in its stomach contents. Different developmental stages of 58 metazoan parasites belonging to Arthropoda, Nematoda and Platyhelminthes were detected in its mouth and digestive tract. The lepocreadiid Allolepidapedon fistulariae was reported for the first time from the Mediterranean and, with the exception of this species, all the parasites found were reported for the first time in this host. This new record of F. commersonii may confirm the rapid range expansion of this Lessepsian migrant in the western Mediterranean Sea, as well as the presence of its endoparasite A. fistulariae.One adult female bluespotted cornetfish Fistularia commersonii was captured near the coast of
Arbatax (Sardinia, Italy) in late October 2005. Macroscopic and microscopic analysis of the
gonad revealed a postspawning ovary. Several body parts of the damselfish Chromis chromis
were found in its stomach contents. Different developmental stages of 58 metazoan parasites
belonging to Arthropoda, Nematoda and Platyhelminthes were detected in its mouth and
digestive tract. The lepocreadiid Allolepidapedon fistulariae was reported for the first time from
the Mediterranean and, with the exception of this species, all the parasites found were reported
for the first time in this host. This new record of F. commersonii may confirm the rapid range
expansion of this Lessepsian migrant in the western Mediterranean Sea, as well as the presence
of its endoparasite A. fistulariae
North-easternmost record of Halosaurus ovenii (Actinopterygii: Notacanthiformes: Halosauridae) in the Mediterranean Sea, with notes on its biology
No full textA single adult female specimen of Halosaurus ovenii Johnson, 1864 was captured by trammel nets at a depth of about 200 m off the coast of Arbatax (Sardinia, Italy) in early April 2007. Macroscopic and microscopic analysis of the gonad showed a postspawning ovary. This is the fourth documented capture of this fish in the Mediterranean Sea, representing the north-easternmost record for this species in this geographic area. Furthermore, the present specimen was fished at the shallowest depth ever recorded before
FEEDING ECOLOGY OF ALEPOCEPHALUS ROSTRATUS (OSTEICHTHYES, ALEPOCEPHALIDAE) ON THE CENTRAL WESTERN MEDITERRANEAN SLOPE (SARDINIAN CHANNEL).
No full textArtificial dens as a management tool for Octopus vulgaris: evidence from a Collaborative Fisheries Research project (central western Mediterranean Sea).
No full textThe aim of the present study was to evaluate, through a Collaborative Fisheries Research (CFR) project, the efficacy of artificial dens as a possible integrative action for the management of O. vulgaris in the wild. Artificial dens, anchored on rocky substrates at a depth of 38–42 m in a temporary Fully Protected Area (FPA) off the western coast of Sardinia (central western Mediterranean Sea), showed their effectiveness as a temporary and/or safe site for Octopus vulgaris spawning. The suitability of these artificial dens was demonstrated by the presence of egg strings and females in parental care, and by the fact that all of the brooding-phases until the hatching had taken place inside. The presence of abundant cobbles, appeared to be a key factor in the building of a solid barrier for protection at the entrance of the spawning artificial dens, similar to those seen in natural dens. In addition, our results demonstrate the potential coexistence of artificial dens with natural ones, suggesting their potential use as integrative tool for the management of O. vulgaris. Close collaboration with fishermen in the framework of a CFR project within FPA may increase the success of this management action, through the enforcement of the area. Brooding details and laid egg features revealed by the monitoring are reported and discussed
Leiopathes glaberrima forest from south west Sardinia: a thousand years old nursery area for the small spotted catshark Scyliorhinus canicula.
No full textPresence of over 200 spotted catshark Scyliorinus canicula egg capsules associated with long lived black coral Leiopathes
glaberrima was observed in the South West Coast of Sardinia, describing a thousand years old nursery area for Elasmobranches.
The forest, composed by 153 colonies, was discovered during a ROV survey carried out in October 2011 over a rocky elevation of
the sea bottom, at depths between 188 and 210 meters. The described zone represents an important component of the ecosystem
that deserves special protection
Corallium rubrum and Eunicella cavolini: Distribution, population structure and co-occurrence in the deep Mediterranean Sea
No full textThe precious red coral, Corallium rubrum, and the yellow gorgonian, Eunicella cavolini, have been frequently reported as co-occurring species in the deep Mediterranean Sea. However, knowledge regarding spatial distribution of the two species in the deep sea is still fragmented, as well as potential drivers of their co-occurrence. This study aims to provide data on the status of deep-dwelling red coral populations, which are now the main target of commercial harvesting, study the demography of the yellow gorgonian in the deep sea, and finally analysing their variability when co-occur. Both species exhibited the highest population density at deeper depths and the presence of an inverse relationship between population density and colony height. We found a high percentage (40% on average) of red coral harvestable colonies (> 10 mm basal diameter), as well as of living colonies (77% as average). Our study evidenced that most of co-occurring colonies were found below 130 m depth. Red coral density did not significantly vary with the presence of E. cavolini, whereas the yellow gorgonian showed significant higher density when co-occur with red coral, even if with lower height. Distance-based linear modelling (DistLM) revealed that red coral density significantly influenced the presence of the yellow gorgonian, emphasizing the need for proper conservation strategies of red coral populations in order to preserve habitat complexity and associated diversity
Evolutionary animation in the tremendously speciational skates (Elasmobranchii, Rajoidea)
