Editing Houtman Abrolhos

{{Short description|Group of islands and reefs off Western Australia}}
{{distinguish|text=[[Abrolhos Archipelago]] in the Atlantic Ocean}}
{{Use Australian English|date=March 2014}}
{{Use dmy dates|date=September 2021}}
{{Infobox islands
| name             = Houtman Abrolhos
| image_name       = Houman Abrolhos bay.jpg
| image_caption    = A bay in the Houtman Abrolhos
| image_size       =
| native_name      = 
| native_name_link = 
| sobriquet        =
| location         = [[Indian Ocean]]
| coordinates      = {{coord|28|43|S|113|47|E|region:AU-WA|display=inline,title}}
| archipelago      = Houtman Abrolhos
| total_islands    = 122
| major_islands    = 
| area_km2         = 16.4
| rank             =
| length_km        =
| width_km         =
| coastline_km     =
| highest_mount    = 
| elevation_m      = 
| country          = Australia
| country_admin_divisions_title     = [[States and territories of Australia|State]]
| country_admin_divisions           = [[Western Australia]]
| country_admin_divisions_title_1 = [[Divisions of the Australian House of Representatives|Federal electorates]]
| country_admin_divisions_1 = [[Division of Durack|Durack]]<ref name="fedgov"/>
| country_admin_divisions_title_2 = [[Electoral districts of Western Australia|State electorate]]
| country_admin_divisions_2 = [[Electoral district of Geraldton|Geraldton]]<ref name="stategov"/>
| country_admin_divisions_title_3 = [[Local government areas in Western Australia|LGA]]
| country_admin_divisions_3 = [[City of Greater Geraldton]]<ref>{{Cite web|title=Abrolhos Islands Tourism|url=https://www.cgg.wa.gov.au/Profiles/cgg/Assets/ClientData/Council_Policy/2_3_-_Abrolhos_Islands_Tourism_-_Version_2_-_23_June_2020.pdf|access-date=1 August 2020|website=[[City of Greater Geraldton]]|archive-date=27 March 2021|archive-url=https://web.archive.org/web/20210327001317/https://www.cgg.wa.gov.au/Profiles/cgg/Assets/ClientData/Council_Policy/2_3_-_Abrolhos_Islands_Tourism_-_Version_2_-_23_June_2020.pdf|url-status=dead}}</ref>
| population       = 6<ref>{{cite web|url=https://quickstats.censusdata.abs.gov.au/census_services/getproduct/census/2016/quickstat/SSC50654?opendocument|title=2016 Census QuickStats: Houtman Abrolhos|website=quickstats.censusdata.abs.gov.au|access-date=16 June 2019|archive-date=16 June 2019|archive-url=https://web.archive.org/web/20190616145216/https://quickstats.censusdata.abs.gov.au/census_services/getproduct/census/2016/quickstat/SSC50654?opendocument|url-status=dead}}</ref>
| population_as_of = 2016 census
| density_km2 =
| ethnic_groups = [[Australians]]
| website = 
| additional_info  =Southernmost true coral reef in the Indian Ocean
|pushpin_map = Western Australia#Australia#Indian Ocean
|pushpin_mark=Cercle rouge 100%.svg
|pushpin_mark_width =20
|pushpin_relief  = yes
}}
[[File:Rat Island (Houtman Abrolhos) photo 2.jpg|thumb|Aerial photograph of [[Rat Island (Houtman Abrolhos)|Rat Island]] (Easter Group)]]
The '''Houtman Abrolhos''' (often called the '''Abrolhos Islands''') is a chain of 122 islands and associated [[coral reef]]s in the [[Indian Ocean]] off the west coast of Australia about {{convert|80|km}} 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 [[shipwreck]]s, the most famous being two Dutch ships: {{ship||Batavia|1628|2}}, which was wrecked in 1629 (followed by massacre of over 100 survivors by mutineers), and {{ship||Zeewijk|1725|2}}, wrecked in 1727.

The islands are an [[Unincorporated areas of Australia|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 [[Houtman Abrolhos Islands National Park|national park]] by the state government.

==Geography==
{{Imageframe|width=250|content={{Image label begin|image=Houtman Abrolhos.jpg|width=250|float=right}}{{Image label|x=0.16|y=0.30|scale=250|text=[[Wallabi Group|<span style="color:#fff;">Wallabi Group</span>]]}}{{Image label|x=0.39|y=0.87|scale=250|text=[[Easter Group|<span style="color:#fff;">Easter Group</span>]]}}{{Image label|x=0.62|y=1.32|scale=250|text=[[Pelsaert Group|<span style="color:#fff;">Pelsaert Group</span>]]}}{{Image label end}}|caption=Houtman Abrolhos from space|link=File:Houtman Abrolhos.jpg|align=right}}
[[File:Abrolhos North-Island.jpg|thumb|Aerial photograph of the southern half of North Island, looking westwards and showing the seasonal fishing camp]]
The Houtman Abrolhos [[archipelago]] is in the [[Indian Ocean]] off the west coast of Australia, about {{convert|80|km}} west of Geraldton in the state of [[Western Australia]]. Its 122 islands and associated coral reefs<ref name="Cocky">{{cite web | url = http://www.ga.gov.au/bin/distancedraw2?rec1=270693&placename=Houtman+Abrolhos&place1=GERALDTON&place1long=114.614441&place1lat=-28.779169 | title = Great Circle Distance between GERALDTON and HOUTMAN ABROLHOS | work = As the Cocky Flies | publisher = Geoscience Australia, Australian Government | access-date = 2007-11-15 | archive-date = 24 September 2015 | archive-url = https://web.archive.org/web/20150924020424/http://www.ga.gov.au/bin/distancedraw2?rec1=270693&placename=Houtman+Abrolhos&place1=GERALDTON&place1long=114.614441&place1lat=-28.779169 | url-status = dead }}</ref> 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 {{convert|17|km}} by {{convert|10|km|0}}, and also takes in the outlying [[North Island (Houtman Abrolhos)|North Island]] {{convert|14|km|0}} to the north-west. The main islands of the Wallabi Group are North Island, [[West Wallabi Island]], [[East Wallabi Island]] and [[Beacon Island (Houtman Abrolhos)|Beacon Island]].<ref name="OceanDots">{{cite web | title = Houtman Abrolhos | work = oceandots.com | url = http://www.oceandots.com/indian/houtman/ | archive-url = https://web.archive.org/web/20101223015139/http://www.oceandots.com/indian/houtman/ | archive-date = 2010-12-23 | url-status = usurped | access-date = 2007-10-13}}</ref> The group is best known for the shipwreck of ''[[Batavia (1628 ship)|Batavia]]'' on [[Morning Reef]] near Beacon Island in 1629,<ref name="WASD 1316">{{Western Australian Shipwrecks Database | name = Batavia | id = 1316}}</ref> and the subsequent [[mutiny]] and massacre that took place among the survivors.<ref name="Dash 2002"/>

The Easter Group lies to the southeast of the Wallabi Group, from which it is separated by a {{convert|9|km|mi|adj=mid|-wide}} channel named [[Middle Channel]]. It is about {{convert|20|x|12|km}}, and consists of a number of islands, including [[Rat Island (Houtman Abrolhos)|Rat Island]], [[Wooded Island]], [[Morley Island]], [[Suomi Island]] and [[Alexander Island (Houtman Abrolhos)|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 (Houtman Abrolhos)|Middle Island]], [[Square Island]], [[Long Island (Houtman Abrolhos)|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.<ref name="Edwards 1970">{{cite book | first = Hugh | last = Edwards | author-link = Hugh Edwards (journalist) | year = 1970 | title = The Wreck on the Half Moon Reef | location = Australia | publisher = Angus & Robertson | isbn = 978-0-207-13275-9}}</ref> Other wrecks include ''[[Ocean Queen (ship)|Ocean Queen]]'', wrecked on the Half Moon Reef in 1842; ''[[Ben Ledi (ship)|Ben Ledi]]'', wrecked off Pelsaert Island in 1879; ''Windsor'', wrecked on the Half Moon Reef in 1908.;<ref name="Abrolhos Special">Australia 1:100000 Topographic Survey, Map sheet 1640 (Edition 1): Abrolhos Special</ref> and possibly ''[[Ridderschap van Holland (1681)|Ridderschap van Holland]]'' in 1694 and ''[[Aagtekerke (1724)|Aagtekerke]]'' in 1727.

==Governance==
The islands are a part of Western Australia. They are part of the [[Electoral district of Geraldton]],<ref>{{cite web |url=http://www.boundaries.wa.gov.au/electoral-distribution/current-boundaries |title=Current Boundaries |author=<!--Not stated--> |date= |website=www.boundaries.wa.gov.au |publisher=[[Western Australian Electoral Commission]] |access-date=17 February 2023 |quote=}}</ref> and the [[City of Greater Geraldton]].<ref name=":0">{{cite web |url=https://maps.slip.wa.gov.au/landgate/locate/ |title=SLIP Map |author=<!--Not stated--> |date= |website=maps.slip.wa.gov.au |publisher=[[Landgate]] |access-date=17 February 2023 |quote=}}</ref> In July 2019, the Houtman Abrolhos was declared a [[Houtman Abrolhos Islands National Park|national park]] by the [[Western Australian Government]].<ref name=":1">{{cite news |last1=Meachim |first1=Laura |title=Houtman Abrolhos National Park listed in bid to protect pristine island chain |url=https://www.abc.net.au/news/2019-07-25/pristine-houtman-abrolhos-islands-listed-as-national-park/11342490 |access-date=2021-05-19 |work=ABC News |publisher=Australian Broadcasting Corporation |date=2019-07-25}}</ref>

