Euastacus wiowuru


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Euastacus wiowuru
Species Authority: Morgan, 1986

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor/s: Coughran, J., Furse, J. & Lawler, S.
Reviewer/s: Collen, B. & Richman, N.
Contributor/s: Livingston, F., Livingston, F., Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G.
Eastacus wiowuru has been assessed as Near Threatened . This species has an estimated extent of occurrence (EOO) of 7,900 km2 and, although there is no population data available and no obvious fragmentation of range, there is a perceived decline in distribution from the species' historical range. Targeted studies in areas from where it was previously known, have not produced successive sightings. Therefore this species does not completely satisfy the criteria for listing as Vulnerable under criteria B. Monitoring of the range of this species is suggested to determine at what rate it is being lost across its range and if it is in fact becoming fragmented.

Geographic Range [top]

Range Description: This species is endemic to Australia. It inhabits streams in central Victoria from the Dandenong Mountains, east of Melbourne, north-east to Eildon and Dandongadale, east to Woods Point and Erica and southeast to the region of Thorpdale. Included in this range are tributaries of the Yarra, Murray and Latrobe Rivers and some small coastal streams. This species usually occurs at altitudes greater than 200 m above sea level, and specimens have been collected at altitudes greater than 1,400 m above sea level, habitat that is snow covered in winter (Morgan 1986). This species has an extent of occurrence (EOO) of approximately 7,901 km2. Recent searches within many of these areas have not been successful, although a population has been found on top of Mount Buffalo, which is a national park (S. Lawler pers. comm. 2008).
Australia (Victoria)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: There is no population information available for this species (J.Coughran and J.M. Furse pers. comm. 2009). There is some evidence that this species is being replaced by Euastacus armatus in at least part of its range (the Buffalo River). Indeed, searches in the area where this species was found by Horwitz (1980) have only found E. armatus (S. Lawler pers. comm. 2009).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology:

Much of the range of this species has been cleared, and this species is most commonly found where vegetation is intact (Morgan 1986). Natural vegetation in the region includes mountain ash and tree ferns, with some dry sclerophyll forest at lower altitudes (Morgan 1986). This species is restricted to cool headwaters of streams and rivers (S. Lawler pers. comm. 2008). 

Systems: Freshwater

Threats [top]

Major Threat(s): This species is susceptible to threats such as climate change, over-exploitation and the introduction of exotic species. This species is particularly susceptible to altered hydrological regimes and severe weather events (J. Coughran and J.M. Furse pers. comm. 2009). Climate change modelling predicts that southeastern mainland Australia will experience a warmer and drier climate, leading to decreased run-off and soil moisture (Chiew and McMahon 2002, Howden 2003). This alteration of hydrological regimes is likely to impact environmental flows, particularly in areas of increasing demand for domestic, industrial and agricultural water supplies (Hennessy 2006).

Although technically protected by recreational fishing regulations, this species attains a relatively large size and may be susceptible to over exploitation through fishing pressure (J. Coughran and J.M. Furse pers. comm. 2009). Morgan (1983) observed evidence of heavy fishing activities in the Latrobe River system, and noted that populations of Euastacus could be heavily impacted in a single weekend of heavy fishing pressure. Recreational fishing (in particular the taking of large adults) has the capacity to lead to serious and far reaching impacts on population structure, such as the stunted population phenomenon (Huner and Lindqvist 1985, Tulonen et al. 2008) and impairment of reproductive success in females (Tulonen et al. 2008).

There is also the potentially large scale threats from exotic fishes such as Brown Trout or Redfin Perch, which are prevalent throughout the region (Davies and McDowall 1996, Rowe et al. 2008). Other exotic species, such as cats, foxes, pigs, goats, that have generally been found to impact on crayfish (Green and Osbourne 1981, Horwitz 1990, Merrick 1995, Eyre et al. 1997, ACT Government 2007, O'Brien 2007) also occur in this species' range (DEH 2004a,c,d,e) and could have localized impacts on this species. Invasion of habitat by other crayfish species has also been noted as a threat, along with pollution and habitat alteration (S. Lawler pers. comm. 2008).

Conservation Actions [top]

Conservation Actions:

There are no species-specific conservation measures in place for this species, although this species has been found within the Alpine National Park and the Mount Buffalo National Park in recent surveys (S. Lawler pers. comm. 2008). Further research should include population assessment and monitoring, biological and life history information, habitat requirements, investigations into thermal tolerance and resilience to exotic species (J. Coughran and J.M. Furse pers. comm. 2009). Furthermore, in Victoria, a minimum recreational fishing size of 90 mm orbital carapace length (OCL) applies to spiny crayfish (DPI 2007). This species does not attain that size, so is indirectly protected by this restriction (J. Coughhran and J.M Furse pers. comm. 2009).

Citation: Coughran, J., Furse, J. & Lawler, S. 2010. Euastacus wiowuru. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <>. Downloaded on 18 April 2014.
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