Abrolhos Islands Visitors Guide
About the Abrolhos Islands
Pristine waters, a rich biodiversity of marine and other wildlife, historic shipwrecks and their attendant tales, both wild and romantic, of human savagery and triumph over adversity, and a modern, thriving rock lobster industry are all part of the magic that is the Houtman Abrolhos Islands.
Commonly referred to as “The Abrolhos”, the islands are named after Dutch Commander Frederik de Houtman, who came across several of the low-lying, coral-reef fringed islands in June 1619. The word Abrolhos is thought to be derived from the Portuguese expression Abre os olhos, meaning “keep your eyes open”.
The 122 islands lie 60km west of Geraldton on Western Australia's midwest coast. They are clustered into three main groups – Wallabi, Easter and Pelsaert - and spread from north to south across 100km of ocean. The islands and their surrounding reef communities are a meeting place for tropical and temperate sea life and form one of the State's unique marine areas.
The Abrolhos Islands are an A-class Reserve managed by the Department of Fisheries for the conservation of flora and fauna, for tourism, and for purposes associated with fishing industries. The waters surrounding the islands have special status as a Fish Habitat Protection Area for the conservation of fish and fish breeding areas and the aquatic ecosystem, and for the management of aquatic tourism and recreational activities.
The islands lie in the stream of the warm, southward-flowing Leeuwin Current, which funnels warm, low-nutrient, tropical water from the Pacific Ocean down past Indonesia and along Western Australia's continental shelf. It carries a cargo of larvae, eggs and juveniles of many species of corals and other marine life far south of their usual range. The current maintains water temperatures throughout the winter at around 20 to 22 ºC, enabling corals and tropical species of fish and invertebrates to thrive in latitudes where they wouldn't normally survive.
The Abrolhos are among Australia's most important sites for breeding seabirds. Schools of pelagic (fish that live in the surface or middle depths of the ocean) baitfish provide a ready source of food for significant colonies of noddies, shearwaters and terns, which breed and roost in the islands' mangroves, sand dunes and foreshores.
More than 90 species of seabird have been identified on the islands - a sanctuary free of introduced predators. Capitalising on this bounty of smaller seabirds is the white-breasted or white-bellied sea eagle, a natural predator that occurs here in unusually large numbers. Interestingly, some of these birds, including shearwaters and petrels, nest underground, burrowing into the soft sand to make a cool, protected haven for their young.
The islands also mark the northern-most habitat of the Australian sea lion (Neophoca cinerea). Once abundant, the Australian sea lion is now classified as a ‘vulnerable species'.
Wildlife and vegetation
The Islands are home to an array of protected flora and fauna that have adapted uniquely to the diverse range of island ecosystems. The Abrolhos are among Australia's most important sites for breeding seabirds. These include a subspecies of the lesser noddy that has its only breeding colony in the Abrolhos, which is a protected haven for their young. Around 10 species of land birds are also present at the Abrolhos with the Abrolhos Islands painted button-quail being notable as it is endemic (found nowhere else) to the Abrolhos.
A total of 25 terrestrial species (many of which are endemic to the Abrolhos) of reptiles occur on the islands: 11 species of skink (including the Abrolhos spiny-tailed skink), seven species of geckos, four species of legless lizard, one species of dragon (the Abrolhos dwarf bearded dragon), one species of elapid (front fanged snake), one species of python and the marine green turtle. Two terrestrial mammal species are found on the Abrolhos: the Tammar wallaby occurs on East and West Wallabi and was introduced to North Island; while the bush rat occurs on West and East Wallabi. Many of the above fauna have special status with either State, or Commonwealth recognition. Scientific interest in these species and their habitats is high and research is undertaken into many aspects of the islands' wildlife. More information is available from the Maritime Museum of WA in Geraldton.
There are over 140 species of native flora at the Abrolhos, all are classified as protected. Some of these are recognised as being of a “priority species” that have very high conservation values. Some of the vegetation communities (groups of plants) habitating the islands are: coastal and dune heath, Dwarf shrubland, Saltlakes and low saltbush flats, mangals (patches of mangrove forest) and eucalypt mallee. Some of these communities are highly sensitive to disturbance and have slow rates of regeneration. The shruby Nitra bush is common on many of the islands. It provides shelter to sealion pups and a nesting platform for some species of seabird.
Shipwrecks
The Dutch East India Company's vessels, Batavia and Zeewijk, are probably the best known of the Abrolhos wrecks. The Batavia hit Morning Reef, near Beacon Island in the Wallabi Group, in 1629 while the Zeewijk was wrecked on Half-Moon Reef in the Pelsaert Group in 1727. Eighteen other historic wrecks have been discovered in Abrolhos waters.
Geological history
The islands of the Abrolhos are geologically diverse, with North Island, the Wallabis', Rat Island and Gun Island being classified as “mainland remnant” type islands made up of limestone, siltstone, and marls of continental origin that have been isolated by rising sea levels over the last 8,000-10,000 years. In contrast, the newly created adjacent islands, such as Long, Suomi and Pelsaert, consist of coral rubble of more recent origin.
Island industries
The islands' abundant bird and marine life provided the basis for the guano mining and fishing industries that emerged during Australia's colonial period. Guano, a fertiliser derived from bird excreta, was mined on a commercial scale from the 1880s to the 1920s, and again in the mid-1940s. Reminders of this industry include stone guano jetties on Pelsaert, Gun and Big Rat islands, and the foundations of the small gauge railway on Big Rat and Pelsaert. Mounds of limestone tailings are cast into unusual shapes on Big Rat and Gun islands.
Commercial fishing for trepang (sea cucumber) or beche-demer (Holothuria spp.) was conducted on a small scale at the Abrolhos for a period from the mid-1800s.
The Abrolhos was noted as a potential commercial crayfish (western rock lobster) site by the WA Government as early as 1904. Today, the western rock lobster (Panulirus cygnus) is the State's most valuable commercial fishery. The waters around the Abrolhos are an important lobster-breeding habitat - it has been estimated that about 50 per cent of the WA lobster fishery's egg production comes from the Abrolhos. Hence, careful management and conservation of these breeding stocks are of vital importance to the sustainability of the entire fishery.
During the limited rock lobster fishing season, from 15 March to 30 June each year, around 150 licensed fishers, their families and deckhands take up temporary residence on 22 designated islands. These fishers account for about 15 per cent of the fishery's total catch of around 11,000 tonnes in the 14-week season.
Pearl farming is another Abrolhos industry. The highly-prized black pearl is produced from hatchery-raised black lipped pearl oysters at eight aquaculture sites in the archipelago.
There are also licensed commercial finfish and scallop fisheries at the Abrolhos.
Visitors
Every year the rich fish life, unique coral reef formations, birdlife, shipwrecks and the wild beauty of the Abrolhos attract an increasing number of visitors. Many come as invitees of commercial fishing licence holders. Others come on diving or fishing charters, or to observe the wildlife, explore the history or simply experience the islands' unique environment.
The islands' marine and terrestrial environments are fragile and need the protection of visitors and of fishers who temporarily reside there. These natural resources are part of the aquatic heritage of all Australians and are listed on the Register of the National Estate. Visitors are asked to ensure their activities have minimal impact on the islands' natural environment see secrion on ‘Code of Conduct' in this brochure).
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