Mercury and selenium in blue shark (Prionace glauca, L. 1758) and swordfish (Xiphias gladius, L. 1758) from two areas of the Atlantic Ocean

2007 ◽  
Vol 150 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Vasco Branco ◽  
Carlos Vale ◽  
João Canário ◽  
Miguel Neves dos Santos
Keyword(s):  
Atlantic Ocean ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Xiphias Gladius

scholarly journals Reproductive characteristics for the blue shark (Prionace glauca) in the North Atlantic Ocean

2022 ◽  
Vol 120 (1) ◽  
pp. 26-38
Author(s):  
Katie Viducic ◽  
Lisa J. Natanson ◽  
Megan V. Winton ◽  
Austin Humphries
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Reproductive Characteristics ◽  
The North ◽  
The North Atlantic

scholarly journals Reproduction of the Blue Shark Prionace glauca in the South-Western Equatorial Atlantic Ocean

1994 ◽  
Vol 60 (5) ◽  
pp. 487-491 ◽  
Author(s):  
Fabio H. V. Hazin ◽  
Kohei Kihara ◽  
Kazuyuki Otsuka ◽  
Clara E. Boeckman ◽  
Elizabeth C. Leal
Keyword(s):  
Atlantic Ocean ◽  
Equatorial Atlantic ◽  
The South ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Equatorial Atlantic Ocean

Incidental catch associated with swordfish longline fisheries in the south-west Atlantic Ocean

1998 ◽  
Vol 49 (7) ◽  
pp. 633 ◽  
Author(s):  
Yamandú H. Marín ◽  
Federico Brum ◽  
Luis C. Barea ◽  
Julio F. Chocca
Keyword(s):  
Abundant Species ◽  
High Price ◽  
The South ◽  
Blue Shark ◽  
Western Atlantic ◽  
Prionace Glauca ◽  
Thunnus Alalunga ◽  
Xiphias Gladius ◽  
Longline Fisheries ◽  
Number Of Individuals

This paper describes the composition of the harvest by species of two vessels operating with two different pelagic longline systems aimed at swordfish (Xiphias gladius). Four zones were surveyed in the Uruguayan EEZ and international waters in the south-western Atlantic. Data were collected by observers on board who recorded the number of individuals in each of the species caught. In all, 50 species were caught, of which 15 were cartilaginous fish, 27 were teleosts and eight were ‘non- fish’ species (birds, mammals and turtles). The most abundant species were blue shark (Prionace glauca) (43%), swordfish (27%) and albacore tuna (Thunnus alalunga) (9%). The abundances of blue shark and of swordfish differed significantly between the two rigging systems and among the four zones. The catch was classified into three marketing groups: primary marketing (swordfish and high-price tuna), secondary marketing (non-target species but marketable) and discards (with no commercial value). In terms of numbers, the first two groups represented between 91% and 72% of the species collected. This percentage may vary if the catch is analysed by weight, as only part of the carcass and shark fins are used. Resumen. Se describe la composición por especies de la captura de dos buques que operaron con dos sistemas diferentes de palangre pelágico dirijido a la extracción de pez espada (Xiphias gladius). Se relevaron quatros áreas que abarcaron la ZEE uruguaya y aguas internacionales en el O. Atlántico. Los datos fueron colectados a bordo por observadores, registrando la captura en número de la totalidad de las especies. Se contabilizó un total de 50 especies capturadas, de las cuales 15 corresponden a peces cartilaginosos, 27 a peces óseos y 8 a ‘non-pisces’ (aves, mamíferos y quelonios). Las especies más representadas fueron el tiburón azul (Prionace glauca) (43%), seguida por pez espada (27%) y albacora (Thunnus alalunga) (9,0%). La presencia de tiburón azul y pez espada mostró diferencias significativas comparando los dos sistemas de construcción del palangre y las zonas. Se clasificó la captura en tres grupos de comercialización: comercialización primaria (pez espada y atunes de elevado valor), comercialización secundaria (especies diferentes de la objetivo pero comercializables), y decarte (sin valor comercial). Las dos primeras acumularon entre el 91% y 72% de las piezas capturadas. Este porcentaje puede variar si se analiza la captura en peso, ya que de los tiburones se aprovechan las aletas y solamente parte de las carcasas.

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.

scholarly journals Deadly impalement of a blue shark Prionace glauca by a swordfish Xiphias gladius

2017 ◽  
Vol 18 (2) ◽  
pp. 340 ◽  
Author(s):  
J. PENADÉS-SUAY ◽  
J. TOMÁS ◽  
F. J. AZNAR
Keyword(s):  
Cause Of Death ◽  
Early Stage ◽  
Western Mediterranean ◽  
Defensive Strategy ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Stage Of Development ◽  
Xiphias Gladius ◽  
Allometric Analysis ◽  
The Brain

In September, 2016, an adult female blue shark (Prionace glauca) 247 cm long stranded alive on the coast of Valencia (Spain, Western Mediterranean) but died shortly afterwards. The necropsy revealed ongoing pregnancy, with 65 embryos in early stage of development, and a healthy condition with no signs of starvation. Two fishing hooks surrounded by scarred tissue were detected in the mandible, indicating past interaction with fisheries. In addition, a fragment of the tip of a swordfish (Xiphias gladius) rostrum (length: 18 cm long, width: 0.5 cm (distal) and 3 cm (proximal)) was removed from the animal. The fragment had pierced the head producing an incision of 3.5 cm close to the left eye, crossing the head anterior to the pre-orbital process. No apparent damage was observed in the olfactory capsule or the eye, but the fragment had penetrated both sides of the skull causing extensive lesions in the brain, which were inferred to be the cause of death. Allometric analysis suggested that the swordfish was ca. 110 cm long, corresponding to a juvenile 1-2 yrs old. Swordfish had previously been reported driving their rostrum into pelagic sharks, allegedly as a defensive strategy. However, this is the first report of impalement as the direct cause of death in blue sharks.

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