Editing Houtman Abrolhos (section)

===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>