scholarly journals Distribution and spatio-temporal biomass trends of red mullets across the Mediterranean

2020 ◽  
Vol 83 (S1) ◽  
pp. 43
Author(s):  
George Tserpes ◽  
Enric Massutí ◽  
Fabio Fiorentino ◽  
Maria Teresa Facchini ◽  
Claudio Viva ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Species Abundance ◽  
Dynamic Factor Analysis ◽  
Dynamic Factor ◽  
Combined Effects ◽  
Relative Importance ◽  
Mullus Surmuletus ◽  
The Mediterranean ◽  
Spatio Temporal ◽  
Trawl Surveys

The present work examines the spatio-temporal biomass trends of Mullus barbatus and Mullus surmuletus in the Mediterranean Sea through the analysis of a time series of data coming from the Mediterranean International Trawl Surveys (MEDITS), accomplished annually from 1994 to 2015. The biomass of both species showed clear declining trends below 150 to 200 m depth, which were steeper in the case of M. barbatus. Increases in temporal biomass trends were observed for M. barbatus from 2008 onward in most geographic sub-areas (GSAs), while stability was mostly observed for M. surmuletus. For both species, dynamic factor analysis revealed similarities among neighbouring GSAs and the subsequent cluster analysis identified two major GSA groups corresponding to the eastern and western basins of the Mediterranean. Overall, the results suggested that the combined effects of fishing and environmental conditions determine species abundance variations, but the relative importance of each component may vary among areas.

scholarly journals The shifting distribution of Mediterranean fishes: a spatio-temporal assessment based on Local Ecological Knowledge .

2019 ◽  
Author(s):  
Ernesto Azzurro ◽  
Valerio Sbragaglia ◽  
Jacopo Cerri ◽  
Michel Bariche ◽  
Luca Bolognini ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Temporal Dynamics ◽  
Local Ecological Knowledge ◽  
Rapid Change ◽  
Species Abundance ◽  
Global Ocean ◽  
Small Scale ◽  
Ecological Knowledge ◽  
The Mediterranean ◽  
Spatio Temporal

A major problem worldwide is the rapid change in species abundance and distribution, which is rapidly restructuring the biological communities of many ecosystems under changing climates. Tracking these transformations in the marine environment is crucial but our understanding is often hampered by the absence of historical data and by the practical challenge of survey large geographical areas. Here we focus on the Mediterranean Sea, a region which is warming faster than the rest of the global ocean, tracing back the spatio-temporal dynamic of species, which are emerging the most in terms of increasing abundances and expanding distributions. To this aim, we accessed the Local Ecological Knowledge (LEK) of small-scale and recreational fishers reconstructing the dynamics of fish perceived as ‘new’ or increasing in different fishing area. Over 500 fishers across 95 locations and 9 different countries were interviewed and semi-quantitative information on yearly changes in species abundance was collected. Overall, 75 species were mentioned by the respondents, being the most frequent citations related to warm-adapted species of both, native and exotic origin. Respondents belonging to the same biogeographic sectors described coherent spatio-temporal dynamics, and gradients along latitudinal and longitudinal axes were revealed. This information provides a more complete understanding of recent bio-geographical changes in the Mediterranean Sea and it also demonstrates that adequately structured LEK methodology might be applied successfully beyond the local scale, across national borders and jurisdictions. Acknowledging this potential through macro-regional coordination, could pave the ground for future large-scale aggregations of individual observations, increasing our potential for integrated monitoring and conservation planning at the regional or even global level.

scholarly journals Distribution and abundance of Citharus linguatula, Lepidorhombus boscii (Risso, 1810) and Solea vulgaris, (Osteichthyes, Pleuronectiformes) in the Mediterranean Sea

2002 ◽  
Vol 66 (S2) ◽  
pp. 83 ◽  
Author(s):  
Paolo Sartor ◽  
Mario Sbrana ◽  
Nicola Ungaro ◽  
Chiara A. Marano ◽  
Corrado Piccinetti ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Size Composition ◽  
Demographic Structure ◽  
Depth Stratum ◽  
Abundance Indices ◽  
The Mediterranean ◽  
Spatio Temporal ◽  
Wide Geographic Distribution ◽  
Temporal Basis ◽  
Trawl Surveys