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.<ref>{{cite web | last=Pin | first=Phoebe | title=Long-awaited Abrolhos Islands management plan 'disappointing' for Midwest tourism advocates | website=ABC News | date=9 November 2022 | url=https://www.abc.net.au/news/2022-11-09/abrolhos-islands-plan-disappoints-tourism-advocates/101613042 | access-date=27 November 2022}}</ref><ref>{{cite book| url= https://www.dbca.wa.gov.au/sites/default/files/2022-10/Houtman%20Abrolhos%20Islands%20National%20Park%20management%20plan%2097%202022%20%281%29.pdf| author=[[Department of Biodiversity, Conservation and Attractions]] | date = 2022| title= Houtman Abrolhos Islands National Park: Management Plan 97| publisher=Department of Biodiversity, Conservation and Attractions |isbn =978-1-925978-52-0}}</ref><ref>{{cite web | title=Abrolhos management plans | website=[[Department of Primary Industries and Regional Development]] | date=21 February 2022 | url=https://yoursay.dpird.wa.gov.au/abrolhos-reserve-fhpa-draft-management-plans | access-date=27 November 2022}}</ref>

==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]].<ref>{{cite journal|title= An Eocene fossiliferous chert artefact from Beacon Island: first evidence of prehistoric occupation in the Houtman Abrolhos, Western Australia|first= Ben|last= Marwick|year= 2002|volume = 20|pages = 461–464|journal = Records of the Western Australian Museum|issn = 0312-3162
}}</ref>

===Discovery by Europeans===
[[File:Desceliers 1550 map - Australia detail.jpg|thumb|Detail from [[Pierre Desceliers]]' 1550 world map, purportedly showing the north west coast of Australia, with an island labelled "Arenes" at the position of the Houtman Abrolhos.]]
[[File:Desceliers 1550 map - detail showing Arenes.jpg|thumb|The island labelled "Arenes".]]
[[File:Caert van't Landt van d'Eendracht (NLA balanced).jpg|thumb|[[Hessel Gerritszoon]]'s 1627 "[[Caert van't Landt van d'Eendracht]]" contains the first use of the name ''Houtman's Abrolhos'' in print.]]
[[File:Caert van't Landt van d'Eendracht (detail showing Houtman Abrolhos).jpg|thumb|Detail of "Caert van't Landt van d'Eendracht", showing features labelled "Fr. Houtman's abrolhos"]]

According to the surviving historical record, the first sighting of the Houtman Abrolhos by Europeans was in 1619, sailing the [[Dutch East India Company|Dutch VOC]] ships ''Dordrecht'' and ''Amsterdam'', only three years after [[Dirk Hartog]] made the first authenticated sighting 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]]:{{efn |Houtman to Managers of the East India Company, October 7, 1619.<ref name="Heeres 1899">{{cite Q |Q132175190 |mode=cs1 |last=Heeres |first=Jan Ernst |orig-year=1899 |editor-first=Colin |editor-last=Choat |access-date=2025-04-19 }}</ref>}}
{{Blockquote|On the 29th do. deeming ourselves to be in an open sea, we shaped our course north-by-east. At noon we were in 29° 32' S. Lat.; at night about three hours before daybreak, we again unexpectedly came upon a low-lying coast, a level, broken country with reefs all round it. We saw no high land or mainland, so that this shoal is to be carefully avoided as very dangerous to ships that wish to touch at this coast. It is fully ten miles in length, lying in 28° 46.}}

The word {{lang |pt |{{linktext|abrolho}}}} is [[Portuguese language|Portuguese]], making the Houtman Abrolhos one of only two Australian places with a Portuguese name, the other being [[Pedra Branca (Tasmania)|Pedra Branca]] in [[Tasmania]].<ref name="McIntyre 1977">{{cite book | first = Kenneth | last = McIntyre |author-link=Kenneth McIntyre| year = 1977 | title = The secret discovery of Australia | publisher = Souvenir Press | location = South Australia | isbn = 978-0-285-62303-3}}</ref> The noun {{lang |pt |abrolhos}} means {{gloss |thorn}}, and originally designated the spiny fruit of the [[bindii]] plant (''Tribulus terrestris''). Etymologically it is a contraction of the Portuguese expression {{lang |pt |abre os olhos}} ({{translation |open your eyes}}; that is, to protect yourself). As a technical term this phytonym was later applied to [[caltrop]]s ([[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.<ref name="Forsyth 1957">{{cite journal | first = John | last = Forsyth | year = 1957 | title = Visit of the yacht Grootenbroeck to the coast of the South-land in 1631 | journal = [[Early Days (journal)|Early Days]] | volume = V | issue = III | pages = 17–26}}</ref> 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,<ref name="Richardson 1983">{{cite journal | last = Richardson | first = W. A. R. | journal = The Globe | issue = 19 | issn=0311-3930 | title = Is Jave La Grande Australia? The Linguistic Evidence concerning the West Coast | pages = 12–13}}</ref> becoming, by Houtman's time, a Dutch [[loan word]] for offshore reefs.<ref name="Dash 2002">{{cite book | first = Mike | last = Dash | year = 2002 | title = Batavia's Graveyard | location = London | publisher = Weidenfeld & Nicolson | isbn = 978-0-575-07024-0}}</ref> Additionally, Frederick De Houtman had at least some grasp of Portuguese, having been sent by Amsterdam merchants to Lisbon from 1592{{snd}}1594 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.<ref>{{cite web|url=https://www.britannica.com/biography/Cornelis-and-Frederik-de-Houtman|title=Cornelis and Frederik de Houtman - Dutch explorers|website=Encyclopedia Britannica}}</ref> 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.<ref name="McIntyre 1977"/> Charting of the islands was previously credited to [[Jorge de Menezes]], but the notion that Menezes visited Australia is now thoroughly discredited, and no other candidate has been proffered.{{Citation needed|date=February 2008}}

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'',<ref name="Collingridge 1895">{{cite book | first = George | last = Collingridge | title = Discovery of Australia | url = https://archive.org/details/cu31924028641516 | year = 1895 | publisher = Hayes Brothers | location= Sydney}} [http://www.gutenberg.net.au/ebooks06/0605401h.html Project Gutenberg of Australia edition]</ref> but that was mocked by {{thinspace|J.|E.}} Heeres in 1898,<ref name="Heeres 1898">{{cite book | first = J. E. | last = Heeres | year = 1898 | title = Abel Janszoon Tasman's Journal | publisher = Frederik Muller and Co | location = Amsterdam | url = http://www.gutenberg.net.au/ebooks06/0600571h.html |edition= Project Gutenberg of Australia }}</ref> and, according to [[J. S. Battye|{{thinspace|J.|S.}} Battye]], "this suggestion can scarcely be regarded seriously. It certainly does not in any way add to the merit of the Portuguese claim".<ref name="Battye 1924">{{cite book | first = James Sykes | last = Battye | year = 1924 | title = Western Australia: A history from its discovery to the inauguration of the Commonwealth | publisher = Oxford at the Clarendon Press | url = http://www.gutenberg.net.au/ebooks05/0500301h.html |edition=Project Gutenberg of Australia}}</ref>

[[File:Houtman1897.JPG|thumb|left|Houtman Abrolhos labelled 'Houtman Rocks' on Western Australia state map for 1897]]

Setting aside the Portuguese claims, the Houtman Abrolhos first appear on a map in 1622, on a little-known [[portolan]] by [[Hessel Gerritsz]].<ref name="Forsyth 1957"/> They are unlabelled, marked merely as a group of small circles.<ref name="Godard 1993">{{cite book | first = Philippe | last = Godard | year = 1993 | title = The first and last voyage of the Batavia | location = Perth | publisher = Abrolhos Publishing | isbn = 978-0-646-10519-2}}</ref> 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''.<ref name="Drake-Brockman 1995">{{cite book | first = Henrietta | last = Drake-Brockman | author-link = Henrietta Drake-Brockman | title = Voyage to disaster | edition = 2nd | publisher = University of Western Australia Press | isbn = 978-1-920694-72-2 | year = 2006}}</ref>

On [[Admiralty (United Kingdom)|British Admiralty]] charts, the islands are labelled ''Houtman's Rocks''.<ref>The ''Western Australian Map'' of 1897 has ''Houtman Rocks''</ref>

===Wreck of ''Batavia''===
{{Main|Batavia (1628 ship)}}
[[File:Ongeluckige voyagie vant schip Batavia (Plate 3).jpg|thumb|A 1647 engraving showing the Beacon Island massacre of survivors of the {{ship||Batavia|1628 ship|2}} shipwreck]]

In 1629, some of the islands were the scene of an infamous shipwreck and mutiny. The Dutch ship {{ship||Batavia|1628 ship|2}}, under the command of [[Francisco Pelsaert]], ran aground on her maiden voyage to the port of [[Batavia, Dutch East Indies|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''===
{{Main|Zeewijk}}
The {{ship||Zeewijk}} was the last of the four Dutch [[East Indiaman|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&nbsp;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 [[guilder]]s and weighing a total of {{convert|3|t|lb|spell=in}}.<ref name="Edwards 1970"/>

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.<ref name="Edwards 1970"/>

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 {{convert|60|ft|m|adj=on|order=flip}} 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.<ref name="Edwards 1970"/>

===Gun Island and phosphate mining===
[[File:Admiralty Chart No 1723 The Houtman Rocks, Published 1845.jpg|thumb|In 1845, the [[British Admiralty]] published a chart of "The Houtman Rocks", based on the 1840 survey of [[John Clements Wickham]] and [[John Lort Stokes]].]]

During [[British Admiralty|Admiralty]]<!--Title of an authority!--> surveys of the north west coast in 1840, crew from {{HMS|Beagle}} 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.<ref>{{kimberly 1897}} p. 15</ref> 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 Edward Broadhurst|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 Island|Gun]] and [[Pelsaert Island|Pelsaert]] islands<ref>[http://museum.wa.gov.au/maritime-archaeology-db/sites/default/files/no._066_abrolhos_historic_0.pdf Abrolhos] wa.gov.au</ref> and had over 40 Malay workers mining and processing the phosphate for export.<ref>{{cite web|url=http://members.westnet.com.au/caladenia/ghosttowns/B.pdf|title=Morowa District Historical Society|year=2009|access-date=2010-11-12|url-status=dead|archive-url=https://web.archive.org/web/20110312055951/http://members.westnet.com.au/caladenia/ghosttowns/B.pdf|archive-date=12 March 2011}}</ref> Over {{convert|48,000|t|e6lb|abbr=off}} was shipped between 1884 and 1896.

