Leschenault Inlet

Posted on Jan 9, 2015


Leschenault InletAquaticBiodiversity

Mangrove stand in the Leschenault Inlet (City of Bunbury).

Mangrove stand in the Leschenault Inlet (City of Bunbury).

Located in the City of Bunbury, the Leschenault Inlet was once connected to the Leschenault Estuary and was known as one waterbody, the Leschenault Inlet Estuary.  At that time, the Leschenault Inlet was the mouth of the Preston River. However, it is now a separate waterbody to the Estuary and is a semi-confined waterbody/lagoon that has significant recreational and social importance to the City of Bunbury. Water levels in the inlet are controlled by a set of flood gates.

Biological and physical values

Close up of the White Mangrove and its aerial roots (City of Bunbury).

Close up of the White Mangrove and its aerial roots (City of Bunbury).

White mangrove: Avicennia marina

  • Small remnant stands of White mangrove (Avicennia marina) are located within the Leschenault Inlet. This vegetation is a relic of an earlier tropical period and is the only population of mangroves south of Shark Bay (EPA 1993).  Given that it is the southern-most occurrence of this species, its presence in the estuary and inlet is scientifically important in the region and is a feature of national significance (Semeniuk & Withers 2000).

Bottlenose dolphins (Tursiop sp.)

  • Bottlenose dolphins are known to spend time in the Leschenault Estuary, inlet and lower section of the Collie and Preston rivers. The dolphin deaths in 2009 and more recently in December 2010 are a cause for concern. Maintaining the health of the estuary and its associated waterways is important to ensure a healthy dolphin population.
Calf Bottlenose Dolphin (Holly Raudino).

Bottlenose Dolphin calf (Holly Raudino).

Birds

  • The estuary and associated wetlands are of considerable importance for waterbirds, with more than 62 species recorded (CALM 1998).

Current Condition and Trends

Water quality and algae

  • Heavy metals, metalloids and nutrients found in sediment likely derived from urban drainage.
  • Nutrient accumulation in sediments above average levels; 2005 snapshot survey showing elevated levels (Semeniuk V and C
    2005a).
  • Occasional blooms of low toxicity with harmless diatoms Skeletonema, Chaetoceros and Asterionella sp. Presence of harmless
    dinoflagellates Katodinium, Oxyrrhis and Peridinium sp.
  • Prolific growth of macroalgae in the summer months.
  • High tidal exchange prevents the accumulation of elevated soluble nutrient concentrations within the water column.

Land use pressure

Leschenault Inlet surrounded by urban residential and industrial areas, including Bunbury Port (photo: J. Hugues-Dit-Ciles)

Leschenault Inlet surrounded by urban residential and industrial areas, including Bunbury Port (photo: J. Hugues-Dit-Ciles)

  • The inlet is surrounded by intensive urban land use, housing and industrial developments. Thus the inlet is highly modified with a high proportion being artificially retained; remnant foreshore is only associated with the mangrove population on the northern foreshore.

Leschenault Inlet and Climate Change

 

 

SWCC Strategic Priority

The Leschenault Inlet is identified within SWCC’s NRM Strategy as a second order priority asset under the Aquatic Biodiversity theme.

Projects

 

 

Source:

 

Header and thumbnail images supplied by City of Bunbury.

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