scholarly journals Life-history traits of a commercial ray, Raja brachyura from the central western Mediterranean Sea

2014 ◽  
Vol 16 (1) ◽  
pp. 90 ◽  
Author(s):  
C. PORCU ◽  
A. BELLODI ◽  
R. CANNAS ◽  
M. F. MARONGIU ◽  
A. MULAS ◽  
...  
Keyword(s):  
Life History ◽  
Mediterranean Sea ◽  
Growth Function ◽  
Western Mediterranean ◽  
Published Data ◽  
Slow Growth Rate ◽  
Western Mediterranean Sea ◽  
Management Measures ◽  
History Of ◽  
Age Model

In the present study the life history of blonde ray Raja brachyura from Sardinian waters (central-western Mediterranean) was investigated and the results compared with previously published data on this species. The age, growth and reproduction were studied using 1792 specimens caught between 2005 and 2013. Females ranged from 13.1 to 105.5 cm in Total length (TL) and males from 18 to 96.5 cm TL. This species was sexually dimorphic, with TL females attaining a larger size than males. Both females and males showed allometric growth (b>3) and we found significant differences in the relationship between length and weight among sexes. The von Bertalanffy growth function (3 parameters), which provided the following values: L∞ = 111.14 cm TL, k = 0.10 and t0 = -1.3 for females, and L∞ = 108.81 cm TL, k = 0.11 and t0 = -1.2 for males, was the best-fit age model. R. brachyura showed a relatively slow growth rate with males slightly more rapid than females. Length and age at maturity were 87.2 cm and 14 years for females and 80.8 cm and 10 years for males. This ray exhibited a restricted reproductive cycle from late May to August, confirmed by the seasonal evolution of GSI values. Ovarian fecundity reached a maximum of 44 yolked follicles. Given the relative abundance in the Sardinian seas, it is hoped that the results can be useful in the implementation of basic management measures in order to ensure the sustainability of catches of this species in the Mediterranean Sea.

scholarly journals Parasites of the head of Scomber colias (Osteichthyes: Scombridae) from the western Mediterranean Sea

2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Salvatore Mele ◽  
Maria Pennino ◽  
Maria Piras ◽  
José Bellido ◽  
Giovanni Garippa ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Western Mediterranean ◽  
Parasite Fauna ◽  
Point Of View ◽  
Published Data ◽  
Multivariate Techniques ◽  
Western Mediterranean Sea ◽  
Scomber Colias ◽  
Non Parametric

AbstractThe metazoan parasite assemblage of the head of 30 specimens of the Atlantic chub mackerel (Scomber colias) from the western Mediterranean Sea was analysed. Eight species of parasites were found, four mazocraeid monogeneans: Grubea cochlear (prevalence = 10%), Kuhnia scombercolias (59%), K. scombri (52%), Pseudokuhnia minor (86%); three didymozoid trematodes: Nematobothrium cf. faciale (21%), N. filiforme (41%), N. scombri (7%); and one laerneopodid copepod: Clavelissa scombri (7%). Results were compared with previously published data from 14 localities of the eastern Mediterranean Sea and the Atlantic Ocean, using non-parametric univariate and multivariate analyses, and the whole parasite fauna of S. colias was compared with that of the congeners (S. australasicus, S. japonicus and S. scombrus). Parasites showed to reflect the biogeographical and phylogenetic history of host. From a methodological point of view, the use of both non-parametric univariate and multivariate techniques proved to be effective tools to detect dissimilarities between parasite assemblages.

scholarly journals Sea surface temperature variability in the central-western Mediterranean Sea during the last 2700 years: a multi-proxy and multi-record approach

2015 ◽  
Vol 11 (6) ◽  
pp. 5439-5508 ◽  
Author(s):  
M. Cisneros ◽  
I. Cacho ◽  
J. Frigola ◽  
M. Canals ◽  
P. Masqué ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Sediment Cores ◽  
Atlantic Multidecadal Oscillation ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Ice Age ◽  
Western Mediterranean Sea ◽  
General Cooling ◽  
Age Model ◽  
Cooling Trend

