Hunter Estuary

What is an Estuary?

Estuaries are semi-enclosed waterbodies with open (or intermittently open) connections with the ocean ⁽¹⁾. They are the tidal portion of a waterbody, and the area where freshwater draining from the catchment mixes with ocean waters ⁽²⁾.
 

The Hunter Estuary  

The Hunter Estuary is the tidal portion of the Hunter River. The estuary extends up to the tidal limit of the Hunter River at Oakhampton (65km from the ocean), the Paterson River at Gostwyck (75km from the ocean), and the Williams River at the Seaham Weir (46km from the ocean).
 
The Hunter Estuary is one of the most complex estuaries in NSW to manage because it is subject to a range of pressures from mining, agriculture, industry and urbanisation, but is also home to internationally important shorebirds and wetlands.
 
A number of significant conservation sites are found within the Hunter Estuary, including the Hunter Wetlands National Park, Kooragang Wetland Rehabilitation Project and Hunter Wetlands Centre.
 

The Hunter Estuary is so important that it is internationally recognised. The Hunter Estuary wetlands (including Kooragang Wetlands, Stockton Sandspit and the Hunter Wetlands Centre) are one of only 12 wetlands protected in NSW by an international agreement called the Ramsar convention. The wetlands are protected because they are home to a number of threatened and internationally important species.
 

To promote the international importance of the Hunter Estuary Ramsar wetlands, Newcastle and Port Stephens councils have signed a Sister Wetland Agreement, called the Kushiro Agreement, with six Japanese councils.  A migratory shorebird called the Latham's Snipe (Gallinago hardwickii) is of particular interest to the two countries. The Latham's Snipe breeds in the Kushiro wetlands and migrates to the Hunter Estuary over the Australian summer to avoid the harsh Japanese winter.
 

Latham's Snipe (Gallinago hardwickii) (Source: NSW DPI)

Shorebirds are birds that are regularly found along our coastal and river shorelines. Shorebirds can be migratory (fly overseas) or non-migratory (stay in Australia). Migratory shorebirds can travel over 20,000km in a year. The Bar Tailed Godwit has been tracked flying non-stop for 11,700 kilometres over nine days ⁽³⁾.  
 

Bar Tailed Godwit (Limosa lapponica) (Source HBOC)
 
The Hunter Estuary is the most important estuary in NSW for shorebirds as it home to a large number, and great diversity, of shorebirds ⁽⁴⁾. Our estuary is one of only 20 sites in Australia that forms part of the East Asian-Australasian Flyway ⁽⁵⁾. The East Asian-Australasian flyway is a path that migratory shorebirds fly, which extends from Alaska and Russia, down to Australia and New Zealand ⁽⁶⁾. There are 23 countries within the flyway, and 54 species of migratory shorebirds use the flyway ⁽⁶⁾. The East Asian-Australasian flyway is one of nine flyways across the world that is used by migratory shorebirds ⁽⁶⁾.

The Hunter Bird Observers Club undertook a study in 2007 to identify the bird species that can be found in the Hunter Estuary.
 

 Pacific Golden Plover (Pluvialis fulva) (Source HBOC)
 
Unfortunately, since records commenced in the 1970s, there has been a significant decline in the numbers of shorebirds found in the Hunter Estuary ⁽⁴⁾. The decline in bird numbers is due to both local and international issues, with the leading cause of decline being habitat loss ⁽⁷⁾. In the Hunter Estuary, large areas of mudflats have been lost to land reclamation and the expansion of mangroves, which has considerably reduced the habitat available for shorebirds ⁽⁷⁾.

 
Grey-tailed Tattler (Tringa brevipes) (Source HBOC)

As migratory shorebirds rely on habitats in different countries to survive, they require international protection. Australia has signed three international agreements to help protect migratory shorebirds, including:
 

• Japan - Australia Migratory Bird Agreement (JAMBA)
• China - Australia Migratory Bird Agreement (CAMBA)
• Republic of Korea - Australia Migratory Bird Agreement (ROKAMBA).

