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Euastacus valentulus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA ARTHROPODA MALACOSTRACA DECAPODA PARASTACIDAE

Scientific Name: Euastacus valentulus
Species Authority: Riek, 1951

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor(s): Coughran, J. & Furse, J.
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.
Justification:

Although there are several potential threats to the species, it has a relatively broad geographical range without any apparent lowland barriers. Overall the species appears to be stable, with broad habitat tolerances. In the absence of any data to confirm that the species is in widespread decline, it can be considered Least Concern.

Geographic Range [top]

Range Description:

This species is endemic to Australia. It ranges from Currumbin Creek, South-East Queensland, 90 km South to the Ballina area of New South Wales and West to Woodenbong, a distance of approximately 100 km (J. Coughran and J.M Furse pers. comm. 2009). The range is drained by the Tweed, Richmond and Clarence Rivers, and small coastal streams (Morgan 1997). This species is found in an altitudinal range from close to sea level, up to 600 m above sea level. This species has a distribution of approximately 20,000  km2 (J. Coughran and J.M Furse pers. comm. 2009).

Countries:
Native:
Australia (New South Wales, Queensland)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population:

This species may be locally abundant within its range (J. Coughran and J.M Furse pers. comm. 2009).

Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: This species occurs within rivers and streams from close to sea level to 600 m above sea level in rainforest, wet sclerophyll forest and in cleared pasture (Morgan 1997).




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 susceptible to climate change, particularly with regard to altered hydrological regimes and severe weather events (Chiew and McMahon 2002, Howden 2003, Hughes 2003, Pittock 2003, Hennessy 2006, Westoby and Burgman 2006, IPCC 2007). A large scale flood event in the Numinbah Valley (Queensland) in January 2008 resulted in a mass crayfish kill of this species, several hundred small and medium sized (approximately 40mm orbital carapace length (OCL)) crayfish had apparently been overwhelmed by the large volume of storm induced flow and had been buried in the alluvium, up to 50 m away from the stream channel (Furse in prep., J.Coughran and J.M Furse pers. comm. 2009). More recently a similar event (involving greater than 10000 crayfish) has been documented in the United Kingdom (Lewis and Morris 2008). If climate change increases the frequency of large scale flood events, mass crayfish strandings and kills may become more common (J.Coughran and J.M Furse pers. comm. 2009).

This species is susceptible to over exploitation through fishing pressure, and there is recent data to suggest the size and abundance of the species appears to be declining at key recreational fishing spots in New South Wales (Coughran et al. in prep., J.Coughran and J.M Furse pers. comm. 2009). However, the species' overall distribution includes many areas that are inaccessible to recreational fishers. Recreational fishing (in particular the taking of large adults) has the capacity to lead to serious and far reaching impacts on population structure (i.e. the stunted population phenomenon (Huner and Lindqvist 1985, Tulonen et al. 2008), including impairment of reproductive success in females (Tulonen et al. 2008).

Other threats to this species include the potential large scale threat from Cane Toads (Bufo marinus) (DEH 2004b) although there are no specific data on impacts for this species (J. Coughran and J.M. Furse pers. comm. 2009). Exotic species (cats, foxes, pigs, goats) that have generally been found to impact on crayfish (Green and Osborne 1981, Horwitz 1990, Merrick 1995, Eyre et al. 1997, ACT Government 2007, O'Brien 2007) which also occur in this species' range (DEH 2004a,c,d,e) and these exotic species could have localized impacts on this species.

Conservation Actions [top]

Conservation Actions:

There are no species-specific conservation measures in place for this species. However, its distribution coincides with several national parks (J.Coughran and J.M Furse pers. comm. 2009). In New South Wales, a minimum recreational size limit of 90 mm orbital carapace lenght (OCL ) is in place for any spiny crayfish (NSW DPI 2007). Only four (including this species) of the more than 35 Euastacus species in New South Wales attain that size, so the regulation may in fact increase fishing pressure on these species (J.Coughran and J.M Furse pers. comm. 2009). All 'spiny crayfish' (Euastacus) species in Queensland are officially no take species under the Fisheries Act 1994 and must be released if captured (DPIF 2007). There is no information available on the levels of compliance, although evidence of illegal poaching is frequently observed across its range (J.Coughran and J.M Furse pers. comm. 2009). Further research is needed to determine the abundance of this species, and to what extent it is being impacted upon by threat processes within its range.


Citation: Coughran, J. & Furse, J. 2010. Euastacus valentulus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 25 October 2014.
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