Abstract. This study analyses the evolution of sea surface conditions during the last 2700 years in the central-western Mediterranean Sea based on six records as measured on five short sediment cores from two sites north of Minorca (cores MINMC06 and HER-MC-MR3). Sea Surface Temperatures (SSTs) were obtained from alkenones and Globigerina bulloides-Mg/Ca ratios combined with δ18O measurements to reconstruct changes in the regional Evaporation–Precipitation (E–P) balance. We reviewed the G. bulloides Mg/Ca-SST calibration and re-adjusted it based on a set of core top measurements from the western Mediterranean Sea. According to the regional oceanographic data, the estimated Mg/Ca-SSTs are interpreted to reflect spring seasonal conditions mainly related to the April–May primary productivity bloom. In contrast, the Alkenone-SSTs signal likely integrates the averaged annual signal. A combination of chronological tools allowed synchronizing the records in a common age model. Subsequently a single anomaly stack record was constructed for each proxy, thus easing to identify the most significant and robust patterns. The warmest SSTs occurred during the Roman Period (RP), which was followed by a general cooling trend interrupted by several centennial-scale oscillations. This general cooling trend could be controlled by changes in the annual mean insolation. Whereas some particularly warm SST intervals took place during the Medieval Climate Anomaly (MCA) the Little Ice Age (LIA) was markedly unstable with some very cold SST events mostly during its second half. The records of the last centuries suggest that relatively low E–P ratios and cold SSTs dominated during negative North Atlantic Oscillation (NAO) phases, although SST records seem to present a close positive connection with the Atlantic Multidecadal Oscillation index (AMO).

scholarly journals Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation

Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 871
Author(s):  
Antonello Mulas ◽  
Andrea Bellodi ◽  
Pierluigi Carbonara ◽  
Alessandro Cau ◽  
Martina Francesca Marongiu ◽  
...  
Keyword(s):  
Life History ◽  
Mediterranean Sea ◽  
Stomach Content Analysis ◽  
Western Mediterranean ◽  
Reproductive Period ◽  
Cartilaginous Fish ◽  
Management Actions ◽  
Western Mediterranean Sea ◽  
Ecological Features ◽  
Key Species

Cartilaginous fish are commonly recognized as key species in marine ecosystems for their fundamental ecological role as top predators. Nevertheless, effective management plans for cartilaginous fish are still missing, due to the lack of knowledge on their abundance, distribution or even life-history. In this regard, this paper aims at providing new information on the life-history traits, such as age, maturity, reproductive period, in addition to diet characteristics of eleven rare cartilaginous fish inhabiting the Central-Western Mediterranean Sea belonging to the orders Chimaeriformes (Chimaera monstrosa), Hexanchiformes (Heptranchias perlo and Hexanchus griseus), Myliobatiformes (Aetomylaeus bovinus and Myliobatis aquila), Rajiformes (Dipturus nidarosiensis and Leucoraja circularis), Squaliformes (Centrophorus uyato, Dalatias licha and Oxynotus centrina) and Torpediniformes (Tetronarce nobiliana), useful for their assessment and for future management actions. Particularly, the present paper provides for the first time the age estimation of D. nidarosienis and L. circularis which were both found capable of becoming older than ten years. In addition, the present study updates the sizes of first maturity of C. uyato and D. licha, which appeared to be capable of reproducing earlier than what was previously hypothesized, representing very valuable information for a better understanding of these rare species populations status and, eventually, their conservation. On the basis of the stomach content analysis, it was possible to identify five different predator groups.

scholarly journals Changes in Life History Traits of Small Pelagic Fish in the Western Mediterranean Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Marta Albo-Puigserver ◽  
Maria Grazia Pennino ◽  
Jose María Bellido ◽  
Ana Isabel Colmenero ◽  
Ana Giráldez ◽  
...  
Keyword(s):  
Life History ◽  
Mediterranean Sea ◽  
Body Condition ◽  
Life History Traits ◽  
Seawater Temperature ◽  
Western Mediterranean ◽  
Pelagic Fish ◽  
Additive Models ◽  
Small Pelagic Fish ◽  
Western Mediterranean Sea

