The Houtman Abrolhos (often called the Abrolhos Islands) is a chain of 122 islands and associated coral reefs in the Indian Ocean off the west coast of Australia about west of Geraldton, Western Australia. It is the southernmost true coral reef in the Indian Ocean, and one of the highest latitude reef systems in the world.
It is one of the world's most important seabird breeding sites, and the centre of Western Australia's largest single-species fishery, the western rock lobster fishery. It has a small seasonal population of fishermen, and a limited number of tourists are permitted for day trips, but most of the land area is off-limits as a conservation habitat. It is the site of numerous shipwrecks, the most famous being two Dutch ships: , which was wrecked in 1629 (followed by massacre of over 100 survivors by mutineers), and , wrecked in 1727.
The islands are an unincorporated area with no municipal government, subject to direct administration of the Government of Western Australia. In July 2019, the Houtman Abrolhos was declared a national park by the state government.
Geography
The Houtman Abrolhos archipelago is in the Indian Ocean off the west coast of Australia, about west of Geraldton in the state of Western Australia. Its 122 islands and associated coral reefs comprise three island groups, the Wallabi Group, Easter Group and Pelsaert Group.
The most northerly group, the Wallabi Group, consists of an island clump about by , and also takes in the outlying North Island to the north-west. The main islands of the Wallabi Group are North Island, West Wallabi Island, East Wallabi Island and Beacon Island. The group is best known for the shipwreck of Batavia on Morning Reef near Beacon Island in 1629, and the subsequent mutiny and massacre that took place among the survivors.
The Easter Group lies to the southeast of the Wallabi Group, from which it is separated by a channel named Middle Channel. It is about , and consists of a number of islands, including Rat Island, Wooded Island, Morley Island, Suomi Island and Alexander Island.
Further to the southeast, across Zeewijk Channel, lies the Pelsaert Group, the most southerly true coral reef in the Indian Ocean. The main islands of this group are Middle Island, Square Island, Long Island, Pelsaert Island, Basile Island and the Mangrove Group. A great many ships have been wrecked in the Pelsaert Group, most notably Zeewijk, which was wrecked on the Half Moon Reef in 1727, the survivors staying on Gun Island for some time afterwards. Other wrecks include Ocean Queen, wrecked on the Half Moon Reef in 1842; Ben Ledi, wrecked off Pelsaert Island in 1879; Windsor, wrecked on the Half Moon Reef in 1908.;Australia 1:100000 Topographic Survey, Map sheet 1640 (Edition 1): Abrolhos Special and possibly Ridderschap van Holland in 1694 and Aagtekerke in 1727.
Governance The islands are a part of Western Australia. They are part of the Electoral district of Geraldton, and the City of Greater Geraldton. In July 2019, the Houtman Abrolhos was declared a national park by the Western Australian Government.
In early November 2022, the government published its three-part plan to manage the site in the following 10 years, based on research and community consultation carried out after the preceding two years. Some critics thought that the plan did not encourage land-based tourism to the archipelago enough. A spokesperson for Western Australia's Department of Primary Industries and Regional Development said that their top priority is preservation of the wildlife on the islands.
History Aboriginal people visited the islands during the Holocene, as indicated by the discovery on Beacon Island of a flaked stone artefact made from Eocene fossiliferous chert.
Discovery by Europeans
According to the surviving historical record, the first sighting of the Houtman Abrolhos by Europeans was in 1619, sailing the Dutch VOC ships Dordrecht and Amsterdam, only three years after Dirk Hartog made the first authenticated sighting by a European of what is now Western Australia, and only 13 years after the first authenticated European voyage to Australia by the Duyfken, in 1606. Discovery of the islands was credited to Frederick de Houtman, Captain-General of Dordrecht, as it was Houtman who later wrote about the discovery in a letter to the directors of the Dutch East India Company:
The word is Portuguese, making the Houtman Abrolhos one of only two Australian places with a Portuguese name, the other being Pedra Branca in Tasmania. The noun means , and originally designated the spiny fruit of the bindii plant (Tribulus terrestris). Etymologically it is a contraction of the Portuguese expression (; that is, to protect yourself). As a technical term this phytonym was later applied to caltrops (chevaux de frise), i.e. "spiked obstructions", and Portuguese sailors used the word to refer to offshore reefs.
Houtman thus named the islands using a Portuguese loanword that was current in the Dutch marine terminology of the time. John Forsyth states that the islands are named after the Abrolhos Archipelago off the east coast of Brazil, which was discovered and named by Portuguese navigators early in the 16th century. That position is supported by the fact that Houtman was familiar with the Abrolhos Archipelago, having sailed through it in 1598. Others assert that abrolhos was a Portuguese lookout's cry which, like many other Portuguese maritime terms, was taken up by sailors of other nationalities, becoming, by Houtman's time, a Dutch loan word for offshore reefs. Additionally, Frederick De Houtman had at least some grasp of Portuguese, having been sent by Amsterdam merchants to Lisbon from 15921594 with his brother Cornelis to learn about the Portuguese route to the Indies. Frederick also appears to have been a keen linguist, having published the first-known Dutch-Malay and Dutch-Malagasy dictionaries in 1603. He appears to have been fluent-enough in Portuguese that he might have used an evocative Portuguese word if it described the area better than any Dutch word did.
