THREATENED SPECIES SCIENTIFIC COMMITTEE Established under the Environment Protection and Biodiversity Conservation Act 1999

The Minister’s delegate approved this Conservation Advice on 16/12/2016

Conservation Advice

Paragalaxias mesotes

Arthurs paragalaxias

Conservation Status

Paragalaxias mesotes (Arthurs paragalaxias) is listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) effective from 7 June 2005.

Species can also be listed as threatened under state and territory legislation. For information on the current listing status of this species under relevant state or territory legislation, see http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl .

The main factors that are the cause of the species being eligible for listing in the Endangered category are that the Arthurs paragalaxias is suspected to have undergone a severe decline in numbers due to the very severe decline in its area of occupancy, and the severe decline in its extent of occurrence (TSSC 2005). The species was previously known to occur at Woods Lake, but declined markedly to the point that it was considered extinct in that lake until 2007, when fish were translocated there from Arthurs Lake (TSSC 2005; Hardie et al., 2011). This leaves a single population existing within Arthurs Lake (TSSC 2005). The species' geographic distribution is restricted and is precarious for its survival (TSSC 2005).

The quality of the habitat in which the remaining population of Arthurs paragalaxias occurs has also declined and potential remains for the remaining habitat to further decline in quality if water levels are not appropriately managed for the purposes of irrigation and hydroelectricity (TSSC 2005). Ongoing degradation of habitat is likely to cause the species to continue to decline (TSSC 2005).

Description

The Arthurs paragalaxias, family Galaxiidae, is a small, bullet-shaped freshwater fish, reaching a maximum length of approximately 80 mm (Fulton 1990; McDowall & Fulton 1996; Allen et al., 2002). The species is distinctively and boldly olive-green to golden overall in colour, with an irregular pattern of dark green-grey bands and patches on the back and sides, with a silvery- grey belly (Fulton 1990; McDowall & Fulton 1996; Allen et al., 2002). The fins are translucent with a slight pigmentation in the rays (Allen et al., 2002). Like other Paragalaxias species and in comparison to Galaxias species, it has a large dorsal fin originating almost above the pelvic fin (TSS 2006). The species has a relatively long head, blunt snout and large mouth in comparison to the body (McDowall & Fulton 1996).

Distribution

The Arthurs paragalaxias is endemic to central Tasmania, and only naturally occurred in Arthurs Lake and Woods Lake on the Central Plateau (Fulton 1990; McDowall 2006). Both Arthurs Lake and Woods Lake were originally once small, natural lakes in close proximity of each other on the elevated Central Plateau (McDowall 2006). Both have had dams installed Paragalaxias mesotes (Arthurs paragalaxias) Conservation Advice Page 1 of 6

where water once naturally flowed out of from, so that the lakes could be regulated for supplying irrigation.

The population of Arthurs paragalaxias once found in Woods Lake declined markedly until the late 1980s when it was considered extinct in that lake, but translocations of 173 and 467 individuals from Arthurs Lake occurred in 2002 and 2008 respectively (TSSC 2005; McDowall 2006; Hardie et al., 2011). Two Arthurs paragalaxias were captured in routine monitoring of Woods Lake in 2008 suggesting that a population may have re-established there (IFS unpublished data, cited in Hardie et al., 2011). The species was also found in a man-made canal which transfers water from Arthurs Lake to the nearby Great Lake (Hydro Tas unpublished data, cited in Hardie et al., 2011), but there is no information yet on the viability of this population.

The Arthurs paragalaxias occurs within the Tasmanian Central Highlands Interim Biogeographic Regionalisation for Australia (IBRA) Bioregion and the South Natural Resource Management Region.

The distribution of the Arthurs paragalaxias is not known to overlap with any EPBC Act-listed threatened ecological community.

