98-406: The whale shark ( Rhincodon typus ) is a slow-moving, filter-feeding carpet shark and the largest known extant fish species . The largest confirmed individual had a length of 18.8 m (61.7 ft). The whale shark holds many records for size in the animal kingdom, most notably being by far the most massive living non-cetacean animal. It is the sole member of the genus Rhincodon and
196-430: A cilium . The inner segment contains organelles and the cell's nucleus, while the outer segment contains the light-absorbing materials. The outer segments of cones have invaginations of their cell membranes that create stacks of membranous disks. Photopigments exist as transmembrane proteins within these disks, which provide more surface area for light to affect the pigments. In cones, these disks are attached to
294-453: A standard length of 15 m (49.2 ft) and an estimated total length at 18.8 m (61.7 ft) was reported from the Arabian Sea in 2001. In a 2015 study reviewing the size of marine megafauna , McClain and colleagues considered this female as being the most reliable and accurately measured. On 7 February 2012, a large whale shark was found floating 150 kilometres (93 mi) off
392-950: A different opsin : OPN1SW , OPN1MW , and OPN1LW , respectively. These cones are sensitive to visible wavelengths of light that correspond to short-wavelength, medium-wavelength and longer-wavelength light respectively. Because humans usually have three kinds of cones with different photopsins , which have different response curves and thus respond to variation in color in different ways, humans have trichromatic vision . Being color blind can change this, and there have been some verified reports of people with four types of cones, giving them tetrachromatic vision. The three pigments responsible for detecting light have been shown to vary in their exact chemical composition due to genetic mutation ; different individuals will have cones with different color sensitivity. Humans normally have three types of cones, usually designated L , M and S for long, medium and short wavelengths respectively. The first responds
490-400: A filter-feeder due to its bill proportions being similar to those of shoveler ducks . It is unique in being a large, flightless marine animal, unlike the smaller still volant flamingos and prions. Traditionally, Ctenochasmatoidea as a group has been listed as filter-feeders, due to their long, multiple slender teeth, clearly well adapted to trap prey. However, only Pterodaustro showcases
588-466: A highly effective source of fertilizer and animal feed In the U.S., researchers are investigating potential to model the use of shellfish and seaweed for nutrient mitigation in certain areas of Long Island Sound. Bivalves are also largely used as bioindicators to monitor the health of an aquatic environment, either fresh- or seawater. Their population status or structure, physiology, behaviour, or their content of certain elements or compounds can reveal
686-517: A kind of rudimentary filter feeding, using their long, slender teeth to trap small fish, though probably lacking the pumping mechanism of Pterodaustro . In essence, their foraging mechanism was similar to that of modern young Platanista " dolphins ". Filter feeding habits are conspicuously rare among Mesozoic marine reptiles , the main filter feeding niche being seemingly instead occupied by pachycormid fish. However, some sauropsids have been suggested to have engaged in filter feeding. Henodus
784-459: A larger male unsuccessfully attempted to mate with a smaller, immature female. The capture of a ~10.6 m (35 ft) female in July 1996 that was pregnant with ~300 pups indicated that 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
882-494: A military doctor associated with British troops stationed in Cape Town , described it the following year. The name "whale shark" refers to the animal's appearance and large size; it is a fish, not a mammal , and (like all sharks) is not closely related to whales . Whale sharks possess a broad, flattened head with a large mouth and two small eyes located at the front corners. Unlike many other sharks, whale shark mouths are located at
980-399: A peak sensitivity at 498 nm, roughly halfway between the peak sensitivities of the S and M cones.) All of the receptors contain the protein photopsin , with variations in its conformation causing differences in the optimum wavelengths absorbed. The color yellow, for example, is perceived when the L cones are stimulated slightly more than the M cones, and the color red is perceived when
1078-438: A proper pumping mechanism, having up-turned jaws and powerful jaw and tongue musculature. Other ctenochasmatoids lack these, and are now instead thought to have been spoonbill -like catchers, using their specialised teeth simply to offer a larger surface area. Tellingly, these teeth, while small and numerous, are comparatively unspecialised to the baleen-like teeth of Pterodaustro . Boreopterids are thought to have relied on
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#17328688788251176-452: A speed of 6 cm per minute. However, because Leuconia has more than 2 million flagellated chambers whose combined diameter is much greater than that of the canals, water flow through chambers slows to 3.6 cm per hour. Such a flow rate allows easy food capture by the collar cells. Water is expelled through a single osculum at a velocity of about 8.5 cm/second: a jet force capable of carrying waste products some distance away from