==Tenure, governance and management==
The islands are a part of the [[Division of Durack]] in the federal [[Australian House of Representatives|House of Representatives]]<ref name="fedgov">{{cite web|url=https://www.aec.gov.au/profiles/wa/files/2021/2021-AEC-WA-A3-Durack-Final.pdf|title=Electoral division of Durack
|website=aec.gov.au|access-date=26 May 2024}}</ref> and the [[electoral district of Geraldton]] in the [[Western Australian Legislative Council]].<ref name="stategov">{{Cite web|url=https://www.boundaries.wa.gov.au/electoral-distribution/current-boundaries|title=Current Boundaries &#124; Electoral Boundaries WA|website=www.boundaries.wa.gov.au|accessdate=4 October 2023}}</ref> 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. Others were more recently formed from [[coral]] rubble.

==Oceanography==

===Bathymetry===
The Houtman Abrolhos lies in the Indian Ocean about 60 kilometres (40&nbsp;mi) off the coast of Western Australia, near the edge of Australia's [[continental shelf]]. At less than 50 metres (160&nbsp;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&nbsp;ft/mi). About five kilometres (3&nbsp;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&nbsp;ft/mi).<ref name = "Pearce 1997">{{cite book | first = AF | last = Pearce | year = 1997 | chapter = The Leeuwin Current and the Houtman Abrolhos Islands, Western Australia | editor = Wells, FE | title = The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia | volume = 1 | pages = 11–46 | publisher = Western Australian Museum | location = Perth}}</ref>

The islands of each island group arise from a single [[carbonate platform]], so the waters within an island group are mostly shallow. The channels between groups are {{convert|40|to|50|m}} deep, so no impediment to the exchange of offshore and inshore waters.<ref name="Pearce 1997"/>

===Currents===
The Houtman Abrolhos lies almost directly in the path of the [[Leeuwin Current]], which draws warm, low-saline water of tropical origin southwards along the coast of Western Australia. This current flows all year round, but is strongest during [[southern hemisphere]] winter months. In general the Leeuwin Current runs along the shelf break, and thus passes close by the western edge of the Abrolhos. It meanders, sometimes passing well out to sea and sometimes directly through the island chain, bathing it in warm tropical water;<ref name="Pearce 1997"/> Although the direction of the Leeuwin Current is predominantly southerly, [[Shark Bay, Western Australia|Shark Bay]] and the Houtman Abrolhos together act as a [[topography|topographical]] trigger for the forming of [[eddy (fluid dynamics)|eddies]],<ref name="Waite 2007">{{cite journal | first1 = A. M. | last1 = Waite | year = 2007 | title = The Leeuwin Current and its eddies: An introductory overview | journal = Deep-Sea Research Part II | volume = 54 | pages = 789–796 | doi = 10.1016/j.dsr2.2006.12.008 | last2 = Thompson | first2 = P | last3 = Pesant | first3 = S | last4 = Feng | first4 = M | last5 = Beckley | first5 = L | last6 = Domingues | first6 = C | last7 = Gaughan | first7 = D | last8 = Hanson | first8 = C | last9 = Holl | first9 = C | last10 = Koslow | issue = 8–10 | first10 = T. | last11 = Meuleners | first11 = M. | last12 = Montoya | first12 = J.P. | last13 = Moore | first13 = T. | last14 = Muhling | first14 = B.A. | last15 = Paterson | first15 = H. | last16 = Rennie | first16 = S. | last17 = Strzelecki | first17 = J. | last18 = Twomey | first18 = L.| bibcode = 2007DSRII..54..789W |display-authors=2}}</ref> so the Abrolhos can experience currents from any direction, even when the Leeuwin Current is flowing strongly.<ref name="Pearce 1997"/>

Unlike most other major ocean currents, there is no large-scale [[coastal upwelling]] associated with the Leeuwin Current. There is limited evidence for some sporadic, localised upwelling in the vicinity of the Abrolhos, but if so it appears to have little effect on the extremely low levels of nutrients in the water.<ref name="Pearce 1997"/>

===Temperature and salinity===
[[File:Houtman Abrolhos sea temperature and salinity.png|thumb|Mean monthly temperature versus [[salinity]] for the Houtman Abrolhos and the adjacent coast in 1994, showing the Houtman Abrolhos to be much less variable.]]

Sea temperature at the islands varies according to a diurnal cycle, with the water at its coldest between six and eight in the morning, and at its warmest between three and four in the afternoon. In summer the daily temperature range is around 1&nbsp;°C (2&nbsp;°F); in winter it is about half that.<ref name="Pearce 1997"/>

There is also an annual cycle, with sea temperature varying by a little less than 4&nbsp;°C (7&nbsp;°F) over the year, peaking at nearly 24&nbsp;°C (75&nbsp;°F) in March, and falling to around 20&nbsp;°C (68&nbsp;°F) in September. This variability is much less than in nearby coastal waters, which reaches a similar peak in summer but drops as low as 18&nbsp;°C (64&nbsp;°F) in winter. The relatively low variability in sea temperatures at the Abrolhos is largely attributable to the Leeuwin Current, which bathes the islands in warm tropical water during winter months.<ref name="Pearce 1997"/>

A similar annual pattern occurs in [[salinity]]. There is a clear seasonal variation, with values ranging from a summer high of around 35.7 [[parts per trillion|ppt]], to a winter low of around 35.4 ppt. As with water temperatures, the variability in salinity is much smaller than in coastal waters, where summer salinity reaches 36.4 ppt. This difference is partly due to the low-salinity waters of the Leeuwin Current, but there are a number of other factors involved, including high evaporation of coastal waters in summer.<ref name="Pearce 1997"/>

Temperatures can also vary substantially from year to year. Annual mean temperatures vary by as much as 1&nbsp;°C (2&nbsp;°F); with cooler years usually cooler throughout the year. There is evidence that annual mean temperatures are related to [[El Niño-Southern Oscillation]] events.<ref name="Pearce 1997"/>

The [[water column]] is generally well-mixed, with no evidence of a significant [[halocline]] or [[thermocline]]. Mean differences in water temperature between sea surface and sea bed range from only half a degree (Celsius; 1&nbsp;°F) in summer to almost zero in winter, and differences in salinity are very small even when the Leeuwin Current is at its strongest.<ref name="Pearce 1997"/>

===Sea levels===
As with the rest of southwestern Australia, [[tide]]s at the Houtman Abrolhos are small and irregular. There is little tidal data available for the islands, but what there is accords very closely with the data for Geraldton. Geraldton tides follow a diurnal pattern, with maximum tidal ranges of around 1 metre (3&nbsp;ft).<ref name="Pearce 1997"/>

Mean sea levels at Geraldton show seasonal fluctuations, being higher in winter when the Leeuwin Current is at its peak. There are also variations from year to year, which are strongly associated with the [[El Niño-Southern Oscillation]] (ENSO) cycle. Apparently, ENSO events induce a weaker Leeuwin Current, which results in lower sea levels.<ref name="Pearce 1997"/>

There is no published information on wave heights in the Abrolhos. In the open ocean, waves are typically a little over two metres high all year round. Nearer the mainland, they are usually less than {{convert|1.2|m}}, with a calmer period in March and April, and another in October and November.<ref name="Pearce 1997"/>

==Climate==
{{As of|2012}}, the Australian [[Bureau of Meteorology]] has not published [[climate|climatic]] data for the Houtman Abrolhos. An [[automatic weather station]] has been installed on [[North Island (Houtman Abrolhos)|North Island]] since 1990, and hourly measures of [[precipitation (meteorology)|precipitation]], [[air temperature]], [[wind speed]], [[wind direction]], [[relative humidity]] and [[atmospheric pressure]] have been publicly available since then. Based on this and other data, researchers have put together a picture of the Abrolhos' climate.

The islands have a [[Mediterranean climate]] ([[semi-arid climate]], or BSh, under [[Köppen climate classification]]) with warm dry summers and cooler, wet winters. Mean temperatures range from {{convert|9.3|to|19.5|°C}} in July, and from {{convert|19.1|to|32.4|°C}} in February. These temperatures have a substantially smaller range than on the mainland: the summer temperature is typically a degree cooler, while winter temperatures are a good deal warmer. This is due to the influence of the ocean, and to the Leeuwin Current.

86% of the rain falls between April and September; on average there are 89 raindays, resulting in {{convert|469|mm}} of rain. The wettest month is June, when over {{convert|100|mm}} typically falls. In contrast, only about {{convert|70|mm}} can be expected to fall between October and March.

It is nearly always windy. During summer a high pressure ridge lies to the south, causing persistent winds from the southeast or southwest, at speeds exceeding {{convert|17|knots|m/s|order=flip}} almost half the time. During autumn and winter, the ridge moves northwards, increasing the atmospheric pressure over the islands, resulting in highly variable winds. Winter tends to produce both the strongest gales and the most frequent periods of calm.

In addition to these winds, there is daily pattern of land breezes in the morning, followed by the onset of south-westerly sea breezes in the afternoon. This pattern is caused by temperature differences between the land and the ocean, and is not as strong in the Houtman Abrolhos as on the mainland, but is present nonetheless.

Three classes of storm have been identified for the region. Brief squalls may occur between December and April. A [[tropical cyclone]] occurs in the area about once in three years, between January and April; these may generate extremely high wind speeds that are potentially destructive. During winter, [[extra-tropical cyclone]]s sometimes pass south of Geraldton, generating winter gales with gusts of up to 35 metres per second, the wind direction from the northwest initially, then gradually moving around to southerly.

