scholarly journals Acoustic correction factor estimate for compensating vertical diel migration of small pelagics

2021 ◽  
Author(s):  
ANGELO BONANNO ◽  
MARCO BARRA ◽  
ANDREA DE FELICE ◽  
MARIANNA GIANNOULAKI ◽  
MAGDALENA IGLESIAS ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Mediterranean Sea ◽  
Correction Factor ◽  
Pelagic Fish ◽  
Tyrrhenian Sea ◽  
Fish Community Structure ◽  
Northern Spain ◽  
Small Pelagic Fish ◽  
Acoustic Data ◽  
The Mediterranean

Differences in acoustic estimates of small pelagic fish biomass, due to data acquisition during daytime and nighttime surveys, have been recognized for many years as a problem in acoustic surveys. In the absence of a single rule for all species and for all locations, some expert groups identified specific time intervals for acoustic data acquisition in relation to the schooling behavior of the target species. In the Mediterranean Sea, the research groups working in the MEDIAS (Mediterranean International Acoustic Survey) agreed on the importance that acoustic sampling are conducted only during day-time. Only when available time does not permit to complete the survey during daytime, data collection might be extended. In this case, working on data collected during both daytime and nighttime, a bias may occur in the biomass estimates. In order to evaluate and correct such bias, specific experiments were performed in some geographical sub-areas of the Mediterranean Sea. The data analysis allowed the estimation of a mean correction factor for the Strait of Sicily, where five surveys were carried out in different years. The correction factor was estimated also for the Adriatic Sea, Tyrrhenian Sea and Northern Spain; the observed variability among areas highlighted the importance of the spatial and temporal coverage of the survey area in order to obtain reliable estimates of the correction factor. Further studies are necessary to improve the interpretation of the obtained estimates in relation to area-related peculiarities such as zooplankton composition and abundance along with small pelagic fish community structure. 

scholarly journals Ophelia roscoffensis Augener, 1910: a new polychaete record in Italian waters

Check List ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 489-495
Author(s):  
Emanuele Mancini ◽  
Francesco Tiralongo ◽  
Daniele Ventura ◽  
Andrea Bonifazi
Keyword(s):  
Mediterranean Sea ◽  
First Record ◽  
Posidonia Oceanica ◽  
Tyrrhenian Sea ◽  
The Mediterranean

Ophelia roscoffensis Augener, 1910 is an opheliid worm identifiable by the number of anterior abranchiate chaetigers and the number of the gill pairs. Although it was already reported in the Mediterranean Sea, it has never been found in the Italian waters. This study represents the first record of Ophelia roscoffensis in the Italian waters. A total of 18 specimens were collected along the coast of Civitavecchia (Tyrrhenian Sea) in a Posidonia oceanica (L.) Delile bed at a depth of 7 m.

scholarly journals Investigation of Hg Content by a Rapid Analytical Technique in Mediterranean Pelagic Fishes

2018 ◽  
Author(s):  
Giuseppa Di Bella ◽  
Roberta Tardugno ◽  
Nicola Cicero
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Area ◽  
Pelagic Fish ◽  
Analytical Technique ◽  
Weekly Intake ◽  
Tolerable Weekly Intake ◽  
Direct Mercury Analyzer ◽  
Mercury Analyzer ◽  
Global Concern ◽  
The Mediterranean

Mercury (Hg) fish and seafood contamination is a global concern and needs worldwide sea investigations in order to protect consumers. The aim of this study was to investigate the Hg concentration by means of a rapid and simple analytical technique with direct Mercury Analyzer (DMA-80) in pelagic fish species, Tetrapturus belone (spearfish), Thunnus thynnus (tuna) and Xiphias gladius (swordfish) caught in the Mediterranean Sea. Hg contents were evaluated also in Salmo salar (salmon) as pelagic fish not belonging to the Mediterranean area. The results obtained were variable ranging between 0,015-2,562 mg kg-1 for T. thynnus specie, 0,477-3,182 mg kg-1 for X. gladius, 0,434-1,730 mg kg-1 for T. belone and 0,004-0,019 mg kg-1 for S. salar, respectively. The total Hg tolerable weekly intake (TWI) and % tolerable weekly intake (TWI%) values according to the European Food Safety Authority (EFSA) were calculated. The results highlighted that the pelagic species caught in the Mediterranean Sea should be constantly monitored due to their high Hg contents as well as their TWI and TWI% with respect to S. salar samples.

