Dangerous Reef

For other uses, see Dangerous.
Dangerous Reef

Dangerous Reef, near Pt. Lincoln, a bird colony and seal habitat. Circa 1932.
(State Library of South Australia PRG PRG-458-1-1-9)
Dangerous Reef
Geography
Location Spencer Gulf
Coordinates 34°49′03″S 136°13′03″E / 34.81744479°S 136.21747697°E / -34.81744479; 136.21747697Coordinates: 34°49′03″S 136°13′03″E / 34.81744479°S 136.21747697°E / -34.81744479; 136.21747697
Area 12 ha (30 acres)[1]
Highest elevation 3 m (10 ft)[1]
Administration
Australia
Demographics
Population 0
Coordinates[2]

Dangerous Reef is an island and reef system located in Spencer Gulf in the Australian state of South Australia about 32.5 kilometres (20.2 mi) east-south east of the city of Port Lincoln. It is the southernmost member of the Sir Joseph Banks Group. It has been the site of a navigation aid since 1911. It is notable as the site of a breeding colony of Australian sea lions. The waters adjoining its shore are notable as a place to view great white sharks to the extent that it was both a popular gamefishing and shark cage diving venue during the twentieth century, and was used to film footage for the following motion pictures - Blue Water White Death and Jaws. The island has enjoyed protected area status since 1900 and it has been part of the Sir Joseph Banks Group Conservation Park since 1989.

Description

Dangerous Reef is located in Spencer Gulf about 32.5 kilometres (20.2 mi) east-south east of the city of Port Lincoln, about 17 kilometres (9 nmi) north-northeast of Observatory Point on the northeast coast of Thistle Island and is about 17.5 kilometres (10.9 mi) east of the nearest point of the mainland on the Eyre Peninsula.[1][3][4] Officially, it is described in one source as being a “reef.”[2] In another official source, it is considered to be an island as it is listed as being part of the island group known as the Sir Joseph Banks Group despite being located about 15.5 kilometres (9.6 mi) south-southwest of Stickney Island, the nearest group member.[1][5] Dangerous Reef itself is described as consisting of “a chain of four large rocks” with the tallest reaching a height of 3 metres (9.8 ft) with the remainder being “barely dry” at low tide as well as some other “small rocks.”[1][4] At high tide, the island/reef system has an area of dry land covering about 12 hectares (30 acres) while at low tide, the system dries to an area of about 40 hectares (100 acres).[2] Access to the island/reef system which is subject to permission by the responsible government agency due to the island group’s protected area status (refer below) is either via boat or helicopter.[6]

Formation, geology and oceanography

Dangerous Reef was formed about 8400 years ago following the rise of sea levels at the start of the Holocene.[7] The island/reef system consists of an “isolated inselberg ridge” formed of “much eroded peneplained granite or granite gneiss belonging to the Lincoln Complex of granitic rocks intruded during the Kimban Orogeny, 1600 to 1800 Ma.” As of 1982, it was reported that the island/reef system has no soil apart from that derived as the “broken down by-product of sea-lion and seabird excrement”.[1][8] The island/reef system extends from the “largest rock” for a distance of 1.39 kilometres (0.75 nmi) to the west and for a distance of 4.6 kilometres (2.5 nmi) to the south-east. The south-eastern end of the reef system is reported as experiencing waves that “break heavily.”[3][4] Water depths greater than 18.3 metres (60 ft) are reported within 4.6 kilometres (2.5 nmi) of the reef system.[4]

Flora and fauna

Flora

As of 1982, only the “largest rock” was vegetated and this consisted of two plant species - Mueller's Saltbush and Leafy Peppercress.[9]

Fauna

Vertebrate animals are represented by mammals and birds. A breeding colony of Australian sea lions which is located on the “largest rock” was reported in 1994 as being the second largest colony for this species of pinniped.[1] As of 1982, the island/reef system also supports breeding colonies of black-faced shag, silver gull and Pacific gull.[9]

History

European use

Discovery

Dangerous Reef was discovered and named by the British navigator, Matthew Flinders, on 19 March 1802.[2] While the name of the reef is attributed to Flinders in official sources, it has been suggested by Ernest Scott, the historian and the author of book, The Life of Captain Matthew Flinders R.N., that Dangerous Reef is an example of a feature for which Flinders wrote a descriptive remark about on his charts, i.e. to identify it as a navigation hazard. The descriptive remark for this and other features have been retained and subsequently used as the name of the features on charts and maps.[10]