In Australia, migratory shorebirds are protected by Federal legislation called the Environment Protection and Biodiversity Conservation Act 1999.
 
Council is working with the National Parks and Wildlife Service, Hunter Bird Observers Club, Kooragang Wetlands Rehabilitation Project, and others, to ensure the future of shorebirds in our estuary.
 

Green and Golden Bell Frog

The Green and Golden Bell Frog (Litoria aurea) is a type of Tree Frog which used to be very common ⁽⁸⁾. In fact, the Green and Golden Bell Frog was the first frog that Captain Cook's fleet saw in Australia ⁽⁸⁾. Unfortunately, the frog is now very rare and is protected at a state and federal level ⁽⁸⁾.
 
The frog is now limited to 43 isolated key populations in NSW ⁽⁸⁾. Two of these populations are found in the Hunter Estuary, at Kooragang Island and Hexham Swamp ⁽⁸⁾. The frog population in the Hunter Estuary is under threat from industrial development, increased saline inundation, disease (Chytrid fungus), predation by introduced pests, and poor water quality ⁽⁹⁾.
 
Further information about the Green and Golden Bell Frog can be found at the Office of Environment and Heritage website. 
 

Green and Golden Bell Frog (Litoria aurea) (Source: Jo Erskine NPWS)
 

Estuarine Shore Crabs

Council has developed a guide to the types of crabs that can be found along the shore of our estuary.
 

Key vegetation types found within the Hunter Estuary include:
 

• Mangroves which are a group of trees and shrubs found in the intertidal zone between the land and river ⁽¹⁰⁾
• Saltmarsh which is a community of grasses, herbs and shrubs found in the intertidal zone ⁽¹¹⁾

• Seagrasses which are marine plants that look like grasses ⁽¹²⁾.

Two species of mangrove can be found in the Hunter Estuary, including the River Mangrove (Aegiceras corniculatum) and the Grey Mangrove (Avicennia marina) ⁽¹⁰⁾. River Mangroves can be identified by their brown bark and rounded tips of the leaves ⁽¹⁰⁾. Grey Mangroves have grey bark, a pointed tip on their leaves and above ground roots called pneumataphores ⁽¹⁰⁾.

 
Grey Mangrove (Avicennia marina) pneumataphores
 
The Hunter Estuary has the largest area of mangroves in NSW, covering 19.217km^{2 (13)}.  Mangroves provide valuable food and habitat for a range of animals, especially fish.
 
Saltmarsh is a threatened species that is protected at both the state and federal level. Common saltmarsh species found in the Hunter Estuary include Seablite (Suaeda australis), Glasswort (Sarcocornia quinqueflora), Saltwater Couch (Sporobolus virginicus) and Sea Rush (Juncus kraussii).
 
The Hunter Estuary has the fourth largest area of saltmarsh in NSW, covering 5.204km^{2 (13)}. Saltmarsh provides valuable food and habitat for a range of animals, especially birds (including migratory shorebirds).
 
Seagrasses are different to seaweed ⁽¹²⁾. Seagrasses are land plants that have moved into the marine environment ⁽¹²⁾. Unlike seaweed, seagrasses flower and can absorb nutrients from the sediments.  Six seagrass species can be found in NSW, including Strapweed (Posidonia australis) and Paddleweed (Halophila spp.) ⁽¹²⁾.
 
The Hunter Estuary does not have any seagrass ⁽¹⁴⁾. Small areas of Sea Tassel (Ruppia spp.) have been found in the estuary, but Sea Tassel is not considered a true seagrass because it can live in freshwater and is pollinated above the water surface ⁽¹²⁾. Seagrass has not been seen in the Hunter River for the past 45 years ⁽¹⁴⁾. All other rivers similar to the Hunter River in NSW have seagrass, so it is thought that the Hunter River would have historically had seagrass ⁽¹⁴⁾. The reasons for the absence of seagrass in the Hunter River are not well understood, however it is thought that high turbidity and poor water quality may be contributing to the lack of seagrass.
 
Another important type of estuarine vegetation found in Newcastle is Swamp Oak (Casuarina glauca) forest. Swamp Oak forest is a threatened species which is protected by state legislation. Further information about this threatened species can be found at the Office of Environment and Heritage website.
  
