This Conservation Advice was approved by the Delegate of the Minister on 17 December 2013

Approved Conservation Advice for tenuimanus (hairy marron)

(s266B of the Environment Protection and Biodiversity Conservation Act 1999)

This Conservation Advice has been developed based on the best available information at the time this Conservation Advice was approved; this includes existing and draft plans, records or management prescriptions for this species.

Description

Cherax tenuimanus (hairy marron), family , also known as the Margaret River hairy marron or the Margaret River marron, is a large freshwater that can grow to more than 38 cm in total length. They are one of the largest freshwater crayfish species in the world with specimens having been recorded in excess of 2 kg (Nguyen et al., 2002). The hairy marron has tufts of hair-like setae on the carapace and other body surfaces (Molony et al., 2004, cited in TSSC, 2006). Adults are readily identified as being different to the smooth marron (C. cainii), but hybrids are more difficult to identify (Lawrence, cited in Molony, 2002).

Conservation Status

The hairy marron is listed as critically endangered under the name Cherax tenuimanus (Hairy Marron). This species is eligible for listing as critically endangered under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) as it has a very restricted geographic distribution with an estimated extent of occurrence of less than 50 km of the Margaret River. The species’ geographic distribution is precarious for its survival given the nature of ongoing threats (TSSC, 2006).

The species is also listed as critically endangered under the Wildlife Conservation Act 1950 (Western Australia) and critically endangered under the IUCN Red List of Threatened Species Version 2013.1 (Austin & Bunn, 2010).

Cultural Significance

Marron is derived from the Noongar word marran (Yallop et al., 2005), which may derive from a word for ‘food’ or ‘bread’ (ACWA, 2013). The closely related smooth marron was a major traditional food source (Whiteland, pers. comm., cited in Carter, 2013) and similar use of the hairy marron probably occurred.

Distribution and Habitat

The hairy marron occurs in the Margaret River in the south-west of Western Australia (TSSC, 2006). In 2004, the species was known from eleven sites along a 50 km stretch of the river, with the majority of populations known from pools within a 10 km2 area of the upper reaches (Bunn, 2004, cited in TSSC, 2006). The upper reaches of the river are within state forest (CALM, 2005). The species is absent from the heavily degraded middle reaches and extremely rare in the lower reaches (Moloney et al., 2004, cited in TSSC, 2006). It may now be extinct from the lower reaches (Department of Fisheries, 2011).

The total population size of the hairy marron is estimated to be 10 000 (TSSC, 2006). Long term surveys (1970–2000s) carried out by the Western Australian Department of Fisheries show a decline in the range and abundance of the hairy marron (Molony & Bird, 2002). The hairy marron prefers sandy areas, particularly where detritus (organic matter) accumulates, and requires in-stream structural diversity for protection (Molony et al., 2004, cited in TSSC, 2006).

Cherax tenuimanus (hairy marron) Approved Conservation Advice Page 1 of 5 This Conservation Advice was approved by the Delegate of the Minister on 17 December 2013

This species occurs within the Jarrah Forest IBRA Bioregion and the South West Region Natural Resource Management Region. The distribution of this species is not known to overlap with any EPBC Act-listed threatened ecological community.

Threats

The main identified threats to the hairy marron are competition from smooth marron and changes to the middle and lower reaches of the Margaret River. The smooth marron was introduced into the Margaret River in the early to mid-1980s (Molony, 2002) and rapidly displaced the hairy marron (Jenour et al., 2007). The smooth marron has higher rates of population growth (Bunn, 2004, cited in TSSC, 2006) due to higher fecundity and more aggressive behaviour (Molony et al., 2002). The river has been greatly modified with reduced water quality (Molony et al., 2004, cited in TSSC, 2006) and now has changed flow regimes caused by weirs/dams, riparian/catchment vegetation clearing and water diversions (Molony & Bird, 2002; Molony et al., 2002). Degraded water quality has influenced the smooth marron’s ability to replace the hairy marron (Bunn, 2004, cited in TSSC, 2006; Molony et al., 2004, cited in TSSC, 2006).

The main potential threats to the hairy marron are fishing and hydrological changes due to local anthropological impacts.

