<P> Interspecific competition between the great white shark and the orca is probable in regions where dietary preferences of both species may overlap . An incident was documented on 4 October 1997, in the Farallon Islands off California in the United States . An estimated 4.7--5.3 - meter (15--17 ft) female orca immobilized an estimated 3--4 - meter (9.8--13.1 ft) great white shark . The orca held the shark upside down to induce tonic immobility and kept the shark still for fifteen minutes, causing it to suffocate . The orca then proceeded to eat the dead shark's liver . It is believed that the scent of the slain shark's carcass caused all the great whites in the region to flee, forfeiting an opportunity for a great seasonal feed . Another similar attack apparently occurred there in 2000, but its outcome is not clear . After both attacks, the local population of about 100 great whites vanished . Following the 2000 incident, a great white with a satellite tag was found to have immediately submerged to a depth of 500 m (1,600 ft) and swum to Hawaii . In 2015, a pod of orcas was recorded to have killed a great white shark off South Australia . In 2017, along the South African coast, four great whites were found washed ashore with their livers removed with what was described as' surgical precision' . Local scientists claim that pods of orcas in the area were to blame for the attacks . </P> <P> It is unclear how much of a concurrent increase in fishing for great white sharks has caused the decline of great white shark populations from the 1970s to the present . No accurate global population numbers are available, but the great white shark is now considered vulnerable . Sharks taken during the long interval between birth and sexual maturity never reproduce, making population recovery and growth difficult . </P> <P> The IUCN notes that very little is known about the actual status of the great white shark, but as it appears uncommon compared to other widely distributed species, it is considered vulnerable . It is included in Appendix II of CITES, meaning that international trade in the species requires a permit . As of March 2010, it has also been included in Annex I of the CMS Migratory Sharks MoU, which strives for increased international understanding and coordination for the protection of certain migratory sharks . A February 2010 study by Barbara Block of Stanford University estimated the world population of great white sharks to be lower than 3,500 individuals, making the species more vulnerable to extinction than the tiger, whose population is in the same range . According to another study from 2014 by George H. Burgess, Florida Museum of Natural History, University of Florida, there are about 2,000 great white sharks near the California coast, which is 10 times higher than the previous estimate of 219 by Barbara Block . </P> <P> Fishermen target many sharks for their jaws, teeth, and fins, and as game fish in general . The great white shark, however, is rarely an object of commercial fishing, although its flesh is considered valuable . If casually captured (it happens for example in some tonnare in the Mediterranean), it is misleadingly sold as smooth - hound shark . </P>

How many great white sharks are in the world
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