| Common names: shark (English), tiburón (Espanol) |
Rhincodon typus Smith, 1828
Robust body; snout very short and broad; eye small, round; mouth wide, transverse, a little behind tip of snout; five long gill slits, last three over pectoral fin; two dorsal fins, first over pelvics, second and smaller fin over anal; tail fin almost symmetrical, with large lower lobe; tail base flattened, with large keel that continues forward as crest along body and over gill slits, with two more crests above along body.
Dark, with prominent white spots.
Size: 12 m (old visual records to 21 m).
Habitat: pelagic in nearshore and offshore waters.
Depth: 0-240 m.
This species is distributed worldwide in tropical and subtropical seas, including throughout the eastern Pacific.
Whale sharks are a highly migratory, pelagic species distributed throughout the world's tropical seas, typically being found between 30°N and 35°S latitude and occasionally as high as 41°N and 36.5°S. Nearly every coastal nation within these latitudes has recorded whale sharks in its waters. They are known to inhabit both deep and shallow coastal waters of subtropical zones and lagoons of coral atolls and reefs. This species can regularly be found in the offshore waters of Australia, Belize, Ecuador, Mexico, the Philippines, and South Africa.
Biogeographic Regions: oriental (Native ); ethiopian (Native ); australian (Native ); oceanic islands (Native ); indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )
Other Geographic Terms: cosmopolitan
Global Endemism: All species, TEP non-endemic, Circumtropical ( Indian + Pacific + Atlantic Oceans), "Transpacific" (East + Central &/or West Pacific), All Pacific (West + Central + East), East Pacific + Atlantic (East +/or West), Transisthmian (East Pacific + Atlantic of Central America), East Pacific + all Atlantic (East+West)
Regional Endemism: All species, Eastern Pacific non-endemic, Tropical Eastern Pacific (TEP) non-endemic, Continent + Island (s), Continent, Island (s)
Climate Zone: North Temperate (Californian Province &/or Northern Gulf of California), Northern Subtropical (Cortez Province + Sinaloan Gap), Northern Tropical (Mexican Province to Nicaragua + Revillagigedos), Equatorial (Costa Rica to Ecuador + Galapagos, Clipperton, Cocos, Malpelo), South Temperate (Peruvian Province )
Whale Sharks are found almost all year round off the east coast of Taiwan (Province of China) (Leu et al. 1997), Honduras (A. Antoniou pers. comm.) and near the Seychelles (Gudger 1932). Ongoing studies on the population of Whale Sharks around Seychelles inner islands indicate that, although occasional shark sightings are made throughout the year, there are two seasonal peak sighting periods from June to August and October to November (Marine Conservation Society Seychelles, unpubl.). Similar patterns of infrequent year-round sightings and seasonal feeding aggregations of larger numbers (tens, to low hundreds) are recorded from many areas. Aggregations of whale shark occur in Indian coastal waters between December and April (Silas 1986), March-June in Tanzania (Yahya and Jiddawi pers. comm.), in Mozambique and northern KwaZulu-Natal (South Africa) from November to January (Beckley et al. 1997), off the coast of Somalia in September, off Chile during October, in the Sea of Cortez around May-June and October-November, in the Gulf of Mexico between August and September (Clark and Nelson 1997), off the coast of Belize in April/May to June (Heyman et al. 2001), in the Bohol Sea of the Philippines between April and May (Trono 1996, Alava et al. 2002), in the Coral Sea, near the Great Barrier Reef during November and December (McPherson 1990), at Ningaloo Reef in Western Australia in March-May (Norman 1999) and at Christmas Island in the Indian Ocean between November and January. There are also occasional reports from the Florida Keys (E. De Sabata pers. comm.). Although whale sharks have been sighted in numerous other regions, these sightings are generally sporadic and seasonal.
Recent developments in electronic and satellite tagging of Whale Sharks have demonstrated that these animals undertake multi-annual and very long-distance migrations. These include over 2,000 km from north-west Australia towards Asia (pers. obs. 2002), 550 km within a few weeks (Graham and Roberts in prep.), a 2,000 km two month migration from the Mindanao Sea, inner Philippines, to 280 km south of Vietnam (Eckert et al. 2002) and a 13,000 km migration in over 37 months from the Gulf of California, Mexico, to near Tonga (Eckert and Stewart 2001). Three sharks tagged in the Seychelles, Indian Ocean, in 2001 travelled west to Zanzibar, north-west to Somalia, and over 5,000 km to the coast of Thailand, respectively (Rowat 2002).
Regularity: Regularly occurring
Type of Residency: Year-round
This species is the largest known fish, with the largest specimen recorded at 20 meters long. Whale sharks have spindle shaped, fusiform bodies, which are widest at the midsection and taper at the head and tail. There are three prominent longitudinal ridges (carinae) along the dorsal sides. The head is depressed, broad and flattened, with a large terminal mouth that can measure up to 1.5 meters across, containing up to 300 rows of hundreds of tiny, hooked, and replaceable teeth. The gill slits are very large and are internally modified into filtration screens that are used for retaining small prey. At the front of the snout they have a pair of small nares with rudimentary barbels; these nares lack the circumnarial folds and grooves present in other shark species. Like other pelagic sharks, they have a large dorsal fin along with a smaller second dorsal fin and a semi-lunate caudal fin. Males have claspers, which are modified anal fins. The skin is studded with dermal denticles, which are tooth-like scale structures that are considered to be hydrodynamically important, reducing drag and functioning as a form of parasite repellent. The integument has distinct markings and patterns that resemble a checkerboard, composed of light spots and stripes over a dark body, creating a disruptive coloration pattern. Color can range from different shades of grey, blue or brown, with typical pelagic countershading. Coloration remains the same over the shark's lifespan, making it an ideal character for photo identification of individuals. The skeleton consists of thick flexible cartilage, and a rib cage is absent, which significantly reduces body weight. Body rigidity is provided by a sub-dermal complex of collagen fibers that act as a type of flexible "corset" that the locomotory muscles attach to from the backbone, to make a light and mechanically efficient system.