==Biogeography==
Under the [[Interim Biogeographic Regionalisation for Australia]] (IBRA), the islands of the Houtman Abrolhos fall within the [[Geraldton Hills]] subregion of the [[Geraldton Sandplains]] region.<ref name="IBRA 5.1">{{cite book|author=[[Environment Australia]] |title=Revision of the Interim Biogeographic Regionalisation for Australia (IBRA) and Development of Version 5.1 – Summary Report |publisher=[[Department of the Environment and Water Resources]], [[Government of Australia|Australian Government]] |url=http://www.deh.gov.au/parks/nrs/ibra/version5-1/summary-report/index.html |access-date=2007-01-31 |archive-url=https://web.archive.org/web/20060905215218/http://www.deh.gov.au/parks/nrs/ibra/version5-1/summary-report/index.html |archive-date=5 September 2006 |url-status=dead }}</ref><ref name="IBRA 6.1">[http://www.deh.gov.au/parks/nrs/ibra/version6-1/index.html IBRA Version 6.1] data {{webarchive |url=https://web.archive.org/web/20060908221444/http://www.deh.gov.au/parks/nrs/ibra/version6-1/index.html |date=8 September 2006 }}</ref> The main [[biogeography|biogeographic]] significance of the islands is their isolation, allowing them to provide [[Refugium (population biology)|refugia]] for such threatened fauna as [[Tammar wallaby|tammar wallabies]] (''Macropus eugenii''), [[Australian sea lion]]s (''Neophoca cinerea'') and rare breeding seabirds.<ref name="Desmond 2001">{{cite book | first = Anthony | last = Desmond |author2=Alanna Chant | year = 2001 | chapter = Geraldton Sandplains 2 (GS2 – Geraldton Hills subregion) | chapter-url = http://www.naturebase.net/pdf/science/bio_audit/geraldton_sandplains02_p265-292.pdf | access-date = 2008-03-02 | title = A Biodiversity Audit of WA | url = http://www.naturebase.net/content/view/960/1397/ | publisher = Department of Environment and Conservation | location = Western Australia}}</ref>

In marine terms, the Houtman Abrolhos is located within the [[Southwest Shelf Transition]], an [[Integrated Marine and Coastal Regionalisation of Australia]] (IMCRA) [[biotone]] that takes in the continental shelf from [[Perth, Western Australia|Perth]] to [[Geraldton, Western Australia|Geraldton]]. This province is defined as the area of shelf where tropical waters intergrade into temperate, thus supporting both tropical and temperate biota.<ref name="IMCRA 3.3">{{cite book|title=Interim Marine and Coastal Regionalisation for Australia: an ecosystem-based classification for marine and coastal environments |url=http://www.environment.gov.au/coasts/mbp/publications/imcra/pubs/imcra3-3.pdf |access-date=2008-02-19 |author=IMCRA Technical Group |publisher=Environment Australia, Department of the Environment, Australian Government |url-status=dead |archive-url=https://web.archive.org/web/20080803001612/http://www.environment.gov.au/coasts/mbp/publications/imcra/pubs/imcra3-3.pdf |archive-date=3 August 2008 }}</ref><ref name="IMCRA 4.0 data">IMCRA 4.0 data</ref> In addition, this area contains the highest concentration of west coast endemics.<ref name="Wells 1997">{{cite book | first = Fred E. | last = Wells | year = 1997 | chapter = Introduction to the marine environment of the Houtman Abrolhos Islands, Western Australia | pages = 1–10 | editor = Wells, F. E.| title = The marine flora and fauna of the Houtman Abrolhos islands, Western Australia, Volume 1 | publisher = Western Australian Museum}}</ref>

Consistent with this, the Houtman Abrolhos contains a mix of tropical, temperate and west coast endemic fauna, resulting in unusual associations such as the occurrence of tropical corals in close association with temperate macro-algae. The proportions of tropical, temperate and west coast endemic biota vary from taxonomic group to group, but in general the biota is dominated by tropical species. This is attributable to the location of the Houtman Abrolhos at the northern limit of the Southwest Shelf Transition, together with the warming influence of the Leeuwin Current.<ref name="Wells 1997"/>

Under IMCRA, the Southwest Shelf Transition divides into two meso-scale bioregions. One is named ''Abrolhos Islands'', and covers the shelf waters surrounding the Houtman Abrolhos, with an area of {{convert|6,645|km2}}. The other bioregion, [[Central West Coast]], covers the remaining area.<ref name="IMCRA 3.3"/><ref name="IMCRA 4.0 data"/>

==Terrestrial flora==
The vegetation of the Houtman Abrolhos islands is dominated by [[Chenopodiaceae|chenopod]] shrubs. The flora is generally the same as the coastal flora of the adjacent mainland, with the exception of the islands' mangrove, saltbush and salt lake vegetation.<ref name="Harvey 2001">{{cite journal | author1 = Harvey, J. M.  | author2 =  Alford, J. J. | author3 =  Longman, V. M.  | author4 =  Keighery, G. J. | year = 2001 | title = A flora and vegetation survey of the Houtman Abrolhos, Western Australia | journal = CALMScience | volume = 3 | issue = 4 | pages = 521–623}}</ref>

===Flora===
{{Main|Flora of the Houtman Abrolhos}}
[[File:Nitraria billardierei.jpg|thumb|''[[Nitraria billardierei]]'' (nitre bush), pictured here in [[Adelaide]], South Australia, is the most widely distributed plant species in the Houtman Abrolhos]]

The [[vascular plant|vascular flora]] of the Houtman Abrolhos has been thoroughly surveyed, and species lists have been published for 119 islands. As of 2001, these lists totalled 239 species from 68 families. A further six species have been collected in the Houtman Abrolhos, but cannot be allocated to islands because insufficient location information was recorded. There have also been collections of [[moss]]es, [[Hepatica|liverwort]]s and [[lichen]]s, but no information has been published on these non-vascular groups.<ref name="Harvey 2001"/>

The islands with the greatest floristic diversity are East and West Wallabi Islands, with 124 and 97 species respectively. 54 species occur in all three island groups. The most widely distributed species are ''[[Nitraria billardierei]]'' (nitre bush), which has been recorded on 106 islands; the exotic ''[[Mesembryanthemum crystallinum]]'' (iceplant), on 88 islands; ''[[Threlkeldia diffusa]]'' (coast bonefruit), on 72 islands; and ''[[Atriplex cinerea]]'' (grey saltbush), on 70 islands. On the other hand, ''[[Eucalyptus oraria]]'' (ooragmandee) and ''[[Acacia didyma]]'' occur only on East Wallabi Island.<ref name="Harvey 2001"/>

As of 2001, five species of priority flora occurred on the islands.<ref name="Harvey 2001"/> One, ''[[Acacia didyma]]'', is no longer considered a priority species.<ref name="FloraBase 13079">{{FloraBase | name = ''Acacia didyma'' A.R.Chapman & Maslin | id = 13079}}</ref> The remaining priority species are  ''[[Chthonocephalus tomentellus]]'', which is rated Priority Two under the Department of Environment and Conservation's [[Declared Rare and Priority Flora List]];<ref name="FloraBase 7934">{{FloraBase | name = ''Chthonocephalus tomentellus'' (F.Muell.) Benth. | id = 7934}}</ref> ''[[Calocephalus aervoides]]'' and ''[[Galium migrans]]'', both Priority Three;<ref name="FloraBase 7887">{{FloraBase | name = ''Calocephalus aervoides'' (F.Muell.) Benth. | id = 7887}}</ref><ref name="FloraBase 322">{{FloraBase | name = ''Galium migrans'' Ehrend. & McGill. | id = 322}}</ref> and ''[[Lepidium puberulum]]'', Priority Four.<ref name="FloraBase 3043">{{FloraBase | name = ''Lepidium puberulum'' Bunge | id = 3043}}</ref>

Ninety-five exotic species from 29 families have been recorded. In general, islands that have or had human settlements are the weediest. Of greatest concern is the noxious weed ''[[Lycium ferocissimum]]'' (African boxthorn), which has long spines that can trap birds. This weed was recorded on the islands as early as 1970. Efforts to eradicate it began in 1990;<ref name="Harvey 2001"/> there was a lull in eradication in the late 1990s, but the program was later reinstated,<ref name="Fisheries 2007"/> and in July 2007, the Department of Environment and Conservation reported that the species had been eradicated from 14 of the 18 islands on which it had been recorded.<ref>{{cite web | title = African boxthorn eradication close | work = NatureBase | publisher = Department of Environment and Conservation, Government of Western Australia | url = http://www.naturebase.net/content/view/2828/770/  | access-date = 2008-01-01}}</ref> Other noxious weeds include ''[[Opuntia stricta]]'' (prickly pear),<ref name="Harvey 2001"/> ''[[Verbesina encelioides]]'' and ''[[Echium plantagineum]]'' (Paterson's curse).<ref name="Fisheries 2007"/>

==Terrestrial fauna==

===Birds===
[[File:Terns, Pelsaert Island.jpg|thumb|[[Tern]]s, [[Pelsaert Island]], 1895]]

The Houtman Abrolhos is home to around 100 species of bird; for a complete list, see [[list of birds of the Houtman Abrolhos]]. Six species are land birds, and three are shore birds. The remainder, the vast majority, are [[seabird]]s. Most seabird species have a tropical distribution, but some occur in both tropical and warm-temperate seas, and a small number are warm-temperate only.<ref name="Storr 1986">{{cite journal | author1 = Storr, G. M. | author2 =  Johnstone, R. E.  | author3 =  Griffin, P. | year = 1986 | title = Birds of the Houtman Abholhos, Western Australia | journal = Records of the Western Australian Museum | issue = Supplement No. 24}}</ref>

