1.1.7.3 Aquatic species and communities

1.1.7.3.1 Classification of aquatic habitats

Seven estuaries and 15 wetlands are nationally protected as listed in DIWA (Department of the Environment, 2014; Table 23). Of these, the Gippsland Lakes (including Lake King wetlands, Lake Victoria wetlands and Lake Wellington wetlands) and Corner Inlet are internationally listed on the Ramsar List of Wetlands of International Importance.

Some 8349 wetlands occupying 152,631 ha (Table 24) have been identified and mapped within the Gippsland Basin bioregion by the DELWP. A total of 426 wetlands are classified as estuarine (47% of wetland area), 5344 as lacustrine (6%), three as marine (40%), and 2068 as palustrine (7%). A further 508 are classified as lacustrine or palustrine (<1%). Further wetland descriptions are given in Table 24.

Close to 9000 km of rivers, creeks, streams flow through the Gippsland Basin bioregion of which 142 rivers are ephemeral and 32 are perennial. Only 18 rivers in the Gippsland Basin bioregion are listed under the regional Heritage Rivers Act 1992, including the Bemm, Snowy and Thomson perennial rivers, as rivers requiring protection to reserve valuable features (referred to as Heritage rivers). Detailed stream condition in East and West Gippsland Catchment Management Authorities, determined between 2004 and 2010 (DEPI, 2010), provides baseline stream condition information. In general, the lower reaches on the Mitchell and Snowy rivers are in poor health in East Gippsland while the majority of rivers in West Gippsland are in moderate to poor health across the Gippsland Plains. The Latrobe River, which flows to Lake Wellington, is classed as poor and very poor along its reaches across the plains (DEPI, 2010).

Table 23 Nationally important wetlands in the Gippsland Basin bioregion listed in A Directory of Important Wetlands in Australia (Department of the Environment, 2014c)

Data: Department of the Environment, (Dataset 6)

^a-Gippsland Lakes estuary

Table 24 Area of wetlands in the Gippsland Basin bioregion under four classes, incorporating wetland description

Data: Department of Environment and Primary Industries (Dataset 7)

1.1.7.3.2 Ramsar wetlands

There are two Ramsar-listed wetland complexes within the Gippsland Basin bioregion:

These wetlands provide important habitat to migratory birds, with 43 listed as threatened in the EPBC Act migratory species for the Gippsland Lakes and 17 for Corner Inlet (Table 25).

The Gippsland Lakes

The Gippsland Lakes is made up of a group of coastal lagoons and marshes that are separated from the sea by sand dunes and Ninety Mile Beach. Within the Gippsland Lakes, 11 Ramsar wetland types occur and include:

These provide a wide range of habitats including submerged and emergent macrophytes (e.g. seagrass beds), plankton-dominated open water and fringing wetland (fresh, brackish and hypersaline) vegetation that support nationally and internationally threatened wetland species, waterbird breeding, and fish spawning.

The Gippsland Lakes support 86 waterbird species (BMT WBM, 2011b), many of which are listed under the Japan-Australia Migratory Birds Agreement (JAMBA) 1986, China-Australia Migratory Birds Agreement (CAMBA) 1974 and/or the Republic of Korea-Australia Migratory Birds Agreement (ROKAMBA) 2007 and are EPBC Act listed as threatened Migratory species (Table 25). The Gippsland Lakes were reported to regularly support 40,000 to 50,000 waterbirds during the 1990s (DSE, 2003). More recent data suggest that they regularly support significantly lower populations – approximately 20,000 waterbirds (BMT WBM, 2011b). Waterbirds utilising freshwater habitats have experienced the most decline. Deep freshwater marshes, salt marsh and shallow permanent saline wetland habitats sustained the highest usage rates by waterbirds in the Gippsland Lakes (Corrick and Norman, 1980).

The Gippsland Lakes Ramsar site provides habitat for two nationally threatened frog species (Table 22), which depend on the presence of permanent, still-to-low flowing freshwater bodies, with aquatic and fringing vegetation. The persistence of these frog populations is mostly dependent on the maintenance of:

Three nationally threatened wetland-associated flora species occur within the Gippsland Lakes Ramsar site (Table 22). Water regimes that support these species are unknown (BMT WBM, 2011b), however it is likely at least two of the species are water dependent (Table 22).