1274-725: A swarm gulping, while lowering their tongue so that the head's ventral grooves expand and vastly increase the amount of water taken in. Baleen whales typically eat krill in polar or subpolar waters during summers, but can also take schooling fish, especially in the Northern Hemisphere. All baleen whales except the gray whale feed near the water surface, rarely diving deeper than 100 m (330 ft) or for extended periods. Gray whales live in shallow waters feeding primarily on bottom-living organisms such as amphipods . Bivalves are aquatic molluscs which have two-part shells . Typically both shells (or valves) are symmetrical along
1372-459: A very large tank is required and it has specialized feeding requirements. Their large size and iconic status have also fueled an opposition to keeping the species in captivity, especially after the early death of some whale sharks in captivity and certain Chinese aquariums keeping the species in relatively small tanks. The first attempt at keeping whale sharks in captivity was in 1934 when an individual
1470-642: A very short period. The whale shark kept at Dubai's Atlantis, The Palm was rescued from shallow waters in 2008 with extensive abrasions to the fins and after rehabilitation it was released in 2010, having lived 19 months in captivity. Marine Life Park in Singapore had planned on keeping whale sharks but scrapped this idea in 2009. Filter feeder Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters , food particles or smaller organisms ( bacteria , microalgae and zooplanktons ) suspended in water, typically by having
1568-424: A water current which is used for circulation. Dissolved gases are brought to cells and enter the cells via simple diffusion . Metabolic wastes are also transferred to the water through diffusion. Sponges pump remarkable amounts of water. Leuconia , for example, is a small leuconoid sponge about 10 cm tall and 1 cm in diameter. It is estimated that water enters through more than 80,000 incurrent canals at
1666-470: 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. 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. In ram filter feeding,
1764-400: A white belly marked with an arrangement of pale grey or white spots and stripes that is unique to each individual. The skin can be up to 15 cm (5.9 in) thick and is very hard and rough to the touch. The whale shark has three prominent ridges along its sides, which start above and behind the head and end at the caudal peduncle . The shark has two dorsal fins set relatively far back on
1862-585: Is "an environmental management strategy by which nutrients are removed from an aquatic ecosystem through the harvest of enhanced biological production, including the aquaculture of suspension-feeding shellfish or algae". Nutrient removal by shellfish, which are then harvested from the system, has the potential to help address environmental issues including excess inputs of nutrients ( eutrophication ), low dissolved oxygen, reduced light availability and impacts on eelgrass, harmful algal blooms, and increases in incidence of paralytic shellfish poisoning (PSP). For example,
1960-403: Is accomplished through filter feeding, using the krill's developed front legs, providing for a very efficient filtering apparatus: the six thoracopods form a very effective "feeding basket" used to collect phytoplankton from the open water. In the animation at the top of this page, the krill is hovering at a 55° angle on the spot. In lower food concentrations, the feeding basket is pushed through
2058-496: Is also directionally nonuniform, peaking at a direction that receives light from the center of the pupil; this effect is known as the Stiles–Crawford effect . It is possible that S cones may play a role in the regulation of the circadian system and the secretion of melatonin but this role is not clear yet. The exact contribution of S cone activation to circadian regulation is unclear but any potential role would be secondary to
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#17328688788252156-419: 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 minimizes fouling of the filter pad surface. Whale sharks have been observed "coughing", presumably to clear a build-up of particles from
2254-428: Is responsible for color vision . Cones function best in relatively bright light, called the photopic region, as opposed to rod cells , which work better in dim light, or the scotopic region. Cone cells are densely packed in the fovea centralis , a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. Conversely, they are absent from
2352-772: Is seen by divers in many places, including the Bay Islands in Honduras, Thailand, Indonesia ( Bone Bolango , Cendrawasih Bay ), the Philippines, the Maldives close to Maamigili (South Ari Atoll), 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,
2450-566: Is the largest non- cetacean animal in the world. However, the maximum size and growth patterns of the species are not well understood. Limited evidence, mostly from males, suggests that sexual maturity occurs around 8 to 9 meters (26 to 30 ft) in length, with the possibility of females sexually maturing at a similar size or larger. Various studies have aimed to estimate the growth and longevity of whale sharks, either by analysing evidence from vertebral growth rings or measurements taken from re-sighted sharks over several years. This information
