Class: Cartilaginous fishes (Chonrichthyes)
Order: Nursesharks (Orectolobiformes)
Family: Whaleshark (Rhincodontidae) Rhincodon
Species: Whaleshark (Rhincodon Typus)Field Marks
unmistakable huge shark, one of three large filter feeding species,
with a broad, flat head and truncated snout, immense transverse,
virtually terminal mouth in front of eyes, minute, extremely
numerous teeth, and unique filter screens on its internal gill
slits, prominent ridges on sides of body with the lowermost
one expanding into a prominent keel on each side of the caudal
peduncle, a large first dorsal and small second dorsal and anal
fin, lunate or semilunate caudal fin without a prominent subterminal
notch, and an unique checkerboard pattern of light spots, horizontal
and vertical stripes on a dark background.Geographical Distribution Circumglobal
in tropical and warm t emperate seas, oceanic and coastal.
Western Atlantic: New York to central Brazil and including Gulf
of Mexico and Caribbean.
Eastern Atlantic, Senegal, Mauritania, Cape Verde islands, Gulf
Indo-West and central Pacific:
South Africa and Red Sea to Pakistan, India, Sri Lanka, Malaysia,
Thailand, China, Japan, Philippines, Indonesia (Kalimantan,
Java, Irian Jaya), Papua New Guinea, Australia (Queensland,
Northern Territory), New Caledonia, Hawaiian Islands.
EasterPacific: Southern California, to northern Chile. TOPHabitat and Biology
epipelagic oceanic and coastal, tropical and warm-temperate
pelagic shark, often seen far offshore but coming close inshore
and sometimes entering lagoons of coral, atolls. It is generally
seen or otherwise encountered close to or at the surface,
as single individuals or in schools or aggregations of up
to hundreds of sharks. In the Indian Ocean it is common in
Thailand, around the Seychelles, Mauritius, Zanzibar, Madagascar,
Mozambique and northernmost Natal.
In the western Pacific it is common in the Kuroshio current
in the fishing grounds for skipjack. It is reportedly abundant
from Cabo San Lucas to Acapulco in the eastern Pacific, and
in the Gulf of Mexico and the Caribbean in the western Atlantic.
It apparently prefers areas where the surface temperature
is 21 to 25 C with cold water of 17 C or less upwelling into
it, and salinity of 34 to 34.5 ppt; these conditions are probably
optimal for production of plankton and small nektonic organisms,
all of which are prey of the whale shark.
Whale sharks are apparently highly migratory, with their movements
probably timed with blooms of planktonic organisms and changes
in temperatures of water masses. They are often associated
with schools of pelagic fishes, especially scombrids.
uncertain, possibly oviparous or ovoviviparous. In 1953 a
large eggcase, 30 cm long, 14 cm wide and 9 cm thick containing
a nearly full-term 36 cm embryo whale shark was collected
from the Gulf of Mexico, and the assumption was made that
the species is oviparous. However, the rarity of 'free-living'
whaleshark eggs, the extreme thinness and lack of tendrils
on the only known case, the considerable yolk and partially
developed gill sieve in the only known embryo, and the presence
of umbilical scars on larger free living specimens 55 cm long
suggests an alternative explanation, that the Gulf of Mexico
egg was aborted before term, and that the whale shark is ovoviviparous.
The type of ovoviviparity practiced by the whale shark would
be a relatively simple
sort very similar to that of the related nurse sharks (Ginglymostomatidae),
with retention of the egg case in utero until the embryo hatches.
Alternatively, the egg cases of the whale shark might be retained
in utero for 'most of the development of their embryos, then
ejected at a late stage of development. Hence the mode of
reproduction of the whale shark must be considered uncertain,
with ginglymostomatid-like ovoviviparity a distinct possibility.
The smallest free-living whale sharks are from 55 to 56 cm
long, the smallest of which has an umbilical scar (properly
vitelline scar). One adult female whale shark was recorded
as having 16 egg cases in its uteri.
whale shark is a versatile suction filter-feeder, and feeds
on a wide variety of planktonic and nektonic organisms. Masses
of small crustaceans are regularly reported, along with small
and not so small fishes such as sardines, anchovies, mackerels,
and even small tunas and albacore as well as squids. The whale
shark feeds at or close to the surface, and often assumes
a vertical position with its mouth above. Phytoplankton often
occurs in the stomachs of whale sharks, but whether this is
a major component of the diet of this shark is rather doubtful.
The suction-filter mechanism of the whale shark is more versatile
than the dynamic filter mechanism of the basking shark in
the range of prey species that can be taken. The basking shark,
with its scooplike mouth, hydrodynamically 'clean' gillrakers,
and huge gill slits, has little if any suction capacity and
must depend on its relatively slow forward motion to carry
animals into its mouth; this limits it to eating small planktonic
crustaceans and other invertebrates. The whale shark is not
dependent on forward motion to operate its filters, and can
probably achieve relatively high intake velocities of water
into its mouth, that enable it to readily ingest larger, active
nektonic prey in addition to masses of planktonic crustaceans.
A disadvantage of the suction plankton feeding of the whale
shark over the dynamic method used by the basking shark is
that the structures involved can filter a far smaller volume
of water per unit time and hence are far less efficient in
concentrating diffuse plankters.
Hence the whale shark may be more dependent on high concentrations
of plankters than the basking shark to optimally utilized
such food, but has the option of utilizing nektonic organisms
The whale shark is generally considered harmless, and very
large individuals have been examined and ridden by divers
without the sharks reacting aggressively, although they may
show curiosity and approach divers to apparently examine them.
However, there have
been a few cases of whale sharks butting sport fishing boats,
possibly after being excited and hooked fishes being played
from the boats or by bait. More often human beings inadvertently
assault whale sharks, by ramming them with ships and boats
as they bask on the surface.
But now more and more we have to learn that whale sharks are
slaughtered by fishermen. We should protect this rare creature
as good as possible and put much more effort in gathering
data of the whale shark. If you have seen one, report to us
where and when, size, gender if possible, special marks etc.
We will collect these data and make them available to scientific
researches, protection organizations or whoever has a need
The whale shark has been kept in captivity in Japan; at the
time of writing this account a good-sized individual has been
housed in a large oceanarium tank in Okinawa for over a year,
and feeds readily at the surface of the tank.
Size: Maximum total length uncertain, possibly to 18 m,. but
specimens rare above 12 m; 13.7 m is often given as the maximum
measured, 12.1 m the most recently accurately measured. Most
reported are between 4 and 12 m. This is by far the world's
Interest : to Fisheries: Apparently of relatively
limited interest for fisheries. Small harpoon fisheries exist
in Pakistan and India; it may also be taken in China, and
has been captured and utilized in Senegal; it is eaten by
people either fresh or dried salted and used to treat boat
hulls in Pakistan.
long, slim fish with broad depressed head; lower jaw projects
past upper jaw; dark lateral stripe extends through eye to
tail; first dorsal fin comprised of 7 to 9 free spines; when
young, has conspicuous alternating black and white horizontal
Similar Fish: remora, Echeneis naucrates.
Where found: both inshore and near shore inhabiting inlets,
bays, and among mangroves; frequently seen around bouys, pilings,
and wrecks and as pilot fish for whale sharks and other big
Size: common to 30 pounds.
Florida Record: 103 lbs., 12 ozs.
Remarks: spawns in spring and early summer; feeds on crabs,
squid, and small fish.
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