Two live sightings of Sowerby's beaked whale (Mesoplodon bidens) from the western Mediterranean (Tyrrhenian Sea)

2017 ◽  
Vol 98 (5) ◽  
pp. 1003-1009 ◽  
Author(s):  
Luca Bittau ◽  
Mattia Leone ◽  
Adrien Gannier ◽  
Alexandre Gannier ◽  
Renata Manconi
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Beaked Whale ◽  
Long Distance ◽  
The North ◽  
Western Mediterranean Sea ◽  
Beaked Whales ◽  
Species Groups ◽  
The Mediterranean

Sowerby's beaked whale (Mesoplodon bidens) was previously known in the Mediterranean Sea from a single live stranding of two individuals in the French Riviera. We report here on two live sightings in the western Mediterranean, central-western Tyrrhenian Sea off eastern Corsica (Montecristo Trough) and off eastern Sardinia (Caprera Canyon) in 2010 and 2012, respectively. In both cases single individuals, possibly the same individual, occurred within groups of Cuvier's beaked whales (Ziphius cavirostris) suggesting inter-specific interactions. Based on our close observations of mixed-species groups of Sowerby's and Cuvier's beaked whales, we hypothesize that some previous long-distance sightings of beaked whales in the Mediterranean may not be reliably attributed to Z. cavirostris. The present sightings and previous live stranding indicate that the western Mediterranean Sea is the easternmost marginal area of M. bidens within the North Atlantic geographic range. Notes on behaviour are also provided.

First record of Amphiura securigera (Echinodermata: Ophiuroidea) in the Tyrrhenian (Mediterranean) Sea

2000 ◽  
Vol 80 (1) ◽  
pp. 175-176
Author(s):  
P. Rinelli
Keyword(s):  
Mediterranean Sea ◽  
First Record ◽  
Water Circulation ◽  
Brittle Star ◽  
Tyrrhenian Sea ◽  
Bathymetric Range ◽  
First Finding ◽  
The Mediterranean

The first finding of the brittle star Amphiura securigera (Echinodermata: Ophiuroidea) in the Tyrrhenian Sea is reported. According to literature data, biotopic and edaphic features of the bottom indicate that this species preferentially lives in detritic mud-free biotopes characterized by good water circulation. Present data show that in the Mediterranean Sea A. securigera extends its bathymetric range as far as the circalittoral and upper bathyal floors.

scholarly journals Eukaryotic community composition in the sea surface microlayer across an east-west transect in the Mediterranean Sea

2020 ◽  
Author(s):  
Birthe Zäncker ◽  
Michael Cunliffe ◽  
Anja Engel
Keyword(s):  
Mediterranean Sea ◽  
Community Composition ◽  
Significant Proportion ◽  
Sea Surface ◽  
Surface Microlayer ◽  
Tyrrhenian Sea ◽  
Ionian Sea ◽  
Western Basin ◽  
Sea Surface Microlayer ◽  
The Mediterranean

Abstract. The sea surface microlayer (SML) represents the boundary layer at the air-sea interface. Microbial eukaryotes in the SML potentially influence air-sea gas exchange directly by taking up and producing gases, and indirectly by excreting and degrading organic matter, which may modify the viscoelastic properties of the SML. However, little is known about the controlling factors that influence microbial eukaryote community composition in the SML. We studied the composition of the microbial community, transparent exopolymer particles and polysaccharides in the SML during the PEACETIME cruise along a west-east transect in the Mediterranean Sea, covering the western basin, Tyrrhenian Sea and Ionian Sea. At the stations located in the Ionian Sea, fungi were found in high relative abundances determined by 18S sequencing efforts, making up a significant proportion of the sequences recovered. At the same time, bacterial and phytoplankton counts were decreasing from west to east, while transparent exopolymer particle (TEP) abundance and total carbohydrate (TCHO) concentrations remained the same between Mediterranean basins. Thus, the presence of substrates for fungi, such as Cladosporium known to take up phytoplankton-derived polysaccharides, in combination with decreased substrate competition by bacteria suggests that fungi could be thriving in the neuston of the Ionian Sea.

scholarly journals Changes in ventilation of the Mediterranean Sea during the past 25 year

Ocean Science ◽  
2014 ◽  
Vol 10 (1) ◽  
pp. 1-16 ◽  
Author(s):  
A. Schneider ◽  
T. Tanhua ◽  
W. Roether ◽  
R. Steinfeldt
Keyword(s):  
Mediterranean Sea ◽  
Deep Water ◽  
Adriatic Sea ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Deep Water Formation ◽  
Technical Problems ◽  
Water Formation ◽  
The Mediterranean ◽  
Transient Tracer

Abstract. Significant changes in the overturning circulation of the Mediterranean Sea has been observed during the last few decades, the most prominent phenomena being the Eastern Mediterranean Transient (EMT) in the early 1990s and the Western Mediterranean Transition (WMT) during the mid-2000s. During both of these events unusually large amounts of deep water were formed, and in the case of the EMT, the deep water formation area shifted from the Adriatic to the Aegean Sea. Here we synthesize a unique collection of transient tracer (CFC-12, SF6 and tritium) data from nine cruises conducted between 1987 and 2011 and use these data to determine temporal variability of Mediterranean ventilation. We also discuss biases and technical problems with transient tracer-based ages arising from their different input histories over time; particularly in the case of time-dependent ventilation. We observe a period of low ventilation in the deep eastern (Levantine) basin after it was ventilated by the EMT so that the age of the deep water is increasing with time. In the Ionian Sea, on the other hand, we see evidence of increased ventilation after year 2001, indicating the restarted deep water formation in the Adriatic Sea. This is also reflected in the increasing age of the Cretan Sea deep water and decreasing age of Adriatic Sea deep water since the end of the 1980s. In the western Mediterranean deep basin we see the massive input of recently ventilated waters during the WMT. This signal is not yet apparent in the Tyrrhenian Sea, where the ventilation seems to be fairly constant since the EMT. Also the western Alboran Sea does not show any temporal trends in ventilation.

