Wilson Inlet (for Thomas Braidwood Wilson

Statement of Significance

Wilson Inlet is the focal point of a large catchment area and home to complex and varied ecosystems. The Inlet formed a focal point for Noongar people who managed and utilised the Inlet and its abundant natural resources during the later Holocene period (anytime from around 6000 years ago after the Inlet formed), though they would have inhabited the area long before this time. Extensive archaeological remains found at multiple locations in and around Wilson Inlet attest to its function during traditional times as a significant cultural landscape that was utilised by Noongar people for a variety of cultural activities and resource acquisition.
Fish traps, lizard traps, gnamma holes (man-made granite waterholes), burials, stone artefacts, tool making sites and ceremonial materials all exist at different locations around Wilson Inlet today as physical manifestations of the ways in which Noongar people engaged with Wilson Inlet in the past. None of the archaeological features exist in isolation from one-another or from the ecosystems and natural features of which they are a part. The features are all important components of a cultural landscape now, just as they were components in a cultural system in the past.
Noongar cultural systems at Wilson Inlet in the past were interwoven with the landscape and its ecosystems, just as today the cultural landscape is an inherent part of the natural landscape.
If we are to recognise and value the Noongar cultural features associated with Wilson Inlet we need to understand that each and every feature is part of an extended ecocultural landscape and does not exist in isolation. The term “eco-cultural landscape” in this document refers to the interaction of natural and cultural features within the landscape. In isolation, archaeological remains represent a static record of past activities. In their full natural context however, cultural features exist as part of a living, changing landscape and living culture. That is, information on past land-use activities and cultural materials (e.g. archaeological remains) is interacting with changing natural processes and land-use practices to form a living cultural landscape. Archaeological evidence of past cultural systems is static but the interaction of modern Noongar people with this cultural landscape is dynamic and forms the basis of a living cultural landscape.
The Noongar community, as cultural custodians at Wilson Inlet wish to care for and conserve the natural health and beauty of the Inlet and its catchment. Noongar custodians place a high importance on the whole of Wilson Inlet and its tributaries as an eco-cultural landscape. The preservation of cultural values at Wilson Inlet is dependent upon maintaining ecological values and on the active involvement of Traditional Owners in managing the Inlet.
Wilson Inlet, with its brackish water and large volume has a rich and diverse fauna compared with other seasonally closed estuaries of the south coast of Western Australia. Wilson Inlet is also a relatively intact example of this estuary types and is highly significant for the continued survival of a large number of estuarine and estuary/marine flora and fauna species. Wilson Inlet contains a relatively large and intact expression of Ruppia megacarpa seagrass meadows representative of the seasonally closed estuarine systems of the south coast of WA. This community is likely to be the largest estuarine meadow in the region. The seagrass meadows of this inlet are important to large number of vertebrates and invertebrates as habitat, feeding areas and breeding sites. Wilson Inlet contains a diverse fish and benthic macro-invertebrates fauna with some species occurring in high concentrations. Sixty-five species of fish have been recorded in Wilson Inlet, which is the largest number of any estuarine system on the south coast of WA. The inlet has been the centre of detailed study into ecology, biology and water quality of this estuarine ecosystem. Wilson Inlet and its catchment has been studied more intensely than any other estuary of the south coast.
Wilson Inlet is a very important wader and water bird site in the Albany region, south coastal area and WA. The Wilson Inlet has a very high diversity of waterbirds. Seventy-three waterbird species have been recorded which is the highest number within the south coast region and ranks the site fourth in the whole of the south west of WA. The area is the tenth most important wader site in WA and the fourth most important site in the south west of Australia. Nineteen species covered by treaties, (JAMBA) and (CAMBA) have been recorded and it is very likely that Wilson Inlet is of Ramsar Quality as an internationally important wetland/estuarine system.
The site is of critical importance for the maintenance of the Australian and international populations of several species of wader birds. Over the last decade one percent or more of the National and international flyway population of at least four species have been recorded at the site. These include greenshank (ranked five in Australia and two in WA), red necked stint, (ranked eight in Australia and four in the WA), red necked avocet (ranked three in WA and two in the south west) and banded stilt.
The inlet is an important summer refuge for a high number of waterbirds within the Albany region and the south coastal area. Close to 6,000 ducks, swans and coots regularly use the estuary during March. This is between one third to a one half of the end of summer south coast waterbird population.
Wilson Inlet is also one of the most important estuaries/wetlands in the south west of Australia for black swan, Eurasian coot and blue billed duck. The inlet is also important as a nesting site for the rare fair tern. The Wilson Inlet has considerable aesthetic values which are held in high esteem by the Denmark and regional community. It is considered to be one of the most delightful inlets that occur on the south coast.

