The White Shark is widely distributed, and located throughout temperate and sub-tropical regions in the northern and southern hemispheres. It is primarily found in the coastal and offshore areas of the continental and insular shelves and offshore continental islands. The White Shark is most frequently encountered off South Africa, southern Australia, northern California and the northeastern United States (Last & Stevens 1994). In Australia, its range extends primarily from Moreton Bay in southern Queensland, with at least one record as far north as Mackay, (Paterson, 1990:154) around the southern coastline and to North West Cape in Western Australia (Bruce 1995).
While White Sharks are uncommon in Australian waters there are areas where encounters appear to be more frequent. These include; waters in and around seal and sea lion colonies in general, Neptune Islands, South Australia, Wilsons Promontory, Victoria (particularly juveniles) the coastal region between Newcastle and Port Stephens, New South Wales (particularly juveniles) and the Recherche Archipelago and the islands off the lower west coast of Western Australia.. D’Ombrain (1957) described packs of White Sharks and larger solitary sharks in the waters around Dangerous Reef and from the Pages (near Kangaroo Island) to Nuyts Archipelago in the Great Australian Bight. Large White Sharks were also taken in the past off Cape Moreton (which was a whaling station) in Queensland (D’Ombrain 1957). Edwards (1997) describes his White Shark filming exploits off Cheynes Beach whaling station Western Australia in 1976. Whaling activities and stations were something of a magnet for White Sharks due to the easily available food from moored whale carcasses and discarded offal (Mead 1973, Grady 1986). Large numbers of sharks, some of which are White Sharks (Coastwatch reports to Environment Australia), often attend floating whale carcasses.
Long-term movement patterns of White Sharks are poorly known. However the White Shark is capable of swimming long distances and for extended periods. For example, offshore tracking of a large shark with sonic tags indicated that it moved 190 kilometres in 2.5 days at an average cruising speed of 3.2 kilometres per hour (Carey et al. 1982 in Bruce 1992). Recent tracking of a satellite tagged shark called ‘Neale‘ recorded 2946km over 113 days. Other archival and satellite tag research in Australian waters has also recorded shark movements mainly restricted to shelf and coastal waters and swimming depths down to 94 m (Bruce. B, D. Malcolm H. & Stevens J.D. 2001)
There are several reports of individual White Sharks being sighted at the same locality over several years (Bruce 1992, Strong et al. 1996, Klimley and Anderson 1996) and tagged White Sharks recaptured up to 1400 km from the point of tagging (Cliff et al. 1996). They may also move in and out of areas at the limits of their range on a seasonal basis in some areas (for example in the Mediterranean – see Fergusson 1996).
There is evidence that some larger non-breeding individuals have a wider temperature range and penetrate tropical waters where carcharinid sharks are located, and may also pass through the waters off oceanic islands. Captures of adult specimens at the Azores Islands indicate that some degree of transoceanic migrations over considerable distance may occur (Compagno 1984a In Fergusson 1996). In the case of the Azores this may be as a (largely) west-to-east nomadic journey within the Gulf Stream from North America (Fergusson 1996: 337). Rare mid-ocean records are also known from the Pacific, at the Hawaiian, Marshall, and Easter Islands (Fergusson 1996), and there have been reports of sightings of the shark in the tropical south-west Indian Ocean, including Madagascar, Mauritius and Kenya (where a pregnant female was taken in 1996 in an artisanal fishery) (Natal Sharks Board). All the sharks in these cases appear to be large (greater than 4 metres). This suggests that equatorial waters may be a deterrent to large-scale movement but not a complete barrier. A possible mechanism is tropical submergence, where the shark descends into and travels within deeper, cool oceanic waters across the equatorial zone. Consequently, populations may not be genetically isolated (Fergusson 1998).