2548-432: Is therefore called ' ultraviolet ' light. People with aphakia , a condition where the eye lacks a lens, sometimes report the ability to see into the ultraviolet range. At moderate to bright light levels where the cones function, the eye is more sensitive to yellowish-green light than other colors because this stimulates the two most common (M and L) of the three kinds of cones almost equally. At lower light levels, where only
2646-766: Is used to model growth curves, which can predict asymptotic length. The growth curves produced from these studies have estimated asymptotic lengths ranging from 15 to 21.9 meters (49 to 72 ft). A 2020 study looked at the growth of whale shark individuals over a 10-year period around the Ningaloo Reef and concluded the species exhibits sexual dimorphism with regard to size, with females growing larger than males. The study found that males on average reach 8 to 9 meters (26 to 30 ft) in length. The same study had less female data but estimated an average length of around 14.5 m (48 ft). However, this value dropped to 12.1 m (40 ft) if data from aquarium whale sharks
2744-481: The Atlantic menhaden , a type of herring , lives on plankton caught in midwater. Adult menhaden can filter up to four gallons of water a minute and play an important role in clarifying ocean water. They are also a natural check to the deadly red tide . In addition to these bony fish, four types of cartilaginous fishes are also filter feeders. The whale shark sucks in a mouthful of water, closes its mouth and expels
2842-471: The Cetacea (whales, dolphins, and porpoises), are characterized by having baleen plates for filtering food from water, rather than teeth. This distinguishes them from the other suborder of cetaceans, the toothed whales (Odontoceti). The suborder contains four families and fourteen species. Baleen whales typically seek out a concentration of zooplankton, swim through it, either open-mouthed or gulping, and filter
2940-656: The Galapagos Islands, Saint Helena , Isla Mujeres ( Caribbean Sea ), La Paz, Baja California Sur and Bahía de los Ángeles in Mexico , the Seychelles , West Malaysia , islands off eastern peninsular Malaysia , India , Sri Lanka , Oman , Fujairah , Puerto Rico , and other parts of the Caribbean . Juveniles can be found near the shore in the Gulf of Tadjoura , near Djibouti , in
3038-575: The Horn of Africa . There is currently no robust estimate of the global whale shark population. The species is considered endangered by the IUCN due to the impacts of fisheries, by-catch losses, and vessel strikes, combined with its long lifespan and late maturation. In June 2018 the New Zealand Department of Conservation classified the whale shark as "Migrant" with the qualifier "Secure Overseas" under
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3136-462: The M and L cones. The ratio of M and L cones varies greatly among different people with regular vision (e.g. values of 75.8% L with 20.0% M versus 50.6% L with 44.2% M in two male subjects). Like rods, each cone cell has a synaptic terminal, inner and outer segments, as well as an interior nucleus and various mitochondria . The synaptic terminal forms a synapse with a neuron bipolar cell . The inner and outer segments are connected by
3234-467: 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
3332-729: The New Zealand Threat Classification System . 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. In 2010, the Gulf of Mexico oil spill resulted in 4,900,000 barrels (780,000 m) of oil flowing into an area south of
3430-584: The optic disc , contributing to the blind spot . There are about six to seven million cones in a human eye (vs ~92 million rods), with the highest concentration being towards the macula . Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of color. They are also able to perceive finer detail and more rapid changes in images because their response times to stimuli are faster than those of rods. Cones are normally one of three types: S-cones, M-cones and L-cones. Each type expresses
3528-554: The vertebrates . Nearly all tunicates are suspension feeders , capturing planktonic particles by filtering sea water through their bodies. Water is drawn into the body through the inhalant buccal siphon by the action of cilia lining the gill slits. The filtered water is then expelled through a separate exhalant siphon. To obtain enough food, a typical tunicate needs to process about one body-volume of water per second. Flamingos filter-feed on brine shrimp . Their oddly shaped beaks are specially adapted to separate mud and silt from
3626-565: 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. It was reported in 2014 that hundreds of whale sharks were illegally killed every year in China for their fins, skins, and oil. The whale shark is popular in the few public aquariums that keep it, but its large size means that
3724-791: The Galápagos, Quintana Roo in Mexico, Mafia Island of Pwani Region in Tanzania, Inhambane province in Mozambique, the Philippines , around Mahe in the Seychelles, the Gujarat and Kerala coasts of India, Taiwan , southern China and Qatar . In 2011, more than 400 whale sharks gathered off the Yucatan Coast. It was one of the largest gatherings of whale sharks recorded. Aggregations in that area are among
