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.

scholarly journals Aggressive interactions between juvenile swordfishes and blue sharks in the Western Mediterranean: a widespread phenomenon?

2019 ◽  
Vol 20 (2) ◽  
Author(s):  
JAIME PENADÉS-SUAY ◽  
PABLO GARCÍA-SALINAS ◽  
JESÚS TOMÁS ◽  
FRANCISCO JAVIER AZNAR
Keyword(s):  
Computed Tomography ◽  
Western Mediterranean ◽  
Defensive Strategy ◽  
Blue Shark ◽  
Prionace Glauca ◽  
X Ray ◽  
Aggressive Interactions ◽  
Open Questions ◽  
Widespread Phenomenon ◽  
The Right

There are numerous reports of billfishes spearing objects, marine organisms, and even humans. Whether or not this behaviour is intentional and, if so, what is its functional meaning, are open questions. In 2016, an adult blue shark (Prionace glauca) was found to be killed by a juvenile swordfish (Xiphias gladius) in the western Mediterranean. Here we report on three more recent cases involving both species in the same area. In February 2017, an adult male blue shark was found stranded in Garrucha (Spain) with a fragment of a juvenile swordfish’s rostrum (18cm long x 2cm wide at proximal end) inserted in its cranium. In March 2017, an adult pregnant female blue shark was stranded alive on the coast of Ostia (Italy) but died shortly afterwards; a fragment of a juvenile swordfish’s rostrum (25x3cm) was found allocated between the eye and the cranium. Finally, in February 2018, an adult female blue shark appeared stranded in the coast of Vera (Spain), with a putative impalement injury anterior to the right eye but without an associated bill fragment. Surprisingly, X-ray and computed tomography revealed an older injury in the right nostril, with a small piece of a juvenile swordfish’s rostrum (5.3x1.2cm). These cases suggest that juvenile swordfish would drive their rostrum into blue sharks as a defensive strategy that is likely to be far from anecdotal. We suggest that no regular cases of these interactions are reported because they occur at high sea and evidence of them, when available, can easily be overlooked.

The effects of actinomycin D on the early development of quail and chick embryos

Development ◽  
1971 ◽  
Vol 25 (3) ◽  
pp. 385-403
Author(s):  
F. S. Billett ◽  
Patricia Bowman ◽  
Doreen Pugh
Keyword(s):  
Actinomycin D ◽  
Early Stage ◽  
Selective Inhibition ◽  
Vitelline Membrane ◽  
Chick Embryos ◽  
Messenger Rnas ◽  
Stage Of Development ◽  
Effective Inhibition ◽  
Total Dna ◽  
The Brain

In agreement with previous work it has been found that treatment of chick embryos at an early stage of development with small concentrations of actinomycin D (2·0–4·0 × 10−8m) produces abnormalities of the brain, neural tube and somites but allows near normal development of heart and blood islands. Similar effects are produced on quail embryos by even smaller concentrations of actinomycin D (0·8–1·0 × 10−8m). In addition to the effect on the embryo, actinomycin D severely restricts the outgrowth of the explanted blastoderm; an effect which becomes obvious after about 8 h culture and coincides with the detachment of the blastoderm edge from the supporting vitelline membrane. Histological examination of the edge of the blastoderm shows that many cells have been killed by the actinomycin D. The pronounced effect of actinomycin D on the growth of the blastoderm cannot be ignored as a factor which causes the embryos to develop abnormally and it is suggested that it may even be the primary cause of the abnormalities. Under these circumstances any interpretation of the effects produced in the embryos in terms of the selective inhibition, or lack of inhibition, of specific messenger RNAs by actinomycin D seems to be unwarranted. Using [3H]actinomycin D an estimate has been made of the concentration of the compound in the blastoderm tissues at the time when the embryonic abnormalities are produced. The total DNA content of the blastoderms has also been determined. These measurements indicate that the ratio between actinomycin D molecules and guanosine residues in the treated tissue is very low (of the order of 1:20000) and would probably not allow an effective inhibition of DNA-dependent RNA synthesis.

