Orectolobiformes Orectolobiformes Rhincodontidae Rhincodontidae

Jeff GuertinJeff Guertin10/09/0710/09/07

One GenusOne Genus

Only one genus and species, Only one genus and species, Rhincodon typusRhincodon typus, also known as the , also known as the whale sharkwhale shark

Etymology: Greek, rhyngchos = Etymology: Greek, rhyngchos = snout, muzzle + Greek, odous, snout, muzzle + Greek, odous, odontos = tooth, teeth odontos = tooth, teeth

First identified in 1828First identified in 1828 Believed to be about 60 million years Believed to be about 60 million years

oldold

General CharacteristicsGeneral Characteristics

Five large gill openings, the fifth Five large gill openings, the fifth behind origin of pectoral finbehind origin of pectoral fin

Elongated gill rakersElongated gill rakers Blunt head with terminal mouthBlunt head with terminal mouth Reduced teeth (up to 300 rows)Reduced teeth (up to 300 rows) Two dorsal fins, one anal fin, no Two dorsal fins, one anal fin, no

dorsal or anal spinesdorsal or anal spines Broad snoutBroad snout

Distinctive FeaturesDistinctive Features

Distinctive FeaturesDistinctive Features

A unique color pattern of light spots and A unique color pattern of light spots and vertical and horizontal stripes, in the form of a vertical and horizontal stripes, in the form of a checkerboardcheckerboard

World’s largest fish (maximum reported length World’s largest fish (maximum reported length 13.7 m)13.7 m)

No subterminal notch on caudal finNo subterminal notch on caudal fin Pattern of spots and stripes unique to each Pattern of spots and stripes unique to each

animalanimal Large first and small second dorsal finLarge first and small second dorsal fin Very large pectoral fins (much larger than Very large pectoral fins (much larger than

pelvic)pelvic)

Distinctive FeaturesDistinctive Features

HabitatHabitat

Inhabit tropical and subtropical habitats Inhabit tropical and subtropical habitats circumgloballycircumglobally

Primarily pelagic with coastal feeding Primarily pelagic with coastal feeding aggregations at times (migrations)aggregations at times (migrations)

Up to 700mUp to 700m Usually solitary, but found in feeding Usually solitary, but found in feeding

aggregations of over 100 individualsaggregations of over 100 individuals Males range over larger distances than Males range over larger distances than

femalesfemales

HabitatHabitat

Food HabitsFood Habits Feeds on planktonic and nektonic prey, Feeds on planktonic and nektonic prey,

such as small fishes (sardines, anchovies, such as small fishes (sardines, anchovies, mackerel, juvenile tunas and albacore), mackerel, juvenile tunas and albacore), small crustaceans and squids small crustaceans and squids

Have homodont teeth (all the same shape Have homodont teeth (all the same shape and no abrupt change in size) which is rare and no abrupt change in size) which is rare for sharksfor sharks

No nictitating membrane; use the No nictitating membrane; use the extraocular muscles to rotate the entire extraocular muscles to rotate the entire eye back into the orbit to protect it from eye back into the orbit to protect it from abrasion during feedingabrasion during feeding

Food HabitsFood Habits

Ram filter feedersRam filter feeders

Food HabitsFood Habits Can hang vertically in the water column, where Can hang vertically in the water column, where

they will suck prey into the mouth or rise they will suck prey into the mouth or rise vertically out of the water and sick back under vertically out of the water and sick back under creating an inflow of water and prey into their creating an inflow of water and prey into their mouthsmouths

Whale sharks are highly migratory, with their Whale sharks are highly migratory, with their movements probably timed with blooms of movements probably timed with blooms of planktonic organisms and changes in planktonic organisms and changes in temperatures of water massestemperatures of water masses During March and April, they aggregate on the During March and April, they aggregate on the

continental shelf of central western Australian coast in continental shelf of central western Australian coast in response to coral spawning events that occur each response to coral spawning events that occur each yearyear

Make regular oscillations between the surface and the Make regular oscillations between the surface and the bottom off the coast, probably to search for food bottom off the coast, probably to search for food throughout the water columnthroughout the water column

Food HabitsFood Habits

Size, Age, GrowthSize, Age, Growth

Average size is 8m, can grow up to 12.5m; Average size is 8m, can grow up to 12.5m; largest specimen regarded as accurately largest specimen regarded as accurately recorded was caught in 1947 near India recorded was caught in 1947 near India (12.65m, ~47,00lbs) (12.65m, ~47,00lbs) Reports of specimen as large as 18mReports of specimen as large as 18m

Little known about age and growth ratesLittle known about age and growth rates Age estimates unknown, but thought to be Age estimates unknown, but thought to be

well over 60 years (maybe upwards of 100)well over 60 years (maybe upwards of 100) Females as large as 8-9m have been found to Females as large as 8-9m have been found to

be immaturebe immature

ReproductionReproduction

Originally thought to be oviparous, Originally thought to be oviparous, but in 1995 a female was harpooned but in 1995 a female was harpooned off the coast of Taiwan which showed off the coast of Taiwan which showed that they are ovoviviparous; litter size that they are ovoviviparous; litter size was over 300 pups was over 300 pups Sex ratio was about 1:1Sex ratio was about 1:1

Give birth to pups 40-60cm bigGive birth to pups 40-60cm big Sexual maturity estimated at 30 years Sexual maturity estimated at 30 years

of age, but really unknownof age, but really unknown

PredatorsPredators Some whales and dolphins (killer whales)Some whales and dolphins (killer whales) A juvenile specimen was found in the A juvenile specimen was found in the

stomach of a blue shark (stomach of a blue shark (Prionace Prionace glaucaglauca). Another specimen was found in ). Another specimen was found in the gut contents of a blue marlin the gut contents of a blue marlin ((Makaira nigricansMakaira nigricans). ).

Many parasitic copepods were found on Many parasitic copepods were found on the lining of the pharynx of a small the lining of the pharynx of a small (60cm total length) whale shark from (60cm total length) whale shark from Taiwan. Taiwan.

HumansHumans

ConservationConservation Status is vulnerableStatus is vulnerable Utilized fresh, frozen, dried and salted Utilized fresh, frozen, dried and salted

for human consumption, liver processed for human consumption, liver processed for oil, fins used for shark-fin soup, for oil, fins used for shark-fin soup, cartilage for health supplements and skin cartilage for health supplements and skin for leather productsfor leather products

Used in Chinese medicineUsed in Chinese medicine Large size, slow growth, and late Large size, slow growth, and late

maturation limit recruitment and make maturation limit recruitment and make whale sharks susceptible to whale sharks susceptible to overexploitation. overexploitation.

Remoras inside Remoras inside the cloaca of a the cloaca of a

femalefemale

With golden pilot jacks Swimming with a

diver

http://youtube.com/watch?v=dUMUSFLyZpU (remora catching a free ride)

BibliographyBibliography