scholarly journals Investigation of Hg Content by a Rapid Analytical Technique in Mediterranean Pelagic Fishes

Separations ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 51 ◽  
Author(s):  
Giuseppa Di Bella ◽  
Roberta Tardugno ◽  
Nicola Cicero
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Area ◽  
Pelagic Fish ◽  
Analytical Technique ◽  
Weekly Intake ◽  
Tolerable Weekly Intake ◽  
Direct Mercury Analyzer ◽  
Mercury Analyzer ◽  
Global Concern ◽  
The Mediterranean

Mercury (Hg) fish and seafood contamination is a global concern and needs worldwide sea investigations in order to protect consumers. The aim of this study was to investigate the Hg concentration by means of a rapid and simple analytical technique with a direct Mercury Analyzer (DMA-80) in pelagic fish species, Tetrapturus belone (spearfish), Thunnus thynnus (tuna) and Xiphias gladius (swordfish) caught in the Mediterranean Sea. Hg contents were evaluated also in Salmo salar (salmon) as pelagic fish not belonging to the Mediterranean area. The results obtained were variable, ranging between 0.015–2.562 mg kg−1 for T. thynnus species, 0.477–3.182 mg kg−1 for X. gladius, 0.434–1.730 mg kg−1 for T. belone and 0.004–0.019 mg kg−1 for S. salar, respectively. The total Hg tolerable weekly intake (TWI) and tolerable weekly intake % (TWI%) values according to the European Food Safety Authority (EFSA) were calculated. The results highlighted that the pelagic species caught in the Mediterranean Sea should be constantly monitored due to their high Hg contents as well as their TWI and TWI% with respect to S. salar samples.

scholarly journals Biology and new records of the invasive species Branchiomma bairdi (Annelida: Sabellidae) in the Mediterranean Sea

2013 ◽  
Vol 14 (1) ◽  
pp. 162 ◽  
Author(s):  
A. ARIAS ◽  
A. GIANGRANDE ◽  
M.C. GAMBI ◽  
N. ANADON
Keyword(s):  
Mediterranean Sea ◽  
Histological Study ◽  
High Capacity ◽  
Reproductive Pattern ◽  
Simultaneous Hermaphrodite ◽  
Tyrrhenian Sea ◽  
Central Mediterranean ◽  
The Mediterranean ◽  
Lessepsian Migration ◽  
Short Time

First observations on the reproductive biology of the alien polychaete Branchiomma bairdi (McIntosh, 1885) (Sabellidae) in the Mediterranean Sea are provided as well as additional Mediterranean records of the species which can help to understand its introduction and spreading. Re-examination of the specimens from Miseno harbour (Tyrrhenian Sea, Italy) revealed the presence of B. bairdi in the central-Mediterranean since September 2004. The histological study of individuals collected in Malta revealed that the species is a simultaneous hermaphrodite, developing male and female gametes in the same body segments; embryos are brooded inside the parent tube. However, there is evidence also for asexual reproduction. The species shows a different reproductive pattern from the previously reported population from the eastern-Pacific; this demonstrates its great plasticity and adaptability. Branchiomma bairdi has an invasive behaviour, colonizing large areas in relatively short-time, and reaching relatively high densities (c.a. 50 individuals/m2). Its expansion throughout several Mediterranean localities is largely a consequence of the high capacity of this species to colonize extremely different habitats and substrates, to the occurrence of sexual and asexual reproductive strategies, and the combination of both. Further, B. bairdi appears to be particularly abundant in confined and anthropogenic degraded areas. Finally, our findings strongly suggest that the pathway of introduction in the Mediterranean, previously hypothesized as the Suez Canal (Lessepsian migration), is most likely via the Gibraltar Strait.

Space utilization by key species of the pelagic fish community in an upwelling ecosystem of the Mediterranean Sea

Hydrobiologia ◽  
2017 ◽  
Vol 821 (1) ◽  
pp. 173-190 ◽  
Author(s):  
A. Bonanno ◽  
M. Barra ◽  
R. Mifsud ◽  
G. Basilone ◽  
S. Genovese ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Fish Community ◽  
Pelagic Fish ◽  
Space Utilization ◽  
Key Species ◽  
Pelagic Fish Community ◽  
The Mediterranean
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