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.

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

Polychlorinated biphenyls and DDT in swordfish (Xiphias gladius) and blue shark (Prionace glauca) from Brazilian coast

Chemosphere ◽  
2007 ◽  
Vol 67 (9) ◽  
pp. S48-S53 ◽  
Author(s):  
Claudio Eduardo de Azevedo e Silva ◽  
Antonio Azeredo ◽  
José Lailson-Brito ◽  
João Paulo Machado Torres ◽  
Olaf Malm
Keyword(s):  
Polychlorinated Biphenyls ◽  
Brazilian Coast ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Xiphias Gladius

When prey becomes killer: does a double lethal attack on a blue shark reveal a precise defensive strategy in young swordfish?

2020 ◽  
Vol 100 (5) ◽  
pp. 831-836 ◽  
Author(s):  
Teresa Romeo ◽  
Pietro Battaglia ◽  
Domenico Macaluso ◽  
Giuseppe Tagliavia ◽  
Teresa Manuela Vicchio ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Mediterranean Sea ◽  
Rare Case ◽  
Defensive Strategy ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Strait Of Sicily ◽  
Computed Tomography Scanning ◽  
The Right ◽  
Tomography Scanning

AbstractIn this paper a rare case of a double swordfish mortal attack against an adult blue shark (Prionace glauca) is reported. A female blue shark, with a total length of 3 m, was found stranded along the southern Sicilian coast (Strait of Sicily, Mediterranean Sea) on 30 May 2018. The analysis of this carcass revealed the presence of two swordfish bill fragments, impaled in the shark head; the former on the snout, the latter near the eye. The results of anatomical and computed tomography scanning analysis on the head of the blue shark showed that the larger bill fragment (19.7 cm) probably determined the death of this animal, having been impaled in a vital point, just behind the right eye. The analysis of both these events and other similar swordfish-shark interactions reported in the literature makes possible the hypothesis that young swordfish specimens put in place a precise defensive strategy against their potential predators or competitors, aimed at hitting vulnerable and vital points and delivering a mortal blow.

The Application of UX Research in New Energy Vehicle Innovation

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Menghan TAO ◽  
Ning XIAO ◽  
Xingfu ZHAO ◽  
Wenbin LIU
Keyword(s):  
Early Stage ◽  
Rapid Expansion ◽  
The Other ◽  
Innovative Product ◽  
Stage Of Development ◽  
New Energy ◽  
New Energy Vehicle ◽  
The One ◽  
New Energy Vehicles ◽  
Degree Of Innovation

New energy vehicles(NEV) as a new thing for sustainable development, in China, on the one hand has faced the rapid expansion of the market; the other hand, for the new NEV users, the current NEVs cannot keep up with the degree of innovation. This paper demonstrates the reasons for the existence of this systematic challenge, and puts forward the method of UX research which is different from the traditional petrol vehicles research in the early stage of development, which studies from the user's essence level, to form the innovative product programs which meet the needs of users and being real attractive.

Isotopic niches of the blue shark Prionace glauca and the silky shark Carcharhinus falciformis in the southwestern Indian Ocean

2012 ◽  
Vol 17 (1) ◽  
pp. 83-92 ◽  
Author(s):  
N Rabehagasoa ◽  
A Lorrain ◽  
P Bach ◽  
M Potier ◽  
S Jaquemet ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Silky Shark ◽  
Carcharhinus Falciformis ◽  
Southwestern Indian Ocean

Seasonal migrations of pregnant blue shark Prionace glauca in the northwestern Pacific

2020 ◽  
Author(s):  
Y Fujinami ◽  
K Shiozaki ◽  
Y Hiraoka ◽  
Y Semba ◽  
S Ohshimo ◽  
...  
Keyword(s):  
Northwestern Pacific ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Seasonal Migrations
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