When numbers of individuals are taken into account, the tropical birds overwhelmingly dominate. The islands are one of the most important breeding sites for tropical seabirds in Australia and have been identified by [[BirdLife International]] as an [[Important Bird Area]] (IBA).<ref>{{cite web|url=http://www.birdata.com.au/iba.vm |title=IBA: Houtman Abrolhos |access-date=2011-07-08 |work=Birdata |publisher=Birds Australia |url-status=dead |archive-url=https://web.archive.org/web/20110706102341/http://www.birdata.com.au/iba.vm |archive-date=6 July 2011 }}</ref> They contain by far the largest colonies of [[wedge-tailed shearwater]] in the eastern Indian Ocean, with over a million breeding pairs recorded there in 1994.<ref name="Fuller 1994">{{cite journal |author1=Fuller, P. J. |author2=Burbidge, A. A. |author3=Owens, R. | year = 1994 | title = Breeding seabirds of the Houtman Abrolhos, Western Australia | journal = [[Corella (journal)|Corella]] | volume = 18 | issue = 4 | pages = 97–113}}</ref> They also contain Western Australia's only breeding [[seabird colony|colonies]] of the [[lesser noddy]], and the largest colonies in Western Australia of the [[little shearwater]], [[white-faced storm petrel]], [[common noddy]], [[Caspian tern]], [[crested tern]], [[roseate tern]] and [[fairy tern]]. In addition, they contain important breeding areas for the [[Pacific reef heron]], [[Pacific gull]], [[bridled tern]], [[white-bellied sea eagle]] and [[osprey]].<ref name="Storr 1986"/><ref name="Fisheries 2003"/>

There are two subspecies of bird endemic to the islands. The [[Abrolhos painted button-quail]] occurs only on five islands in the Wallabi Group, and is protected as rare under the ''[[Wildlife Conservation Act 1950]]''. Also gazetted as rare, the Australasian subspecies of the lesser noddy, ''Anous tenuirostris melanops'', breeds only on [[Wooded Island]], [[Morley Island]] and [[Pelsaert Island]].<ref name="Fisheries 2003"/>

===Mammals===
[[File:Abrolhos North-Island3.jpg|thumb|A [[tammar wallaby]] on North Island]]

Only two species of land mammal are indigenous to the Houtman Abrolhos, the [[tammar wallaby]] (''Macropus eugenii'') and the [[bush rat]] (''Rattus fuscipes''). Both are native only to West and East Wallabi Islands,<ref name="Abbott 1995">{{cite journal |author1=Abbott, I.  |author2=Burbidge, A. A. | year = 1995 | title = The occurrence of mammal species on the islands of Australia: A summary of existing knowledge | journal = CALMScience | volume = 1 | issue = 3 | pages = 259–324}}</ref> although ''R.&nbsp;fuscipes'' has not been collected on East Wallabi Island since August 1967, and is probably extinct there.<ref name="Cooper 2006">{{cite journal |author1=Cooper, N.K. |author2=How, R.A. |author3=Desmond, A. | year = 2006 | title = Probable local extinction of the Bush Rat, ''Rattus fuscipes'', on East Wallabi Island in the Houtman Abrolhos | journal = [[Western Australian Naturalist]] | volume = 25 | issue = 2 | pages = 61–71}}</ref> The tammar wallaby was seen on West Wallabi Island by survivors of the ''Batavia'' shipwreck, and recorded by [[Francisco Pelsart]] in his 1629 ''Ongeluckige Voyagie''. This represents the first recorded sighting of a [[Macropodidae|macropod]] by Europeans,<ref name="Pearson 2005">{{cite book|first=Michael |last=Pearson |year=2005 |title=Great Southern Land: The maritime exploration of Terra Australis |publisher=Department of the Environment and Heritage, Government of Australia |url=http://www.environment.gov.au/heritage/publications/pubs/great-southern-land.pdf |access-date=2007-12-21 |isbn=978-0-642-55185-6 |archive-url=https://web.archive.org/web/20070929132830/http://www.environment.gov.au/heritage/publications/pubs/great-southern-land.pdf |archive-date=29 September 2007 |url-status=dead }}</ref> and probably also the first sighting of an Australian mammal.<ref name="Storr 1965">{{cite journal | first = Glen | last = Storr | year = 1965 | title = The physiography, vegetation and vertebrate fauna of the Wallabi Group, Houtman Abrolhos | journal = Journal of the Royal Society of Western Australia | volume = 48 | issue = 1 | pages = 1–14}}</ref> Tammar wallabies were introduced to North Island from East Wallabi Island by fishermen, probably in the 1950s, but failed to establish themselves. In 1987 they were reintroduced again, this time successfully. By the 2000s, there were over 400 wallabies on the island, resulting in [[overgrazing]] of native vegetation and increased [[erosion]]. Research into the effectiveness of controlling population levels by the use of implanted contraceptives was begun in 2005,<ref name="ABC">{{cite web | title = "Pill" plan for growing wallaby population | url = http://www.abc.net.au/news/2005-06-16/pill-plan-for-growing-wallaby-population/1593926 | publisher = ABC News Online |date = 15 June 2005 | access-date = 6 September 2015}}</ref> but in July 2007 the research was discontinued and the population culled instead.<ref>{{cite news |url = http://www.abc.net.au/news/2012-12-24/plan-to-cull-wallabies-on-abrohlos-island/4442908 | title = Wallabies may be culled on Abrolhos island | publisher = ABC News (Australian Broadcasting Company) | access-date = 26 November 2017 | date = 24 December 2012 | first = Sarah | last = Taillier}}</ref>

Two introduced mammals are established on the islands. The [[domestic cat]] (''Felis silvestris catus'') was introduced to Rat Island around 1900, and the [[house mouse]] (''Mus musculus'') was introduced onto North Island in the 1970s, presumably with food. In 1995 the house mouse was reported as also present on Rat Island for many years before 1987,<ref name="Abbott 1995"/> but a recent report makes no mention of this.<ref name="Burbidge 2004">{{cite book|author=Burbidge, A. A. |year=2004 |title=Introduced mammals on Western Australian islands: Improving Australia's ability to protect its island habitats from feral animals |edition= Final report for the Australian Government Department of the Environment and Heritage |publisher=Department of Conservation and Land Management, Government of Western Australia |url=http://www.environment.gov.au/biodiversity/invasive/publications/wa-islands/index.html |access-date=2007-12-21 |archive-url=https://web.archive.org/web/20071021093319/http://www.environment.gov.au/biodiversity/invasive/publications/wa-islands/index.html |archive-date=21 October 2007 |url-status=dead }}</ref> In addition, three introduced mammals were previously established in the Houtman Abrolhos, but have since been eradicated. The [[black rat]] (''Rattus rattus'') was established on Pigeon and Rat Islands, but has been eradicated by poisoning. The [[European rabbit]] (''Oryctolagus cuniculus'') has been introduced at various times onto Leo Island, Middle Island, Morley Island, Pelsaert Island and Wooded Island. In the case of Pelsaert Island, it is not clear whether it ever established; in all other cases, established populations have been eradicated by poisoning.<ref name="Abbott 1995"/><ref name="Burbidge 2004"/> The [[domestic goat]] (''Capra aegagrus hircus'') is also reported to have been present on East Wallabi Island, but is no longer.<ref name="Storr 1986"/>

===Reptiles===
[[File:Abrolhos West Wallabi Is DSCN7917.JPG|thumb|An [[Abrolhos dwarf bearded dragon]] (''Pogona minor minima'') on West Wallabi Island]]

23 terrestrial reptile species are known to occur on the islands of the Houtman Abrolhos.<ref name="How 2004">{{cite journal | author1 = How, R. A. | author2 =  Pearson D. J. | author3 =  Desmond, A. | author4 =  Maryan, B. | year = 2004 | title = Reappraisal of the reptiles on the islands of the Houtman Abrolhos, Western Australia | journal = [[The Western Australian Naturalist]] | volume = 24 | issue = 3 | pages = 172–178}}</ref> This relatively low biodiversity is apparently due to the homogeneity of habitat on the islands, which provide few distinct [[ecological niche]]s.<ref name="Kitchener 1982">{{cite journal |author1=Kitchener, D. J.  |author2=How, R. A. | year = 1982 | title = Lizard species in small mainland habitat isolates and islands off south-western Western Australia | journal = Australian Wildlife Research | volume = 9 | pages = 357–363 | doi = 10.1071/WR9820357 | issue = 2}}</ref> The most significant terrestrial reptile species are the spiny-tailed skink (''[[Stokes's skink|Egernia stokesii stokesii]]'') and the carpet python (''[[Morelia spilota imbricata]]''), both of which are listed as rare and therefore afforded special protection under the ''[[Wildlife Conservation Act 1950]]''; and the Abrolhos dwarf bearded dragon (''[[Pogona minor minima]]''), a Houtman Abrolhos endemic that is listed as a Priority 4 species by the [[Department of Environment and Conservation (Western Australia)|Department of Environment and Conservation]].<ref name="Fisheries 2003"/> For a full list of species, see [[list of reptiles of the Houtman Abrolhos]].

===Amphibians===
Specimens of the pobblebonk (''[[Limnodynastes dorsalis]]'') and the turtle frog (''[[Myobatrachus gouldii]]'') were collected from the Houtman Abrolhos during the Percy Sladen Trust Expedition of 1913 and 1915, but no amphibians have been recorded on the islands since that time.<ref name="How 2004"/>

==Marine flora==

===Algae===
260 species of [[benthic]] [[algae]] have been recorded at the Houtman Abrolhos. This figure comprises 178 species of [[red algae]] (Rhodophyta), 50 species of [[brown algae]] (Phaeophyta) and 32 species of [[green algae]] (Chlorophyta). Both temperate and tropical species are present, in many cases near the northern or southern extent of their range.<ref name="Huisman 1997">{{cite book | author = Huisman, John M. | year = 1997 | chapter = Marine benthic algae of the Houtman Abrolhos Islands, Western Australia | pages = 177–237 | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Western Australia: Volume 1 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2}}</ref> For a full list, see [[list of algae of the Houtman Abrolhos]].