Information on distribution, relative abundance and size composition of the pleuronectiform species Citharus linguatula, Lepidorhombus boscii and Solea vulgaris was obtained during the MEDITS trawl surveys, carried out in a wide area of the Mediterranean Sea from 1994 to 1999. The three species showed a wide geographic distribution, as they were collected in all the macro-areas investigated, but with some differences in degree of presence among the 40 geographic sectors. Variations in abundance indices, analysed on a spatio-temporal basis with a Generalised Linear Model, were mostly related to the depth stratum and the macro-area. C. linguatula and S. vulgaris were especially found from 10 to 100 m depth, while L. boscii was most abundant on bottoms ranging from 100 to 500 m depth. The three species showed the highest abundance indices (kg/km2) in the Gulf of Lions, in the Greek Seas and along the Sardinian coasts. Especially for L. boscii and C. linguatula, the demographic structure showed that the sampled populations were mainly constituted by juveniles. The lowest biomass and abundance indices were obtained for S. vulgaris, whose catch was mainly composed of adult fish.

scholarly journals Distribution and abundance of Eledone cirrhosa (Lamarck, 1798) and Eledone moschata (Lamarck, 1798) (Cephalopoda: Octopoda) in the Mediterranean Sea

2002 ◽  
Vol 66 (S2) ◽  
pp. 143 ◽  
Author(s):  
Paola Belcari ◽  
Georges Tserpes ◽  
María González ◽  
Eugenia Lefkaditou ◽  
Bojan Marceta ◽  
...  
Keyword(s):  
Depth Distribution ◽  
Size Composition ◽  
Major Area ◽  
Frequency Distributions ◽  
The Mediterranean ◽  
Spatio Temporal ◽  
Wide Geographic Distribution ◽  
Temporal Basis ◽  
The Mediterranean Basin ◽  
Trawl Surveys

Information on distribution, abundance and size composition of the two octopods Eledone cirrhosa and E. moschata was obtained from the MEDITS trawl surveys, carried out in a wide area of the Mediterranean basin from 1994 to 1999. Both species showed a wide geographic distribution, as they were collected in all the major areas investigated. E. cirrhosa showed a wide depth distribution, down to the 800 m isobath, while E. moschata was mostly restricted to within 200 m. Further analysis on spatio-temporal basis with a Generalised Linear Model, evidenced that differences among major areas, depth strata and their interaction were always significant. In the case of E. cirrhosa, differences among years and year-major area interaction were also significant. Two cohorts can be singled out in the size frequency distributions of E. cirrhosa, whereas only one mode can be clearly distinguished in most of the length distributions of E. moschata.

scholarly journals Seasonal Dynamic Factor Analysis and Bootstrap Inference: Application to Electricity Market Forecasting

Technometrics ◽  
2011 ◽  
Vol 53 (2) ◽  
pp. 137-151 ◽  
Author(s):  
Andrés M. Alonso ◽  
Carolina García-Martos ◽  
Julio Rodríguez ◽  
María Jesús Sánchez
Keyword(s):  
Factor Analysis ◽  
Electricity Market ◽  
Seasonal Dynamic ◽  
Dynamic Factor Analysis ◽  
Dynamic Factor ◽  
Bootstrap Inference

scholarly journals Container Throughput Forecasting Using Dynamic Factor Analysis and ARIMAX Model

2017 ◽  
Vol 29 (5) ◽  
pp. 529-542 ◽  
Author(s):  
Marko Intihar ◽  
Tomaž Kramberger ◽  
Dejan Dragan
Keyword(s):  
Factor Analysis ◽  
Goodness Of Fit ◽  
Moving Average ◽  
Real Data ◽  
Information Criteria ◽  
Dynamic Factor Analysis ◽  
Forecasting Model ◽  
Dynamic Factor ◽  
Macroeconomic Indicators ◽  
The Impact

