scholarly journals Genetic differentiation and phylogeography of Mediterranean-North Eastern Atlantic blue shark (Prionace glauca, L. 1758) using mitochondrial DNA: panmixia or complex stock structure?

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4112 ◽  
Author(s):  
Agostino Leone ◽  
Ilenia Urso ◽  
Dimitrios Damalas ◽  
Jann Martinsohn ◽  
Antonella Zanzi ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Spatial Genetic Structure ◽  
Population Expansion ◽  
Phylogeographic Structure ◽  
Blue Shark ◽  
Prionace Glauca ◽  
North Eastern ◽  
The Mediterranean

BackgroundThe blue shark (Prionace glauca, Linnaeus 1758) is one of the most abundant epipelagic shark inhabiting all the oceans except the poles, including the Mediterranean Sea, but its genetic structure has not been confirmed at basin and interoceanic distances. Past tagging programs in the Atlantic Ocean failed to find evidence of migration of blue sharks between the Mediterranean and the adjacent Atlantic, despite the extreme vagility of the species. Although the high rate of by-catch in the Mediterranean basin, to date no genetic study on Mediterranean blue shark was carried out, which constitutes a significant knowledge gap, considering that this population is classified as “Critically Endangered”, unlike its open-ocean counterpart.MethodsBlue shark phylogeography and demography in the Mediterranean Sea and North-Eastern Atlantic Ocean were inferred using two mitochondrial genes (Cytb and control region) amplified from 207 and 170 individuals respectively, collected from six localities across the Mediterranean and two from the North-Eastern Atlantic.ResultsAlthough no obvious pattern of geographical differentiation was apparent from the haplotype network, Φst analyses indicated significant genetic structure among four geographical groups. Demographic analyses suggest that these populations have experienced a constant population expansion in the last 0.4–0.1 million of years.DiscussionThe weak, but significant, differences in Mediterranean and adjacent North-eastern Atlantic blue sharks revealed a complex phylogeographic structure, which appears to reject the assumption of panmixia across the study area, but also supports a certain degree of population connectivity across the Strait of Gibraltar, despite the lack of evidence of migratory movements observed by tagging data. Analyses of spatial genetic structure in relation to sex-ratio and size could indicate some level of sex/stage biased migratory behaviour.

Biological characteristics of blue shark, Prionace glauca, in the Mediterranean Sea

2009 ◽  
Vol 89 (6) ◽  
pp. 1233-1242 ◽  
Author(s):  
Persefoni Megalofonou ◽  
Dimitris Damalas ◽  
Gregorio de Metrio
Keyword(s):  
Sex Ratio ◽  
Mediterranean Sea ◽  
Oocyte Diameter ◽  
Longline Fishery ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Ovary Weight ◽  
Caudal Vertebrae ◽  
The Mediterranean ◽  
Age Estimates

A total of 870 blue sharks ranging from 70 to 349 cm in total length (LT) were sampled from the swordfish longline fishery in the Mediterranean Sea during the period 1998–2003. Males predominated and the sex-ratio (1:1.8) showed an increase in the proportion of males as size of fish increased. Gonad observation revealed that females smaller than 120 cm LT had immature ovaries with no mature oocytes, while mature ovaries with visible yolky oocytes were present in specimens larger than 203 cm LT. Ovary weight varied from 4–137 g and maximum oocyte diameter was 21.1 mm in mature females. All males smaller than 125 cm LT were immature while males larger than 187 cm LT were mature, as indicated by the presence of heavily calcified claspers, which extended beyond the posterior end of the pelvic fins. Length at 50% maturity (L50) was estimated to be 202.9 cm LT for males and 214.7 cm LT for females. Age estimates using caudal vertebrae ranged from 1 to 12 years, while age at 50% maturity was estimated at 4.9 years for males and 5.5 year for females.