Range mass: 30844 (high) kg.
Range length: 20 (high) m.
Average length: 7 m.
Other Physical Features: ectothermic ; bilateral symmetry
Catalog Number: USNM 231756
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes
Collector(s): C. Stone
Year Collected: 1858
Locality: Gulf of California, Mexico, Pacific
Inshore/Offshore: Offshore, In & Offshore, Inshore
Water Column Position: Surface, Near Surface, Mid Water, Water column only
Habitat: Water column
FishBase Habitat: Pelagic
This species prefers surface waters between 21° and 30°C. These giant zooplanktivores are usually found in coastal zones with high food productivity. Data collected from archival tags demonstrated that this species has the ability to dive to depths exceeding 1700 meters and can also tolerate temperatures as low as 7.8°C.
Range depth: 1700 (high) m.
Habitat Regions: tropical ; saltwater or marine
Aquatic Biomes: pelagic ; reef ; coastal ; brackish water
Habitat and Ecology
No long-term studies have produced validated growth rates in the wild, age at maturity, or maximum age for this species, although Pauly (2002) has tentatively suggested a slow growth rate and a 5-6% annual mortality rate for adult R. typus and estimated longevity as 60 to >100 years, for a total length of 14 m. Wintner's (2000) study of vertebral growth rings recorded three mature males with 20, 24 and 27 growth rings at 903, 922 and 945 cm TL respectively, and an immature female with 22 rings and 577 cm TL (calculated from a precaudal length of 445 cm). The presence of scars and abrasions on the claspers of several sharks over 9 m (TL) at Ningaloo Marine Park (Norman 1999) also suggests that sexual activity, at least in males, is not common prior to attaining this length. Wintner (2000) also found that adding a theoretical data point at 100 years and 14 m TL produced a Bertalanffy growth curve with lower standard errors and Linf closer to the reported maximum length than did 60 years and 14 m TL.
The Fishbase (www.fishbase.org) default life history tool for this species is set at a maximum length of 20 m TL and, strangely, Linf of 14 m TL. This yields an estimated age at maturity of nine years at 560 cm TL, a generation time of 21 years and longevity of 59 years. Most of these parameters are clearly too low. Recalculating these data for Linf 20 m TL yields an age at maturity of 21 years at 770 m TL (still low). Generation time becomes an estimated 63 years and longevity almost 150, which seems too high for a warm water species, although recorded for some species of sturgeon Acipenseridae.
Chang et al. (1997) considers that a breeding ground for whale sharks apparently lies close to Taiwan (Province of China). However, the length of gestation, localities of birth, and frequency of reproduction are not yet known for this species and require further study.
Because of their large size, Whale Sharks are probably not subject to extensive predation after reaching maturity. There are only two reports of juvenile whale sharks taken by another animal: a Blue Marlin (A. Goorah pers. comm.) and a Blue Shark (Kukuyev 1996). Several Whale Sharks from Ningaloo Reef possess scars that may be the result of shark attack at an early age (Norman 1999) and two orcas Orcinus orca have been filmed attacking, killing and consuming an 8m whale shark (O'Sullivan and Mitchell 2000).
The Whale Shark is one of only three species of shark that filter feeds, the other two being the Megamouth (Megachasma pelagios) and Basking Shark (Cetorhinus maximus) (Compagno 1984a). Unlike these two, the Whale Shark does not rely on forward motion for filtration, but is able to hang vertically in the water and suction feed by closing its gill slits and opening its mouth (Compagno 1984a). Rhincodon typus is believed to be able to sieve zooplankton as small as 1 mm in diameter through the fine mesh of their gill-rakers (Taylor 1994), typically feeding on a variety of planktonic and nektonic prey, small crustaceans and schooling fishes and even occasionally ingesting small tuna and squid (Last and Stevens 1994, Clark and Nelson 1997, Norman 1999).
Habitat Type: Marine
From 2 to 3000 meters.
Habitat: pelagic. World's largest fish. An oceanic and coastal species often seen offshore but coming close inshore, sometimes entering lagoons or coral atolls. Forms schools and often associated with groups of pelagic fishes. Feeds on planktonic and nektonic prey, such as small crustaceans, small fishes, squid, and tuna. Probably ovoviviparous (Ref. 6871). Edible and utilized dried-salted (Ref. 9987). Used in Chinese medicine (Ref. 12166).
Water temperature and chemistry ranges based on 87 samples.
