The blue shark is the only shark present in the
Prionace genus and it belongs to the Carcharhinidae family.
This shark is one of the few known to be practically diffused in all the
moderate, tropical and subtropical seas of the planet, in pelagic waters
but also coastlines.
Prionace glauca was common in the Mediterranean, especially in Adriatic. The verb into the past is justified from the fact that the blue shark is the shark mostly submitted to the pressure of the commercial fishing: every year around 20 million samples are captured and killed. (the principal motive for the captures is tied up to the use of the fins to realize the "soup of fins of shark" very in demand in the Asian market. We don't have to forget that the Food and Drug Administration of the United States has inserted the shark meat among the foods that children and pregnant women should avoid to eat, because of the risks of mercury and other heavy metals)
Currently there aren't complete studies on the global
course of blue shark population, but it is probable, seen the elevated
number of captures, that is in action a meaningful reduction of this
The blue shark is potentially considered a dangerous shark for the man, even if in the "classifications of the dangerous sharks" it results among the last places. Is the curiosity of this fish, toward what it happens around him, that can make to approach him and to create risky situations, even if not provoked attacks are rare. It seems that this shark is more docile and calm during the day, while in the late afternoon, when in water the brightness decreases, it becomes more curious and tenacious also approaching himself to the coasts.
The maximum dimensions arrive to 380-400 cm of length
and up to 170 kg of weight, even if the averages dimension are of
150-200 cm. (T.H.Lineaweaver and R.H.Backus speak of a blue shark,
fished to the hook, of 480 cm of length and 186 kg of weight, September
1° th 1960 offshore Rockport, Massachusetts)
The blue shark is able of to reach elevated speeds in water but he normally stirs with walk a lot of redoubt, smaller of 2 km/h, and he doesn't even love to chase particularly fast preys. This shark is present in great number when there are great quantities of food to disposition as afloat carcasses of whales and rests (always of sea mammals) while during the other moments of his life is a rather solitary animal.
The diet consists of: cefalopods (cuttlefishes and
squids), small fishes (also of backdrop), invertebrate, eggs of pelagic
fish and sea birds.
The blue shark is a shark that completes great migratory movements, commonly covering the 3000 km coming to overcome the 6000 km. The principal moves are taken place every year through the Atlantic ocean, following and exploiting the Tide of the Gulf, in a circuit that departs from the Caraibic seas, along the coasts of the United States up to the coasts of Europe, going down then thin in African waters to complete the circuit returning toward the Caraibic seas.
This shark often swims in great groups, formed
only from male samples or females, of the same dimensions, and is not
known he anchors the motive for this behavior, conflicting with the
solitary nature of the animal..
The blue shark would seem to be able to reach the 20
years of life, but as already mentioned, because of the elevated
captures from the man, it is not known if the world population of this
shark is drastically (as it is probable) decreasing..
Alieuticà (about fishing), Oppiano poem of
3500 verses, where there is an original legend on the shark Prionace
glauca, considered ideal parent:
qualcosa turba i mari devastati
Marco Angelozzi - www.prionace.it
E' assolutamente vietata la
riproduzione, anche parziale, del testo e delle