Australian Wetlands Database

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Pitt Water-Orielton Lagoon

Overview

Key facts and figures:

Date of listing:

16 November 1982

Pitt Water-Orielton Lagoon, Photo: D. Ziegeler

Australian Ramsar site number:

6

Criteria: 

2, 3, 4, 8, 9

State/Territory:

Tasmania

Area:

3334 hectares

Drainage Division or IMCRA  region:

Tasmanian Drainage Division; Bruny marine bioregion

Wetland type: 

  • B - Marine subtidal aquatic beds; includes kelp beds, sea-grass beds, tropical marine meadows
  • D - Rocky marine shores; includes rocky offshore islands, sea cliffs
  • E - Sand, shingle or pebble shores; includes sand bars, spits and sandy islets; includes dune systems and humid dune slacks
  • F - Estuarine waters; permanent water of estuaries and estuarine systems of deltas
  • G - Intertidal mud, sand or salt flats
  • H - Intertidal marshes; includes salt marshes, salt meadows, saltings, raised salt marshes; includes tidal brackish and freshwater marshes

Key features of the site:

The Pitt Water-Orielton Lagoon Ramsar site is located on the south-east coast of Tasmania, approximately 20 kilometres east of the city of Hobart, between the towns of Cambridge and Sorell. Pitt Water is an almost land-locked body of tidal salt water with a narrow entrance to Frederick Henry Bay. Orielton Lagoon is separated from Pitt Water by a causeway constructed in 1868. The whole area is protected from the open sea by a large mid-bay spit and associated dunefield.

Most of the Ramsar site is open water fringed by saltmarsh communities, mudflats and rocky shores. The large areas of tidal mud and sand flats leaves extensive areas exposed as suitable feeding areas for wading birds.

The vegetation communities present include succulent saline herbland, saline sedgeland/rushland and coastal grassland. The site provides breeding habitat for a number of beach-nesting shorebirds including the Caspian Tern and Red-capped Plover. Migratory birds that utilise the Ramsar wetland include the Eastern Curlew, Bar-tailed Godwit, Common Greenshank, Curlew Sandpiper, Double-banded Plover and Red-necked Stint. Threatened species listed in Tasmania recorded at the site include the Great-crested Grebe, Fairy Tern and Little Tern.

Pitt Water-Orielton Lagoon was traditionally used by Indigenous people of the area and the Ramsar site contains some middens and other evidence of Indigenous occupation. Currently the area has a diversity of landuses including pastureland grazing, forestry, irrigated cropland, residential development, shellfish aquaculture, recreation and nature conservation.

Justification of the listing criteria:

The Pitt Water-Orielton Lagoon Ramsar site meets five of the nine criteria:

Criterion 2: The Pitt Water-Orielton Lagoon Ramsar site supports the Tasmanian endemic viviparous sea star Parvulastra vivipara which is listed as ‘vulnerable’ under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999 and the Tasmanian Threatened Species Protection Act 1995. .

Criterion 3: Pitt Water-Orielton Lagoon is an important area for migratory birds, saltmarshes and fish. Twenty-seven bird species that occur in and around Pitt Water-Orielton Lagoon are listed under international migratory bird conservation agreements.

The area contains an array of plant species which are considered to be rare in Tasmania. This includes six plant species listed as threatened in Tasmania, such as Lemon Beauty-head, Slender Water-mat, Fennel Pondweed and Sea Lavender. Saltmarshes also form a critical component of the Pitt Water – Orielton Lagoon Ramsar site, not only for their biological values but also for the role they play in sedimentary processes and hydrology of the shoreline

The rocky shores of Pitt Water are also critical habitat for the endemic and threatened sea star, Parvulastra vivipara. This sea star is of particular importance as it is one of only four sea star species worldwide known to bear live young instead of eggs. About 40 species of fish have been recorded in the Ramsar site

Criterion 4: As an extensive and diverse wetland, the site is considered to be a significant refuge in times of drought. It is the most southern major summer feeding ground for waterbirds in Australia, and a number of resident and a few migratory waterbirds breed within the site. The site also supports the threatened live-bearing sea star, Parvulastra vivipara which breed throughout the year.

Criterion 8: The southern part of the site is a protected shark nursery area, and upper Pitt Water is a significant nursery area for the School Shark, with the highest concentration of juvenile sharks in south-east Australia. Pitt Water is also a nursery area for the Gummy Shark.

Criterion 9: The Tasmanian endemic viviparous sea star Parvulastra vivipara is limited to about 13 sites, of which Pitt Water-Orielton Lagoon hosts the greatest numbers, about 45% of the total population

Please see the More Information page for additional information on this Ramsar site and access to the Ramsar Information sheets and other associated site documents.