The Department of the Environment has prepared survey guidelines for the Arthurs paragalaxias. The survey guidelines are intended to provide guidance for stakeholders on the effort and methods considered appropriate when conducting a presence/absence survey for species listed as threatened under the EPBC Act. http://www.environment.gov.au/epbc/publications/threatened-fish.html

Relevant Biology/Ecology

The Arthurs paragalaxias is restricted to freshwater habitats and is primarily a lacustrine (lake- dwelling) species (Fulton 1990; McDowall & Fulton 1996; McDowall 2006). Very little else is known about its biology and ecology, including its life cycle (McDowall & Fulton 1996; Allen et al., 2002). The Arthurs paragalaxias feeds on microcrustaceans such as copepods, ostracods and cladocerans and aquatic insects and larvae, such as chironomid and caddis larvae, and oligochaetes (Fulton 1982; McDowall & Fulton 1996; Allen et al., 2002).

There is little information on when the Arthurs paragalaxias spawns, but samples of the species collected in April and May had already spawned, suggesting that spawning could have taken place in spring or summer (Fulton 1982). Ripening females have been observed in September (TSS 2006). Eggs and milt have been stripped from ripe fish in early November and several of the eggs have been incubated for 25 days before hatching (IFS unpubl. data, cited in TSS 2006). Larvae were approximately 9 mm long soon after hatching (TSS 2006).

Threats

Competition and predation by the alien fish species, brown trout ( Salmo trutta ), and a barrier to movement between the two lakes in which the Arthurs paragalaxias exists are the primary threats to the species (IFC 1989; TSS 2006). Other likely threats include changes to water quality and sudden changes to water levels within the lakes it occurs (TSS 2006).

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Table 1 – Threats impacting the Arthurs paragalaxias in approximate order of severity of risk, based on available evidence.

Threat factor Threat Evidence base type and status

Invasive species

Competition suspected Populations of Arthurs paragalaxias continue to coexist with and predation current brown trout (Salmo trutta ) in Arthurs Lake and Woods Lake. by alien fish However, it is highly likely that the alien brown trout are species generally negatively impacting on the species, given that there is evidence of predation on the only other galaxiid species which occurs in these lakes, the Galaxias tanycephalus (saddled galaxias), based on analysis of trout gut contents from Woods Lake (IFC 1989).

The chance of introduction of other alien fish species is a threat to Arthurs paragalaxias. As of 2015, European carp (Cyprinus carpio ) were present in Lake Sorell 8 km to the west of Woods Lake, and in 2006 redfin perch ( Perca fluviatilis ) were abundant in the Lagoon of Islands 2 km to the south- west (TSS 2006; IFS 2015a). These species have been demonstrated to negatively impact on other galaxiid species and would likely impact on Arthurs paragalaxias if they were introduced to the lakes it inhabits (TSS 2006).

Fragmentation

Barrier known Constructed in 1965, Arthurs Dam blocked the water flow via created by current the Upper Lake River between Arthurs Lake downstream to Arthurs Dam Woods Lake (TSS 2006). Arthurs Dam now fragments the species into two discrete populations under normal conditions (TSS 2006).

Habitat loss, disturbance and modifications

Deterioration suspected Since being used for irrigation supply, Woods Lake has in water current experienced ongoing issues with high levels of turbidity and quality nutrients and it receives high nutrient input from the Ripple Creek diversion (Hydro Tas 1999; Hydro Tas 2001; IFS 2015b). High turbidities may damage fish gills (TSS 2006), affect fish feeding (Rowe et al., 2002) and affect the algal- based food chain (TSS 2006).

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Sudden suspected Water from Arthurs Lake has been used for power generation changes in current and from Woods Lake for irrigation (Hydro Tas 1999). Water water levels drawdown has the potential to dewater Arthurs paragalaxias habitat and eggs in shallow lake margins (TSS 2006).

Conservation Actions

Conservation and management priorities

Invasive species

o Develop and implement a management plan designed to inhibit ongoing breeding success of brown trout in Arthurs Lake and Woods Lake, such as the strategic placement of barriers to stop trout accessing inflowing streams to spawn, and to prevent the introduction of other alien fish species including, but not limited to, redfin perch and European carp.

o Do not stock salmonids into Arthurs Lake or Woods Lake.

Fragmentation

o Consider further translocations of Arthurs paragalaxias from the Arthurs Lake population to Woods Lake to overcome effects of fragmentation caused by the Arthurs Dam wall.