Depth range (m): 0 - 384
Temperature range (°C): 10.259 - 27.173
Nitrate (umol/L): 0.483 - 26.232
Salinity (PPS): 34.060 - 36.017
Oxygen (ml/l): 2.803 - 4.831
Phosphate (umol/l): 0.106 - 1.551
Silicate (umol/l): 0.769 - 13.198
Depth range (m): 0 - 384
Temperature range (°C): 10.259 - 27.173
Nitrate (umol/L): 0.483 - 26.232
Salinity (PPS): 34.060 - 36.017
Oxygen (ml/l): 2.803 - 4.831
Phosphate (umol/l): 0.106 - 1.551
Silicate (umol/l): 0.769 - 13.198
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Diet: octopus/squid/cuttlefish, Pelagic crustacea, zooplankton, pelagic fish eggs, bony fishes
Whale sharks are known to prey on a range of planktonic and small nektonic organisms that are spatiotemporally patchy. These include krill, crab larvae, jellyfish, sardines, anchovies, mackerels, small tunas, and squid. Whale sharks are able to feed by suction, ram-feeding, and active surface ram-feeding. In ram filter feeding, the fish swims forward at constant speed with its mouth partially or fully open, straining prey particles from the water by forward propulsion. This is also called ‘passive feeding’, as there is little if any pumping of the gills. This type of feeding usually occurs when prey is present at low density. At Ningaloo Reef, ram filter feeding is associated with the presence of copepods and chaetognaths. Suction feeding is achieved by opening the mouth forcefully, sucking or gulping in prey. Water is ejected through the gills when the mouth is closed, filtering out the trapped prey. Whale sharks often do this while stationary, in a vertical or horizontal position. This type of feeding is associated with medium-density prey. Active surface ram-feeding occurs when an individual is at the surface with the top of its mouth above the waterline. The shark swims strongly, often in a circular path, collecting neustonic prey. This behavior is usually associated with dense plankton conditions. Planktonic prey is captured by filtering seawater through a filter-like device containing five sets of porous pads on each side of the pharyngeal cavity. The backmost pair is nearly triangular in shape, and leads into a narrow esophagus. The pads are interconnected by a tissue raphe (ridge), so that water entering the pharyngeal cavity has to pass through the pads prior to passing over the gills and out through the external gill slits. Whale sharks can sift prey as small as 1 mm through the fine mesh of their gill rakers. They also have several rows of small teeth, but these seem to play little if any role in feeding. In all methods of feeding, the filtration pads will at some time become blocked with particles and the shark will clear them by back-flushing, where they appear to cough underwater, ejecting a stream of debris. Muscle tissue shows a positive relationship with the size of the fish, suggesting that as they increase in size, their diets change to include prey items of a larger size and higher trophic level. A comparison of the diets of juveniles and larger individuals indicates an ontogenetic transition from pelagic prey species to coastal prey species.
Animal Foods: fish; mollusks; aquatic crustaceans; cnidarians; zooplankton
Plant Foods: phytoplankton
Foraging Behavior: filter-feeding
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods, Eats other marine invertebrates); planktivore
As large, filter-feeding fish, whale sharks affect local populations of zooplankton and small nekton by consuming these organisms. Two siphonostomatoid copepods are uniquely hosted by whale sharks: Prosaetes rhinodontis is found on the surface of the filtration pads and is thought to be parasitic, while Pandarus rhincodonicus feeds on bacteria on the surface of the skin. Most whale sharks are hosts to sharksuckers and common remora. Smaller varieties of sharksucker, such as white suckerfish, are often found living in the mouth and peribrachial cavity, as well as in the spiracle.
- Pandarus rhincodonicus (Subclass Copepoda, Subphylum Crustacea)
- Prosaetes rhinodontis (Subclass Copepoda, Subphylum Crustacea)
- Sharksucker (Echenei naucrates)
- White suckerfish (Remorina albescens)
- Common remora (Remora remora)
Whale sharks have very few natural predators due to their large size when mature. Human activities and poaching have considerably reduced their number. Small individuals are vulnerable since they haven’t fully developed and their size makes them an easy prey for blue marlin and blue sharks. Orcas are known to attack and consume whale sharks up to 8 m in size. Evidence of a whale shark being attacked by a larger shark was recorded off Australia. This individual was sighted in 2002 with a missing fin and large bite marks, most likely inflicted by a great white shark.
A whale shark’s best defensive adaptation is its skin, which is covered in dermal denticles that makes it very tough, along with a thick layer of cartilage. Numerous individuals have been seen with bite marks and scars from predators, indicating they have survived those attacks.
- Orca (Orcinus orca)
- Blue shark (Prionace glauca)
- Blue marlin (Makaira mazara)
- Great white shark (Carcharodon carcharias)
- Humans (Homo sapiens)
Anti-predator Adaptations: cryptic
Diseases and Parasites
DMS in the odor landscape of the sea
Dimethyl Sulfide or DMS is present throughout the ocean(1). It’s an important odor component of many fish and shellfish, including clams, mussels, oysters, scallops, crabs and shrimp(2-9). Where does it come from? Usually from the marine plants they feed on.
