Shark Bay

       
Shark Bay is a World Heritage Site in the Gascoyne region of Western Australia. It is an area centred approximately on 25°30′S 113°30′ECoordinates: 25°30′S 113°30′E, 800 kilometres north of Perth, on the westernmost point of Australia. An expedition led by Dirk Hartog happened upon the area in 1616, becoming the second group of Europeans known to have visited Australia.Shark Bay was named by William Dampier, in 1699.

The area has a population of fewer than 1,000 people and a coastline of over 1,500 kilometres. The half-dozen small communities making up this population occupy less than 1% of the total area.

Shark Bay World Heritage Site

The World Heritage status of the region was created and negotiated in the 1990s.

Description

The bay itself covers an area of 10,000 km2, with an average depth of 10 metres. It is divided by shallow banks and has many peninsulas and islands. The coastline is over 1,500 km long. It is located in the transition zone between three major climatic regions and between two major botanical provinces.

Dirk Hartog Island is of major historic significance due to early explorers landing upon it. In 1616, Dirk Hartog landed at Inscription Point on the north end of Dirk Hartog Island and marked his discovery with a plate, inscribed with the date and nailed to a post. This plate was then replaced by Willem de Vlamingh and returned to Holland. It is now kept in the National Museum of Holland. A replica can be found in the Shark Bay Discovery Centre in Denham.

Bernier and Dorre islands in the north-west corner of the heritage area are among last-remaining habitats of Australian mammals threatened with extinction. They are used, with numerous other smaller islands throughout the marine park, to release threatened species that are being bred at Project Eden in François Peron National Park. These islands are free of feral non-native animals which might predate the threatened species, and so provide a safe haven of pristine environment on which to restore species that are threatened on the mainland.

The Australian Wildlife Conservatory is the guardian of Faure Island, off Monkey Mia. Seasonally, turtles come here to nest and are the subject of studies conducted in conjunction with the Western Australian Department of Environment and Conservation (DEC) on this sheltered island.

Shark Bay is an area of major zoological importance. It is home to about 10,000 dugongs (sea cows), around 10% of the world's population, and there are many Indo-Pacific bottlenose dolphins, particularly at Monkey Mia. The area supports 26 threatened Australian mammal species, over 230 species of bird, and nearly 150 species of reptile. It is an important breeding and nursery ground for fish, crustaceans, and coelenterates. There are over 323 fish species, with many sharks and rays.

Some Bottlenose Dolphins in Shark Bay exhibit one of the few known cases of tool use in marine mammals (along with sea otters): they protect their nose with a sponge while foraging for food in the sandy sea bottom.

Shark Bay has the largest known area of seagrass, with seagrass meadows covering over 4000 km2 of the bay. It includes the 1030 km2 Wooramel Seagrass Bank, the largest seagrass bank in the world. Shark Bay also contains the largest number of seagrass species ever recorded in one place; twelve species have been found, with up to nine occurring together in some places. The seagrasses are a vital part of the complex environment of the bay. Over thousands of years, sediment and shell fragments have accumulated in the seagrasses to form vast expanses of seagrass beds. This has raised the sea floor, making the bay shallower. Seagrasses are the basis of the food chain in Shark Bay, providing home and shelter to various marine species and attracting the dugong population.

In Shark Bay's hot, dry climate, evaporation greatly exceeds the annual precipitation rate. Thus, the seawater in the shallow bays becomes very salt-concentrated, or 'hypersaline'. Seagrasses also restrict the tidal flow of waters through the bay area, preventing the ocean tides from diluting the sea water. The water of the bay is 1.5 to 2 times more salty than the surrounding ocean waters.

At Hamelin Pool in the south of the bay, living microbes are building stromatolites that are over 3000 years old. The Hamelin Pool contains the most diverse and abundant examples of stromatolite forms in the world.

It is now hypothesized that some of these stromatolites contain a new form of chlorophyll, chlorophyll f.

Shark Bay was inscribed as a World Heritage Site in 1991. The site covers an area of 23,000 square kilometres. It includes many protected areas and conservation reserves, including Shark Bay Marine Park, Francois Peron National Park, Hamelin Pool Marine Nature Reserve, Zuytdorp Nature Reserve and numerous protected islands.

Denham and Useless Loop both fall within the boundary of the site but are specifically excluded from it. Shark Bay was the first to be classified on the Australian World Heritage list.

Discovery Centre

Facilities around the World Heritage area, provided by the Shire of Shark Bay and DEC, include a new Discovery Centre in Denham which provides interactive displays and comprehensive information about the features of the region.

Access

Access to Shark Bay is by air via Shark Bay Airport, and by the World Heritage Drive, a 150-km link road between Denham and the Overlander Roadhouse on the North West Coastal Highway.