Studies of Great White Sharks sighted at pinniped colonies indicate that the sharks appear to be largely transient, with a few longer term residents (Klimley and Anderson 1996, Strong et al. 1992). Individuals are known to return to feeding grounds annually on a seasonal basis. A number of studies indicate that some populations appear often to be small and highly localised, with a high degree of site attachment. For example, in one study in the Spencer Gulf area (South Australia), 36 per cent of sharks were resighted always in their original location (Strong et al. 1992). A further study in South Africa found that of 147 Great White Sharks tagged, 30 individuals were resighted a total of 59 times, one of which was resighted 10 times. Of the 30, all but two were resighted at the same area in which they were originally observed (Ferreira and Ferreira 1996). The resighting of individual Great White Sharks at particular localities is well documented in other areas of the world (Bruce 1995), such as Western Cape (South Africa) (Cliff et al 1996) and California (Klimley and Anderson 1996).Research suggests that White Shark populations may segregate according to size and gender, and for reproduction. Strong et al. (1992) found that, in South Australia, the ratio of females to males was 6:1 at Dangerous Reef and other inshore islands, whereas around the offshore islands of the North and South Neptunes it was 1:20. This segregation can fluctuate with location and over time(Strong et. al. 1996).
Habitat and Diet
White Sharks are normally found in inshore waters in the vicinity of rocky reefs and islands, and often near seal colonies. They have been caught at varying depths to 1280m (Compagno 1984). While White Sharks are widely distributed they appear to be far more common in some locations such as South Africa, Australia and United States of America than at others. Particular areas are also seen as important pupping grounds.
White Sharks have few natural predators and do not feed continuously; a large meal such as a seal may last a medium sized shark for as long as a week (Bruce 1995). White Sharks appear to exhibit an age/size preference for certain foods. This developmental change in diet reveals a preference for fish in the juvenile White Sharks (less than 2.7 metres) ((Bruce. B, D. Malcolm H. & Stevens J.D. 2001). As they increase in size the diet will expand to include other sharks, rays , marine reptiles, sea birds and marine mammals. Some larger White Sharks that change their diet to include marine mammals may also continue to prey on finfish (for example snapper) and other sharks. In areas of suitable habitat where large seal and sea lion populations reside, they are the preferred prey for adult White Sharks. Ellis and McCosker (1991) noted that there are very few regions of the world that support White Shark populations without a corresponding pinniped population. Where there are concentrations of cetaceans large White Sharks will actively hunt small cetaceans and scavenge on available carcasses of larger species (Long and Jones 1996).
Life History
Due to their rarity and large size, it is relatively difficult to obtain information on the biology of White Sharks (NSW Fisheries 1997).
Reproductive Biology
Female White Sharks mature at between 4.5-5.0 metres and attain a greater length and weight than males (Francis 1996). Males mature at about 3.6 - 3.8 metres . (Bruce. B, D. Malcolm H. & Stevens J.D. 2001). Minimum ages at maturity for females and males are estimated to be 18 and 10 years, respectively. (Bruce. B, D. Malcolm H. & Stevens J.D. 2001).
The reproductive mode of the White Shark is thought to be oophagy, where embryos eat large numbers of nutritive unfertilised eggs that are ovulated during gestation (Compagno et al., 1997, Francis 1996,). The gestation period is unknown but is estimated to exceed 12 months (possibly 18 months) with females breeding only every 2-3 years (. (Bruce. B, D. Malcolm H. & Stevens J.D. 2001).). Female White Sharks produce up to 10 pups per litter (Francis 1996).
Young
Pups are fully developed and independent at birth; 1.2 – 1.5 metres in length; and may weigh up to 32 kg (Compagno et al. 1997). It is not known whether White Sharks give birth in particular pupping areas. Juveniles (estimated to be less than 1.5 m in length) are most commonly captured between December and June suggesting a summer-autumn pupping period. . (Bruce. B, D. Malcolm H. & Stevens J.D. 2001).
Longevity of adults
There have been few studies on age and growth of White Sharks (Calliet et al. 1985, Cliff et al. 1996). Most specimens examined have been less than five metres in length and methods of age determination have yet to be validated. Longevity in White Sharks is unknown but is considered to be in excess of 30 years.