Many species of plants and algae produce DMS, but not all species produce significant amounts of it. Nearly all of these are marine, and they tend to be in closely related groups with other DMS-producers, including Chlorophyte (green) seaweeds, the Dinophyceae in the dinoflagellates, and some members of the Chrysophyceae and the Bacillariophyceae (two classes of diatoms). Other large groups, like cyanobacteria and freshwater algae, tend not to produce DMS. (10,11)
Why do these groups produce DMS? In algae, most researchers believe a related chemical, DMSP, is used by the algae for osmoregulation- by ensuring the ion concentration inside their cells stays fairly close to the salinity in the seawater outside, they prevent osmotic shock. Otherwise, after a sudden exposure to fresh water (rain at the sea surface, for instance) cells could swell up and explode. In vascular plants, like marsh grasses and sugar cane, it’s not clear what DMS is used for. (12,13)
Freshly harvested shellfish can smell like DMS because DMSP has accumulated in their tissue from the algae in their diet. Some animals, including giant Tridacna clams and the intertidal flatworm Convoluta roscoffensis, harbor symbiotic algae in their tissues, which produce DMSP; this may not be important to their symbioses, but for Tridacna, the high DMS levels can be a problem for marketing the clams to human consumers. After death, DMSP begins to break down into DMS. A little DMS creates a pleasant flavor, but high concentrations offend the human palate.(2,14)
Not all grazers retain DMS in their tissues, though. At sea, DMS is released when zooplankton feed on algae. It’s been shown in the marine copepods Labidocera aestiva and Centropages hamatus feeding on the dinoflagellate Gymnodinium nelson that nearly all the DMS in the consumed algae is quickly released during feeding and digestion.(15) This has a disadvantage for the grazing zooplankton. Marine predators, like procellariiform seabirds, harbor seals, penguins, whale sharks, cod, and coral reef fishes like brown chromis, Creole wrasse and boga, can use the smell of DMS to locate zooplankton to feed on. (8,16,17)
It’s not easy to measure how much DMS is released from the Ocean into the air every year. Recent estimates suggest 13-37 Teragrams, or 1.3-3.7 billion kilograms. This accounts for about half the natural transport of Sulfur into the atmosphere, is the conveyor belt by which Sulfur cycles from the ocean back to land. In the atmosphere, DMS is oxidized into several compounds that serve as Cloud Condensation Nuclei (CCN). The presence of CCN in the air determines when and where clouds form, which affects not only the Water cycle, but the reflection of sunlight away from the Earth. This is why climate scientists believe DMS plays an important role in regulating the Earth’s climate. (12,18)
Life History and Behavior
Whale sharks have small, circular eyes that are positioned laterally on the head, creating a wide field of vision. The broad, blunt shape of the head and the position of the eyes suggest that they may have binocular vision. Whale shark eyes are able to follow swimmers at distances of 3 to 5 meters away, suggesting that they are capable of picking out objects and movement at close range. Most sharks have ampullae of Lorenzini, which are pit-like organs clustered around the head that detect weak electric and magnetic fields and may help with navigation. The inner ear of this species is the largest known in the animal kingdom, and the diameter of the semicircular canals is near the theoretical maximum dimensions for such structures. With such large hearing structures, it is likely that whale sharks are most receptive to long wavelength and low frequency sounds, suggesting that some sort of auditory communication between conspecifics may exist. The olfactory capsules in whale sharks are spherical and rather large, so it is likely that they would have similar chemo-sensory detection abilities to those of other orectolobiform species, such as nurse sharks (Ginglymostoma cirratum). Whale sharks possess a mechanosensory lateral line system, but its capabilities are unknown. The lateral line enables sharks to react to water currents (rheotaxis). Whale sharks show a similar response to currents and can register their movement across the lines of force of the earth’s magnetic field, which is believed to assist in navigation. The lateral line also helps with prey detection, feeding, and prey capture.
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical ; electric ; magnetic
Whale sharks (Rhincodon typus) are often thought to be solitary behemoths that live and feed in the open ocean. Scientists at the Smithsonian Institution and colleagues, however, have found that this is not necessarily the case, finding that whale sharks can be gregarious and amass in the hundreds to feed in coastal waters.
Whale sharks are obligate lecithotrophic livebearers, a reproductive mode where eggs are fertilized internally, and develop in the female until the end of the embryonic phase or later. There is no maternal nutrient transfer to the pups, which are sustained by egg yolk sacs while carried inside the mother. In 1995, a 10.6 m female was harpooned off the eastern coast of Taiwan. She had an approximate number of 304 embryos, ranging in length from 42 to 63 cm. Many were still within their egg cases and had external yolk sacs. The egg capsules were amber with a smooth texture and had a respiratory opening on each side. The largest embryos were found free of their egg cases, with no external yolk sacs, indicating they were ready to be released. This proved that the species is a livebearer with aplacental viviparous development. The litter was the largest recorded in any shark species, with a sex ratio of 50:50. Whale sharks are born at an average length of 55 cm. The smallest recorded live specimen was found in the Philippines, measuring 38 centimeters. Growth in whale sharks is believed to be higher during the younger stages of life, gradually slowing after maturity. The largest individual reported to date was a Tawainese specimen in 1987 at 20 meters, while the next largest specimen was 18.8 meters in total length from the Indian fishery. Growth rates of whale sharks that were measured in aquaria show that pups grow faster than larger juveniles and females grow faster and even larger than males. In juveniles, the upper lobe of the caudal fin is considerably longer than the lower lobe, but this changes to a semi-lunate form as the juveniles mature into adults.
Development - Life Cycle: indeterminate growth
Information on the lifespan of whale sharks is very limited. Due to their advanced age at sexual maturity, it is believed that they may have lifespans exceeding 100 years.
Status: wild: unknown (low) years.
Status: captivity: 9 (high) years.
Status: wild: 150 (high) years.
Status: captivity: unknown (high) years.
