Editing Houtman Abrolhos (section)

==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]].