Search results for " Mediterranean sea."
showing 10 items of 201 documents
Effects of recreational scuba diving on Mediterranean fishes: evidence of involuntary feeding?
2013
Despite a large body of literature assessing the impacts of recreational scuba diving on marine habitats, little attention has been paid to the potentially harmful effects this has on fishes. The aim of this study was the assessment of the immediate response of different fish species to divers’ activities. A decrease of fishes’ natural diffidence towards divers is shown, probably due to an enhanced availability of their prey as a result of divers’ contacts with the substrate.
Recent expansion of Northeast Atlantic and Mediterranean populations of Melicertus (Penaeus) kerathurus (Crustacea: Decapoda).
2009
We analysed the genetic diversity of Melicertus kerathurus (Penaeidae), a commercially valuable penaeid shrimp that is distributed in the Mediterranean Sea and eastern Atlantic Ocean. We examined the polymorphism of a 494 bp DNA segment of the mitochondrial COI region in 173 individuals, sampled in nine Mediterranean and two Atlantic samples, covering the whole range of the species from the tropical waters of the Gulf of Guinea to the eastern part of the Mediterranean Sea. The mean nucleotide and haplotype diversities were π = 0.00275 and h = 0.718, respectively, for the global data set, with the highest values occurring in the African samples and the lowest in the Adriatic Sea. A clear sam…
Summer aggregation of common eagle ray, Myliobatis aquila (Chondrichthyes: Myliobatidae), in the Marine Protected Area of the Egadi Islands (southwes…
2021
Author(s): Grancagnolo, Desiree; Arculeo, Marco | Abstract: We report for the first time in Italian waters a periodic and frequent presence of a summer aggregation of common eagle ray Myliobatis aquila in the island of Marettimo (southwestern Tyrrhenian Sea), which is part of the Marine Protected Area of the Egadi Islands. These aggregation could be related to different phenomena such as reproduction, feeding or simply as a transit zone.
New body metrics to determine asteroid size and weight directly in the field
2015
Asteroids are an important group of predators in many marine ecosystems. The measure of body size is crucial in studying asteroid biology as this variable affects both prey selection and predation impact. Current field techniques for estimating asteroid size (i.e. total length TL, total weight TW) include the measure of correlated variables, such us the central disk (CD) and arm length (AL). However, these variables are often time-consuming and require a direct handling of the organism. We tested the accuracy of new asteroid body metrics, the arm height (AH) or arm width (AW), to rapidly estimate body size in asteroids. AH and AW were measured in three of the most common Mediterranean aster…
A survey of ovarian maturation in a population of Aristeus antennatus [Crustacea: Decapoda)
1995
Are there any distinct genetic sub-populations of sand smelt, Atherina boyeri (Teleostei: Atherinidae) along Italian coasts? Evidence from allozyme a…
2007
Two hundred and ninety-nine specimens of Atherina boyeri, collected from five Mediterranean sites (three from the open sea (Chioggia, Catania and Gaeta) and two from river mouths (the Birgi and S. Bartolomeo rivers) were analyzed in order to confirm previous genetic studies. Eigtheen loci were scored from 12 enzymatic systems, 3 of which were polymorphic: EST*, PGM* and PGI*. Mean Fst value (0.300, p< 0.05) indicated a high genetic heterogeneity. Pairwise Fst and genetic distance revealed that samples from the river mouths (Birgi and S. Bartolomeo) were grouped separately from the open sea samples (Catania, Chioggia and Gaeta). These results are in agreement with the most recent classificat…
The late Messinian "Lago-Mare" event and the Zanclean Reflooding in the Mediterranean Sea: New insights from the Cuevas del Almanzora section (Vera B…
2020
Abstract The return to normal marine conditions in the Mediterranean Sea after the end of the Messinian Salinity Crisis (MSC), that led to the deposition of thick evaporitic succession followed by settlement of brackish to freshwater conditions of the “Lago-Mare”, is still subject to extensive debate between two opposite scenarios. One scenario implies an abrupt reflooding through the Gibraltar gateway of the Mediterranean Sea previously disconnected from the world ocean and partly desiccated. The second scenario postulates that the Mediterranean Sea kept a high-water level throughout the Messinian Salinity Crisis and was connected continuously to the Atlantic Ocean and to the Paratethys. T…
Microplastics in the Center of Mediterranean: Comparison of the Two Calabrian Coasts and Distribution from Coastal Areas to the Open Sea
2021
Plastic is everywhere—increasing evidence suggests that plastic pollution is ubiquitous and persistent in ecosystems worldwide. Microplastic pollution in marine environments is particularly insidious, as small fragmentation can increase interaction with biota and food chain access. Of particular concern is the Mediterranean Sea, which has become a large area of accumulation of plastic debris, including microplastics, whose polymeric composition is still largely unknown. In this study, we analyzed the polymeric composition, particle size distribution, shape, and color of small plastic particles (ranging from 50 to 5000 µm) collected from the sea surface in six stations at the center of the M…
Impact of Plastic Debris on the Gut Microbiota of Caretta caretta From Northwestern Adriatic Sea
2021
Plastic pollution is nowadays a relevant threat for the ecological balance in marine ecosystems. Small plastic debris (PD) can enter food webs through various marine organisms, with possible consequences on their physiology and health. The loggerhead sea turtle (Caretta caretta), widespread across the whole Mediterranean Sea, is a “flagship species,” useful as indicator of the general pollution level of marine ecosystems. Ingested PD accumulate in the final section of turtles’ digestive tract before excretion. During their transit and accumulation, PD also interact with the residing microbial community, with possible feedback consequences on the host’s health. To explore the possible relati…
Molecular diversity of dolphinfish (Coryphaena hippurus) shows the merging of endemic and widespread haplotypes in the Mediterranean Sea
2015
Molecular data on Coryphaena hippurus (Linnaeus, 1758) from western and central Mediterranean Sea were reported and compared. The aim of the study was to study the mitochondrial molecular structuring of the species at different geographical scales: localities, sub-basins, and oceans. Results show the absence of a sharp population structure inside the Mediterranean Sea, and the isolation of the Mediterranean dolphinfishes from those inhabiting the Atlantic Ocean