Lifespan, longevity, and ageing
Genetic data from the previously mentioned embryos suggested that they were all sired by the same father. This indicates that a single male can fertilize an entire litter, suggesting that females utilize a form of sperm storage to fertilize the eggs in successive phases. If this reproductive behavior is typical for this species, it would suggest that they mate rarely with a single individual, and that breeding or mating areas with large numbers of adults will not be found in this species. Observations of sex and age segregation in tagged individuals, compared with this genetic data, lead researchers to believe that females may exhibit natal philopatry (returning to their birthplace in order to breed).
Mating System: polygynandrous (promiscuous)
There is currently limited evidence to accurately determine the age of sexual maturity in whale sharks, but it is suggested that it can take up to 30 years. Information regarding the frequency with which they can reproduce, and when and where this may happen, is currently unknown. Juveniles found in coastal waters of Taiwan, the Philippines, and India suggest that these locations may be important breeding areas.
Breeding interval: Unknown
Breeding season: Unknown
Range number of offspring: >300 (high) .
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); ovoviviparous ; sperm-storing
Due to their ovoviviparous reproductive strategy, female whale sharks provide protection to their internally developing young until they hatch from their eggs and are born. Like all sharks, there is no parental care shown by the females towards pups after they are born.
Parental Investment: pre-hatching/birth (Protecting: Female)
Molecular Biology and Genetics
Barcode data: Rhincodon typus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Rhincodon typus
Public Records: 14
Specimens with Barcodes: 19
Species With Barcodes: 1
CITES: Listed, Appendix II
Due to their docile lifestyle and very limited defenses, whale sharks have become prone to exploitation. Currently, their global conservation status is "vulnerable to extinction", because populations are decreasing in many locations as a result of reduction by unregulated fisheries. Whale sharks can also be injured by boats and propeller strikes. This species is legally protected in Australian Commonwealth waters and the states of Queensland, Tasmania and Western Australia, the Maldives, Philippines, India, Thailand, Malaysia, Honduras, Mexico, in US Atlantic waters, and in a small sanctuary area off of Belize. Full legal protection is under consideration in South Africa and Taiwan. In 1999 the whale shark was listed on Appendix II of the Bonn Convention for the Conservation of Migratory Species of Wild Animals. This identifies it as a species whose conservation status would benefit from the implementation of international cooperative agreements. This regulation has been enforced since February 2003, and requires fishing states to demonstrate that all exports are from a sustainably managed population, along with monitoring exports and imports. In Western Australian waters, Whale sharks are fully protected under the Wildlife Conservation Act of 1950.
US Federal List: no special status
CITES: appendix ii
State of Michigan List: no special status
IUCN Red List of Threatened Species: vulnerable
IUCN Red List Assessment
Red List Category
Red List Criteria
The Whale Shark (Rhincodon typus) is a cosmopolitan tropical and warm temperate species and is the world's largest living chondrichthyan. Its life history is poorly understood, but it is known to be highly fecund and to migrate extremely large distances. Populations appear to have been depleted by harpoon fisheries in Southeast Asia and perhaps incidental capture in other fisheries. High value in international trade, a K-selected life history, highly migratory nature and normally low abundance make this species vulnerable to commercial fishing. Dive tourism involving this species has recently developed in a number of locations around the world, demonstrating that it is far more valuable alive than fished.
- 1996Data Deficient
- 1994Indeterminate(Groombridge 1994)
- 1990Indeterminate(IUCN 1990)
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: GNR - Not Yet Ranked
Fishermen in the Maldives used to take 20-30 Whale Sharks per year for their oil, but reported declining catches during the 1980s to early 1990s (Fowler 2000). In a study in the Philippines, it was found that in 1997 there was a 29% decline in the whale shark catch at two of the primary sites, despite an increase in effort due to rising prices for exported products (Alava et al. 2002). The increased fishing effort and falling catches led to the 1998 fishery ban, although illegal fishing and attempted export of meat still continues on a small scale, with shipments having been impounded by customs authorities (Anon 2002b).
In Pakistan, the flesh was traditionally eaten either fresh or salted, and liver oil used for treating boats (Compagno 1984a). The number of sharks taken each year was small and often accidental bycatch (Silas 1986, Seshagiri Rao 1992). Recent landings are unknown.
A traditional small-scale seasonal harpoon fishery in India took whale sharks for their liver oil (Prater 1941, Rao 1986, Silas 1986, Vivekanandan and Zala 1994). About 40 were harpooned during April 1982 (Silas 1986), but demand for "tofu shark" meat in Taiwan (Province of China) led to increased fishing effort in Gujarat during the 1990s (Hanfee 2001). Prices rose significantly after 1997, with 279 Whale Sharks taken in January-May 1999. One hundred and forty-five sharks were taken offshore (10-15 km) in December 1999, and 160 in coastal waters in January-May 2000. The fishery closed in May 2001, when the Indian Ministry of Environment and Forests legally protected whale sharks in territorial waters.
Whale Sharks have been targeted for many decades in Taiwan (Province of China), but catches appear to have declined since the 1980s (Chen et al. 1996, Joung et al. 1996). Billfish harpooners from Hengchun Harbour, fishing south of Penghu, reportedly landed 50-60 Whale Sharks each spring in the mid-1980s, but annual landings at this location subsequently declined to about 10 sharks, and fewer still in 1994 and 1995. In 1995, landings throughout Taiwan (Province of China) were approximately 250-272, around 158 taken as bycatch in set nets, 114 by harpoon (Chen et al. 1996). The government introduced a Whale Shark reporting system in 2001. This and other sources indicate that the total number of Whale Sharks caught during 2001 was 89 (38 by set nets, 36 in the billfish harpoon fishery and 15 by other methods), and that 94 sharks weighing about 104 t in total were landed during the 12 months from March 2001 to March 2002 (Anon 2002b, Chen and Phipps 2002). The domestic catch has apparently declined by 60-70% since surveyed by Chen et al. (1996). Chen and Phipps (2002) note that the sum of the reported catch and imports is smaller than the quantity of Whale Shark meat on the domestic market, indicating that official data under-represent imports.