No full textIn spite of high level of morphological, reproductive and ecological conservativism, skates (suborder Rajoidea) are a group of highly diverse cartilaginous fish, whose evolution and diversification started since Late Cretaceous likely driven by Gondwanaland breakup and continental plate migration. More than 200 nominal species are presently inventoried being distributed over all Oceans, latitudes and marine ecosystems. Since speciation has been tremendous in such ancient monophyletic group, we have reconstructed evolutionary patterns and processes in the biogeographically monophyletic Eastern Atlantic skate faunas at multiple taxonomic levels by analyzing population genetic structure, phylogeographical and phylogenetic relationships in key-role taxa and clades. Variation patterns of genomic, nuclear and mitochondrial loci in Raja species revealed that geographical subpopulation structuring and cryptic speciation strongly contributed to the evolution of taxa diversity during Pliocene-Pleistocene. Comparative analysis of mitochondrial phylogenies and zoogeography of species belonging to the genera Raja, Leucoraja, Rajella, Dipturus, Amblyraja and Rostroraja revealed that present fauna diversity evolved since Early Miocene. The allopatric speciation and accumulation of genome divergence over time seem to be the predominant processes in shaping species diversity in these clades. However, the occurrence of relatively recent sympatric sister species indicate that also the rapid onset of highly efficient reproductive barriers could be relevant for cladogenesis in such group. Conspecific subpopulations geographically structured, adjacent sibling species and allopatric divergent sister species appeared rather like evolutionary animation of such still intriguing fish clade
Spatial distribution and habitat characterization of marine animal forest assemblages along nine submarine canyons of Eastern Sardinia (central Mediterranean Sea)
Full text linkSubmarine canyons are peculiar habitats of the continental margin due to their hydrodynamic and geomorphological features. Coral assemblages forming marine animal forests (MAFs) are one of the key benthic components dwelling in these habitats, where they enhance the substrate's heterogeneity and provide shelter, feeding and spawning habitats for a wide variety of species. They are also considered Vulnerable Marine Ecosystems (VMEs), since their fragile three-dimensional framework and slow growth rate exposes them to multiple anthropogenic stressors. Understanding the coupling processes between environmental factors and the scale at which coral assemblages develop in these habitats, is an essential step towards their protection. This study aims to identify MAFs along submarine canyons in the central Mediterranean basin (Eastern Sardinia) on the basis of video transects carried out using Remotely Operated Vehicle and test the influence of environmental variables (silt coverage, distance from the coast, water depth and slope of the substrate) in driving the spatial distribution variability. We identified nine MAF assemblages dwelling in both rocky and silted substrate, from 90 to 220 m depth. We found that the most significant variability in densities and diversity of MAF assemblages occurs mostly within canyons rather than among canyons that are distant hundreds of km apart. Distance-based linear modelling (DistLM) identified silt coverage and water depth as the main factors explaining the observed variability. Overall our study provided new insights on MAFs composition and spatial distribution in submarine canyons which are, in turn, strongly influenced by local physical conditions. Such results emphasized the need for sound in situ conservation strategies in order to preserve MAFs and their ecological role
Microplastics in the crustaceans Nephrops norvegicus and Aristeus antennatus: Flagship species for deep-sea environments?
Full text linkIngestion of microplastics (MPs) has been documented in several marine organisms, but their occurrence in deep-sea species remains almost unknown. In this study, MPs were investigated in two economically and ecologically key crustaceans of the Mediterranean Sea, the Norwegian lobster Nephrops norvegicus and the shrimp Aristeus antennatus. Both the species were collected from 14 sites around Sardinia Island, at depths comprised between 270 and 660 m. A total of 89 and 63 stomachs were analysed for N. norvegicus and A. antennatus respectively, and more than 2000 MPs-like particles were extracted and sorted for identification and characterization by μFT-IR. In N. norvegicus, 83% of the specimens contained MPs, with an average abundance of 5.5 ± 0.8 MPs individual-1, while A. antennatus showed a lower frequency of ingestion (67%) and a lower mean number of MPs (1.66 ± 0.1 MPs individual-1). Composition and size of particles differed significantly between the two species. The non-selective feeding strategy of N. norvegicus could explain the 3-5 folds higher numbers of MPs in its stomach, which were mostly composed of films and fragments derived by polyethylene and polypropylene single-use plastic items. Contrarily, most MPs in the stomachs of A. antennatus were polyester filaments. The MPs abundance observed in N. norvegicus is among the highest detected in Mediterranean species considering both fish and invertebrates species, and provides novel insights on MPs bioavailability in deep-sea habitats. The overall results suggest that both N. norvegicus and A. antennatus, easily available in common fishery markets, could be valuable bioindicators and flagship species for plastic contamination in the deep-sea
Deep-Dwelling Populations of Mediterranean Corallium rubrum and Eunicella cavolini: Distribution, Demography, and Co-occurrence
Full text linkCorallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in the deep rocky habitats of the Mediterranean Sea with a high hydrodynamic and moderate eutrophication. Their spatial distribution and demography in the deep sea are mainly affected by temperature and direct and indirect anthropogenic activities; however, knowledge of the factors that potentially influence their co-existence is scarce. This paper provides novel data on the distribution and demography of these two species, at depths between 50 and 290 m in the Western Mediterranean Sea, providing insights on their co-occurrence. Both species exhibited the highest population density at deeper sites (>150 m), showing an inverse size–density relation. Density values ranged from 0.03 colonies m−2 to 32 and 80 col. m−2 for yellow gorgonian and red coral, respectively. The two species co-occurred in 13% of the total frames examined, mostly dwelling between 120 and 160 m depth. Distance-based linear modeling (DistLM) emphasized that when co-occurring the variability of the two species’ densities were significantly driven by the density— rather than the morphology (i.e., height)—of the other species. We stress the need for further studies to elucidate the possible mutual effects of suspension feeders and to test the role of different environmental factors potentially influencing inter-specific relationships
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