It has been argued by proponents of the theory of Portuguese discovery of Australia that the Portuguese name is evidence that the islands were charted by Portuguese navigators in the 16th century. Kenneth McIntyre, for example, claimed that Houtman was in possession of Portuguese maps of the west coast of Australia, and that he named the islands "abrolhos" in accordance with the name on those maps. Charting of the islands was previously credited to Jorge de Menezes, but is now only listed as a possibility.
The primary piece of evidence used to support the claim of Portuguese priority is the 16th century Dieppe maps, some of which are alleged to show the west coast of Australia, including an island at the position of the Houtman Abrolhos. That island is unlabelled on most of the Dieppe maps but, on Pierre Desceliers' 1550 map, it is labelled Arenes. In 1895, George Collingridge suggested that Arenes was a corruption of Abrolhos, Project Gutenberg of Australia edition but that was mocked by Heeres in 1898, and, according to Battye, "this suggestion can scarcely be regarded seriously. It certainly does not in any way add to the merit of the Portuguese claim".
Setting aside the Portuguese claims, the Houtman Abrolhos first appear on a map in 1622, on a little-known portolan by Hessel Gerritsz. They are unlabelled, marked merely as a group of small circles. They are first named in print in Gerritsz' 1627 map Caert van't Landt van d'Eendracht, where they bear the label Fr. Houtman's abrolhos. On a map produced by Gerritsz the following year, they are labelled Houtman's Abrolhos.
On British Admiralty charts, the islands are labelled Houtman's Rocks.The Western Australian Map of 1897 has Houtman Rocks
Wreck of Batavia
In 1629, some of the islands were the scene of an infamous shipwreck and mutiny. The Dutch ship , under the command of Francisco Pelsaert, ran aground on her maiden voyage to the port of Batavia, the capital of the Dutch East Indies. Pelsaert and some of his crew set off in an open boat to Batavia (now Jakarta) to get help. A group of the crew who remained on some of the islets terrorised and killed many of the other crew and passengers, including women and children. When Pelsaert returned, a number of the culprits were executed.
Wreck of Zeewijk
The was the last of the four Dutch East Indiamen to be wrecked on the west coast of Australia. Due to the Ship's Council having made the inexplicable decision to disregard sailing orders and actually seek out the west coast of Australia, the ship ran onto the Half Moon Reef at about 7:30 pm on 9 June 1727. It did not break up immediately, and the heavy swell made evacuation impossible until 18 June. The longboat was launched on that day, and the crew and stores were thereafter gradually transferred to nearby Gun Island. Later, the men landed ten chests of money, containing 315,836 guilders and weighing a total of .
The crew of Zeewijk were stranded in the Pelsaert Group for ten months, during which time they lived off seals, seabirds, eggs, and victuals salvaged from the wreck. They obtained some water from rainfall, but were forced to explore throughout the group in search of further supplies. A great many men died on the islands, including two boys who were accused of sodomy and marooned on separate islands of the Mangrove Group.
On 10 July the longboat, fitted for a voyage and crewed with eleven men, was sent to Batavia to obtain help. It never arrived there, and nothing is known of its fate. Four months later the castaways began building a boat, sufficient to carry all the men and the money chests. Completed in March 1728 and affectionately named Sloepie ("little sloop"), it was the first ocean-going vessel built in Australian history. On 26 March 1728, the surviving men set sail for Batavia, arriving in Sunda Strait late the following month.
Gun Island and phosphate mining
During Admiralty surveys of the north west coast in 1840, crew from discovered a brass gun of about three pounds calibre, an iron swivel on which paint still adhered as well as numerous other artefacts signifying European occupation, on the largest island in the Pelsart Group. The commander, John Clements Wickham, named the place Gun Island and the passage between the Easter and Pelsart Groups, Zeewijk Channel. p. 15 Later during the 19th century many islets were used by men collecting guano.
A lease to mine rock phosphate on the islands was obtained by Charles Broadhurst in 1884. After surveying the area he constructed a plant, stone jetty and tramways on Rat Island, a number of buildings on Rat, Gun and Pelsaert islandsAbrolhos wa.gov.au and had over 40 Malay workers mining and processing the phosphate for export. Over was shipped between 1884 and 1896.
Tenure, governance and management The islands are a part of the Division of Durack in the federal House of Representatives and the electoral district of Geraldton in the Western Australian Legislative Council. Management is vested in the Department of Fisheries.
Geology Some of the islands are considered to be remnants of the mainland isolated by rising sea level during the last 8,000 to 10,000 years, while others were more recently formed from coral rubble and are made of limestone under a layer of sand, cemented coral rubble and shingle.
Oceanography
Bathymetry The Houtman Abrolhos lies in the Indian Ocean about 60 kilometres (40 mi) off the coast of Western Australia, near the edge of Australia's continental shelf. At less than 50 metres (160 ft) deep, the shelf is quite shallow. It is also fairly level, the depth increasing to the west at a modest gradient of about 1.3 metres per kilometre (7 ft/mi). About five kilometres (3 mi) to the west of the Houtman Abrolhos lies the shelf break, beyond which the seabed falls away much more steeply, averaging around 50 metres per kilometre (260 ft/mi).