scholarly journals Establishing length-at-age references in the red mullet, Mullus barbatus L. 1758 (Pisces, Mullidae), a case study for growth assessments in the Mediterranean Geographical Sub-Areas (GSA)

2011 ◽  
Vol 12 (2) ◽  
pp. 316 ◽  
Author(s):  
M.L. BIANCHINI ◽  
S. RAGONESE
Keyword(s):  
Partial Information ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Grey Literature ◽  
Growth Line ◽  
Red Mullet ◽  
Mullus Barbatus ◽  
Reference Length ◽  
The Mediterranean

Length at age data are a fundamental tool for the assessment of exploited fish populations, their use requiring the identification of the ‘unit stock’. At the present, however, the spatial reference for stock assessment in the Mediterranean Sea is based on a grid of 30 arbitrary Geographical Sub Areas (GSA). Since older data rarely respect the GSA borders, the authors propose to reconstruct the historical data within a common frame and to assess a single reference length at age, together with the corresponding von Bertalanffy growth parameters, to be used as a broad benchmark for analyses inter and intra GSAs. This approach was tested using, as a case study, the red mullet (Mullus barbatus L. 1758), one of the most investigated fish of the whole Mediterranean basin. Published and grey literature was browsed, to get direct and/or indirect length at age estimations. To establish a common baseline and maximize the use of partial information, a vBGF (L∞, total length in mm, and Ky-1) was fitted to length at age data whenever possible. 56 Mediterranean sets were utilized; an overall reference growth line was estimated by sex, discussing its adequacy to the life traits of the species.

scholarly journals Explorative analysis on red mullet (Mullus barbatus) ageing data variability in the Mediterranean

2020 ◽  
Vol 83 (S1) ◽  
pp. 271 ◽  
Author(s):  
Pierluigi Carbonara ◽  
Walter Zupa ◽  
Aikaterini Anastasopoulou ◽  
Andrea Bellodi ◽  
Isabella Bitetto ◽  
...  
Keyword(s):  
Growth Models ◽  
Age Groups ◽  
Geographical Location ◽  
Principal Component ◽  
Age Validation ◽  
Large Variability ◽  
False Rings ◽  
Red Mullet ◽  
Mullus Barbatus ◽  
The Mediterranean

The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation schemes, including variations in theoretical birthdate and number of false rings considered, in addition to differences in the experience level of readers. The present work analysed the influence of these variations and the geographical location of sampling on red mullet ageing using a multivariate approach (principal component analysis). Reader experience was the most important parameter correlated with the variability. The number of rings considered false showed a significant effect on the variability in the first age groups but had less influence on the older ones. The effect of the theoretical birthdate was low in all age groups. Geographical location had a significant influence, with longitude showing greater effects than latitude. In light of these results, workshops, exchanges and the adoption of a common ageing protocol based on age validation studies are considered fundamental tools for improving precision in red mullet ageing.

Patterns of genetic differentiation between two co-occurring demersal species: the red mullet (Mullus barbatus) and the striped red mullet (Mullus surmuletus)

2009 ◽  
Vol 66 (9) ◽  
pp. 1478-1490 ◽  
Author(s):  
J. A. Galarza ◽  
G. F. Turner ◽  
E. Macpherson ◽  
C. Rico
Keyword(s):  
Gene Flow ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Flow Patterns ◽  
Ecological Features ◽  
Red Mullet ◽  
Mullus Barbatus ◽  
Mullus Surmuletus ◽  
The Mediterranean ◽  
Demersal Species

The accurate identification of genetic partitioning is of primarily importance when devising conservation management strategies for today’s marine resources. The great variety of genetic structure displayed by demersal species underscores the need for the identification of common patterns that can be found across species. Here, we analyse allele frequency variation at 10 microsatellite loci of two congener demersal fish, the red mullet ( Mullus barbatus ) and the striped red mullet ( Mullus surmuletus ), from the Atlantic Ocean and the Mediterranean Sea. The results indicate that two different gene flow patterns exist between these species. The red mullet’s genetic distribution was found to be highly structured, resembling that of a metapopulation composed by independent, self-recruiting subpopulations with some connections between them. The striped red mullet displayed less genetic heterogeneity within the Mediterranean Sea and a substantial gene flow reduction between the Atlantic Ocean and Mediterranean Sea. Our results indicate that gene flow patterns in the demersal environment can be substantially different between closely related species with highly comparable biology, suggesting that biogeographic boundaries can affect demersal species in a different way despite common ecological features and spatial overlap. We conclude that the delimitation of such boundaries could be determined by the fine differences in life history traits between species.

Population dynamics and stock assessment of deep water rose shrimp Parapenaeus longirostris (Lucas, 1846) from the Mediterranean Coast of Morocco

2020 ◽  
Vol 67 (2) ◽  
Author(s):  
Hesham Awadh ◽  
Mustapha Aksissou
Keyword(s):  
Population Dynamics ◽  
Deep Water ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Mediterranean Coast ◽  
Parapenaeus Longirostris ◽  
Exploitation Rate ◽  
The Mediterranean ◽  
Yield Per Recruit