===Seagrass===
Only ten species of seagrass have been recorded at the Houtman Abrolhos. Seven of these are temperate species at or near the northern limit of their range; the other three have a tropical distribution. That there are so few tropical species may be due to periods of low sea temperatures, or the small areas of suitable habitat at the Abrolhos; alternatively it may be that more collecting effort is needed in habitats that suit tropical species. The seagrass species recorded at the Houtman Abrolhos islands are:<ref name="Brearley 1997">{{cite book | author = Brearley, Anne | year = 1997 | chapter = Seagrasses and isopod borers from the Wallabi Islands, Houtman Abrolhos Islands, Western Australia | pages = 63–73 | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Western Australia: Volume 1 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2}}</ref>
{| style="width:100%;"
|- valign="top"
|
* ''[[Amphibolis antarctica]]''
* ''[[Amphibolis griffithii]]''
* ''[[Halophila decipiens]]''
* ''[[Halophila ovalis]]''
|
* ''[[Posidonia angustifolia]]''
* ''[[Posidonia australis]]''
* ''[[Posidonia coriacea]]''
|
* ''[[Posidonia sinuosa]]''
* ''[[Syringodium isoetifolium]]''
* ''[[Thalassodendron pachyrhizum]]''
|}

==Marine fauna==

===Fish===
[[File:Thalassoma lunare.jpg|thumb|The [[moon wrasse]], pictured here at the Great Barrier Reef, is one of the most abundant fish species at the Houtman Abrolhos]]

At last count, a total of 389 species of fish have been recorded from the Houtman Abrolhos. 16 species occur in very large numbers; in decreasing order of abundance, these are:<ref name="Hutchins 1997b">{{cite book | author = Hutchins, J Barry | year = 1997 | chapter = Checklist of fishes of the Houtman Abrolhos Islands, Western Australia | title = The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia | volume= 1 | editor = Wells, FE | publisher = Western Australian Museum | pages = 239–53}}</ref>
* ''[[Pomacentrus milleri]]'' (Miller's damsel)
* ''[[Scarus schlegeli]]'' (Schlegel's parrotfish)
* ''[[Stethojulis strigiventer]]'' (stripebelly wrasse)
* ''[[Coris auricularis]]'' (western king wrasse)
* ''[[Kyphosus cornelii]]'' (western buffalo bream)
* ''[[Choerodon rubescens]]'' (baldchin groper)
* ''[[Chromis westaustralis]]'' (West Australian puller)
* ''[[Thalassoma lutescens]]'' (green moon wrasse)
* ''[[Scarus ghobban]]'' (blue-barred orange parrotfish)
* ''[[Abudefduf sexfasciatus]]'' (scissortail sergeant)
* ''[[Thalassoma lunare]]'' (moon wrasse)
* ''[[Stegastes obreptus]]'' (western gregory)
* ''[[Halichoeres brownfieldi]]'' (Brownfield's wrasse)
* ''[[Amblygobius phalaena]]'' (white-barred goby)
* ''[[Asterropteryx semipunctatus]]'' (starry goby)
* ''[[Anampses geographicus]]'' (scribbled wrasse)
Commercially important species include ''[[Pagrus auratus]]'' (pink snapper), ''Choerodon rubescens'' (baldchin groper), ''[[Glaucosoma hebraicum]]'' (westralian dhufish) and ''[[Plectropomus leopardus]]'' (coral trout).<ref name = "Webster 2002" /> For a complete list of fish species recorded at the Houtman Abrolhos, see [[List of fishes of the Houtman Abrolhos]].

About two-thirds of the total number of species are tropical in distribution, the remainder being subtropical or warm-temperate. This ratio also holds for the most abundant species, eleven of the sixteen species being tropical.<ref name = "Hutchins 1997b"/> On the other hand, over 70% of tropical species occur in extremely low numbers, so low in fact that they are thought not to maintain breeding populations at the Abrolhos; rather, populations are maintained by [[larva]]e carried to the islands by the Leeuwin Current from populations further north.<ref name="Hutchins 1997a">{{cite book | author = Hutchins, J. Barry | year = 1997 | chapter = Recruitment of tropical reef fishes in the Houtman Abrolhos Islands, Western Australia | title = The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia, Volume 1 | editor = Wells, F. E. | publisher = Western Australian Museum | pages = 83–87}}</ref>

===Marine mammals===
The Houtman Abrolhos maintains a breeding population of [[Australian sea lion]]s (''Neophoca cinerea''), probably numbering between 75 and 100. Historical data suggests numbers were previously much higher;<ref name="Abbott 1979">{{cite journal | first = Ian | last = Abbott | title = The past and present distribution and status of sea lions and fur seals in Western Australia | journal = Records of the Western Australian Museum | volume = 7 | issue = 4 | pages = 375–390}}</ref> for example, in 1727, survivors of the ''Zeewyk'' shipwreck killed over 150 sea lions in the Southern Group alone. This has led to a 1727 population estimate of between 290 and 580 animals for the entire Houtman Abrolhos. Populations apparently fell dramatically between the 1840s and the 1880s, largely due to extensive commercial [[seal hunting|sealing]] in the area. In addition to direct killing of the animals, it is likely that much of the [[mangrove]] habitat on the islands was cleared as fuel for [[trypot]]s, and this may have affected the survival of young pups. Populations are thought to have been fairly stable for the last fifty years, although the lack of genetic diversity in the smaller population remains of concern, as does [[climate change]].<ref name="Campbell 2005">{{cite book| first = R. | last = Campbell | year = 2005 | title = Historical distribution and abundance of the Australian sea lion (''Neophoca cinerea'') on the west coast of Western Australia | series = Fisheries Research Report No. 148 | publisher = Department of Fisheries, Government of Western Australia}}</ref>

Sea lions come ashore to rest on leeward beaches throughout the island chain, but only a small number of these "haulout sites" are used for breeding. Breeding has been observed on [[Serventy Island]], [[Gilbert Island (Houtman Abrolhos)|Gilbert Island]], [[Alexander Island (Houtman Abrolhos)|Alexander Island]], [[Suomi Island]], [[Keru Island]], [[Square Island]], [[Stick Island]], [[Gibson Island (Houtman Abrolhos)|Gibson Island]], [[Gun Island]], [[Morley Island]] and [[Wooded Island]]. All but the last three of these are considered current breeding sites, and are therefore considered by the Department of Fisheries to have a high conservation value.<ref name="Fisheries 2003">{{cite book | title = Inventory of the Land Conservation Values of the Houtman Abrolhos Islands  |date=October 2003 | series = Fisheries Management Paper No. 151 | publisher = Department of Fisheries, Government of Western Australia | issn = 0819-4327}}</ref>

Little information is available on other marine mammals at the Abrolhos, as no direct research on this subject has been undertaken. Sightings of the [[humpback whale]] (''Megaptera novaeangliae''), followed by [[southern right whale|southern rights]] (''Eubalaena australis''),<ref name=GovFish>[http://www.fish.wa.gov.au/documents/occasional_publications/fop105.pdf Exploring the Houtman Abrolhos Islands] fish.wa.gov.au</ref> are common between April and October, when the whales are migrating. Other marine mammals sometimes sighted at the islands include [[pygmy Bryde's whale]] (''Balaenoptera edeni''), [[orca]] (''Orcinus orca''), [[bottlenose dolphin]] (''Tursiops aduncus''), [[common dolphin]] (''Delphinus delphis''),<ref name=GovFish /> and [[striped dolphin]] (''Stenella coeruleoalba'').<ref name="Webster 2002">{{cite book|title=Towards an assessment of the natural and human use impacts on the marine environment of the Abrolhos Islands, Volume 1: Summary of existing information and current levels of human use |version=Fisheries Research Report No 134 |year=2002 |publisher=Department of Fisheries, Government of Western Australia |url=http://www.fish.wa.gov.au/docs/frr/frr134/frr134_v1.pdf |access-date=2007-12-01 |url-status=dead |archive-url=https://web.archive.org/web/20071026002807/http://www.fish.wa.gov.au/docs/frr/frr134/frr134_v1.pdf |archive-date=26 October 2007 }}</ref>

===Marine reptiles===
The [[green turtle]] (''Chelonia mydas'') and the [[loggerhead turtle]] (''Caretta caretta'') both live in the waters off the Houtman Abrolhos, albeit in low numbers. Neither species breeds in the area, as water temperatures are too low.<ref name="Webster 2002"/>

===Coral===
[[File:Houtman Abrolhos coral (Saville-Kent).jpg|thumb|[[William Saville-Kent]] painted these corals while visiting the Houtman Abrolhos in 1894. He referred to them as ''[[Madrepora]]'', but that name was then applied to virtually any hard coral, and the genus as now circumscribed does not occur in the Abrolhos.]]

The Houtman Abrolhos is unusual in having a luxuriant and diverse living coral reef at such a high latitude. 194 species in 50 genera have been recorded there,<ref name="Veron 1988">{{cite journal |author1=Veron, J. E. N.  |author2=Marsh, L. M. | year = 1988 | title = Hermatypic corals of Western Australia: records and annotated species list | journal = Records of the Western Australian Museum | volume = Supplement 29 | pages = 1–136}}</ref> all but two of which are tropical. This is a surprisingly high coral diversity, considering the high latitude of the reef, and the relatively low diversity of other biota.<ref name="Veron 1988"/> For a full list, see [[list of corals of the Houtman Abrolhos]].

The coral reef community at the Houtman Abrolhos is unusual in having tropical coral growing alongside and in direct competition with, temperate [[seaweed]]. As a result of this competition for light, space and nutrients, coral at the Houtman Abrolhos tends to grow more slowly and die younger than is usual. Reef production is to a large extent due to the production of carbon by [[coralline algae]] rather than by coral.<ref>{{Cite journal|last=Chrisholm|first=John R.M.|date=2003|title=Primary Productivity of Reef-Building Crutose Coralline Algae|url=https://pdfs.semanticscholar.org/376a/d9431a329b7eb1a51e91c57d859775153c37.pdf|archive-url=https://web.archive.org/web/20180330080234/https://pdfs.semanticscholar.org/376a/d9431a329b7eb1a51e91c57d859775153c37.pdf|url-status=dead|archive-date=2018-03-30|journal=Limnol. Oceanogr.|volume=48|issue=4 |pages=1376–1387|doi=10.4319/lo.2003.48.4.1376 |s2cid=18706826}}</ref>

===Crustaceans===
[[File:Panulirus cygnus juv 01 gnangarra (cropped).jpg|thumb|A juvenile [[western rock lobster]] at the Naturalist Marine Research Centre, [[Hillarys Boat Harbour]], [[Perth, Western Australia|Perth]]]]

The most notable species of [[crustacean]] at the Houtman Abrolhos is the [[western rock lobster]] (''Panulirus cygnus''). 44 species of crab and 9 species of [[amphipod]] were recorded there by the Percy Sladen Trust Expedition of 1916.

