Distribution and habitat
The whale shark inhabits most tropical and warm-temperate waters. The fish is generally pelagic, living in the available sea but not in the better depths of the ocean, even though it is known to occasionally dive to depths of as much as you, 800 metres (5, 900 ft).|17| Seasonal feeding aggregations occur for several coastal sites including the southern and eastern parts of South Africa; Saint Helena Area in the South Atlantic Sea; Gulf of Tadjoura in Djibouti, Gladden Spit in Belize; Ningaloo Reef in Western Australia; Kerala|18|, Lakshadweep, Gulf of Kutch and Saurashtra coast of Gujarat in India;|19| Útila in Honduras; Southern Leyte; Donsol, Pasacao and Batangas in the Dubai; off Isla Mujeres and Isla Holbox in Yucatan and Bahía de los Ángeles in Baja California, México; Maamigili island, Maldives; Ujung Kulon National Park in Indonesia; Cenderawasih Bay Country wide Park in Nabire, Papua, Indonesia; Flores Island, Dalam negri; Nosy Be in Madagascar; off Tofo Beach near Inhambane in Mozambique; the Tanzanian islands of Mafia, Pemba, Zanzibar; Gulf of Tadjoura in Djibouti, the Advertising Dimaniyat Islands in the Gulf of mexico of Oman and Approach Hallaniyat islands in the Arabian Sea; and, very rarely, Eilat, Israel and Aqaba, Michael jordan. Although typically seen overseas, it has been found closer to territory, entering lagoons or coral reefs atolls, and near the lips of estuaries and rivers. Its range is generally limited to about 30° latitude. It is capable of diving to depths of at least 1, 286 m (4, 219 ft),|20| and is migratory.|9| On 7 February 2012, a large whale shark was found floating 150 kilometres (93 mi) off the coastline of Karachi, Pakistan. The size of the specimen was said to be between 11 and 12 m (36 and 39 ft), with a weight of around 15, 000 kilogram (33, 000 lb).|21|
In 2011, more than 400 whale sharks gathered off the Yucatan Coast. It was one of the largest gatherings of whale fishes recorded.|22| Aggregations in that area are among the most reliable seasonal gatherings praised for whale sharks, with huge numbers occurring in most years between May and September. Connected ecotourism has grown rapidly to unsustainable levels.|23|
Neither mating nor pupping of whale sharks has been discovered.
The capture of a feminine in July 1996 that was pregnant with three hundred pups indicated whale sharks are ovoviviparous.|9||24||25| The ova remain in the body and the females give birth to live small which are 40 to 60 cm (16 to twenty four in) long. Evidence indicates the pups are not every born at once, but rather women retains sperm from one pairing and produces a steady stream of pups over a lengthened period.|26| That they reach sexual maturity at around 30 years and their lifespan is an estimated 70|9| to 100 years.|27|
On 7 March 2009, marine scientists in the Thailand discovered what is believed to be the actual living specimen of the whale shark. The young shark, measuring only 38 cm (15 in), was located with its tail tied to a stake at a beach front in Pilar, Sorsogon, Thailand, and was released into the outdoors. Based on this discovery, a few scientists no longer believe this area is just a feeding ground; this site may be a birthing floor, as well. Both young whale sharks and pregnant females have been seen in the marine environments of Saint Helena inside the South Atlantic Ocean, exactly where numerous whale sharks can be spotted during the summer.
The whale shark is a filtration feeder - one of just 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 reddish crab larvae |30| and small nektonic life, such as small squid or fish. It also passes on clouds of eggs during mass spawning of fish and corals.|31| The many rows of vestigial teeth play no part in feeding. Feeding arises either by ram filtration, in which the animal opens their mouth and swims onward, pushing water and food into the mouth, or by active suction feeding, in which the pet opens and closes it is mouth, sucking in amounts of water that are then expelled through the gills. In both cases, the filter pads serve to separate meals from water. These exceptional, 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 filtration system pad surface, not perpendicularly through it, before moving to the outside, while denser food particles continue to the back from the throat.|32| This can be an extremely efficient filtration approach that minimizes fouling on the filter pad surface. Whale sharks have been observed "coughing", presumably to clear a build-up of particles from the filtration pads. Whale sharks move to feed and possibly to reproduce.
2019-01-10 9:12:29
No comments:
Post a Comment