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An additional record of the non-indigenous species (NIS) Seriola fasciata from the southern coast of Sicily (Central Mediterranean Sea)
Get PDFAn additional record of the non-indigenous species (NIS) Seriola fasciata from the southern coast
of Sicily (Central Mediterranean Sea) is here described in this note.
The catch record is the first in the area and confirms the key role of the area for NIS spreading.
In addition, an updated map of its spatial distribution is provided as well as a discussion on the
possible misidentification and competition with the native greater amberjack Seriola dumerili
How Fishery Collapses: The Case of Lepidopus caudatus (Pisces: Trichiuridae) in the Strait of Sicily (Central Mediterranean)
Get PDFThe silver scabbardfish Lepidopus caudatus is a mesopelagic species living on the shelf
and slope down to 600 m in temperate seas all around the world. In the Mediterranean,
the species is caught mainly by longlines with a marked seasonality. In the early 90s in
the Strait of Sicily (Central Mediterranean Sea), a new fishery targeting L. caudatus was
developed. This fishery uses an ad hoc pelagic trawl gear called “spatolara.” Vessels
using spatolara have increased from 1 in 1993 to 10 in 2007 with a growth of catches of
up to 1,200 tons in 2011. Development of this fishery was not regulated by any specific
management measures and, due to the progressive reduction of catch to 169 tons, only
one vessel was active in 2018. The availability of catch and biomass indices from trawl
survey since the beginning of trawling exploitation allowed providing the first assessment
of the state of L. caudatus stock in the Central Mediterranean (GFCM Geographical
Sub-Area 16) by using data-limited methods. Catch-Maximum Sustainable Yield (CMSY)
and Bayesian State Space Schaefer model (BSM) were fitted to landings and abundance
indices (2004–2018). The Abundance-Maximum Sustainable Yield model (AMSY) was
also applied to survey data from 1994 (1 year after the start of the spatolara fishery) to
2018 to further corroborate the results. BSM prediction of biomass levels was just above
50% of BMSY, whereas AMSY estimated the current stock levels below 50% of BMSY.
The BSM was used for forecasting B/BMSY and catches under different fishing scenarios.
Although current exploitation was very close to FMSY, more than a decade would be
needed to rebuild the stock to biomass levels producing MSY. A faster rebuilding could
be achieved by fishing at least 80% of FMSY, with minimal loss in yield over the next
5–8 years. Following the development of a new fishery since the beginning, the study
provides a further example of how unregulated exploitation leads to a heavy overfished
state of stock and collapse of fishing activities
Physiological stress indicators in the plasma of Scyliorhinus canicula captured by botto trawling at two depths
No full textThe quantification of capture-related physiological stress is an important factor when assessing the potential for post-release survival in sharks that are incidentally captured. In the absence of these biological data and when the post-release fate is unknown, effective management plans cannot be formulated and may lead to highly susceptible shark populations being overfished. Here, we measured the levels of lactate, glucose, alanine amino transferase (ALT), aspartate amino transferase (AST), Ca2+, Na+ K+,Cl - Mg 2+ and Pi in the plasma of mature and immature lesser spotted dogfish (Scyliorhinus canicula, herein dogfish) which were incidentally captured at two depths (shallow: 50-200 m, and deep: 201-500 m) by bottom trawl off the coast of southern Sicily. These values were used as biomarkers and physiological indicators of the secondary stress response associated with capture. This study found that dogfish captured in deeper waters (below 200 m) had elevated levels of glucose, Na+, Ca2+ and K+ compared to those inhabiting depths <200 m. We hypothesize that the elevated levels of physiological stress in dogfish captured at greater depths may be related to the prolonged duration of the interactions with the fishing gear in the area off southern Sicily. Our findings provide new data on the capture-related stress in dogfish and increase the understanding of the potential for post-release survival in sharks captured at two depths by bottom trawl, information that is important for improving the general management plans for the fishery. However, our PC Analysis results revealed that Maturity have a positive contribution from the sample weight, sample length, ALT, AST and a negative contribution from Pi
A new record of a great white shark, Carcharodon carcharias(Chondrichthyes: Lamnidae) in the Strait of Sicily, Central Mediterranean Sea
Get PDFIn November 2015 an immature male individual of great white shark, Carcharodon carcharias
(Linnaeus 1758), was caught as by-catch by a bottom trawler in the Strait of Sicily, in the Central
Mediterranean Sea. The shark, reaching 266 cm in length and weighing 290 Kg, was identified and
measured by means of a video provided by fishers. This record is discussed considering the available
information on the presence of the great white shark in the area and confirms the importance of the
Strait of Sicily for the conservation of this vulnerable species
Chilomycterus reticulatus (Actinopterygii : Tetraodontiformes : Diodontidae) in the southern Sicilian waters, central Mediterranean Sea
Get PDFA recently discovered fish specimen representing the family Diodontidae has been documented in the waters off Mazara del Vallo in southwest Sicily, Italy. A detailed description of the morphological and meristic characteristics of the specimen is reported. Molecular identification was performed through sequence analysis of the Cytochrome Oxidase subunit I (COI). The specimen was identified as Chilomycterus reticulatus (Linnaeus, 1758) both morphologically and genetically. The finding marks the third confirmed record of Chilomycterus reticulatus in the Mediterranean Sea and Italian waters. The significance of the presence of this uncommon
fish in the basin is briefly discussed, shedding light on its occurrence and potential implications.peer-reviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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