Ubaid KhalidWhale Shark Habitat
Whale shark lives in tropical waters but its distribution is circumtropical with the exception of Mediterranean Sea. At times, these sharks are also seen in the Bay of Fundy in Canada and Sea of Okhotsk in Japan to the north. The existence of this species is possibly dependent on surface temperatures because they are not often seen in temperatures below than 21 o C.
Apart from seashores, they are also found in oceanic habitats. Given that they have strong relationship with temperature; in the Indian Ocean, they are concentrated in large numbers within temperatures of 26.5 o to 30 o C. They are nomadic creatures which means they tend to migrate long distances. By means of tethered geopositioning tags, it was observed that on average they sail about 24 to 28 kilometers.
They go down to a depth of at least 1,928 meters and are found in the epipelagic zone for most of their time. However, it is still unknown vis-à-vis what is the stimulus behind the deep-diving pattern of this large fish. The fatty acid dietary studies show whale shark may be attracted toward bathy- and mesopelagic prey in these areas of deep underwater. The young individuals are located feeding in shallow waters (of which 60 percent were male sharks) in the Gulf of California. However, about 84 percent of the adult sharks were found preying on euphasiids (that were scattered in patches) within oceanic waters. It shows the behavior of the whale sharks in these areas i.e. whale sharks are segregated to different feeding patches according to sex and size.
Whale Shark Distribution
The areas where more than 500 whale sharks are sighted are Quintana Roo of Mexico, Ningaloo Reef off west coast of Australia, Mozambique’s province called Inhambane, Darwin Island of Galapagos, Mahe of Seychelles, the Philippines and the Gulf of Oman and the Arabian Gulf. Reports of large number of these individuals are also documented from areas like south of China, Taiwan and shoreline of Gujarat in India.
What’s more, before the start of targeted fisheries, there were almost 1,000 catches of whale shark each year. The Mozambique Channel off the Indian Ocean also contains high density of this species. However the sightings of the whale shark in the Pacific and the Atlantic are not very common. Off the central and western part of the Pacific, the Bismark and Solomon Seas appear to have the highest concentrations of these individuals.
Source:
Pierce, S.J. & Norman, B. 2016. Rhincodon typus. The IUCN Red List of Threatened Species 2016: e.T19488A2365291