3822-422: The L cones are stimulated significantly more than the M cones. Similarly, blue and violet hues are perceived when the S receptor is stimulated more. S Cones are most sensitive to light at wavelengths around 420 nm. However, the lens and cornea of the human eye are increasingly absorptive to shorter wavelengths, and this sets the short wavelength limit of human-visible light to approximately 380 nm, which
3920-530: The accuracy of in-water measurements, including underwater and aerial techniques. Since the 1800s, there have been accounts of very large whale sharks. Some of these are as follows: In 1868, the Irish natural scientist Edward Perceval Wright obtained several small whale shark specimens in the Seychelles . Wright was informed of one whale shark that was measured as exceeding 45 ft (14 m). Wright claimed to have observed specimens over 50 ft (15 m) and
4018-415: 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
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4116-530: The approximate average of 1.7 to 1.8 m (5.6–5.9 ft), based on the local fishermen. Later sources have stated this whale shark as approximately 18 m (59 ft), but the accuracy of the estimate has been questioned. In 1934, a ship named the Maunganui came across a whale shark in the southern Pacific Ocean and rammed it. The shark became stuck on the prow of the ship, supposedly with 15 ft (4.6 m) on one side and 40 ft (12.2 m) on
4214-871: The area. Large adult females, often pregnant, are a seasonal presence around the Galapagos Islands, which may have reproductive significance. One study between 2011 and 2013 found that 91.5% of the whale sharks observed around Darwin Island were adult females. 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 plankton including copepods , krill , fish eggs , Christmas Island red crab larvae and small nektonic life, such as small squid or fish . It also feeds on clouds of eggs during mass spawning of fish and corals. The many rows of vestigial teeth play no role in feeding. Feeding occurs either by ram filtration, in which
4312-420: The average harvested mussel contains: 0.8–1.2% nitrogen and 0.06–0.08% phosphorus Removal of enhanced biomass can not only combat eutrophication and also support the local economy by providing product for animal feed or compost. In Sweden, environmental agencies utilize mussel farming as a management tool in improving water quality conditions, where mussel bioextraction efforts have been evaluated and shown to be
4410-779: The basic research on the keeping of the species was made at these two institutions. Since the mid-1990s, several other aquariums have kept the species in Japan ( Kagoshima Aquarium , Kinosaki Marine World, Notojima Aquarium , Oita Marine Palace Aquarium , and Yokohama Hakkeijima Sea Paradise ), South Korea ( Aqua Planet Jeju ), China ( Chimelong Ocean Kingdom , Dalian Aquarium, Guangzhou Aquarium in Guangzhou Zoo, Qingdao Polar Ocean World and Yantai Aquarium), Taiwan ( National Museum of Marine Biology and Aquarium ), India (Thiruvananthapuram Aquarium) and Dubai ( Atlantis, The Palm ), with some maintaining whale sharks for years and others only for
4508-495: The beating of cilia . Suspended food ( phytoplankton , zooplankton , algae and other water-borne nutrients and particles) are trapped in the mucus of a gill, and from there are transported to the mouth, where they are eaten, digested and expelled as feces or pseudofeces . Each oyster filters up to five litres of water per hour. Scientists believe that the Chesapeake Bay 's once-flourishing oyster population historically filtered
4606-450: The better established role of melanopsin (see also Intrinsically photosensitive retinal ganglion cell ). Sensitivity to a prolonged stimulation tends to decline over time, leading to neural adaptation . An interesting effect occurs when staring at a particular color for a minute or so. Such action leads to an exhaustion of the cone cells that respond to that color – resulting in the afterimage . This vivid color aftereffect can last for
4704-443: The body, a pair of pectoral fins , a pair of pelvic fins and a single medial anal fin . The caudal fin has a larger upper lobe than the lower lobe ( heterocercal ). Whale sharks have been found to possess dermal denticles on the surface of their eyeballs that are structured differently from their body denticles. The dermal denticles, as well as the whale shark's ability to retract its eyes deep into their sockets, serve to protect
4802-532: The capture/stranding and some were released, but initial captive survival rates were low. After the initial difficulties in maintaining the species had been resolved, some have survived long-term in captivity. The record for a whale shark in captivity is an individual that, as of 2021, has lived for more than 26 years in the Okinawa Churaumi Aquarium from Okinawa Ocean Expo Aquarium. Following Okinawa, Osaka Aquarium started keeping whale sharks and most of