Wholesale Whale Shark meat prices in Chinese Taipei peaked at US$7.00/kg in the late 1990s (Liu et al. 2002) when a 10 t shark was worth approximately US$70,000, subsequently falling to US$2.00/kg in 2001 (Chen and Phipps 2002).
Although Ramachandran and Sankar (1990) considered that R. typus was an underexploited species, there are now concerns that Whale Shark populations are decreasing in many locations as a result of stock depletion by unregulated fisheries (Anon 2002b). Ecotourism industries based on viewing Whale Sharks are now developing in several locations, including Mexico, Australia, Philippines, south-eastern Africa, Seychelles, Maldives, Belize and Honduras (Norman 1999, Anon 2002b, Newman et al. 2002). The number of people swimming with Whale Sharks at Ningaloo Reef, Western Australia, during the short whale shark season from March to June, increased from 1,000 in 1993 to almost 5,000 in 2002 (Colman pers. obs. 1997). This well-managed industry contributes significantly to the national and regional economy (overseas participants make up 65-75% of participating tourists).
Ecotourism has taken over from hunting as a significant source of income for Maldivian operators, since the small fishery that once existed ceased after legislation was introduced in 1995 to protect whale sharks (C. Anderson pers. comm.). Similarly, the development of an important whale shark ecotourism industry in areas of the Philippines that experience large seasonal aggregations of whale sharks is now underway (Anon 2002b).
In the Seychelles, 162 tourists/week interacted with R. typus in November 1996 and the industry could be worth US$3-5 million annually there (Newman et al. 2002). Revenues are also significant in several other range states, indeed rather higher than revenues from fisheries for this species (Anon 2002b). To ensure that high levels of tourism do not have an adverse effect on the behaviour of Whale Sharks at these locations and other aggregation sites identified in future, monitoring must continue as a priority.
In Tanzania Whale Shark sightings are apparently on the increase. Surprisingly, fishermen do not actively hunt whale sharks and do not consume the meat; nor do they recognise that the fins may have any value. Four individuals caught in March 2001 were not consumed nor were their fins sold. A very small amount of meat was taken, possibly for medicinal purposes (S. Yahya and N. Jiddawi pers. comm.). They are avoided by net fishermen because of potential damage to the nets. Whale sharks have been sighted for the last few years during the inter-monsoonal period of March-June off Zanzibar. They are caught in purse, drift and gillnet fisheries.
Relevance to Humans and Ecosystems
Whale sharks can become tangled in nets and damage fishing equipment.
Whale sharks are considered food in many countries, with their soft meat being known as "tofu shark". The flesh is a delicacy in the Taiwanese restaurant trade. Although the cartilage fibers in the fins are not good for making soup, they are sold as display or trophy fins in Asian restaurants and the perceived values of their fins appear to have increased over the years. There are recent reports of live individuals being finned in the Maldives and Philippines. Hunting has significantly decreased their numbers. In Pakistan, the flesh is traditionally consumed either fresh or salted, and Whale shark liver oil has been used for treating boat hulls, and as shoeshine. Ecotourism industries based on snorkeling and viewing Whale Sharks are now established in several locations, including Mexico, Australia, Philippines, southeastern Africa, Seychelles, Maldives, Belize and Honduras. In some areas tourism has developed and has become a significant source of income, due to laws that protect and ban the whale shark fishery. In these areas, monitoring must continue to ensure that high levels of tourism do not have a negative effect on the behavior of the species at their aggregation sites.
Positive Impacts: food ; body parts are source of valuable material; ecotourism
The whale shark (Rhincodon typus) is a slow-moving filter feeding shark and the largest known extant fish species. The largest confirmed individual had a length of 12.65 m (41.50 ft) and a weight of more than 21.5 metric tons (47,000 lb), and unconfirmed reports of considerably larger whale sharks exist. Claims of individuals over 14 m (46 ft) long and weighing at least 30 mt (66,000 lb) are not uncommon. The whale shark holds many records for sheer size in the animal kingdom, most notably being by far the largest living nonmammalian vertebrate. It is the sole member of the genus Rhincodon and the family, Rhincodontidae (called Rhiniodon and Rhinodontidae before 1984), which belongs to the subclass Elasmobranchii in the class Chondrichthyes. The species originated about 60 million years ago.
The whale shark is found in tropical and warm oceans and lives in the open sea, with a lifespan of about 70 years. Whale sharks have very large mouths, and as filter feeders, they feed mainly on plankton. The BBC program Planet Earth filmed a whale shark feeding on a school of small fish. The same documentary showed footage of a whale shark timing its arrival to coincide with the mass spawning of fish shoals and feeding on the resultant clouds of eggs and sperm.
The species was distinguished in April 1828 after the harpooning of a 4.6-m-long specimen in Table Bay, South Africa. Andrew Smith, a military doctor associated with British troops stationed in Cape Town, described it the following year. The name "whale shark" comes from the fish's size, being as large as some species of whales and also a filter feeder like baleen whales.