In 2002, the Western Australian Department of Fisheries closed recreational fishing upstream of the junction of Ten Mile Brook and Margaret River; however, there is still a potential threat from illegal fishing or poaching (Molony & Bird, 2002; Molony et al., 2002). The no take zone encompasses the upper reaches.

Threats to the smooth marron may similarly affect the hairy marron. Such potential threats include redfin (Perca fluviatilis) and rainbow trout (Oncorhynchus mykiss) predation, and introduced yabby (Cherax destructor) competition. Larger redfin almost exclusively prey on decapods in the Warren River, particularly the smooth marron (Morgan et al., 2002). It is unknown whether the rainbow trout occurs in the Margaret River but, in other catchments, it eats the smooth marron (Tay et al., 2007). The yabby may out-compete smooth marron due to their earlier sexual maturity and more aggressive behaviours (Molony et al., 2002).

Research Priorities

Research priorities that would inform future regional and local priority actions include:

 Undertake research to determine habitat requirements of the hairy marron and smooth marron (including environmental water requirement), the relationship between morphology and the genetics of individuals (particularly hybrids), reproductive biology of the hairy marron, mechanisms leading to the replacement of the hairy marron by smooth marron and details of interactions between the two species (Koenders, cited in Molony, 2002).  Undertake research to determine effects of predator removal and the associated risk of increased predation by other predators on the species.

Local Priority Actions

The following local priority recovery and threat abatement actions can be done to support the recovery of the hairy marron.

Habitat Loss, Disturbance and Modification  Identify and map critical habitat for hairy marron, commencing with the upper reaches of the Margaret River.  Identify populations of high conservation priority.

Cherax tenuimanus (hairy marron) Approved Conservation Advice Page 2 of 5 This Conservation Advice was approved by the Delegate of the Minister on 17 December 2013

 Determine presence/absence of hairy marron and smooth marron in private dams within the Margaret River catchment.  Monitor the progress of recovery, including the effectiveness of management actions and the need to adapt them if necessary.  Control access routes to suitably constrain public access to known sites on public land.  Suitably control and manage access on private land and other land tenure.  Minimise adverse impacts from land use at known sites.  Ensure there is no disturbance in areas where the hairy marron occurs, excluding necessary actions to manage the conservation of the species.  Manage any disruptions to water flows and liaise with relevant State and local government agencies to manage the extraction of water from the Margaret River and its tributaries.  Support existing catchment and riparian management strategies to improve water quality, aquatic habitat and sediment loads.  Investigate formal conservation arrangements, management agreements and covenants on private land, and for crown and private land investigate and/or secure inclusion in reserve tenure if possible. Translocation and Refuge Populations  Investigate options for establishing additional populations through translocation using appropriate national translocation protocols.  Remove the smooth marron (and hybrids) from the Water Corporation dam at Ten Mile Brook and replace with hairy marron stock (Lawrence et al., 2010). Investigate options for maintaining this dam as a refuge.  Support the existing breeding program (Department of Fisheries, 2011, 2012) and investigate stocking private dams and the Margaret River.  Investigate the potential role of commercial aquaculture of hairy marron in the Margaret River catchment. Predation or Competition  Support existing smooth marron reduction measures in the Margaret River and tributaries (Department of Fisheries, 2011).  Trial fish-out of smooth marron from small reaches of Margaret River (Molony, 2002), possibly focusing on the upper reaches. Ensure that such programs jointly target other predators and competitors, such as the redfin.  Control smooth marron in private dams within the Margaret River catchment.  Control introduced redfin, rainbow trout and yabby to manage threats at known sites. Conservation Information  Raise awareness of the hairy marron within the local community, such as through the development of a brochure/poster to help people to identify the hairy marron, the smooth marron and potential hybrids.  Engage with private landholders and land managers responsible for the land on which populations occur and encourage these key stakeholders to contribute to the implementation of conservation management actions, such as stocking farm dams with the species (Department of Fisheries, 2011).

This list does not necessarily encompass all actions that may be of benefit to the hairy marron, but highlights those that are considered to be of highest priority at the time of preparing the Approved Conservation Advice.

