Destination: Shark Bay World Heritage Area
On the western edge of the Australian continent, about 800km north of Perth, is the Shark Bay World Heritage Area (WHA). Covering more than 22,000km², it is one of the world’s greatest wilderness treasures, with a unique combination of rare wildlife, abundant flora and stunning scenery unlike anywhere else on the planet.
Shark Bay actually comprises two bays in a W shape – one bounded by the Wooramel Coast and Peron Peninsula, and the other by the Edel Land peninsula and Dirk Hartog Island – with a coastline meandering more than 1500km. The local Malgana Aboriginal people know Shark Bay as Gutharraguda, meaning ‘two waters’.
Shark Bay was inscribed on the UNESCO World Heritage list in 1991 because it meets four World Heritage criteria relating to natural values: ecosystems representing the Earth’s evolutionary history, ongoing ecological and biological processes, exceptional natural beauty, and significant natural habitats for in situ conservation. It also contains many sites of cultural and historical significance, such as ancient Aboriginal middens, shipwrecks, and the first European landing on the continent.
The terrestrial landscape is a place of many contrasts. Edel Land is typified by rocky limestone and wind-pruned scrub over long, white sand dunes. Its western edge features dramatic cliffs dropping into the Indian Ocean, while the eastern side has shallow sandy bays peppered with small rocky islands. Similarly, Dirk Hartog, Dorre and Bernier Islands to the north are elongated fingers of limestone overlain with sand dunes. In the centre of Shark Bay, Peron Peninsula has rolling red sand hills dotted with spinifex and plains interspersed with salty gypsum hollows known as ‘birridas’.
The Wooramel coast stretches along the eastern edge of the WHA between the Wooramel and Gascoyne Rivers, which provide the only flows of freshwater into Shark Bay, as well as sediments that form broad deltas and intertidal mudflats with mangrove thickets.
The region lies at the junction of three major climatic zones – the temperate southwest, the semi-arid west and the tropical north – and straddles the transition of two botanical provinces. These diverse ecosystems are renowned for their abundance of life. It is one of the most diverse floral zones in Western Australia with 850 species, of which 51 are endemic to the region, some considered new to science; five of Australia’s 26 endangered mammal species have their only populations in Shark Bay; and more than 230 (35 per cent) of Australia's bird species have been recorded in the WHA.
About 6000 years ago, broad arid valleys were drowned by rising seas to form Shark Bay’s shallow inlets and pools. The bay’s hydrological structure, altered by the Faure Sill and a high evaporation rate, has produced an unusually steep salinity gradient, which has a marked effect on the distribution and abundance of marine organisms across three distinct biotic zones.
Oceanic water from the Indian Ocean swirls into Shark Bay on the warm Leeuwin Current bringing tropical marine life, sharks and rays. Underlying the Leeuwin Current, at depths of around 400m, are cold, nutrient-rich waters from the sub-Antarctic, underwater highways followed by whales on their long migrations.
Metahaline water, one-and-a-half times saltier than the ocean, nurtures vast seagrass meadows that provide food for thousands of dugongs, and habitats for schools of snapper, mullet and whiting that attract predatory dolphins. The hypersaline water of Hamelin Pool, twice as salty as the ocean, has proved the ideal environment for the development of stromatolites (‘living fossils’) and other organisms that have adapted or genetically evolved to its languid shallows, including a cockle, a jellyfish and a pink snapper unique to Shark Bay.
Marine environments cover about 70 per cent of the Shark Bay WHA. The average depth of the clear, sheltered waters is only nine metres, with a sandy bed beautifully patterned with seagrass meadows, channels and banks. The coastline includes tidal flats, mangrove communities and white shell beaches in the shelter of the bay, and rocky reefs and sheer cliffs on the deep seaward sides.
Shark Bay’s sheltered coves and lush seagrass beds are a haven for a multitude of marine species, including green and loggerhead turtles (both endangered); an estimated 11,000 dugongs (about 12.5 per cent of the world population); increasing numbers of humpback and southern right whales that use Shark Bay as a migratory staging post; a famous population of resident bottlenose dolphins; and large numbers of sharks and manta rays (which are now considered globally threatened); a transition between temperate and tropical currents produces a mix of 323 species of fish, 218 bivalves and 80 of coral, as well as communities of sponges and other invertebrates.
SHARK BAY MARINE RESERVES
As well as enjoying World Heritage status, the waters of Shark Bay have special protection within the Shark Bay Marine Park and the Hamelin Pool Marine Nature Reserve. These marine reserves are part of a network along the coast of Western Australia, in place to protect areas of particular value, such as schooling sites, nursery areas, spawning and breeding grounds, and culturally significant places from Aboriginal sites to historic shipwrecks.
The marine reserve network also supports tourism activities like whale watching, dolphin viewing, scuba diving, snorkelling, kayaking and boat tours, and provides opportunities for scientific research and education about marine conservation. Shark Bay Marine Park is zoned to enable multiple use: recreation, commercial and biodiversity conservation. The location and coordinates of these zones, and a guide for the activities permitted in each zone, are shown in a brochure produced by the WA Department of Biodiversity, Conservation and Attractions, which is available online.