4900-926: The case of the buoy barnacle ) depending on the species and the niches they have evolved to occupy. Extant species that rely on such method of feeding encompass numerous phyla , including poriferans ( sponges ), cnidarians ( jellyfish , sea pens and corals ), arthropods ( krill , mysids and barnacles ), molluscs ( bivalves , such as clams , scallops and oysters ), echinoderms ( sea lilies ) and chordates ( lancelets , sea squirts and salps , as well as many marine vertebrates such as most species of forage fish , American paddlefish , silver and bighead carps , baleen whales , manta ray and three species of sharks —the whale shark , basking shark and megamouth shark ). Some water birds such as flamingos and certain duck species, though predominantly terrestrial, are also filter feeders when foraging . Most forage fish are filter feeders. For example,
4998-500: 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). The whale shark inhabits all tropical and warm-temperate seas. The fish is primarily pelagic , and can be found in both coastal and oceanic habitats. Tracking devices have shown that the whale shark displays dynamic patterns of habitat utilization, likely in response to availability of prey. Whale sharks observed off
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#17328688788255096-431: The cones in the human retina. The three types have peak wavelengths in the range of 564–580 nm, 534–545 nm, and 420–440 nm, respectively, depending on the individual. Such a difference is caused by the different opsins they carry, OPN1LW , OPN1MW , and OPN1SW , respectively, the forms of which affect the absorption of retinaldehyde . The CIE 1931 color space is an often-used model of spectral sensitivities of
5194-562: The contamination status of any aquatic ecosystem. They are useful as they are sessile, which means they are closely representative of the environment where they are sampled or placed (caging), and they breathe water all the time, exposing their gills and internal tissues: bioaccumulation . One of the most famous projects in that field is the Mussel Watch Programme in America. Sponges have no true circulatory system ; instead, they create
5292-548: The earlier stages of life but ultimately reach a smaller maximum size. Whale sharks exhibit late sexual maturity. One study looking at free-swimming whale sharks estimated the age at maturity in males at ~25 years. Pupping of whale sharks has not been observed, but mating has been witnessed twice in St Helena . Mating in this species was filmed for the first time in whale sharks off Ningaloo Reef via airplane in Australia in 2019, when
5390-428: The enlarged lower lip which fits onto the bowed upper jaw. As the right whale swims, a front gap between the two rows of baleen plates lets the water in together with the prey, while the baleens filter out the water. Rorquals such as the blue whale , in contrast, have smaller heads, are fast swimmers with short and broad baleen plates. To catch prey, they widely open their lower jaw — almost 90° — swim through
5488-657: The entire whale shark population. It usually roams between 30°N and 35°S where water temperatures are higher than 21 °C (70 °F) but have been spotted as far north as the Bay of Fundy , Canada and the Sea of Okhotsk north of Japan and as far south as Victoria, Australia . Seasonal feeding aggregations occur at several coastal sites such as the Persian Gulf and Gulf of Oman , Ningaloo Reef in Western Australia, Darwin Island in
5586-461: The estuary's entire water volume of excess nutrients every three or four days. Today that process would take almost a year, and sediment, nutrients, and algae can cause problems in local waters. Oysters filter these pollutants, and either eat them or shape them into small packets that are deposited on the bottom where they are harmless. Bivalve shellfish recycle nutrients that enter waterways from human and agricultural sources. Nutrient bioextraction
5684-455: The eyes from damage. Evidence suggests that whale sharks can recover from major injuries and may be able to regenerate small sections of their fins. Their spot markings have also been shown to reform over a previously wounded area. The complete and annotated genome of the whale shark was published in 2017. Rhodopsin , the light-sensing pigment in the rod cells of the retina, is normally sensitive to green and used to see in dim light, but in
5782-453: The female retains sperm from one mating and produces a steady stream of pups over a prolonged period. 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, Sorsogon , Philippines, and was released into
5880-507: The filter between the gill bars is swallowed. Whale sharks have been observed "coughing" and it is presumed that this is a method of clearing a build up of food particles in the gill rakers. The megamouth shark has luminous organs called photophores around its mouth. It is believed they may exist to lure plankton or small fish into its mouth. The basking shark is a passive filter feeder, filtering zooplankton , small fish, and invertebrates from up to 2,000 tons of water per hour. Unlike
5978-488: 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. A juvenile whale shark is estimated to eat 21 kg (46 pounds) of plankton per day. The BBC program Planet Earth filmed
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#17328688788256076-459: The first half of the year. There were a total 168 sightings – 64 of them "re-sightings" or reappearances of previously recorded whale sharks. WWF noted that "very young whale shark juveniles" were identified among the 168 individuals spotted in the first half of 2019. Their presence suggests that the Ticao Pass may be a pupping ground for whale sharks, further increasing the ecological significance of