Cherax tenuimanus (hairy marron) Approved Conservation Advice Page 3 of 5 This Conservation Advice was approved by the Delegate of the Minister on 17 December 2013

References

Aquaculture Council of Western Australia (ACWA) (2013). A Guide to Marron Aquaculture. Viewed: 13 August 2013 Available on the Internet at: http://www.aquaculturecouncilwa.com/marron/guide-to-marron-farming

Austin CM and Bunn J (2010). Cherax tenuimanus. In: IUCN (International Union for Conservation of Nature) (2013). IUCN Red List of Threatened Species. Version 2013.1. Viewed: 3 September 2013 Available on the Internet at: www.iucnredlist.org

Carter JS (2013). More than a meal: marron central to a region’s identity. ABC Rural [Online]. Viewed: 28 October 2013 Available on the Internet at: http://www.abc.net.au/news/2013-10-24/something-about-marron/5041114

Department of Conservation and Land Management (CALM) (2005). Records held in CALM’s rare fauna files. Western Australia: CALM.

Department of Fisheries (2011). Work to implement the hairy marron recovery plan. Government of Western Australia. Viewed: 27 August 2013 Available on the Internet at: http://www.fish.wa.gov.au/About-Us/Media-releases/Pages/_archive/Work-to- implement-the-hairy-marron-recovery-plan.aspx

Department of Fisheries (2012). Research, Monitoring, Assessment and Development Plan 2011-2012. Government of Western Australia.

Jenour C, Williams I, Vercoe P and Lawrence C (2007). Introduced marron displace native marron within the Margaret River by competitive exclusion. In: Lawrence C (ed.) Improved performance of marron using genetic and pond management strategies (pp. 59–72). Final report to Fisheries Research and Development Corporation on Project No. 2000/215. Fisheries Research Contract Report No. 17. Western Australia: Department of Fisheries.

Lawrence C, Hugh C, Larsen R, Ledger J and Vercoe P (2010). Aquatic Fauna – Biological Survey. Ten Mile Brook Dam Margaret River. Fisheries Research Contract Report No. 22. Western Australia: Department of Fisheries.

Molony B (ed.) (2002). Scientific Workshop on the Margaret River Marron. West Australian Marine Research Laboratories May 10, 2002. Department of Fisheries. Government of Western Australia.

Molony BW and Bird C (2002). Annual report on the monitoring of the recreational marron fishery in 2000, with an analysis of long-term data and changes within this fishery. Fisheries Research Report No. 137. Western Australia: Department of Fisheries.

Molony BW, Morrissey NM and Bird C (2002). The West-Australian Recreational Marron Fishery (Cherax tenuimanus, (Smith 1912)): History and Future Challenges. Freshwater Crayfish 13:203–220.

Morgan DL, Hambleton SJ, Gill HS and Beatty SJ (2002). Distribution, biology and likely impacts of the introduced redfin perch (Perca fluviatilis) (Percidae) in Western Australia. Marine & Freshwater Research 53:1211–1221.

Cherax tenuimanus (hairy marron) Approved Conservation Advice Page 4 of 5 This Conservation Advice was approved by the Delegate of the Minister on 17 December 2013

Nguyen TTT, Meewan M, Ryan S and Austin CM (2002). Genetic diversity and translocation in the marron, Cherax tenuimanus (Smith): implications for management and conservation. Fisheries Management and Ecology 9:163–173.

Tay MY, Lymbery AJ, Beatty SJ & DL Morgan (2007) Predation by rainbow trout (Oncorhynchus mykiss) on a Western Australian icon: marron (). New Zealand Journal of Marine and Freshwater Research. 41:197–204.

Threatened Species Scientific Committee (TSSC) (2006). Commonwealth Listing Advice on Cherax tenuimanus. Canberra: Department of the Environment and Heritage. Viewed: 13 August 2013 Available on the Internet at: http://www.environment.gov.au/biodiversity/threatened/species/cherax- tenuimanus.html

Yallop C, Bernard JRL, Blair D, Butler S, Delbridge A, Peters P and Witton N (eds) (2005). Macquarie Dictionary Fourth Edition. The Macquarie Library Pty Ltd.

Cherax tenuimanus (hairy marron) Approved Conservation Advice Page 5 of 5