===Molluscs===
492 species of marine [[mollusc]] have been recorded from the shallow waters of the Houtman Abrolhos. These are predominantly [[gastropod]]s (346 species, 70%) and [[bivalve]]s (124, 25%); the remaining 5% of species consist of [[cephalopod]]s (14 species), [[chiton]]s (5 species) and [[scaphopod]]s (3 species). About two-thirds of the species have a tropical distribution, temperate species account for 20%, and the remaining 11% are endemic to Western Australia.<ref name="Wells&Bryce 1997">{{cite book |author1=Wells, Fred E.  |author2=Bryce, Clay W. | year = 1997 | chapter = A preliminary checklist of the marine macromolluscs of the Houtman Abrolhos Islands, Western Australia | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Volume 2 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2 | pages = 363–383}}</ref> For a full list, see [[List of molluscs of the Houtman Abrolhos]].

The [[southern saucer scallop]] (''Amusium balloti'') is the only commercially important species. This occurs in sheltered areas of medium-fine sand in deep water to the north-east of the reefs; it is usually the dominant species there.<ref name="Glover 1997">{{cite book |author1=Glover, Emily A.  |author2=Taylor, John D. | year = 1997 | chapter = Diversity and distribution of subtidal molluscs from the outer continental shelf, Houtman Abrolhos Islands, Western Australia | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Volume 2 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2 | pages = 281–305}}</ref>

===Echinoderms===
Houtman Abrolhos has an extremely high diversity of [[echinoderms]], with 172 species having been recorded there. 63% of these are tropical species, 14% are temperate, and 22% are endemic to Western Australia. None is endemic to the Houtman Abrolhos.<ref name="Marsh 1994">{{cite book | first = L. M. | last = Marsh | year = 1994 | chapter = Echinoderms of the Houtman Abrolhos Islands, Western Australia and their relationship to the Leeuwin Current | pages = 55–61 | editor = David, B. |editor2=Guille, A. |editor3=Feral, J.-P. |editor4=Roux M.| title = Echinoderms through time | publisher = Balkema | location = Rotterdam}}</ref> Published surveys have not included observations of the [[crown-of-thorns starfish]] (''Ananthaster planci''), but individuals have occasionally been observed there.<ref name="Webster 2002"/> For a complete list of species, see [[list of echinoderms of the Houtman Abrolhos]].

===Sponges, worms and hydroids===
The sponges of the Houtman Abrolhos are poorly studied, although 109 species of [[demosponge]] have been collected there. In the most recent survey, 77 species were collected, of which around half are probably new to science. Only two locations were surveyed in this study, so this figure is likely to represent only a small proportion of the total sponge fauna of the Houtman Abrolhos; the islands are therefore thought to harbour an extremely rich diversity of sponges. A preliminary assessment suggested that there were more temperate species than tropical, which stands in marked contrast to most other groups.<ref name="Fromont 1999">{{cite journal | last = Fromont | first = J. | year = 1999 | title = Demosponges of the Houtman Abrolhos | journal = Memoirs of the Queensland Museum | volume = 44 | pages = 175–183}}</ref>

The [[marine worm]]s identified at the Houtman Abrolhos include 22 species of the [[polychaete]] family [[Terebellidae]],<ref name="Erseus 1997">{{cite book | first = Christer | last = Erséus | year = 1997 | chapter = Marine Tubificidae (Oligochaeta) from the Montebello and Houtman Abrolhos Islands, Western Australia, with descriptions of twenty-three new species | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Volume 2 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2 | pages = 389–458}}</ref> and 16 species of the family [[oligochaete]] family [[Tubificidae]].<ref name="Hutchings 1997">{{cite book | first = Pat | last = Hutchings | year = 1997 | chapter = The Terebellidae (F. Polychaeta) from the Wallabi Group, Houtman Abrolhos Islands, Western Australia | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Volume 2 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2 | pages = 459–501}}</ref> For a list of species, see [[list of worms of the Houtman Abrolhos]].

A total of 38 [[hydroid (zoology)|hydroid]] species have been collected at the Houtman Abrolhos. 34 of these are [[leptothecate]]s, the remainder being [[anthoathecate]]s. 92% of the species attach to temperate algae, the others to coral rubble.<ref name="Watson 1997">{{cite book | first = Jeanette E. | last = Watson | year = 1997 | chapter = The hydroid fauna of the Houtman Abrolhos Islands, Western Australia | editor = Wells, F. E. | title = The marine flora and fauna of the Houtman Abrolhos Islands, Volume 2 | publisher = Western Australian Museum | isbn = 978-0-7309-8553-2 | pages = 503–546}}</ref> For a list of species, see [[list of hydroids of the Houtman Abrolhos]].

==Human uses==

===Fishing and tourism===
Fresh water has always been a significant constraint on any permanent settlement. Aside from the early castaways noted above, the Islands have only had a small seasonal population of fishermen. The present fishermen all have permanent residence elsewhere, mainly in [[Geraldton]], but their island shacks are used as a base during the season. For example, North Island has a seasonal camp for western rock lobster fishers, with individual moorings and simple dwellings. During lobster season, which runs from 15 March to 30 June, the island hosts up to 130 people. The camp is serviced by a carrier boat, the North Islander, which visits the island every three days, bringing supplies and taking out the catch and any domestic waste.

Tourists are not allowed to camp, and the conservation designation of the Island group forbids any real expansion in human occupation.

====Western rock lobster====
The islands are the centre of the [[western rock lobster]] fishery, the largest single-species fishery in Western Australia.

====Saucer scallops====
After Shark Bay, the Houtman Abrolhos supports Western Australia's second largest [[saucer scallop]] fishery.<ref name="Fisheries 2007">{{cite book|title=Management of the Houtman Abrolhos System: A Draft Review 2007–2017 |series=Fisheries Management Paper No. 220 |year=2007 |publisher=Department of Fisheries, Government of Western Australia |url=http://www.fish.wa.gov.au/docs/mp/mp220/fmp220.pdf |archive-url=https://web.archive.org/web/20090609101748/http://www.fish.wa.gov.au/docs/mp/mp220/fmp220.pdf |archive-date=9 June 2009 |access-date=2007-12-01 |url-status=dead }}</ref><ref name="Fisheries 2000">{{cite book |title=Aquaculture Plan for the Houtman Abrolhos Islands |series =Fisheries Management Paper No. 137 |year=2000 |publisher=Department of Fisheries, Government of Western Australia |url=http://www.fish.wa.gov.au/docs/mp/mp137/fmp137.pdf |access-date=2007-12-01 |url-status=dead |archive-url=https://web.archive.org/web/20071010115535/http://www.fish.wa.gov.au/docs/mp/mp137/fmp137.pdf |archive-date=10 October 2007 }}</ref> This fishery is managed under the ''Abrolhos Islands and Mid West Trawl Limited Entry Fishery Notice 1993''. Only 17 licences have been issued, and no more will be made available, as the saucer scallop is considered fully exploited. Licensees are constrained to operate only during scallop season, which generally runs from 1 April to 30 June, and are also subject to restrictions on gear design, boat size and crew numbers.<ref name="DEH 2005">{{cite book | year = 2005 | title = Assessment of the Abrolhos Islands and Mid West Trawl Managed Fishery | publisher = Department of the Environment and Heritage, Australian Government | url = http://www.environment.gov.au/coasts/fisheries/wa/abrolhos-island/index.html | access-date = 2008-05-03}}</ref>

Scallop fishers mainly operate east of the Houtman Abrolhos and between the island groups, in waters deeper than {{convert|30|m}}. Activity is targeted at sheltered areas of bare sand, where scallops tend to settle. Catches vary greatly from year to year; from 2001 to 2003, for example, the total annual catch totalled {{convert|1182|,|195|and|5840|t|e6lb|abbr=off|disp=or}} (whole weight) respectively. This variability is apparently related to the strength of the Leeuwin Current, as strong current is correlated with low scallop recruitment.<ref name="DEH 2005"/>

The total value of the fishery in 2003 was A$19.6 million, although this figure includes a small prawn fishery operating out of [[Port Gregory]]. Most of the catch is frozen and exported to Asia.<ref name="DEH 2005"/>

====Finfish====
The Houtman Abrolhos is the site of some [[wetlining]] activity.

===Aquaculture===
The Department of Fisheries have issued a number of licences to cultivate [[black-lip pearl oyster]]s in the Abrolhos. The first recipient of a license was Abrolhos Pearls in 1996.<ref name="LandLine 2003">{{cite web | title = Landline: 25/5/2003: Abrolhos producing real pearlers | url = http://www.abc.net.au/landline/stories/s861953.htm | author = Murphy, Sean | publisher = [[Australian Broadcasting Corporation]] | access-date = 2007-12-01}}</ref> By 2000, another license had been issued and four more applications had been received.<ref name="Fisheries 2000"/> A year later, there were {{convert|10|km2}} licensed for the culture of pearl oysters in the Abrolhos, of which about 21% was actually in use, carrying over 210,000 shell.<ref name="SOTFR 2001">{{cite web|work=State of the Fisheries Report 2000/2001 |title=Pearling and Aquaculture |url=http://www.fish.wa.gov.au/docs/sof/2000/sof20002001-0401.pdf |publisher=Department of Fisheries, Government of Western Australia |access-date=2007-12-01 |url-status=dead |archive-url=https://web.archive.org/web/20060827081745/http://www.fish.wa.gov.au/docs/sof/2000/sof20002001-0401.pdf |archive-date=27 August 2006 }}</ref> Six licences had been issued by 2002,<ref name="Webster 2002"/> and by 2007 that number had grown to eight.<ref name="Fisheries 2007"/>

95% of the [[pearl]] [[aquaculture]] is carried out in the Pelsaert Group. Most licenses are over areas of sand, but some areas contain small amounts of coral reef.<ref name="Webster 2002"/> The colour of the pearls produced is quite different from that of Pacific black pearls, and this is considered a potential marketing tool.<ref name="SOTFR 2001"/>

In addition to pearl aquaculture, a pilot sea cage [[finfish]] farm was licensed in 2004, although {{As of|2007|lc=y}} the license had not been exercised. Interest has also been expressed in the culture of [[live rock]] and coral for the [[aquarium]] industry.<ref name="Fisheries 2007"/> The Department of Fisheries has identified a number of species as having potential for aquaculture in the Abrolhos, including the Shark Bay pearl oyster (''[[Pinctada albina]]''), the [[maxima clam]] (''Tridacna maxima''), [[rock oyster]]s (''Saccostrea'' sp.), the [[saucer scallop]] (''Amusium balloti''), the western rock lobster, and a number of species of finfish, most of which are [[filter feeder]]s.<ref name="Fisheries 2000"/>

===Mineral exploration===
[[Oil exploration|Petroleum exploration]] wells were drilled in Abrolhos waters in the 1960s and 1970s, but were capped and abandoned. The Abrolhos was amongst the areas released for further exploration in 2002.