Levels of connectivity between longnose skate (Dipturus oxyrinchus) in the Mediterranean Sea and the north-eastern Atlantic Ocean

2010 ◽  
Vol 12 (2) ◽  
pp. 577-582 ◽  
Author(s):  
Andrew M. Griffiths ◽  
David W. Sims ◽  
Andrew Johnson ◽  
Arve Lynghammar ◽  
Matthew McHugh ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
The North ◽  
Eastern Atlantic Ocean ◽  
North Eastern ◽  
The Mediterranean

scholarly journals Absence of spatial genetic structure in common dentex (Dentex dentex Linnaeus, 1758) in the Mediterranean Sea as evidenced by nuclear and mitochondrial molecular markers

PLoS ONE ◽  
2018 ◽  
Vol 13 (9) ◽  
pp. e0203866 ◽  
Author(s):  
Alexiane Viret ◽  
Dimitris Tsaparis ◽  
Costas S. Tsigenopoulos ◽  
Patrick Berrebi ◽  
Andrea Sabatini ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Genetic Structure ◽  
Mediterranean Sea ◽  
Spatial Genetic Structure ◽  
Dentex Dentex ◽  
The Mediterranean

Actinothoe Sphyrodeta (Cnidaria, Actiniaria): The First Records from Portugal and the Mediterranean Sea

1997 ◽  
Vol 77 (1) ◽  
pp. 245-248 ◽  
Author(s):  
R.B. Williams
Keyword(s):  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Mediterranean Coast ◽  
Bay Of Biscay ◽  
Sea Anemones ◽  
Shetland Islands ◽  
The North ◽  
Eastern Atlantic Ocean ◽  
North Eastern ◽  
The Mediterranean

The known geographical distribution of the sea anemone Actinothoe sphyrodeta (Gosse) (Cnidaria, Actiniaria), hitherto generally believed to occur in the north-eastern Atlantic Ocean from the Shetland Islands to the Bay of Biscay, has been extended with new records from the Iberian Peninsula. These records comprise three from the west coast of Portugal and one from the Mediterranean coast of Spain.The sea anemones (Actiniaria) of the north-eastern Atlantic Ocean have been closely studied for at least a century and a half, and along with those of the Mediterranean Sea, constitute perhaps the best known actiniarian fauna in the world. Furthermore, there has long been discussion of the endemicity of Mediterranean sea anemones, and of apparent overlaps between the distributions of some Atlantic and Mediterranean species. It is, therefore, of particular interest when a species thought to have a solely Atlantic or solely Mediterranean distribution is discovered on the ‘wrong’ side of the Strait of Gibraltar. The anemone Actinothoe sphyrodeta (Gosse) was hitherto generally believed to occur only in north-western Europe, with a range from the Shetland Islands to the Bay of Biscay (e.g. Fischer, 1890; Manuel, 1981). It is reported here for the first time from Portugal and from the Mediterranean coast of Spain.

A Near-Uniform Basin-Wide Sea Level Fluctuation of the Mediterranean Sea

2007 ◽  
Vol 37 (2) ◽  
pp. 338-358 ◽  
Author(s):  
Ichiro Fukumori ◽  
Dimitris Menemenlis ◽  
Tong Lee
Keyword(s):  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Ocean Circulation ◽  
Large Scale ◽  
Circulation Model ◽  
Level Fluctuation ◽  
Strait Of Gibraltar ◽  
Sea Level Fluctuation ◽  
The Mediterranean

Abstract A new basin-wide oscillation of the Mediterranean Sea is identified and analyzed using sea level observations from the Ocean Topography Experiment (TOPEX)/Poseidon satellite altimeter and a numerical ocean circulation model. More than 50% of the large-scale, nontidal, and non-pressure-driven variance of sea level can be attributed to this oscillation, which is nearly uniform in phase and amplitude across the entire basin. The oscillation has periods ranging from 10 days to several years and has a magnitude as large as 10 cm. The model suggests that the fluctuations are driven by winds at the Strait of Gibraltar and its neighboring region, including the Alboran Sea and a part of the Atlantic Ocean immediately to the west of the strait. Winds in this region force a net mass flux through the Strait of Gibraltar to which the Mediterranean Sea adjusts almost uniformly across its entire basin with depth-independent pressure perturbations. The wind-driven response can be explained in part by wind setup; a near-stationary balance is established between the along-strait wind in this forcing region and the sea level difference between the Mediterranean Sea and the Atlantic Ocean. The amplitude of this basin-wide wind-driven sea level fluctuation is inversely proportional to the setup region’s depth but is insensitive to its width including that of Gibraltar Strait. The wind-driven fluctuation is coherent with atmospheric pressure over the basin and contributes to the apparent deviation of the Mediterranean Sea from an inverse barometer response.