6174-425: The fish swims forward at constant speed with its mouth fully open, straining prey particles from the water by forward propulsion. This is also called ‘passive feeding’, which usually occurs when prey is present at low density. Due their mode of feeding, whale sharks are susceptible to the ingestion of microplastics . As such, the presence of microplastics in whale shark scat was recently confirmed. Despite its size,
6272-411: The food they eat, and are uniquely used upside-down. The filtering of food items is assisted by hairy structures called lamellae which line the mandibles , and the large rough-surfaced tongue. Prions are specialised petrels with filter-feeding habits. Their name comes from their saw-like jaw edges, used to scope out small planktionic animals. The extinct swan Annakacygna is speculated to be
6370-403: The front of the head rather than on the underside of the head. A 12.1 m (39.7 ft) whale shark was reported to have a mouth 1.55 m (5.1 ft) across. Whale shark mouths can contain over 300 rows of tiny teeth and 20 filter pads which it uses to filter feed . The spiracles are located just behind the eyes. Whale sharks have five large pairs of gills . Their skin is dark grey with
6468-550: The growth rates of free-swimming sharks. Whale sharks have very large mouths and are filter feeders, which is a feeding mode that occurs in only two other sharks, the megamouth shark and the basking shark . They feed almost exclusively on plankton and small fishes and pose no threat to humans. The species was distinguished in April 1828 after the harpooning of a 4.6 m (15 ft) specimen in Table Bay , South Africa. Andrew Smith ,
6566-448: The hinge line. The class has 30,000 species , including scallops , clams , oysters and mussels . Most bivalves are filter feeders (although some have taken up scavenging and predation), extracting organic matter from the sea in which they live. Nephridia , the shellfish version of kidneys , remove the waste material. Buried bivalves feed by extending a siphon to the surface. For example, oysters draw water in over their gills through
6664-416: The land and in the water. When on land, the total length measurement can be affected by how the tail is positioned, either angled as it would be in life or stretched as far as possible. Historically, techniques such as comparisons to objects of known size and knotted ropes have been used for in-water measurements, but these techniques may be inaccurate. Various forms of photogrammetry have been used to improve
6762-413: The megamouth and whale sharks, the basking shark does not appear to actively seek its quarry; but it does possess large olfactory bulbs that may guide it in the right direction. Unlike the other large filter feeders, it relies only on the water that is pushed through the gills by swimming; the megamouth shark and whale shark can suck or pump water through their gills. Manta rays can time their arrival at
6860-504: The most reliable seasonal gatherings known for whale sharks, with large numbers occurring in most years between May and September. Associated ecotourism has grown rapidly to unsustainable levels. Growth, longevity, and reproduction of the whale shark are poorly understood. Vertebral growth bands have been used to estimate the age, growth, and longevity of whale sharks. However, there was uncertainty as to whether vertebrae growth bands are formed annually or biannually. A 2020 study compared
6958-429: The most to light of the longer red wavelengths , peaking at about 560 nm . The majority of the human cones are of the long type. The second most common type responds the most to light of yellow to green medium-wavelength, peaking at 530 nm. M cones make up about a third of cones in the human eye. The third type responds the most to blue short-wavelength light, peaking at 420 nm, and make up only around 2% of
7056-477: The northeast Yucatan Peninsula tend to engage in inshore surface swimming between sunrise and mid-afternoon, followed by regular vertical oscillations in oceanic waters during the afternoon and overnight. About 95% of the oscillating period was spent in epipelagic depths (<200 metres (660 ft)), but whale sharks also took regular deep dives (>500 metres (1,600 ft)), often descending in brief "stutter steps", perhaps for foraging. The deepest recorded dive
7154-445: The only extant member of the family Rhincodontidae , which belongs to the subclass Elasmobranchii in the class Chondrichthyes . Before 1984 it was classified as Rhiniodon into Rhinodontidae. Whale sharks inhabit the open waters of all tropical oceans. They are rarely found in water below 21 °C (70 °F). Whale sharks' lifespans are estimated to be between 80 and 130 years, based on studies of their vertebral growth bands and
7252-494: The other, suggesting a total length of about 55 ft (17 m). Scott A. Eckert & Brent S. Stewart reported on satellite tracking of whale sharks from 1994 to 1996. Out of the 15 individuals tracked, two females were reported as measuring 15 m (49 ft) and 18 m (59 ft). A 20.75 m (68.1 ft) long whale shark was reported as being stranded along the Ratnagiri coast in 1995. A female individual with
