The oceanic white tip shark is
an animal that reenters among the more dangerous five kinds of shark for
the man and also recently (December 2010) it seems to be the responsible
of serious attacks, one of which unfortunately deadly, towards swimmers
in the waters of the tourist place Sharm el Sheikh. Shortly returning to
these episodes, the sharks authors of the accidents would be one or two
Carcharhinuses longimanus and a mako shark (Isurus oxyrinchus),
also inserted among the five most dangerous sharks for the man.
The events are surely unusual,
the series of attacks that happened in few days in the waters of Sharm
el Sheikh doesn't have precedents in those zones, but perhaps also the
probable causes that instigated the predatory instinct of these fishes
don't even have precedents.. In fact hundred carcasses of animals were
present throws the sea in that period and the greater tendency to
attract the sharks with pastures and dying fishes, assuring so to the
scuba divers meetings and strong emotions, made approach also the
oceanic white tip shark, normally present in deep waters and not close
to the coasts..
Returning to the description of the Carcharhinus
longimanus, we confirm, as already mentioned, that this animal is
normally met in waters distant from the coasts, from the middle depth of
150 m and only occasionally is near to the continental reefs. (it
is mostly present instead around the insular reefs)
This shark, that can reach the
four meters of length, swims in all the tropical and sub-tropical seas
of the world and is easily recognizable for some very particular
physical characteristics. The body is thick, mighty, with the first
dorsal fin and the pectoral fins very great, rounds off to the
extremities and with a showy white stain. Also the ventral fins and the
extremities superior and inferior of the caudal fin have a recognizable
stain of white color.
The face of the oceanic white
tip shark is rounded off and the eyes relatively great. The coloration,
in the adult samples present in the ocean Pacific, is near to the grey
one while the present populations in the Red Sea extend more to the
brown one. The abdomen always has a clearer coloration, almost white.
(in the young people can be present small black stains on the fins)
These animals are solitary and are rarely sighted more samples of the
same kind into close contact.
During the day the
oceanic white tip shark swims under the surface of the water, with the
dorsal fin that often escapes and the movements are slow, but this
tendency never has to be underestimated becouse this shark is able of
mighty and immediate releases, both of defensive and offensive nature.
This shark is often accompanied by an elevated number of pilot fishes (Naucrates
ductor) that, despite their name, don't have the assignment to drive
the shark, but they are fishes that follow the shark to take advantage
of some possible residue of food of his meals and perhaps to free him
from some types of parasites. (we have however to remember that some
imprudent pilot fish, perhaps too much sure of his "untouchable
condition", has sadly been seen to finish in the mouth of this shark)
The Carcharhinus longimanus
is defined a curious shark, persistent, dominant and even aggressive
when it competes for the food, above all if in the proximities it is
present also the Carcharhinus falciformis and sometimes show
"nervous behaviors" when it draws near to scuba divers. (the oceanic
white tip shark together with the Carcharhinus falciformis and
Prionace glauca, are the more diffused three kinds of sharks in
pelagic waters, deep and distant from the coasts)
Its preys are very various: fishes, sea turtle, sea birds, squids,
gastropods, shellfishes, carcasses of sea mammals and rays.
This shark is often seen to
swim in the proximities or even together with groups of pilot whales (Globicephala
macrorhynchus and Globicephala melas, mammalian sea belonging
to the family of the Delphinidae) probably to take advantage of
possible rests of food during the moments of hunting of these mighty
mammals. The pilot whales, with their tonnage that can reach six meters
length and three tons of weight are not seemed ever bothered by the
presence of this shark. Is real the tendency of this shark not to
estrange too much from groups of pilot whales, once sighted, probably
not to lose the occasion of a good meal gotten with least efforts..
Despite his curiosity, tenacity
and power, the oceanic white tip shark, considered the statistics that
concern him, it is not so dangerous as could be thought, even if some
attacks are certain to swimmers and toward boats. The Oceanographic
Research Institute of Durban, in the South Africa, considers for example
that this shark has been responsible of different deadly attacks during
the sinking of the ship "Nova Scotia", during the second world war.
We conclude these
considerations on the oceanic white tip shark remembering however that
every animal, dangerous or mild, curious or bashful, mighty or of small
dimensions, great raider or harmless filtering animal, always have to be
respected, admired but also feared, in a world where man is always the
WHITE TIP SHARK
dimensions: 180-200 cm
Maximum dimensions: can reach 400 cm
Distribution: in all the tropical and sub-tropical seas of the
Coloration: bronzy-grey shark, white abdomen with a clean and
irregular separation from that dorsal. This shark is easily recognizable
from the thick and mighty body and from the pectoral fins, very great,
rounded to the extremities and white coloured, always in the terminal
part. The first dorsal fin is great, rounded and it finishes with a
showy white stain. Also the ventral fins and the superior and inferior
extremities of the caudal fin are recognizable for white color. The
second dorsal fin and the anal fin are grey dark bronze coloured. The
face is rounded and the eyes are great.
Reproduction: viviparous with yolk-sac placenta.
with the man: considered a very dangerous shark for the man.
Commercial value: object of sporting and commercial fishing for the
great fins. The populations of this shark seem to be decreased during
the last years.
triangular and serrated to the borders. The teeth of the superior arcade
are greater while those of the inferior arcade are more lengthened and
very powerful, curious and tenacious shark, it normally swims in pelagic
waters, from the surface up to around 180 m of depth. It rarely swims
near to the continental reefs (close to the beaches) while it is being
more frequent around insular reef. This shark is often surrounded by
numerous Naucrates ductor (pilot fishes), it swims slowly, both during
the day and during the night, but it is able of fast releases. The
oceanic white tip shark eats bony fishes, cefalopods, gastropods,
shellfishes, sea birds and races.
This shark is potentially very dangerous for the man and it is
responsible of a certain number of attacks in deep waters, away from
the coasts, in case of castaways.
Bibliography: "Sharks & Rays, Elasmobranch
Guide Of The World". Ralf M. Hennemann,
"Sharks of the world", Leonard Compagno, M. Dando, S. Fowler,
"Sharks", Jeremy Stafford-Deitsch.
Marco Angelozzi -
The oceanic white tip shark
photographs were realized in the Red Sea by Mr. Ahmed Bijou and courtesy
given for this article. Reproduction, even partial, of the text and
this article is absolutely prohibited, without the consent
of the authors.