The population dynamics and stock parameters of the deep water rose shrimp Parapenaeus longirostris (Lucas, 1846) was investigated from the Mediterranean coast of Morocco. Length-frequency data were collected from landings of coastal trawlers at M’diq Port on the Moroccan Mediterranean coast over a period of 13 months from April 2017 to April 2018. The estimated growth parameters were CL∞ = 52.87 mm, K = 0.39 yr-1 and to = - 0.35 .Total mortality coefficient (Z) was estimated as 3.49 yr-1 while the natural mortality estimated using two different methods was 1.89 yr-1 and 1.36 yr-1 and correspondingly the fishing mortality was calculated as 1.51 yr-1 and 2.13 yr-1. Yield per recruit and relative biomass per recruit analysis showed that the value of current exploitation rate (E) is 0.68 which is higher than the exploitation rate E 0.5=0.36, which indicates that the stock is currently overexploited. Hence it is advised to decrease the present exploitation rate by 50% of the current level to sustain the fishery.

scholarly journals Microsatellite analysis of red mullet Mullus barbatus (Perciformes, Mullidae) reveals the isolation of the Adriatic Basin in the Mediterranean Sea

2009 ◽  
Vol 66 (9) ◽  
pp. 1883-1891 ◽  
Author(s):  
Teresa Maggio ◽  
Sabrina Lo Brutto ◽  
Flavio Garoia ◽  
Fausto Tinti ◽  
Marco Arculeo
Keyword(s):  
Genetic Differentiation ◽  
Bayesian Analysis ◽  
Mediterranean Sea ◽  
Microsatellite Analysis ◽  
Restricted Gene Flow ◽  
Tyrrhenian Sea ◽  
Red Mullet ◽  
Mullus Barbatus ◽  
The Mediterranean ◽  
Adriatic Basin

Abstract Maggio, T., Lo Brutto, S., Garoia, F., Tinti, F., and Arculeo, M. 2009. Microsatellite analysis of red mullet Mullus barbatus (Perciformes, Mullidae) reveals the isolation of the Adriatic Basin in the Mediterranean Sea. – ICES Journal of Marine Science, 66: 1883–1891. The red mullet Mullus barbatus is commercially one of the most important demersal fish resources in the Mediterranean. Molecular data on its genetic population structure throughout the Mediterranean are reported. Six microsatellite loci displayed a high degree of expected heterozygosity and a high allele number per locus. The Hardy–Weinberg equilibrium test revealed an overall tendency towards heterozygote deficiency, probably caused by the admixture of various demes. Population differentiation was assessed by analysis of molecular variance (AMOVA) and Bayesian analysis. AMOVA showed that most of the variation was within the population, but the mean value of FST was significant, indicating genetic differentiation among the samples analysed. This differentiation is primarily attributable to the isolation of the Adriatic samples and partly to a weaker substructuring of the populations in the Gulf of Lions, Tyrrhenian Sea, Strait of Sicily, and Ionian Sea. Bayesian analysis also revealed genetic differentiation among the samples analysed, identifying two genetic clusters. The restricted gene flow from and to the Adriatic, also recorded for other fish species, most likely reflects the environmental separation of the Adriatic and suggests that management protocols for the red mullet in the Mediterranean should be revisited.

Geoeconomic Leverage of Natural Gas Resources in the Mediterranean

2019 ◽  
Vol 12 (4) ◽  
pp. 141-155 ◽  
Author(s):  
Ahmed Mahdi
Keyword(s):  
Natural Gas ◽  
Economic Resources ◽  
Tel Aviv ◽  
Economic Influence ◽  
The Mediterranean ◽  
Influence Attempts ◽  
Gas Fields

This article examines the claim that Israel’s natural gas exports from its Mediterranean gas fields will give geopolitical leverage to Tel Aviv over the importing countries. Using the geoeconomic tradition of Klaus Knorr and others who wrote about applying leverage using economic resources to gain geopolitical advantage, it is argued that certain criteria have to be satisfied for economic influence attempts, and that Israel’s gas exports do not satisfy these criteria. They include the importer’s supply vulnerability, the supplier’s demand vulnerability, and the salience of energy as an issue between both countries. Israeli gas exports to Egypt are used as a case study.

The formation of the Egyptian Arabic dialect area

2018 ◽  
Author(s):  
Peter Behnstedt ◽  
Manfred Woidich
Keyword(s):  
Mediterranean Coast ◽  
External Factors ◽  
Internal Factors ◽  
Dialect Contact ◽  
Historical Information ◽  
Egyptian Arabic ◽  
Transitional Area ◽  
The Mediterranean

This chapter deals with the sedentary dialects of Egypt, excluding the bedouin dialects of Sinai and the Libyan bedouin dialects on the Mediterranean coast. It attempts to combine historical information on the settlement of Arabic tribes in Egypt with accounts of present-day Egyptian dialects and those of the regions from which those tribes came, initially Yemen and the Levant, later Hejaz, and then the Maghreb. The diversity of the Egyptian Arabic dialect area is partly explained by external factors, namely different layers of arabization over centuries. It is also explained by internal factors, namely dialect contact, which implies phenomena such as hyperdialectisms. Egypt is seen as a dialect area in its own right, but one that shows phenomena of a transitional area between the Arab East and West. A case study of Alexandria deals with dialect death. The role of substrata is discussed, but is considered negligible.

scholarly journals Health and reproduction of red mullet, Mullus barbatus, in the western Mediterranean Sea

Hydrobiologia ◽  
2015 ◽  
Vol 753 (1) ◽  
pp. 189-204 ◽  
Author(s):  
Dolors Ferrer-Maza ◽  
Marta Muñoz ◽  
Josep Lloret ◽  
Elisabeth Faliex ◽  
Sílvia Vila ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Western Mediterranean Sea ◽  
Red Mullet ◽  
Mullus Barbatus
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