Wilson Inlet – Australia

 
 Ariel view the inlet delta and bar (Photo: Martin Regtien)

Wilson Inlet is a seasonally closed estuary on the south coast of Western Australia. The Inlet has a surface area of 48 sq. km, is 14 km long from east to west, and is about 4 km wide. A sand bar isolates the estuary from the Southern Ocean for about half of the year. The bar is artificially breached each year to prevent flooding of land next to the estuary. The Inlet has an average depth of 1.8 m below mean sea level, and a maximum depth of about 4 metres below mean sea level.

Green Skills Annual Report 2016

 

Report: Shorebirds on WA’s South Coast, 2013

 
 

The Wilson Inlet catchment covers an area of 2,263 sq. km, covering parts of the shires of Albany, Denmark and Plantagenet. The main industries in the region are tourism, agriculture and fishing. Land uses include traditional cropping, intensive horticulture, livestock growing on open pastures and plantation forestry. Soils are made up of a variety of silts, sand, clays and gravel. The coastline is characterised by sandy beaches, granite headlands and sections of limestone cliffs.


The climate of Wilson Inlet catchment is similar to a Mediterranean climate with mild, wet winters and warm to hot, dry summers. Mean annual rainfall ranges from 600 mm inland to 1,100 mm at the coast. The long-term average rainfall has fallen by about 200 mm over the last 100 years and the long-term average temperatures have risen by about 1°C.

The natural vegetation is diverse and complex due to a range of soil and climatic conditions. Before it was cleared for agriculture, much of the low-rainfall northern half of the catchment was Jarrah forest and a variety of open woodlands and shrubs in sandy, swampy soils. The costal plain still supports Jarrah (Eucalyptus marginata) forest, dense woodlands, coastal heath and diverse swamplands. Many species of plants are endemic. 20 species of mammals and 12 species of introduced mammals including with feral pigs, rabbits and foxes of particular concern. Reptiles include tiger snakes and skinks. About 240 species of land, water and marine birds can be seen at different times of the year. Migratory species include waders from Siberia. Clearing of native forests has reduced the abundance of populations of forest species.

The inlet supports a wide variety of fish: Sandy Sprat (Hyperlopus vittatus), Cobbler (Cnigoglnis macrocephalis), Pink Snapper (Chrysophrys auratus), Yellow-eye Mullet (Aldritechetta forsterri), Sea Mullet (Mugil cephalus) and Blue Mackerel (Scomber australasicus).

 

A large amount of waterbird species live in and at the Wilson Inlet: Australian Pelican (Pelecanus conspicillatus), Little Black Cormorant (Phalacrocorax sulcirostris) and Little Pied Cormorant (Phalacrocorax melanoleucus), Black Swan (Cygnus atratus), Grey Teal (Anas gibberifrons), Australian Shoveller (Anas rhynchotis), Blue Billed Duck (Oxyura australis), Red-necked Avocet (Recurvirostra novaehollandiae) and Silver Gull (Larus novaehollandiae).

 

The area surrounding the Wilson Inlet also supports many land bird, mammal and reptile species. Birds like Silvereye (Zosterops lateralis), Wetern Rosella (Platycerus icterotis), New Holland Honeyeater (Phylidonyris novaehollandiae), Tawny Frogmouth (Podargus strigoides), Port Lincon Ringneck (Barnardius zonarius), Purple Crowned Lorikeet (Glossopsitta porphyrocephala) and Red Capped Parrot (Purpureicephalus spurius) live here. Yellow Footed Antechinus (Antechinus flavipes), Honey Possum (Tarsipes rostratus) and Grey Bellies Dunnart (Sminthopsis griseoventer) are mammals, which live in the surrounding area of Wilson Inlet. Also reptiles like Spotted Brown Snake (Pseudodonaja affinis) and Eastern Tiger Snake (Notechis sscutatus) can be found here.


The major threat to Wilson Inlet is eutrophication, with the nutrient enrichment originating from a range of sources in rural and urban areas. The main source is considered to come from fertiliser application to pastures and crops as well as intensive animal production farms. There are a range of other developmental and environmental pressures on Wilson Inlet, its foreshore and its catchment arising from coastal development, weeds, use of pesticides in agriculture and plantation forestry, etc.  Ruppia megacarpa is the main underwater flowering plant in Wilson Inlet. This seaweed is considered by some as a nuisance and by others, including scientists, as a vital part of the estuarine ecosystem, including as an important habitat and nursery for fish. The Inlet is of regional and state wide significance, and has been intensively studied by scientists over the past 15 years.

The organisation "GREEN SKILLS" is a not-for-profit Western Australia based community organisation established in 1989. It is registered as a charity and operates a diverse range of environmental projects, training and employment programs in metropolitan and regional areas. Green Skills has offices in Murdoch, Mundijong, Denmark and Albany. It is employs approximately 25 staff, including 11 in Denmark. It directs some its activities to assisting employment opportunities for disadvantaged sectors of the community, including rural and remote youth, unemployed women and under-employed people. It also manages a Centre for Sustainable Living in Denmark which is a convention centre able to accommodate up to 66 people. Green Skills has a relatively flat management structure with responsibilities spread across the organisation.

Green Skills is recognised across Western Australia as an innovative, professional organisation developing new courses and projects, and assisting other non-government organisations to become more effective.

In November 2010, Green Skills won the Western Australian Environment Awards 2010.

 

Wilson Inlet Shorebird Poster

 

Ecological Trends in Wilson Inlet: The Case for Increased Marine Exchange

The new report compiled by: Associate Professor Jeremy Prince, Dr Ben Chuwen (south coast fisheries including Wilson Inlet), Xavier Launay (aquaculture operator), Brad Kneebone (bird conservationist), Basil Schur (20 year involvement in landcare and Inlet issues) and Owen MacIntosh (An Inlet fisherman and farmer) documents a decline over time in shellfish and fish diversity and the abundance of migratory and endemic shorebirds, including those protected under International Treaties.

 

The report outlines how based studies undertaken since the 1980s on water quality, fish and shorebird communities and oral histories reveal what has happened as the marine influence on the physical regime and fauna has steadily declined.

The report also states that there is a need for land-use planning and management in the Wilson Inlet Catchment to include a more careful consideration of the environmental water requirements of the Inlet.

 

State Agencies and NRM groups should review their policies regarding the plantation sector and further water resource extraction from catchment.

 
 Mixed flock of waders over Morley
 

Contact

Green Skills, Centre for Sustainable Living

Denmark Office

Basil Schur (Project Manager)
Unit 4, 33-35 Strickland Street / P.O. Box 577
Denmark WA 6333, Australia
Phone: +61 89848 3310
Fax: +61 89848 3455

E-mail: bschur@greenskills.org.au
Website: www.greenskills.org.au/; www.denmarkcsl.com.au

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