Guano mining

Dangerous Reef is one of the island sites from which guano was mined under licence from the South Australian Government prior to 1919.[11]

A navigation aid has been in place on the “largest rock” since 1911.[12]

Great white sharks

The waters adjoining Dangerous Reef are notable as a place of aggregation for great white sharks. It was a popular site for gamefishing from early in the 20th century until 1997 when the great white shark became a protected species in Australia.[13][14] Notable gamefishers who visited the waters around Dangerous Reef included the Australian radio personality, Jack Davey, in 1952 and the American novelist, Zane Grey, in 1939.[15][16] In 1969, the island/reef system was one of the sites used for filming of the great white shark documentary, Blue Water White Death.[17] In 1974, footage of live sharks used in the 1975 American film, Jaws was filmed at Dangerous Reef by Ron Taylor.[18] From the 1970s up until 2002, Dangerous Reef was one of the sites used in South Australia for shark cage diving where tourists could observe sharks from within the water.[19]

Protected area status

Dangerous Reef first received protected area status on 29 April 1909 as a bird protection district declared under the Birds Protection Act 1900.[20][21] Since 1989, it has been part of the Sir Joseph Banks Group Conservation Park including the waters within 2 kilometres (1.2 mi) of the island group’s shoreline for the purpose of managing shark cage diving activity.[22][23][24] Since 2012, the waters adjoining the island group have also been part of a sanctuary zone within the Sir Joseph Banks Group Marine Park.[24]

See also

Citations and references

Citations

  1. 1 2 3 4 5 6 7 Robinson et al, 1996, page 271
  2. 1 2 3 4 "Search result for "DANGEROUS REEF (REEF)" (Record no SA0017837)". Department of Planning, Transport and Infrastructure. Retrieved 19 January 2016.
  3. 1 2 DMH, 1985, chart 31
  4. 1 2 3 4 NGA, 2012, page 174
  5. ↑ "Search result for "SIR JOSEPH BANKS GROUP (ISLAND GROUP)" (Record no SA0061743)". Department of Planning, Transport and Infrastructure. Retrieved 20 January 2016.
  6. ↑ Robinson et al, 1996, pages 271 & 437
  7. ↑ Robinson et al, 1996, Page 11
  8. ↑ Robinson et al, 1996, page 253
  9. 1 2 Robinson et al, 1996, pages 271, 427 & 432
  10. ↑ Cooper, 1953, page 130
  11. ↑ Robinson et al, 1996, Page 134
  12. ↑ Robinson et al, 1996, Page 129
  13. ↑ "Sharkfishing Extraordinary.". Observer (Adelaide, SA : 1905 - 1931). Adelaide, SA: National Library of Australia. 5 March 1910. p. 43. Retrieved 21 January 2016.
  14. ↑ DSEWPaC) , 2013, page 26
  15. ↑ "Jack Davey to fish at Dangerous Reef.". Port Lincoln Times (SA : 1927 - 1954). SA: National Library of Australia. 10 April 1952. p. 1. Retrieved 21 January 2016.
  16. ↑ "Zane Grey's first S.A. Shark.". The Advertiser (Adelaide, SA : 1931 - 1954). Adelaide, SA: National Library of Australia. 30 March 1939. p. 18. Retrieved 21 January 2016.
  17. ↑ "Blue Water, White Death (1971)". Turner Classic Movies. Retrieved 21 January 2016.
  18. ↑ Davies, Nathan (19 June 2015). "How a big shark and a little man forced Spielberg to make Jaws even better". The Advertiser. Retrieved 21 January 2016.
  19. ↑ DSEWPaC) , 2013, page 43
  20. ↑ "Bird Protection District" (PDF). South Australian Government Gazette. Adelaide: Government of South Australia. year 1909 (23): 847. 6 May 1909. Retrieved 22 January 2016.
  21. ↑ Robinson et al, 1996, Pages 138 & 140
  22. ↑ Robinson et al, 1996, Page 272
  23. ↑ Baker (Part 4), 2004, page 455-456
  24. 1 2 DEWNR, 2012, page 26

References

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