Revegetation Works
 
Council, Landcare, and others are undertaking ongoing revegetation works around the estuary. The goals of Council's ongoing revegetation works are to:
 

• Protect and enhance shorebird habitat
• Protect and enhance native estuarine habitat values, and threatened vegetation species
• Minimise the impacts of weeds and pests.

Some examples of the works Council has undertaken are shown below.

• Pirate Point 2014
• Pirate Point 2015
• Stockton Ballast Ground 2013
• Stockton Ballast Ground 2015

A number of significant wetland conservation projects are being undertaken by other stakeholders within the Hunter Estuary including the Hexham Swamp Rehabilitation Project, Kooragang Wetlands Rehabilitation Project and Tomago Wetlands Restoration Project.

 
To help protect our estuarine plants and animals, please remember to:
 

• look at estuary creatures (birds, frogs, crabs), but don’t touch
• avoid disturbing the birds
• avoid walking through mangroves and saltmarsh where possible
• take home any discarded fishing tackle and litter.

Council has prepared a number of documents to identify the issues impacting on the estuary, and the management actions that should be undertaken to address the issues. Council undertakes priority works listed in these documents on an ongoing basis.

The Hunter Estuary Processes Study provides background information about the estuary (including flora/fauna, water quality, and bank stability) and identifies the key issues impacting on the estuary.
 
The Hunter Estuary Management Study outlines potential management actions for addressing the key issues impacting on the estuary. The Study was developed after extensive community consultation.
 
The Hunter Estuary Coastal Zone Management Plan contains the list of agreed management actions that Council, and others, aim to implement over time.
 
The Newcastle Coast and Estuary Vegetation Management Plan prioritises on ground works to protect estuarine plants and animals in Newcastle.
 
 

Council is working with a number of stakeholders to develop a water model for the Hunter Estuary. For further information about the model please see the World First Model page.
 

(1) NSW Government. (1992). Estuary Management Manual.
(2) Office of Environment and Heritage. (2015). Estuaries of NSW. 
(3) Department of Environment (2015). Limosa Lapponica - Bar Tailed Godwit. Retrieved from http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=844
(4) Herbert, C. (2007) Distribution, Abundance and Status of Birds in the Hunter Estuary.
(5) East Asian - Australasian Flyway Partnership. (2015). Flyway Site Network. 
(6) Bamford, M., Watkins, D., Bancroft, W., Tischler, G., & Wahl, J. (2008). Migratory Shorebirds of the East Asian - Australasian Flyway; Population Estimates and Internationally Important Sites. Canberra, Australia: Wetlands Inter­national - Oceania.
(7) Herbert, C. (2011). Shorebirds in the Hunter Estuary. 
(8) Department of Environment and Conservation NSW. (2005). Draft Recovery Plan for the Green and Golden Bell Frog (Litoria aurea). Hurstville, NSW: DEC NSW.
(9) Department of Environment and Climate Change (NSW). (2007). Draft Management Plan for the Green and Golden Bell Frog Key Population in the Lower Hunter. Sydney: Department of Environment and Climate Change (NSW).
(10) NSW Department of Primary Industries. (2008). Primefact 746, Mangroves. Retrieved from http://www.dpi.nsw.gov.au/fisheries/habitat/aquatic-habitats/estuarine#saltmarshimportance
(11) NSW Department of Primary Industries. (2023). Primefact 1256, Coastal Saltmarsh. 
(12) NSW Department of Primary Industries. (2007). Primefact 629, Seagrasses. 
(13) Creese, R.G., Glasby, T.M., West, G., and Gallen, C. (2009). Mapping the Habitats of NSW Estuaries. Industry & Investment NSW.
(14) Williams, R.J., Watford, F. A., & Balashov, V. (2000). Kooragang Wetland Rehabilitation Project: History of Changes to Estuarine Wetlands of the Lower Hunter River, NSW Fisheries Final Report Series, 22. Cronulla, NSW: NSW Fisheries.