Distribution and habitat
The whale shark inhabits all tropical and warm-temperate seas. The fish is primarily pelagic, living in the open sea but not in the greater depths of the ocean. Seasonal feeding aggregations occur at several coastal sites such as the southern and eastern parts of South Africa; Saint Helena Island in the South Atlantic Ocean; Gulf of Tadjoura in Djibouti, Gladden Spit in Belize; Ningaloo Reef in Western Australia; Lakshadweep, Gulf of Kutch and Saurashtra coast of Gujarat in India; Útila in Honduras; Southern Leyte; Donsol, Pasacao and Batangas in the Philippines; off Isla Mujeres and Isla Holbox in Yucatan and Bahía de los Ángeles in Baja California, México; Ujung Kulon National Park in Indonesia; Nabire National Park in Indonesia; Nosy Be in Madagascar Off Tofo Reef near Inhambane in Mozambique; the Tanzanian islands of Mafia, Pemba, Zanzibar; the Dimaniyat Islands in the Gulf of Oman and Al Hallaniyat islands in the Arabian Sea; and, very rarely, Eilat, Israel and Aqaba, Jordan. Although typically seen offshore, it has been found closer to land, entering lagoons or coral atolls, and near the mouths of estuaries and rivers. Its range is generally restricted to about 30° latitude. It is capable of diving to depths of at least 1,286 m (4,219 ft), and is migratory. On 7 February 2012, a large whale shark was found floating 150 kilometres (93 mi) off the coast of Karachi, Pakistan. The length of the specimen was said to be between 11 and 12 m (36 and 39 ft), with a weight of around 15,000 kg (33,000 lb).
In 2011, more than 400 whale sharks gathered off the Yucatan Coast. It was one of the largest gatherings of whale sharks recorded.
Gulf of Tadjoura in Djibouti where whale sharks congregate between the months of October and March has become a popular destination for swimming with the gentle giants of the sea.
Whale sharks have a mouth that can be 1.5 m (4.9 ft) wide, containing 300 to 350 rows of tiny teeth and 10 filter pads which it uses to filter feed. Whale sharks have five large pairs of gills. The head is wide and flat with two small eyes at the front. Whale sharks are grey with a white belly. Their skin is marked with pale yellow spots and stripes which are unique to each individual. The whale shark has three prominent ridges along its sides. Its skin can be up to 10 cm (3.9 in) thick. The shark has a pair of dorsal fins and pectoral fins. Juveniles' tails have a larger upper fin than lower fin, while the adult tail becomes semilunate. The whale shark's spiracles are just behind its eyes.
The whale shark is the largest non-cetacean animal in the world. The average size of adult whale sharks is estimated at 9.7 m (31.82 ft) and 9 t (20,000 lb). The largest verified specimen was caught on 11 November 1947, near Baba Island, in Karachi, Pakistan. It was 12.65 m (41.50 ft) long, had a girth of 7 m (23.0 ft), and weighed approximately 25.5 t (56,000 lb), according to a reliable interspecific shark weight formula. Stories exist of vastly larger specimens – quoted lengths of 18 m (59 ft) and 45.5 t (100,000 lb) are common in the popular literature, but no scientific records support their existence. In 1868, the Irish natural scientist Edward Perceval Wright obtained several small whale shark specimens in the Seychelles, but claimed to have observed specimens in excess of 15 m (49.2 ft), and tells of shark specimens surpassing 21 m (68.9 ft).
In a 1925 publication, Hugh M. Smith described a huge animal caught in a bamboo fish trap in Thailand in 1919. The shark was too heavy to pull ashore, but Smith estimated the shark was at least 17 m long, and weighed around 37 t. These measurements have been exaggerated to 43 t and a more precise 17.98 m in recent years. A shark caught in 1994 off Tainan County, southern Taiwan, reportedly weighed 35.8 t (79,000 lb). There have even been claims of whale sharks of up to 23 metres (75 ft) and 100 tonnes (220,000 lb). In 1934, a ship named the Maurguani came across a whale shark in the southern Pacific Ocean, rammed it, and the shark became stuck on the prow of the ship, supposedly with 4.6 m on one side and 12.2 m on the other. No reliable documentation exists for these claims and they remain "fish stories".
The whale shark is a filter feeder – one of only three known filter feeding shark species (along with the basking shark and the megamouth shark). It feeds on macroalgae, plankton, krill, Christmas Island red crab larvae  and small nektonic life, such as small squid or vertebrates. It also feeds on small fish and the clouds of eggs and sperm during mass spawning of fish. The many rows of vestigial teeth play no role in feeding. Feeding occurs either by ram filtration, in which the animal opens its mouth and swims forward, pushing water and food into the mouth, or by active suction feeding, in which the animal opens and closes its mouth, sucking in volumes of water that are then expelled through the gills. In both cases, the filter pads serve to separate food from water. These unique, black sieve-like structures are presumed to be modified gill rakers. Food separation in whale sharks is by cross-flow filtration, in which the water travels nearly parallel to the filter pad surface, not perpendicularly through it, before passing to the outside, while denser food particles continue to the back of the throat. This is an extremely efficient filtration method that minimises fouling of the filter pad surface. Whale sharks have been observed "coughing", presumably to clear a build-up of particles from the filter pads. Whale sharks migrate to feed and possibly to breed.