High genetic differentiation of red gorgonian populations from the Atlantic Ocean and the Mediterranean Sea

2017 ◽  
Vol 13 (8) ◽  
pp. 854-861 ◽  
Author(s):  
Joanna Pilczynska ◽  
Silvia Cocito ◽  
Joana Boavida ◽  
Ester A. Serrão ◽  
Henrique Queiroga
Keyword(s):  
Genetic Differentiation ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
The Mediterranean

Verruca stroemia and Verruca spengleri (Crustacea: Cirripedia): distribution in the north-eastern Atlantic and the Mediterranean Sea

2003 ◽  
Vol 83 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Paulo S. Young ◽  
Helmut Zibrowius ◽  
Ghazi Bitar
Keyword(s):  
Mediterranean Sea ◽  
Black Sea ◽  
Geographic Distribution ◽  
Deep Water ◽  
Southern Spain ◽  
The Black Sea ◽  
The North ◽  
North Eastern ◽  
The Mediterranean ◽  
Gorringe Bank

The geographic distribution of Verruca stroemia and V. spengleri are reviewed. Verruca stroemia ranges from the White, Barents, Norwegian, and North Seas south to Portugal to the Algarve and to Gorringe Bank. All of the records of this species from the Mediterranean Sea are considered to be V. spengleri. Verruca spengleri occurs in the Azores and Madeira archipelagos, in southern Spain (Cádiz), throughout the Mediterranean Sea from Gibraltar to Lebanon, and in the Black Sea. But a distinct deep-water Verruca species seems to occur in the deep Mediterranean.

scholarly journals Echinoderes pterus sp. n. showing a geographically and bathymetrically wide distribution pattern on seamounts and on the deep-sea floor in the Arctic Ocean, Atlantic Ocean, and the Mediterranean Sea (Kinorhyncha, Cyclorhagida)

ZooKeys ◽  
2018 ◽  
Vol 771 ◽  
pp. 15-40 ◽  
Author(s):  
Hiroshi Yamasaki ◽  
Katarzyna Grzelak ◽  
Martin V. Sørensen ◽  
Birger Neuhaus ◽  
Kai Horst George
Keyword(s):  
Atlantic Ocean ◽  
Arctic Ocean ◽  
Distribution Pattern ◽  
Mediterranean Sea ◽  
Deep Sea ◽  
Wide Distribution ◽  
The Arctic ◽  
Sea Floor ◽  
The Arctic Ocean ◽  
The Mediterranean

Kinorhynchs rarely show a wide distribution pattern, due to their putatively low dispersal capabilities and/or limited sampling efforts. In this study, a new kinorhynch species is described,Echinoderespterussp. n., which shows a geographically and bathymetrically wide distribution, occurring on the Karasik Seamount and off the Svalbard Islands (Arctic Ocean), on the Sedlo Seamount (northeast Atlantic Ocean), and on the deep-sea floor off Crete and on the Anaximenes Seamount (Mediterranean Sea), at a depth range of 675–4,403 m. The new species is characterized by a combination of middorsal acicular spines on segments 4–8, laterodorsal tubes on segment 10, lateroventral tubes on segment 5, lateroventral acicular spines on segments 6–9, tufts of long hairs rising from slits in a laterodorsal position on segment 9, truncated tergal extensions on segment 11, and the absence of any type-2 gland cell outlet. The specimens belonging to the populations from the Arctic Ocean, the Sedlo Seamount, and the Mediterranean Sea show morphological variation in the thickness and length of the spines as well as in the presence/absence of ventromedial sensory spots on segment 7. The different populations are regarded as belonging to a single species because of their overlapping variable characters.

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