The paper examines the impact of integration of macroeconomic indicators on the accuracy of container throughput time series forecasting model. For this purpose, a Dynamic factor analysis and AutoRegressive Integrated Moving-Average model with eXogenous inputs (ARIMAX) are used. Both methodologies are integrated into a novel four-stage heuristic procedure. Firstly, dynamic factors are extracted from external macroeconomic indicators influencing the observed throughput. Secondly, the family of ARIMAX models of different orders is generated based on the derived factors. In the third stage, the diagnostic and goodness-of-fit testing is applied, which includes statistical criteria such as fit performance, information criteria, and parsimony. Finally, the best model is heuristically selected and tested on the real data of the Port of Koper. The results show that by applying macroeconomic indicators into the forecasting model, more accurate future throughput forecasts can be achieved. The model is also used to produce future forecasts for the next four years indicating a more oscillatory behaviour in (2018-2020). Hence, care must be taken concerning any bigger investment decisions initiated from the management side. It is believed that the proposed model might be a useful reinforcement of the existing forecasting module in the observed port.

scholarly journals A spatio-temporal cluster analysis of structurally deficient bridges in the contiguous USA

2020 ◽  
Vol 4 ◽  
pp. 100034
Author(s):  
R.W. Amin ◽  
S. Kocak ◽  
H.E. Sevil ◽  
G.P. Peterson ◽  
J.T. Hamilton ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Temporal Cluster ◽  
Spatio Temporal

Analysis of Power Output Time Series in Response to Supramaximal Exercise: An Approach Through Dynamic Factor Analysis

2011 ◽  
Vol 23 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Paula Marta Bruno ◽  
Fernando Duarte Pereira ◽  
Renato Fernandes ◽  
Gonçalo Vilhena de Mendonça
Keyword(s):  
Factor Analysis ◽  
Power Output ◽  
Soccer Players ◽  
Upper Body ◽  
Dynamic Factor Analysis ◽  
Dynamic Factor ◽  
Lower Body ◽  
Supramaximal Exercise ◽  
Output Time ◽  
Pattern Of Variation

The responses to supramaximal exercise testing have been traditionally analyzed by means of standard parametric and nonparametric statistics. Unfortunately, these statistical approaches do not allow insight into the pattern of variation of a given parameter over time. The purpose of this study was to determine if the application of dynamic factor analysis (DFA) allowed discriminating different patterns of power output (PO), during supramaximal exercise, in two groups of children engaged in competitive sports: swimmers and soccer players. Data derived from Wingate testing were used in this study. Analyses were performed on epochs (30 s) of upper and lower body PO obtained from twenty two healthy boys (11 swimmers and 11 soccer players) age 11–12 years old. DFA revealed two distinct patterns of PO during Wingate. Swimmers tended to attain their peak PO (upper and lower body) earlier than soccer players. As importantly, DFA showed that children with a given pattern of upper body PO tend to perform similarly during lower body exercise.

scholarly journals Which cues cause consumers to perceive brands as more global? A conjoint analysis

2015 ◽  
Vol 32 (6) ◽  
pp. 606-626 ◽  
Author(s):  
Sarah De Meulenaer ◽  
Nathalie Dens ◽  
Patrick De Pelsmacker
Keyword(s):  
Cluster Analysis ◽  
Conjoint Analysis ◽  
Consumer Culture ◽  
Design Methodology ◽  
Product Category ◽  
Relative Importance ◽  
Brand Name ◽  
High Involvement ◽  
Content Type ◽  
Practical Implications

Purpose – The purpose of this paper is to investigate how the globalization (vs localization) of different cues (advertising copy, brand name, spokesperson, brand logo) influences consumers’ perceived brand globalness. Design/methodology/approach – The authors conducted conjoint analyses for two products differing in product category involvement (chocolates vs computer) with 200 consumers from the Netherlands. Additionally, based on cluster analysis, the authors divide respondents into two groups: local vs global consumer culture individuals, and the authors compare the results of the conjoint analysis for these two clusters. Findings – Advertising copy is most important in determining perceived brand globalness. The spokesperson and the brand logo determine perceived brand globalness more strongly for a low-involvement product, whereas the brand name is more important for a high-involvement product. Further, the spokesperson and the brand logo are relatively more important for global consumer culture individuals, while local consumer culture individuals find the brand name and advertising copy relatively more important. Practical implications – The most important cue to position a brand as global is the advertising copy. Brand managers of a low-involvement product and/or targeting global-minded consumers should concentrate on the spokesperson and the brand logo to position their brand. Managers of a high-involvement product and/or targeting local-minded people should focus on the brand name. Originality/value – While a number of researchers have emphasized the importance of perceived brand globalness for international consumer behavior, the present study is the first to the authors’ knowledge to investigate the relative importance of different cues in creating perceptions of brand globalness.

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