Habitat loss, disturbance and modifications

o Investigate environmental water releases, similar to those which have been used in the Lake Sorell and Lake Crescent system, especially over spring and summer when breeding occurs for the Arthurs paragalaxias, to increase chances of spawning and recruitment success.

o Add rock piles and artificial substrates to Arthurs Lake and Woods Lake to create additional feeding and refuge habitat for the species.

Survey and monitoring priorities

• Continue to monitor the species’ population annually in the locations that the species is known to occur, and assess the effectiveness of management actions and the need to adapt them if necessary.

Information and research priorities

• Undertake genetic studies to inform decisions on population protection, translocation and captive breeding, to ensure that genetic structure and diversity is maintained, given that all naturally occurring populations are isolated from each other.

• Gain better understanding of key biological and ecological parameters for Arthurs paragalaxias, including breeding biology and response to predators, such as brown trout, and life history traits and key ecological requirements.

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References cited in the advice

Allen, G.R., Midgley, S.H., & Allen, M. (2002). Field Guide to the Freshwater Fishes of Australia . Western Australian Museum, Perth.

Fulton, W. (1982) Observations on the ecology of four species of the genus (Pisces: Galaxiidae) from Tasmania. Australian Journal of Marine and Freshwater Research 33 , 999 – 1016.

Fulton, W. (1990). Tasmanian Freshwater Fishes . Fauna of Tasmania handbook no. 7, University of Tasmania, Hobart.

Hardie, S.A., Macfarlane, K.R., & Barmuta, L.A. (2011). Life histories of galaxiid fishes in Arthurs Lake and Great Lake, Tasmania, and effects of water level fluctuations on their populations . November 2011, Report for Hydro Tasmania, Hobart.

Hydro Tasmania (Hydro Tas) (1999). Environmental Review: South Esk-Great Lake Hydro catchment . Hydro Tasmania Environmental Services.

Hydro Tasmania (Hydro Tas) (2001). Environmental Review: Derwent Hydro Catchment . Hydro Tasmania Environmental Services.

Inland Fisheries Service (IFS) (2015a). Carp Management Program Annual Report 2014-15 . Inland Fisheries Service, Tasmanian Government, New Norfolk, Tasmania.

McDowall, R.M. (2006). Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes?. Reviews in Fish Biology and Fisheries 16 , 233 – 422.

McDowall, R.M., & Fulton, W. (1996). Galaxiids. In: McDowall RM (ed.) (1996). Freshwater fishes of South-Eastern Australia . Reed Books, Chatswood, pp. 52 – 77.

Rowe, D.K., Smith, J., & Williams, E. (2002). Effects of turbidity on the feeding of adult, riverine smelt (Retropinna retropinna ) and inanga ( Galaxias maculatus ). New Zealand Journal of Marine and Freshwater Research 36 , 143 – 150.

Threatened Species Section (TSS) (2006). Recovery Plan: Tasmanian Galaxiidae 2006–2010 . Tasmanian Department of Primary Industries and Water, Hobart, Tasmania.

Other sources cited in the advice

Inland Fisheries Commission (IFC) (1989). Endangered native fish study. Tasmania Inland Fisheries Commission Newsletter 18(2) , 5. Viewed: 1 March 2016 Available on the Internet at: http://www.ifs.tas.gov.au/publications/newsletter-archive

Inland Fisheries Service (IFS) (2015b). Woods Lake water levels and turbidity – Inland Fisheries Service – Managing trout fishing in Tasmania . Inland Fisheries Service, Tasmanian Government. Last modified: 18 August 2015 Viewed: 2 March 2016 Available on the Internet at: http://www.ifs.tas.gov.au/news/woods-lake-water-levels-and-turbidity.

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Threatened Species Scientific Committee (TSSC) (2005). Commonwealth Listing Advice on Arthurs paragalaxias ( Paragalaxias mesotes ). Australian Government Department of Environment and Heritage, Canberra, Australian Capital Territory. Viewed: 1 March 2016 Available on the Internet at: http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=77039

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