The whale shark is an active feeder, targeting concentrations of plankton or fish. It is able to ram filter feed or can gulp in a stationary position. This is in contrast to the passive feeding basking shark, which does not pump water. Instead, it swims to force water across its gills.
Behavior toward divers
Despite its size, the whale shark does not pose significant danger to humans. Whale sharks are docile fish and sometimes allow swimmers to catch a ride, although this practice is discouraged by shark scientists and conservationists because of the disturbance to the sharks. Younger whale sharks are gentle and can play with divers. Underwater photographers such as Fiona Ayerst have photographed them swimming uncomfortably close to humans without any danger.
The shark is seen by divers in many places, including the Bay Islands in Honduras, Thailand, the Philippines, the Maldives, the Red Sea, Western Australia (Ningaloo Reef, Christmas Island), Taiwan, Panama (Coiba Island), Belize, Tofo Beach in Mozambique, Sodwana Bay (Greater St. Lucia Wetland Park) in South Africa, the Galapagos Islands, Isla Mujeres and Bahía de los Ángeles in Mexico, the Seychelles, West Malaysia, islands off eastern peninsular Malaysia, India, Sri Lanka, Oman, Fujairah, and Puerto Rico.
Two whale sharks were featured as the main attraction of Osaka Aquarium Kaiyukan and as of 2005, three whale sharks were in captivity at the Okinawa Churaumi Aquarium in Japan. The Ioworld Aquarium in Kagoshima, Japan, also features a single adult whale shark as a major attraction. One was also on display in the Taiwan, Kenting National Museum of Biology and Aquarium and 5 are on display at the Yantai Aquarium in China. Four whale sharks, two males,Taroko and Yushan, and two females, Alice and Trixie, live in the Georgia Aquarium, in Atlanta, USA. Two male whale sharks, Ralph and Norton, died in captivity at the Georgia Aquarium on 11 January 2007, and 13 June 2007, respectively. The two females were added on 3 June 2006 and two more males in 2007. All six whale sharks were imported from Taiwan, where whale sharks are called tofu sharks because of the taste and texture of the flesh; the fishery from which they came has since closed. Two whale sharks live at Polar Ocean World in Qingdao, China. One whale shark was at the Atlantis Hotel in Dubai, but was released in March 2010.
Neither mating nor pupping of whale sharks has been observed.
The capture of a female in July 1996 that was pregnant with 300 pups indicated whale sharks are ovoviviparous. The eggs remain in the body and the females give birth to live young which are 40 to 60 cm (16 to 24 in) long. Evidence indicates the pups are not all born at once, but rather the female retains sperm from one mating and produces a steady stream of pups over a prolonged period. They reach sexual maturity at around 30 years and their lifespan is an estimated 70 to 100 years.
On 7 March 2009, marine scientists in the Philippines discovered what is believed to be the smallest living specimen of the whale shark. The young shark, measuring only 38 cm (15 in), was found with its tail tied to a stake at a beach in Pilar, Philippines, and was released into the wild. Based on this discovery, some scientists no longer believe this area is just a feeding ground; this site may be a birthing ground, as well. Both young whale sharks and pregnant females have been seen in the waters of Saint Helena in the South Atlantic Ocean, where numerous whale sharks can be spotted during the summer.
The whale shark is targeted by commercial fisheries in several areas where they seasonally aggregate. The population is unknown and the species is considered vulnerable by the IUCN. It is listed, along with six other species of sharks, under the CMS Memorandum of Understanding on the Conservation of Migratory Sharks. In 1998, the Philippines banned all fishing, selling, importing, and exporting of whale sharks for commercial purposes, followed by India in May 2001, and Taiwan in May 2007. They are currently listed as a vulnerable species, but continue to be hunted in parts of Asia, such as Taiwan and the Philippines.
In 2006, Resorts World Sentosa announced its plans to bring in whale sharks for their marine life park. This was met with opposition from seven notable conservation societies. In 2009, the plan was shelved in favour of a search for other alternatives.
In 2010, the Gulf of Mexico oil spill resulted in 4,900,000 barrels (780,000 m3) of oil flowing into an area south of the Mississippi River Delta, where one-third of all whale shark sightings in the northern part of the gulf have occurred in recent years. Sightings confirmed that the whale sharks were unable to avoid the oil slick, which was situated on the surface of the sea where the whale sharks feed for several hours at a time. No dead whale sharks were found.
This species was also added to Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 2003 to regulate the international trade of live specimens and its parts.
In Vietnamese culture, the whale shark is revered as a deity called Cá Ông, which literally translates as "Sir Fish".
In the Philippines, it is called butanding and balilan. The whale shark is featured on the reverse of the Philippine 100-peso bill.
- For a topical guide to this subject, see Outline of sharks.
- Jurassic Shark (2000) documentary by Jacinth O'Donnell; broadcast on Discovery Channel, 5 August 2006
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- General references
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- FAO web page on Whale shark
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- "Rhincodon typus". Integrated Taxonomic Information System. Retrieved 16 November 2005.
- Whale shark (Rhincodon typus) at Wikimedia Commons
- Whale shark (Rhincodon typus) at Wikispecies
- Whale shark (Rhincodon typus) at IUCN Red List
- Whale shark (Rhincodon typus) at Animal Diversity Web
- Whale shark (Rhincodon typus) at FishBase
- Whale shark (Rhincodon typus) at Ocean Biogeographic Information System
- "Whale Sharks, Whale Shark Pictures, Whale Shark Facts". Animals, Animal Pictures, Wild Animal Facts.
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