Pink Lake

	Pink Lake at a glance
	Location:		6 kilometres west of Esperance
	Area:		1061 hectares
Index: Physical Features Hydrological features Ecological features Significance Land tenure & Land Use Disturbances or threats Conservation measures taken Management authority and jurisdiction

      

Landform: Macroscale ovoid lake with salt extraction ponds constructed at the north-east end.

Geological setting: Situated in the Albany-Fraser Orogen, surrounded by low sand dunes and separated from the Southern Ocean by a high, vegetated, calcareous coastal range. The lake bed of silt and clay alluvium overlies siltstones, claystones and sandstones.

Climate: Median and mean annual rainfall at Esperance are 580 mm and 615 mm respectively, mostly falling in May-August; annual evaporation is about 1840 mm.

Water Supply: Surface inflow off disturbed land and roads, and groundwater.

Inundation: Near-permanent, infrequently drying out in autumn; water area is much reduced in summer-autumn.

Water depth: Less than one metre deep in spring.

Water salinity: Generally above 100 ppt (e.g. 174 ppt, August 1979; 115 ppt in winter 1991; 320 ppt in summer 1991).

Water colour: None (the pink colour is from algae - see below).

Plant structural formations: No vegetation in the zone of usual inundation, low shrubland (samphire) occurs near the wetland margins; surrounding areas support open-scrub or are cleared.

A good example of a coastal brine lake with a strong pink colour.

Notable flora:

Threatened Species: None.

Composition: Fringing samphires include Halosarcia sp. The alga Dunaliella salina is abundant because it is favoured by the high salinity and low nutrient levels; it has a pink (beta-carotene) pigment. The alga Microcoleus vaginatus is the dominant component of benthic algal mats in the lake.

Notable fauna (Waterbirds):

Threatened Species: Hooded Plover Charadrius rubricollis sometimes occurs on dry lake bed.

Composition: At least ten species occur, including Red-necked Avocet Recurvirostra novaehollandiae and Pacific Gull Larus pacifica.

Migration Stop-over: Red-necked Stint Calidris ruficollis, and probably also other migrant shorebirds, occur at the lake margins.

Numbers: No systematic surveys made.

Notable fauna (Other taxa):

Threatened Species: None.

Composition: Only one invertebrate, the protozoan Cladostricha sp., was found at this lake in a study that recorded 16 taxa at nearby (less saline) Lake Warden.

Social and cultural values:

Cultural value: The lake's name has been given to roads, buildings and `suburbs' in the vicinity. The lake is often pointed out to passengers on aircraft flying between Perth and the eastern States.

Research: Some research conducted on the potential for commercial production of beta-carotene and on the salt balance of the lake.

Economic: The small-scale commercial saltfield produced more than 10,000 t of salt in the early 1980s.

Aesthetics: The lake is an important visual feature of Esperance and is regarded as a tourist attraction. Elevated views may be enjoyed from a scenic coastal drive which also passes close to the lake shore.

Land tenure & Land Use

Land tenure:

On site: Partly in Nature Reserve 24511 and Government Reserve 22422, some is leasehold.

Surrounding area: No information.

Current land use :

On site: Commercial production of salt.

Surrounding area: Nature conservation, water supply, pasture grazing, rural smallholdings, urban residential area and high human population. A buffer of native vegetation more than 1 km wide occurs in south-west parts of the site, most other parts have much narrower buffers.

Disturbances or threats

Current: Disturbance of dry lake margins by vehicles.

Potential: Eutrophication (inflow of nutrients from farms), ongoing groundwater extraction, ongoing salt production and proposed beta-carotene production each could alter the conditions that favour prolific growth of the pink algae - this possibility is being monitored.

Conservation measures taken

Recommendations have been made on the levels of salt harvesting the lake can sustain and yet retain its pink colour.

Management authority and jurisdiction

The nature reserve is managed by WADCALM for NPNCA. District office located at Esperance. The other reserve is managed by the Shire of Esperance.

South Coast Regional Land and Water Care Strategy: The Esperance-Sandplain Sub-region. Prepared by: the South Coast Regional Assessment Panel and the South Coast Regional Initiative Planning Team, February 1997.