Physical Description

Wilson Inlet is a 14km long and 2km to 4km wide estuary lying parallel to the coast in an east west direction, covering an area of 48kmsq. The inlet is situated on the south coast 49km west of Albany and about 0.5km south of Denmark. The inlet is a relatively large (total volume 85m3 x 106m3) and deep (over 4m in places) lagoonal system with small estuarine reaches into its tributary rivers (the Denmark, 2.5km and the Hay, 5km). A bar closes the estuary off from the sea for several months in most years. Wilson Inlet lies on a narrow coastal plain between the coastal dunes and granite hills to the north and west. South of Wilson Inlet the dunes have hardened to limestone along the Nullaki peninsula. The greater part of the catchments lie in the Albany/Frazer geological province with its Precambrian granitic rock overlain by Quaternary sands and laterite. The headwaters of the Hay River lie mainly in agricultural land and about 70% of the catchment has been cleared. However, around 75% of the Denmark River catchment remains uncleared and the small Nullaki Catchment south of the inlet is close to 100% intact. The inlet is partially divided into eastern and western basins by Pelican Island and the shallow sill between it and Pelican Point on the southern shore. The central area is over 3m deep, but there are extensive shallows around the margins particularly at the eastern and western ends. The water of Wilson Inlet is always brackish and salinity ranges from about 12 to 20 ppt in spring rising to 20 to 30 ppt in summer. Twenty-one genera of micro algae have been observed in Wilson Inlet. The phytoplankton levels are relatively low when compared with those found in other large south western estuarine systems (eg Peel, Harvey, Swan). The seagrass Ruppia Megacarpa is the dominant plant in the estuary and extends over most of the inlet. The following algae have colonised the rocky littoral areas around the inlet; the brown algae (Cystoseira Trinodis and Ectocarpus sp), the red algae Gracilaria Verrucosa and the green algae Chaetomorpha sp, Cladophora sp and Enteromorpha sp.
The composition of the aquatic fauna reflects the hydrological conditions of the inlet. Wilson Inlet, with its brackish water and large volume has a rich and diverse fauna compared with other seasonally closed estuaries of the south coast. The high productivity of the inlet is based on the abundant seagrass meadow which provide resources and habitat for a diverse flora and fauna. Many of species present are confined to estuaries. Most of the fish fauna are considered to be estuarine/marine species, spawning in the sea and returning to the estuary as larvae or juvenile fish. Most species recruited to the estuary from the sea are dependent on the bar being open when eggs, larvae or juveniles are present in the coastal waters. The common estuarine copepods, Acartia sp, Gladioferens Impuripes and Oithona sp dominate the animal plankton of Wilson Inlet and the Denmark and Hay Rivers. The Wilson Inlet has a rich benthic macro invertebrate fauna with thirty-seven species being recorded. Most of the common species, both estuarine and marine affinity species, are widely distributed through out the inlet.
The dominant fauna differs with the bottom substrate. The sand and silty sand environments have a rich fauna dominated by Ceratonereis Aequisetes, Capitella Capitata, Arthritica Semen and Sprisula Trigonella. The seagrass on silty sand also has a diverse fauna and is dominated by Capitella Capitata, Hydrobia Buccinoides, Hydrococcus Brazieri, Arthritica Semen and Palaemonetes Australis. The mud of the deep basins has a typically impoverished fauna with Capitella Capitata and Sprisula Trigonella the only common species. Mobile species which form part of the bottom fauna include crustacea such as crabs (Portunus and Ovalipes) and king prawn (Penaeus Latisukatus). Wilson Inlet has a very diverse fish fauna with includes sixty-five species. Resident estuarine species include anchovy, black bream, cobbler, flathead, gobies and hardyheads. A large number of marine species regularly enter the inlet when the conditions permit. The abundance of seagrass appears to favour cobbler especially and other species indirectly. A commercial fishery operates in Wilson Inlet. Thirty-three species are caught though the bulk of the catch is made up of only a few species such as cobbler, yellow eyed mullet, sea mullet, King George whiting, blue spotted flathead, sea garfish and Australian herring. The western and northern shore of the inlet are mainly rocky (granite) with small swamps and sandy bays with quartz river sand. Several small rocky islands lie close to the shore and there are small granite outcrops in the inlet. Morley Beach at the eastern end is bordered by low beach ridges, behind which there is a swamp and a small beach ridge plain east of the Denmark River mouth. On the southern shore there is granite around Nornalup Point but the rest of the shoreline is sandy along the northern shore of the Nullaki peninsula.
The estuary is fringed with the rush Juncus Kraussii and the salt tolerant paperbark tree Melaleuca Cuticularis around the inlet and the channels and for a short distance up the rivers. Near the mouth Juncus forms either single species stands or mixed with samphire (Sarcocornia Quinqueflora), Samolus Repens and occasional M Cuticularis in salt mashes. In disturbed areas of salt mash introduced grasses such as buffalo grass (Stenotaphrum Secundatum) are present. A total of seventy-three species of water and wader birds have been in Wilson Inlet. Nineteen of these are migratory wader species. The most common waterbird species include black swan (3,250+), Eurasian coot (1,500+), Pacific duck (1,368+), grey teal (1,336+), little black cormorant (1,100+), little pied cormorant (1,000+) and Australian shelduck (420+). The most common waderbirds include red necked stint (15,251+), red necked avocet (2,880+), banded stilt (2,550+) and greenshank (568+). Fairy terns (Sterna Nereis) are a summer visitor to the inlet and regularly breed at Ocean Beach.

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This information is provided voluntarily as a public service. The information provided is made available in good faith and is derived from sources believed to be reliable and accurate. However, the information is provided solely on the basis that readers will be responsible for making their own assessment of the matters discussed herein and are advised to verify all relevant representations, statements and information.