Shark Bay is the traditional country of three Aboriginal language groups: the Malgana, across the bay’s central peninsulas and islands; the Nhanda who occupied the coastal strip south of Edel Land and Tamala down to Kalbarri; and the Yingkarta, along the Wooramel coast north to the Gascoyne River and some way inland. Aboriginal people first inhabited Shark Bay some 30,000 years ago, and moved to and from the area in response to changing sea levels and availability of freshwater and food. Their movements and occupancy stabilised when the sea reached its present level about 6000 years ago.
There are about 130 registered Aboriginal heritage sites in the Shark Bay area, generally close to the shoreline, including quarries, rock shelters, burial sites and middens of discarded shells, bone and other food-related artefacts. Edel Land was a particularly important place for early Aboriginal people with a stone quarry at Crayfish Bay, numerous middens and a burial site on Heirisson Prong. Peron Peninsula was also important with middens found at many locations, as well as fish traps and grinding grooves. All Aboriginal sites and artefacts are protected by law and it is illegal to disturb them.
Following European settlement, many Aboriginal men and women worked in the pearling industry which began in the 1850s and peaked in the 1870s. They gathered oysters in the shallows, skin-dived for them, and collected them in wire dredges towed behind sailing boats. WA’s early pearling industry, from Shark Bay to Broome, was notorious for its ill-treatment of Aboriginal people. Some Aboriginal workers were taken by force and most were not paid wages, just given basic foodstuffs, tobacco and a set of clothes. Living conditions in the pearlers’ camps were poor and many workers died of dysentery and other diseases.
Intimate knowledge of their country made Aboriginal people essential to the pastoral industry when it began in the late 1860s with the introduction of sheep. They were employed to patrol station boundaries, crutch and shear sheep, trap dingoes and foxes, repair mechanical equipment, build fences and yards, sink wells, and break-in horses.
Fishing has remained important to local Aboriginal people through the years and now ecotourism and conservation provide opportunities for management of their traditional country.
The maritime history of Shark Bay began in 1616, when Dirk Hartog made the first landing by a European on Australian soil, at a place now known as Cape Inscription on the northern tip of Dirk Hartog Island. He was followed in 1697 by Willem de Vlamingh. Thereafter, scientific expeditions were led by William Dampier (1699), who named Shark Bay; St Alouarn (1772) who claimed the western half of New Holland for France (though his claim was never enacted); Nicolas Baudin in 1801-03, whose naturalist Francois Peron made a meticulous study of the peninsula that now bears his name; Louis de Freycinet (1818); and Henry Mangles Denham, who surveyed the area in 1858, producing charts that were used into the 1960s.
Shark Bay’s treacherous coastal cliffs and shallow bays have claimed numerous ships over the years, including whalers, cargo boats, fishing boats and pearl luggers. Shipwrecks of historic significance include the Dutch merchant ship Zuytdorp (1712), Paul Pry (1839), the French whaler Perseverant (1841), the British brigantine Macquarie (1878) and the Norwegian whaler Gudrun (1901). While the whereabouts of some wrecks are known, most have never been found.
Though not technically the result of a ‘shipwreck’, a lifeboat from the German surface raider Kormoran came ashore at Carrarang Station with survivors from the ship’s crew, after a naval battle in November 1941 that resulted in the scuttling of Kormoran and the sinking of the Australian light cruiser HMAS Sydney.
Some shipwreck survivors’ camps have been discovered around the Shark Bay coastline, including that associated with the wreck of the French whaler Persévérant at Cape Levillain on the northern tip of Dirk Hartog Island, where archaeologists have discovered brass buttons, glass, ceramics, clay pipes and other artefacts. In the modern era, the wrecking on April 25, 1963 of the prawn trawler Nor 6, on the Zuytdorp Cliffs, and the subsequent 14-day ordeal of its only survivor, skipper Jack Drinan, ranks in the annals of Shark Bay history as one of its greatest tales of ingenuity and endurance, worthy of the monument to the event on the cliffs south of Steep Point.
SETTLEMENT AND INDUSTRY
Guano (seabird droppings) was mined from Shark Bay’s islands in the 1850s, initiating European settlement of the area, but the industry was short-lived as the islands were quickly stripped bare.
Pearling also began around 1850 and peaked in the 1870s, with about 80 boats dredging the banks of Shark Bay. The best pearl shell was sent to England, France and Germany, while lesser-grade shell was discarded or put to novel use, like paving the streets of Freshwater Camp (Denham). The local industry collapsed in the 1930s when the pearl beds were exhausted and plastic buttons replaced mother-of-pearl.
