Do great white sharks migrate to australia?
43619#7
According to a recent study, California great whites have migrated to an area between Baja California Peninsula and Hawaii known as the White Shark Café to spend at least 100 days before migrating back to Baja. On the journey out, they swim slowly and dive down to around . After they arrive, they change behavior and do short dives to about for up to ten minutes. Another white shark that was tagged off the South African coast swam to the southern coast of Australia and back within the year. A similar study tracked a different great white shark from South Africa swimming to Australia's northwestern coast and back, a journey of in under nine months.
These observations argue against traditional theories that white sharks are coastal territorial predators, and open up the possibility of interaction between shark populations that were previously thought to have been discrete. The reasons for their migration and what they do at their destination is still unknown. Possibilities include seasonal feeding or mating.
Great white shark
18875084#5
Johnson was part of the first South African team to successfully attach a satellite transmitters to a great white shark on 24 July 2001.Johnson has tagged Great White Sharks for research purposes. His major scientific discoveries have been the satellite tracking of Nicole (a 3.6m great white shark) on a return migration from South Africa to Australia and back, and documenting the Great White Shark hunting Cape fur seal at night time, a previously unknown behavior. Between 2001 and 2005 Johnson conducted research on the controversial practice of chumming great white shark for tourism, often called cage diving, where he discovered evidence of conditioning, however he did not link this to increased numbers of attacks on human beings. In January 2008 he led a pilot study to Ponto Do Ora (Mozambique) on the Zambezi shark, also known as the Bull shark.
Ryan Johnson (marine scientist)
18877204#0
Stephan Swanson came to prominence as a marine researcher when he successfully placed the satellite transmitter on the famous Great white shark Nicole, the first great white shark ever to be tracked on a 20,000 kilometer migration from South Africa to Australia and back. Due to his ability to handle large marine predators, such as the great white shark, he was contracted as an expedition biologist to travel to Guadeloupe and place satellite transmitters on the dorsal fins of Great Whites. His historical capture and release of a 5m long, 1800 kilogram great white shark is documented in the National Geographic Marine Special "Ultimate Shark".
Stephan Swanson
43619#34
The national conservation status of the great white shark is reflected by all Australian states under their respective laws, granting the species full protection throughout Australia regardless of jurisdiction. Many states had prohibited the killing or possession of great white sharks prior to national legislation coming into effect. The great white shark is further listed as Threatened in Victoria under the Flora and Fauna Guarantee Act, and as rare or likely to become extinct under Schedule 5 of the Wildlife Conservation Act in Western Australia.
Great white shark
43619#9
The great white shark has a robust, large, conical snout. The upper and lower lobes on the tail fin are approximately the same size which is similar to some mackerel sharks. A great white displays countershading, by having a white underside and a grey dorsal area (sometimes in a brown or blue shade) that gives an overall mottled appearance. The coloration makes it difficult for prey to spot the shark because it breaks up the shark's outline when seen from the side. From above, the darker shade blends with the sea and from below it exposes a minimal silhouette against the sunlight. Leucism is extremely rare in this species, but has been documented in one great white shark (a pup that washed ashore in Australia and died). Great white sharks, like many other sharks, have rows of serrated teeth behind the main ones, ready to replace any that break off. When the shark bites, it shakes its head side-to-side, helping the teeth saw off large chunks of flesh. Great white sharks, like other mackerel sharks, have larger eyes than other shark species in proportion to their body size. The iris of the eye is a deep blue instead of black.
Great white shark
43619#55
At present, hang baits are illegal off Isla Guadalupe and reputable dive operators do not use them. Operators in South Africa and Australia continue to use hang baits and pinniped decoys. In South Australia, playing rock music recordings underwater, including the AC/DC album "Back in Black" has also been used experimentally to attract sharks.
Great white shark
3377096#8
Fox, along with his son, Andrew, after more than 40 years, still continue to run Rodney Fox Great White Shark Expeditions, a shark cage diving operation to view great white sharks in the wild off Southern Australia. This operation also acts as a platform for much needed further research of great white sharks as well as encouraging quality natural history documentaries on the species.
Rodney Fox
20067558#14
However it should be noted that shark and bycatch mortality from drum lines is minor compared to Commercial fishing. On average 15 Great white sharks are caught by the NSW and Queensland shark control programme each year, compared to 186 caught in Australia from other activities. Australia's commercial shark fishing industry is catching over 1200 tonne of shark each year, of which 130 are Great white sharks. The NSW prawn trawling industry alone results in 64 tonne of shark as bycatch each year, with two thirds dying. Tuna and swordfish longline fishing off the coast of South Africa reported 39,000 to 43,000 sharks killed each year between 1995 and 2005. "Sharksavers" estimates that in total 50 million sharks are caught unintentionally each year as bycatch by the commercial fishing industry.
Drum line (shark control)
849192#15
However bycatch from shark nets is minor compared to bycatch from other activities. On average 15 Great white sharks are caught by the NSW and Queensland shark control programme each year, compared to 186 caught in Australia from other activities. Australia's commercial shark fishing industry is catching over 1200 tonne of shark each year, of which 130 are Great white sharks. The NSW prawn trawling industry alone results in 64 tonne of shark as bycatch each year, with two thirds dying. Tuna and swordfish longline fishing off the coast of South Africa reported 39,000 to 43,000 sharks killed each year between 1995 and 2005. "Sharksavers" estimates that in total 50 million sharks are caught unintentionally each year as bycatch by the commercial fishing industry.
Shark net
58072100#41
It should be noted that the impact of shark culling is minor compared to bycatch from Commercial fishing. On average 15 Great white sharks are caught by the NSW and Queensland shark control programme each year, compared to 186 caught in Australia from other activities. Australia's commercial shark fishing industry is catching over 1200 tonne of shark each year, of which 130 are Great white sharks. The NSW prawn trawling industry alone results in 64 tonne of shark as bycatch each year, with two thirds dying. Tuna and swordfish longline fishing off the coast of South Africa reported 39,000 to 43,000 sharks killed each year between 1995 and 2005. "Sharksavers" estimates that in total 50 million sharks are caught unintentionally each year as bycatch by the commercial fishing industry.
Shark culling