7350-480: The others. Photobleaching can be used to determine cone arrangement. This is done by exposing dark-adapted retina to a certain wavelength of light that paralyzes the particular type of cone sensitive to that wavelength for up to thirty minutes from being able to dark-adapt, making it appear white in contrast to the grey dark-adapted cones when a picture of the retina is taken. The results illustrate that S cones are randomly placed and appear much less frequently than
7448-438: The outer membrane, whereas they are pinched off and exist separately in rods. Neither rods nor cones divide, but their membranous disks wear out and are worn off at the end of the outer segment, to be consumed and recycled by phagocytic cells. The difference in the signals received from the three cone types allows the brain to perceive a continuous range of colors, through the opponent process of color vision. ( Rod cells have
7546-500: The prey from the water using their baleens. A baleen is a row of a large number of keratin plates attached to the upper jaw with a composition similar to those in human hair or fingernails. These plates are triangular in section with the largest, inward-facing side bearing fine hairs forming a filtering mat. Right whales are slow swimmers with large heads and mouths. Their baleen plates are narrow and very long — up to 4 m (13 ft) in bowheads — and accommodated inside
7644-511: The ratio of Carbon-14 isotopes found in growth bands of whale shark vertebrae to nuclear testing events in the 1950–60s, finding that growth bands are laid down annually. The study found an age of 50 years for a 10 m (33 ft) female and 35 years for a 9.9 m (32 ft) male. Various studies looking at vertebrae growth bands and measuring whale sharks in the wild have estimated their lifespans from ~80 years and up to ~130 years. Evidence suggests that males grow faster than females in
7742-408: The retina, but greatly outnumber rods in the fovea . Structurally, cone cells have a cone -like shape at one end where a pigment filters incoming light, giving them their different response curves. They are typically 40–50 μm long, and their diameter varies from 0.5 to 4.0 μm, being smallest and most tightly packed at the center of the eye at the fovea. The S cone spacing is slightly larger than
7840-439: The rod cells function, the sensitivity is greatest at a blueish-green wavelength. Cones also tend to possess a significantly elevated visual acuity because each cone cell has a lone connection to the optic nerve, therefore, the cones have an easier time telling that two stimuli are isolated. Separate connectivity is established in the inner plexiform layer so that each connection is parallel. The response of cone cells to light
7938-416: The sea floor, constantly collecting particles with their filter basket. They are an important food source for herring , cod , flounder , and striped bass . Mysids have a high resistance to toxins in polluted areas, and may contribute to high toxin levels in their predators. Antarctic krill manages to directly utilize the minute phytoplankton cells, which no other higher animal of krill size can do. This
8036-431: The spawning of large shoals of fish and feed on the free-floating eggs and sperm. This stratagem is also employed by whale sharks. Like all arthropods, crustaceans are ecdysozoans , a clade without cilia . Cilia play an important role for many filter feeding animals, but because crustaceans don't have them, they need to use modified extremities for filter feeding instead. Mysidaceans live close to shore and hover above
8134-407: The sponge. The moon jellyfish has a grid of fibres which are slowly pulled through the water. The motion is so slow that copepods cannot sense it and do not react with an escape response . Other filter-feeding cnidarians include sea pens , sea fans , plumose anemones , and Xenia . Tunicates , such as ascidians , salps and sea squirts , are chordates which form a sister group to
8232-492: The temperature is higher and the full spectrum of light is present. To protect from this instability, the whale shark deactivates the pigment when in shallow water (as otherwise the pigment would hinder full color vision). In the colder environment at 2,000 meters below the surface where the shark dives, it is activated again. The mutations thus allow the shark to see well at both ends of its great vertical range. The eyes have also lost all cone opsins except LWS. The whale shark
8330-433: The three cells of an average human. While it has been discovered that there exists a mixed type of bipolar cells that bind to both rod and cone cells, bipolar cells still predominantly receive their input from cone cells. Other animals might have a different number of cone types (see Color vision ). Cone cells are somewhat shorter than rods, but wider and tapered, and are much less numerous than rods in most parts of
8428-432: The unrelated Cenozoic Mourasuchus shares similar adaptations. Hupehsuchia is a lineage of bizarre Triassic reptiles adapted for suspension feeding. Some plesiosaurs might have had filter-feeding habits. Cone cell Cone cells or cones are photoreceptor cells in the retinas of vertebrates' eyes . They respond differently to light of different wavelengths , and the combination of their responses
8526-402: The upper portion of the growth curves. The largest total length for the species is uncertain due to a lack of detailed documentation of the largest reported individuals. Whale sharks as large as 18 to 20 meters (59 to 66 ft) in length have been reported in scientific literature. However, most whale sharks observed are smaller. Large whale sharks are difficult to measure accurately, both on
