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Euastacus sulcatus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA ARTHROPODA MALACOSTRACA DECAPODA PARASTACIDAE

Scientific Name: Euastacus sulcatus
Species Authority: Riek, 1951

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii) ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor(s): Furse, J. & Coughran, 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:

Euastacus salcatus has been assessed as Vulnerable under criterion B1ab(iii). This species has a severely fragmented distribution, and an extent of occurrence of 8,000 km2. There has been a continuing decline in the quality of habitat due to the destructive nature of a number of exotic species in the area, some of which also predate upon this species. There is also destruction of suitable rainforest habitat in parts of its range. This species also faces the consequences of global temperature rise. As a restricted range species, dependent on cool, clear headwater streams, a slight increase in temperature could rapidly extirpate this species. This species has also been subject to illegal fishing pressure, which is likely to drive significant declines in the population owing to its slow growth rate, coupled with fragmented distribution. Research should be initiated to include population assessment and monitoring, biological and life history information, habitat requirements, and resilience to effects of exotic species.

Geographic Range [top]

Range Description: This species is endemic to Australia. It is a high altitude species that ranges from Mount Tamborine to the Lamington Plateau, southern Queensland, and West along the McPherson Range in both Queensland and New South Wales. Other populations have been recorded on Mount Warning and the Tweed, Richmond and Yabbra ranges (Coughran 2006). The range is drained by Nerang, Albert, Logan, Brisbane, Condamine, Clarence, Richmond, Tweed Rivers and Currumbin and Tallebudgera creeks (Morgan 1988, Furse and Coughran in prep., Coughran 2006). This species has an estimated extent of occurrence of 8,000 km², although it is restricted to high montane areas above 300 m, in rainforest and occasionally wet sclerophyll forest (J. Coughran and J.M. Furse pers. comm. 2009). Importantly, there are clearly several fragmented populations within the species' distribution that are geographically isolated due to mountain ridges and/or intervening lowlands that constitute a barrier to dispersal (Morgan 1997, Ponniah and Hughes 2006). Several of these populations (e.g. Mt Warning, Mt Tamborine, Springbrook, Nightcap, Koreelah) are restricted to areas less than 100 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. 2008). The activity of the species is highly seasonal, with adults rarely encountered in the cooler months (April to September), for unknown reasons (Furse and Coughran in prep., J. Coughran and J.M. Furse pers. comm. 2009). The different populations are well noted for displaying locality-specific colouration differences, and also in developments of spination and setation.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology:

This species occurs in streams at altitudes above 300 m above sea level, in rainforest and wet sclerophyll forest (Morgan 1997). It is restricted to streams where suitable riparian vegetation remains intact (Furse and Wild 2002). As is the case for most Euastacus species, this species prefers well oxygenated, heavily shaded sites (J. Coughran and J.M Furse pers. comm. 2009). Individuals inhabit rock crevices and burrow under rocks and logs or in stream banks (Furse et al. 2004). Although this species occurs in a number of streams, these are headwaters of various different drainages, and therefore the species distribution is clearly fragmented (J. Coughran and J.M Furse pers. comm. 2009). The species is extremely slow growing and takes at least 4-5 years for females to reach sexual maturity (Furse and Wild 2004, Wild and Furse 2004, Coughran 2006, Furse and Coughran in prep.).

Systems: Freshwater

Threats [top]

Major Threat(s): Although this species occurs within national parks across a relatively wide area, it also occurs extensively on private land. The highly fragmented populations are susceptible to localized impacts, including bush fires, forest management practices, habitat destruction and over exploitation by collectors (J. Coughran and J.M. Furse pers. comm. 2009). Land use management on private properties situated at the top of the catchments and within national park properties (e.g. on the Springbrook Plateau, Tamborine and Lamington), could lead to declines in habitat/water quality due to pesticides, pathogens, pollution, siltation and eutrophication (J. Coughran and J.M. Furse pers. comm. 2009). Given the isolated nature of these areas, these factors could lead to significant population declines, or extinction of distinct populations (J. Coughran and J.M. Furse pers. comm. 2009). 

This species is a relatively large species that would be appealing to recreational fishers, and its striking colouration forms renders it a sought-after species for aquarium displays. Illegal harvesting is known to occur at several sites, even within national parks, and over-exploitation is a potential threat given the slow growth and fragmented distribution of the species. 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).

Furthermore, climate change, presents a potential threat to this species including; increasing temperature, alterations to hydrological regimes, severe weather events, loss of suitable rainforest habitat and increased potential for bushfires (Chiew and McMahon 2002, Howden 2003, Hughes 2003, Pittock 2003, Hennessy 2006, Westoby and Burgman 2006, IPCC 2007).

Additionally there is a potentially large scale threat from Cane Toads (Bufo marinus) (DEH 2004b) although there are no specific data on impacts for this species. Other exotic species (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 these exotic species could have localized impacts on this species (J. Coughran and J.M. Furse pers. comm. 2009). Due to the narrow thermal tolerance of this species, and its restricted range (restricted to cool, headwater streams in forested catchments), global temperature increase has resulted in range contraction. This species is further compromised by the presence of exotic species (feral pigs, goats, foxes, Cane Toads and cats) which are known to predate on crayfish and degrade riparian habitat; while the precise effects of these threats on this species are not yet well understood, they are believed to be significantly impacting the long term viability of the population (J. Furse and J. Coughran pers. comm. 2010).

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. Research should be extended on aspects such as population assessment and monitoring, investigations into thermal tolerance and resilience to exotic species. A detailed study into the population genetics of this species is urgently required.

 

In New South Wales, a minimum recreational size limit of 90mm OCL is in place for any spiny crayfish (NSW DPI 2007). Only four of the >35 Euastacus species in NSW attain that size (E. sulcatus, E. spinifer, E. valentulus, E. armatus), so the regulation may in fact increase fishing pressure on these four species. 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.

Citation: Furse, J. & Coughran, J. 2010. Euastacus sulcatus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 22 December 2014.
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