When commercial fishing became an alternative to the waning pearling industry, many shallow-draught pearling cutters were pressed into service as fishing boats, using a beach seine technique used by local Aboriginal people to net sand whiting, bream, sea mullet, tailor and snapper. Since then, fishing has been Shark Bay’s economic mainstay; it is a major source of employment and notable for the long-time involvement of Aboriginal people. Larger vessels based in Carnarvon operate under strict conditions, which include restrictions on boat size, catch size, fishing gear, and must have turtle exclusion devices in prawn nets.
Pastoralism was one of Shark Bay’s earliest and longest-running industries with the dry climate well-suited to sheep. The first pastoral leases were granted in the 1860s and by the 1960s there were about 142,000 sheep grazing on more than 15 sheep stations throughout Shark Bay. However, recurrent drought and the collapse of the wool market in the 1990s forced stations to destock and look for alternative income. Some stations experimented with cattle or goats, while others turned the environment to their advantage through ecotourism.
Today, Shark Bay is a popular destination for nature-based recreation across a wide range of activities – fishing, camping, four-wheel driving, birdwatching, snorkelling, diving, boating, kayaking and photography – and most residents earn their livelihood from industries that rely on the natural environment, such as tourism, hospitality and conservation management.
Hamelin Pool Stromatolites
Hamelin Pool is a partially enclosed basin separated from the open reaches of Shark Bay by the Faure Sill, a bank of sediment, sand and seagrass between Peron Peninsula and the Wooramel coast, that restricts the flow of tides to the Pool. High evaporation, meagre rainfall and restricted tidal flushing combine to make the water south of the sill ‘hypersaline’ (twice as salty as sea water). This hypersalinity, inimical to most organisms, is conducive to the growth of cyanobacteria (single-celled blue-green algae), which trap and bind sediment and each other to form mushroom-like structures called ‘stromatolites’.
Stromatolites are regarded as ‘living fossils’ because cyanobacteria was the first living organism on the planet, inhabiting Earth’s primordial seas 3500 million years ago. They are the oldest form of life on Earth and stromatolite fossils appear in ancient rocks, like those of the nearby Pilbara. Stromatolites played a crucial role in the evolution of higher life forms by producing oxygen through photosynthesis, gradually, over millions of years, increasing the amount of that gas in the atmosphere to its present concentration (about 20 per cent).
Hamelin Pool is one of only four places in the world where living marine stromatolites exist and the Shark Bay colony is by far the biggest and most diverse on earth. The stromatolites at Hamelin Pool began forming between 2000 to 3000 years ago. Some of them are inactive because they have been exposed too long above shallow water and hardened into rock, while most of them continue to grow, at the rate of about 0.4mm a year.
A 200m boardwalk along a purpose-built jetty provides excellent views of the colony, especially at low tide, without damaging these fragile structures. Boating, anchoring, swimming, diving and snorkelling are not permitted over stromatolites or within 300m of the shore in the Hamelin Pool Marine Reserve.
Seagrasses are aquatic flowering plants that form meadows in near-shore brackish or marine waters in temperate and tropical regions. Shark Bay’s waters are clear and shallow, generally less than 10m deep within 1km of the shore, a mixture of warm tropical and cool temperate currents all contributing to a marine environment in which seagrasses flourish.
Shark Bay has the largest seagrass meadows in the world, in both size and diversity. Of the 60 seagrass species that exist globally, 12 grow in Shark Bay (in some places, nine species within a square metre) covering more than 4000km² of the bay’s sandy bottom. The single biggest concentration is the Wooramel Seagrass Bank – at 1030km², it is larger than the Perth metropolitan area. Across Shark Bay, seagrasses produce about 8 million tonnes of leaf material a year – equivalent to four to six wheat crops a year from a land area of comparable size.
Seagrass meadows are literally and figuratively the foundation of Shark Bay marine life, playing a significant and continuing role in the evolution of its diverse aquatic ecosystems; their presence is one of the many reasons Shark Bay is accorded World Heritage status. They stabilise the sea floor, dampen wave action, cleanse water and provide food and habitat for hundreds of marine species – especially for more than 11,000 dugongs, one of the world’s biggest populations.
DEPARTMENT OF BIODIVERSITY, CONSERVATION AND ATTRACTIONS
Parks and Wildlife Service - Shark Bay District 61-63 Knight Terrace, Denham
P (08) 9948 2226
STEEP POINT RANGER STATION
P (08) 9948 3993
27 MHz 68
W www.sharkbay.org and www.dbca.wa.gov.au
SHARK BAY WORLD HERITAGE PROJECT OFFICER
P (08) 9948 2210
MONKEY MIA RESERVE
P (08) 9948 1366
DEPARTMENT OF PRIMARY INDUSTRIES AND REGIONAL DEVELOPMENT
Denham District Office, Knight Terrace, Denham
P (08) 9948 2250
DEPARTMENT OF FISHERIES (DENHAM)
P (08) 9948 1210
BUREAU OF METEOROLOGY
P 1900 955 350
SHARK BAY VOLUNTEER MARINE RESCUE
27 MHz 88
Shark Bay (VMR 675)
P (08) 9948 1376
Carnarvon (VMR 676)
P (08) 9941 3613