8624-749: The water for over half a meter in an opened position, and then the algae are combed to the mouth opening with special setae on the inner side of the thoracopods. Porcelain crabs have feeding appendages covered with setae to filter food particles from the flowing water. Most species of barnacles are filter feeders, using their highly modified legs to sift plankton from the water. Also some insects with aquatic larvae or nymphs are filter feeders during their aquatic stage. Such as some species of mayfly nymphs, mosquito larvae, and black fly larvae. Instead of using modified limbs or mouthparts, some caddisfly larvae produce nets of silk used for filter feeding. The baleen whales (Mysticeti), one of two suborders of
8722-504: The water pass over or through a specialized filtering organ that sieves out and/or traps solids. Filter feeders can play an important role in condensing biomass and removing excess nutrients (such as nitrogen and phosphate ) from the local waterbody , and are therefore considered water-cleaning ecosystem engineers . They are also important in bioaccumulation and, as a result, as indicator organisms . Filter feeders can be sessile , planktonic , nektonic or even neustonic (in
8820-428: The water through its gills . During the slight delay between closing the mouth and opening the gill flaps, plankton is trapped against the dermal denticles which line its gill plates and pharynx . This fine sieve-like apparatus, which is a unique modification of the gill rakers, prevents the passage of anything but fluid out through the gills (anything above 2 to 3 mm in diameter is trapped). Any material caught in
8918-452: The whale shark (and the bottom-dwelling cloudy catshark ) two amino acid substitutions make the pigment more sensitive to blue light instead, the light that dominates the deep ocean. One of these mutations also makes rhodopsin vulnerable to higher temperatures. In humans, a similar mutation leads to congenital stationary night blindness , as the human body temperature makes the pigment decay. This pigment becomes unstable in shallow water, where
9016-406: The whale shark does not pose any danger to humans. Younger whale sharks are gentle and can play with divers. Underwater photographers such as Fiona Ayerst have photographed them swimming close to humans without any danger. Although whale sharks are docile fish, touching or riding the sharks is strictly forbidden and fineable in most countries, as it can cause serious harm to the animal. The shark
9114-526: 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 St Helena in the South Atlantic Ocean, where numerous whale sharks can be spotted during the summer. In a report from Rappler last August 2019, whale sharks were sighted during WWF Philippines ' photo identification activities in
9212-484: Was 1,928 metres (6,325 ft), making the whale shark the deepest diving fish to be recorded. Whale sharks were also observed to remain continuously at depths of greater than 50 metres (160 ft) for three days or more. The whale shark is migratory and has two distinct subpopulations: an Atlantic subpopulation, from Maine and the Azores to Cape Agulhas , South Africa, and an Indo-Pacific subpopulation which holds 75% of
9310-454: Was a placodont with unique baleen-like denticles and features of the hyoid and jaw musculature comparable to those of flamingos. Combined with its lacustrine environment, it might have occupied a similar ecological niche. In particular, it was probably a herbivore , filtering out algae and other small-sized flora from the substrates. Stomatosuchidae is a family of freshwater crocodylomorphs with rorqual-like jaws and minuscule teeth, and
9408-703: Was included. The authors noted that these estimates represent average asymptotic size and are not the maximum sizes possible. Additionally, they acknowledged the potential for regional size variation. Most previous growth studies have had data predominately from males and none have data from sharks over ~10 m (33 ft). Not all previous studies created separate growth curves for males and females, instead combining data from both sexes. Those studies that made sex-specific growth curves have estimated large asymptotic length estimates for males, with lengths of 18 m (59 ft) or more. However, mostly immature males were available in these studies, with few adults to constrain
9506-557: Was kept for about four months in a netted-off natural bay in Izu , Japan. The first attempt of keeping whale sharks in an aquarium was initiated in 1980 by the Okinawa Churaumi Aquarium (then known as Okinawa Ocean Expo Aquarium) in Japan. Since 1980, several have been kept at Okinawa, mostly obtained from incidental catches in coastal nets set by fishers (none after 2009), but two were strandings. Several of these were already weak from
9604-496: Was told of specimens upwards of 70 ft (21 m). 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, and no measurements were taken. Smith learned through independent sources that it was at least 10 wa (a Thai unit of length measuring between a person's outstretched arms). Smith noted that one wa could be interpreted as either 2 m (6.6 ft) or
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