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Conservation Status
The Great White Shark was declared a protected species in 1996 by the NSW Government. In 1999 their threatened species status was elevated to “Vulnerable” to extinction.
Being a protected species means that it is now illegal to harm or have a significant impact on White Sharks in Australian waters. Doing so could result in criminal prosecution. It is also illegal to keep or sell any kind of body part including fins, teeth or jaws without appropriate approval.
Several other countries worldwide have granted Great White Sharks protection status including; South Africa, Namibia, Malta. the Maldives, Mexico and New Zealand.
Distribution and Migration
White Sharks are commonly found in cold and temperate waters - and occasionally in tropical waters.
Great White Sharks are found all along the NSW coastline, and also in QLD, VIC, TAS, SA and WA.
Recent research is showing that Great White Sharks undergo extensive trans-oceanic migration. One example is a White Shark tracked via satellite travelling from South Africa to Western Australia and back again.
Migratory movements within Australia are not well understood, however a male shark tracked between March and June travelled 2946 klms from Victoria to Tasmania then up the East coast of NSW.
Tagging
Pop-up archival satellite tags are used to record localised movements of White Sharks. Data such as depth, water temperature and light levels is stored in the tags memory and after a pre-programmed period, the tags releases from the shark and floats at the surface where the data can be relayed via satellites and sent to NSW DPI scientists.
R-coded acoustic tags transmit signals at specified intervals. These signal are recorded by underwater listening stations. These tags can identify a shark, its depth and surrounding water temperature. There are 60 listening stations along the NSW coast between Queensland and Victoria. This is known as the South East Australian Coastal Acoustic Monitoring System (SEACAMS)
Source:
“Summary of Great White Shark Scientific Information” NSW Department of Primary Industries and Northern Rivers Catchment Management Authority 2008.
Population Decline
Data from various sources including game fishing and shark meshing programs has shown that since the 1960’s White Shark numbers have decreased from 4.5% of the total catch to around 0.6% of the total catch.
The sizes of animals being caught in meshing programs has also reduced.
The scientific name of the Great White Shark is Carcharodon carcharias. They belong to the Mackeral shark family
(also known as the Lamnidae family).
Feeding
As juveniles, White Sharks feed upon fish, squid, smaller sharks and rays, and as they grow above 3.5m their diet may also include marine mammals.
White sharks may hunt alone, or be found in groups depending on the food source, i.e. a whale carcass.
Unlike most other sharks - Great Whites have the ability to maintain their body temperature above that of the surrounding water. This elevated body temperature enables enhanced muscular performance and can result in spectacular aerobatic displays when hunting seals.
Little is known about the age and growth of these sharks. It is thought they may live longer than 30 years, possibly up to 100 years - but this has not yet been proven. They can grow up to 6 metres in length and weigh up to 2 tonnes.
Reproduction
Males reach sexual maturity at around 3-4m in length, and females at around 4-5m.
Reproduction is ovoviviparous - meaning the pups hatch from egg sacs internally and continue to develop in the uterus. They may also eat other eggs that are found in the womb. Gestation is around 12-14 months and can result in a litter of up to 60 pups. At birth each pup measures 1.2 - 1.5m in length and can weigh up to 25 kilograms.
Unfortunately, little is known about location and timing of mating, nursery areas and frequency of pupping.
Pop-up tag
SEACAMS
listening station
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