Many fish species use the marine subtidal aquatic beds in the Gippsland Lakes as a nursery area (BMT WBM, 2011b). There is little known about aquatic invertebrates in the Gippsland Lakes, but they are assumed to perform a number of services such as the basis of food chains, nutrient cycling, breakdown of detritus, habitat for other species, population regulation of other organisms, and maintenance of water quality (BMT WBM, 2011b).

Ecological processes (BMT WBM, 2011b) considered having the strongest influence on the ecological character of the Gippsland Lakes include:

These processes control the variable salinity regime across the Gippsland Lakes and have shaped the ecological patterns and processes. Threats include altered hydrology, invasive species and water pollution (nutrients and sediments).

Corner Inlet

Corner Inlet is a marine embayment that contains tidal channels, sandy barrier islands and drainages from freshwater rivers, creeks and wetlands.

The following Victorian Ministry for Conservation 1980 wetland types occur at Corner Inlet (BMT WBM, 2011a):

In addition, the following Ramsar wetland types also occur at Corner Inlet:

Unconfirmed Ramsar wetland types that may also occur at Corner Inlet include:

Corner Inlet provides a diverse range of marine, estuarine and freshwater wetland habitats (including the largest seagrass beds (Posidonia australis) in Victoria) that support nationally threatened species, bird breeding and fish spawning. Corner Inlet provides habitat for one Critically Endangered and one Endangered bird (Table 22) and 43 Migratory species listed under the JAMBA, CAMBA and/or ROKAMBA (Table 25). The tidal flats and fringing wetland habitats are used by shorebirds for roosting, breeding and feeding. Corner Inlet regularly supports more than 20,000 shorebirds and, at times, more than 40,000. It is also used as a refuge by large aggregations of post-breeding waterbirds when environmental conditions are unfavourable (BMT WBM, 2011a).

Tidal flats, along with the deeper waters, provide habitat for benthic invertebrates. Three of more than 390 marine invertebrates recorded at Corner Inlet appear to be unique to the site and were recommended for listing under the FFG Act as Vulnerable species (BMT WBM, 2011a).

Corner Inlet provides habitat for one nationally threatened frog species (Table 22) which requires permanent or seasonal freshwater flooding and still or slow moving water for breeding to occur and aquatic vegetation for feeding and shelter (EPBC, 2009).

The marine, estuarine and freshwater habitats within Corner Inlet are used by a wide range of fish species (some of commercial interest) for a variety of purposes (including nursery areas, spawning, feeding, shelter, migratory pathway). Three nationally threatened (EPBC Act) Marine species have also been recorded within the Corner Inlet Ramsar site (BMT WBM, 2011a; Table 22).

Corner Inlet also provides food, nesting and nursery areas for many other animals including a variety of reptiles, amphibians, mammals and birds. Approximately 390 species of native flora and 160 species of native terrestrial fauna have been reported at Corner Inlet, as well as a wide variety of marine mammals. Two nationallyVulnerable orchid species occur within the Corner Inlet but these are not considered water dependent (BMT WBM, 2011a; Table 22).

The key threats to the character of Corner Inlet include altered hydrology, climate change, oil spill or marine incident, water pollution (sediment and nutrients), habitat loss due to future development (infrastructure, urban, natural resource), acid sulfate soils, invasive species (flora and fauna) and recreational activities (Department of Sustainability, Environment, Water, Population and Communities, 2011).

Table 25 Migratory shorebirds within Corner Inlet Ramsar site that are listed as EPBC Act Migratory species. Many species are also listed under bilateral agreements as indicated with a box

^a =migratory birds also present in the Gippsland Lakes Ramsar site.

Data: BMT WBM (2011a), BMT WBM (2011b)

Migratory shorebirds in Gippsland Lakes are identified with an asterisk. All species are EPBC Act Migratory listed species

1.1.7.3.3 Marine national parks

Three marine national parks are designated beyond the coastal extent of the bioregion boundary and include Ninety Mile Beach Marine National Park, Wilsons Promontory Marine National Park and Corner Inlet Marine National Park. The condition of marine areas is highly dependent on terrestrial processes and quality of water delivered to the ocean.