Small pelagic fish (SPF) in the western Mediterranean Sea are key elements of the marine food web and are important in terms of biomass and fisheries catches. Significant declines in biomass, landings, and changes in the age/size structure of sardine Sardina pilchardus and anchovy Engraulis encrasicolus have been observed in recent decades, particularly in the northern area of the western Mediterranean Sea. To understand the different patterns observed in SPF populations, we analyzed key life history traits [total length at age, length at maturity, gonadosomatic index (GSI), and body condition (Kn)] of sardine and anchovy collected between 2003 and 2017, from different fishing harbors distributed along a latitudinal gradient from northern to southern Spain. We used Generalized Linear Models (GLM) to estimate the length at maturity and Generalized Additive Models (GAMs) to test the relationship with environmental variables (seawater temperature, water currents, and net primary productivity). The life history traits of both species presented seasonal, interannual and latitudinal differences with a clear decline in length at age, length at first maturity, and body condition, for both species in the northern part of the study area. In the southern part, on the contrary, life history traits did not present a clear temporal trend. The environmental conditions partially explained the long-term changes in life history traits, but the selected variables differed between areas, highlighting the importance of regional oceanographic conditions to understand the dynamics of small pelagic fish. The truncated length-at-age pattern for both species with the disappearance of the larger individuals of the population could have contributed to the poor condition of small pelagic fish populations in the northern part of the western Mediterranean Sea in recent years. In the south area, recent declines in body condition for sardine and anchovy were observed and could be a possible first sign for future population declines. This study highlights the importance of understanding the trade-off between the energy invested in reproduction, maintenance and growth at seasonal and interannual level to advance our knowledge on how environmental and human pressures influence population dynamics of small pelagic fish at local and regional scales.

Metazoan parasites in the head region of the bullet tuna Auxisrochei (Osteichthyes: Scombridae) from the western Mediterranean Sea

2014 ◽  
Vol 89 (6) ◽  
pp. 734-739 ◽  
Author(s):  
S. Mele ◽  
S. Saber ◽  
M.J. Gómez-Vives ◽  
G. Garippa ◽  
F. Alemany ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Fork Length ◽  
Western Mediterranean ◽  
Published Data ◽  
Strait Of Gibraltar ◽  
Head Region ◽  
Metazoan Parasites ◽  
Western Mediterranean Sea ◽  
The Mean ◽  
The Mediterranean

AbstractThe head region of 72 bullet tuna Auxis rochei from the western Mediterranean Sea (south-east Spain and the Strait of Gibraltar) was examined for parasites. Seven metazoan species were found in the fish from south-east Spain: three monogeneans, two trematodes and two copepods, whereas only three species were isolated in the fish from the Strait of Gibraltar. A comparison of the levels of infection of the parasites according to fish size in south-east Spain showed that the prevalence of Didymozoon auxis and the mean abundance of Allopseudaxine macrova were higher in the larger hosts (range of fork length = 38–44 cm) than in the smaller ones (33–37 cm). A comparison of the parasite infections according to geographical region showed that the mean abundances of Nematobothriinae gen. sp. and Caligus bonito were higher in fish from south-east Spain than in those from the Strait of Gibraltar. A comparison of the parasite fauna of A. rochei from the Mediterranean Sea with the published data on Auxis spp. from the Atlantic, Indian and Pacific Oceans revealed the closest similarity between the Mediterranean A. rochei and the Atlantic A. thazard.

scholarly journals Life-history traits of the long-nosed skate Dipturus oxyrinchus, from the central western Mediterranean Sea

2015 ◽  
Vol 2 ◽  
Author(s):  
Bellodi Andrea ◽  
Porcu Cristina ◽  
Marongiu Martina ◽  
Mulas Antonello ◽  
Vittori Stefania ◽  
...  
Keyword(s):  
Life History ◽  
Mediterranean Sea ◽  
Life History Traits ◽  
Western Mediterranean ◽  
Western Mediterranean Sea
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