===Recreation===
[[File:Ernie Dingo diving at the Houtman Abrolhos.jpg|thumb|[[Ernie Dingo]] dives on a coral reef at the Houtman Abrolhos, during shooting for the Australian television show ''[[The Great Outdoors (Australian TV series)|The Great Outdoors]]''.]]

The Abrolhos provides some of the best [[snorkelling]], [[Underwater diving|diving]] and deep sea fishing in the world, along with some of Australia's most significant historical sights, such as the [[shipwreck]] of the ''[[Batavia (1628 ship)|Batavia]]''.

Although an important tourist destination, the tourists are not allowed to stay overnight.

==Cultural references==
The majority of cultural references to the Houtman Abrolhos relate to the islands' shipwrecks, particularly the ''[[Batavia (1628 ship)|Batavia]]''. The events surrounding the loss of the ''Batavia'' is one of the most celebrated episodes in Australian popular history; in the words of [[Henrietta Drake-Brockman]]:<ref name="Drake-Brockman 1995"/>
{{blockquote|In Australia, poets and schoolboys, artists and historians, have been inspired for half a century by the tragedy of an ancient shipwreck, a disaster that piled horror upon horror yet revealed so much of human fortitude as to invite comparison with the epic tales of Greece.}}
The story has spawned a massive body of literature, both fiction and non-fiction,<ref name="Drake-Brockman 1995"/> as well as numerous works in other media.{{Citation needed|date=March 2008}}<ref>{{Cite web|url=http://museum.wa.gov.au/explore/galleries/batavia-discovery-50th-anniversary|title=Batavia Discovery 50th Anniversary {{!}} Western Australian Museum|website=Western Australian Museum|language=en|access-date=2018-09-28}}</ref>

Other shipwrecks, notably ''Zeewijk'' (also spelled ''Zeewyk''), have also become the subject of books and other works. Other cultural references to the Houtman Abrolhos are rare. By far the best known book on it is [[Malcolm Uren]]'s ''Sailormen's ghosts: The Abrolhos islands in three hundred years of romance, history, and adventure''.{{Citation needed|date=March 2008}} First published in 1940, this book saw numerous editions published in the 1940s, and was even republished in 1980 as a "West Australian classic".{{Citation needed|date=March 2008}} In it, Uren tells both the history of the islands and the story of his own visit to the islands.<ref name="Wood 1940">{{cite book | first = Thomas | last = Wood | chapter = Introduction | editor = Uren, Malcolm | year = 1940 | title = ''Sailormen's Ghosts'' | location = Melbourne | publisher = Robertson & Mullens}}</ref>

Other books include William Bede Christie's 1909 ''Christmas on the briny: the innocents abroad, or, a holiday trip to the Abrolhos islands'', Deborah Lisson's 1991 The Devil's Own, and Alison Louise Wright's 1998 ''Abrolhos Islands Conversations''. The latter, a book of interviews and portraits of the people of the Abrolhos, won the Special Award in the 1999 [[Western Australian Premier's Book Awards]].<ref>{{cite web|url=http://www.liswa.wa.gov.au/pbk99win.html |title=Western Australian Premier's Book Awards – 1999 Winners |date=11 June 2007 |publisher=[[State Library of Western Australia]] |quote=Special Award: ''Abrolhos Islands Conversations'' |url-status=dead |archive-url=https://web.archive.org/web/20080723204615/http://www.liswa.wa.gov.au/pbk99win.html |archive-date=23 July 2008 }}</ref>

The islands featured in the first episode of ''[[Surfing the Menu]]'', an eight-part food and travel series produced for the [[Australian Broadcasting Corporation|ABC]] in 2003,<ref name="imdb">{{cite web | title = Surfing the Menu Abrolhos Islands (2003) | url = https://www.imdb.com/title/tt1146854/ | access-date = 2008-02-03 | work = [[Internet Movie Database]] (IMDB)}}</ref> and the following year were featured on ''[[Getaway (TV series)|Getaway]]'', Australia's longest-running and most popular holiday and travel television programme.<ref name="Getaway">{{cite web | title = Abrolhos Islands | url = http://getaway.ninemsn.com.au/article.aspx?id=17939 | access-date = 2008-03-02 | work = Getaway Fact Sheets | archive-date = 10 March 2007 | archive-url = https://web.archive.org/web/20070310110248/http://getaway.ninemsn.com.au/article.aspx?id=17939 | url-status = dead }}</ref> They were the subject of a motion picture entitled ''Eye opener'', published by The Film Centre WA in 1981,{{Citation needed|date=March 2008}} and of a piece of classical music entitled ''Abrolhos: A ceremonial overture'', written by William Stewart in 1988 under commission to the [[Geraldton Town Council]].{{Citation needed|date=March 2008}}

In April 2019 the Houtman Abrolhos became the site of the failure of reportedly one of Australia's biggest drug smuggling operations, worth $73 million.<ref>{{Cite news |date=2022-04-26 |title=How a giant seal helped foil one of Australia's biggest drug smuggling plots |language=en-AU |work=ABC News |url=https://www.abc.net.au/news/2022-04-27/details-of-abrolhos-islands-drug-smuggling-trial-revealed/100959018 |access-date=2022-04-27}}</ref>

In 2020 a Western Australian man briefly established the Houtman Abrolhos Micro Nation, based on Uncle Margie Island.<ref>{{Cite news |date=2021-07-18 |title=Charter operator and self-declared island 'prince' says no to lawyer, bail during court appearance |url=https://www.abc.net.au/news/2021-07-19/prince-of-the-abrolhos-faces-staying-behind-bars/100301122 |access-date=2024-08-06 |work=ABC News |language=en-AU}}</ref> The self-declared 'prince' represented himself in the four-day trial in 2023 and relied on a bevy of pseudolegal claims to challenge the [[Department of Primary Industries and Regional Development|Department of Primary Industries & Regional Development]] (DPIRD).<ref>{{Cite news |date=2023-02-17 |title='Sovereign citizen' argues his claim as the 'prince' of the Abrolhos Islands |url=https://www.abc.net.au/news/2023-02-17/abrolhos-islands-sovereign-citizen-kristin-macdonald-trial/101981926 |access-date=2024-08-06 |work=ABC News |language=en-AU}}</ref>

==See also==
*[[List of islands in the Houtman Abrolhos]]
*[[List of islands of Australia]]

==Notes==
{{Notelist}}

==References==
{{Reflist |30em}}

==General references==
{{Refbegin |30em}}
*Markey, K. L., Abdo, D. A., Evans, S. N., Bosserelle, C. (2016). Keeping it Local: 	Dispersal 	Limitations of Coral Larvae to the High Latitude Coral Reefs of the 	Houtman 	Abrolhos Islands. PLos ONE 11(1).
{{Refend}}

==Further reading==
{{Refbegin |30em}}
*{{cite journal |last=Collins |first=Lindsay |year=1991 |author-link=Lindsay Collins (geologist) |title=The Abrolhos coral reefs – history and present management |journal=Curtin Gazette |issue=Mar |volume=1991 |pages=5–11 |publisher=Curtin University of Technology |location=Perth |issn=1031-136X |oclc=220462414 }}
*{{cite book |first1=Myra |last1=Stanbury |first2=Patrick |last2=Baker |series=Coast Care (Program) |year=2000 |title=Abrolhos Islands archaeological sites: interim report |location=Fremantle |publisher=Australian National Centre of Excellence for Maritime Archaeology |number=Special publication no. 5 |isbn=1-876465-12-3 |oclc=61131278 }}
{{Refend}}

==External links==
*[http://www.fish.wa.gov.au/Documents/recreational_fishing/FHPA/abrolhos_islands_information_guide.pdf Abrolhos Islands Information Guide] {{Webarchive|url=https://web.archive.org/web/20180404083320/http://www.fish.wa.gov.au/Documents/recreational_fishing/fhpa/abrolhos_islands_information_guide.pdf |date=4 April 2018 }}
*[http://www.fish.wa.gov.au/Documents/occasional_publications/fop105.pdf Fisheries Western Australia – Exploring the Houtman Abrolhos Islands]
*[http://www.epa.wa.gov.au/docs/abrolhos/LongIsland_PER_Main.pdf Long Island Tourism Development, Abrolhos Islands] {{Webarchive|url=https://web.archive.org/web/20120310044026/http://www.epa.wa.gov.au/docs/abrolhos/LongIsland_PER_Main.pdf |date=10 March 2012 }}

{{Subject bar |auto=y |portal1=Western Australia |portal2=Islands }}
{{DutchplacenamesAus}}
{{Authority control}}

[[Category:Houtman Abrolhos| ]]
[[Category:Important Bird Areas of Western Australia]]
[[Category:Shipwreck areas of Western Australia]]
[[Category:Islands of the Mid West (Western Australia)]]
[[Category:Maritime history of the Dutch East India Company]]
[[Category:Fishing communities in Australia]]
[[Category:IMCRA meso-scale bioregions]]
[[Category:Temperate Australasia]]