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

Galaxias tanycephalus

saddled galaxias

Conservation Status

Galaxias tanycephalus (saddled galaxias) is listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) effective from 16 July 2000. The species was eligible for listing under the EPBC Act as on 16 July 2000 it was listed as Vulnerable under Schedule 1 of the preceding Act, the Endangered Species Protection Act 1992 (Cwlth).

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 make the species eligible for listing in the Vulnerable category are that the saddled galaxias had a limited distribution, in two lakes in central Tasmania, that was severely fragmented and continuing decline was inferred due to threats from introduced fish and habitat quality changes (TSS 2006).

Description

The saddled galaxias, family Galaxiidae, is a small, stout freshwater fish, reaching a maximum length of approximately 150 mm (Fulton 1990; McDowall & Fulton 1996; Allen et al., 2002; TSS 2006). Adults are olive-grey in colour with a series of dark grey saddle-like markings along the back and upper sides, tending to a silvery belly (Fulton 1990; McDowall & Fulton 1996; Allen et al., 2002; TSS 2006). A purplish sheen may sometimes present on the sides and the dorsal, anal and caudal fins may be amber coloured, sometimes black edges (Fulton 1990; McDowall & Fulton 1996; Allen et al., 2002; TSS 2006). The head is relatively long and tapering for a galaxiid species (Fulton 1990; McDowall & Fulton 1996), as reflected in the species’ name “tanycephalus ” translated to “long-head ”.

Distribution

The saddled galaxias is endemic to central Tasmania, and only occurs in Arthurs Lake and Woods Lake on the Central Plateau (Fulton 1990; McDowall 2006). Both Arthurs Lake and Woods Lake were small, natural lakes in close proximity on the elevated Central Plateau (McDowall 2006) which have had dams installed. Two saddled galaxias have been collected in the Great Lake (which is nearby to Arthurs Lake), outside the species’ natural distribution, in 2009 and 2010, however these appear not to be from an established population (Hardie et al., 2011). These individuals may be vagrants translocated to the Great Lake via the Arthurs Lake – Great Lake flume (Hardie et al., 2011).

Another galaxiid species, Paragalaxias mesotes (Arthurs paragalaxias), has coexisted in both Arthurs Lake and Woods Lake with the saddled galaxias until recently (TSSC 2005). The population of Arthurs paragalaxias once found in Woods Lake declined markedly until the 1990s Galaxias tanycephalus (saddled galaxias) Conservation Advice Page 1 of 6

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; Hardie et al., 2011). Additionally, water releases from Arthurs Lake to Woods Lake, via the upper Lake River, may have transferred additional individuals to Woods Lake between 2002 and 2008 (Hardie et al., 2011). Two fish were subsequently captured in Woods Lake in 2008 during routine population monitoring, suggesting that the population of saddled galaxias may have re-established there to a limited extent (IFS, unpubl. data., cited in Hardie et al., 2011).

The saddled galaxias also coexists with brown trout ( Salmo trutta ) and is said to be more abundant in the more turbid Woods Lakes than Arthurs Lake (IFC 1989; Allen et al., 2002; TSS 2006). It is thought that the species is more prone to trout predation in Arthurs Lake due to its clear waters (IFC 1989; TSS 2006). The examination of gut contents from a large sample of brown trout from Woods Lake found that the saddled galaxias formed a significant part of the species’ diet (IFC 1989).

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

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

The Department of the Environment has prepared survey guidelines for the saddled galaxias. 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 saddled galaxias is restricted to freshwater habitats and is primarily a lacustrine (lake- dwelling) species, though is occasionally found in the lower reaches of streams flowing into the lakes (McDowall & Fulton 1996). Larvae and juveniles form shoals in open lake water (McDowall & Fulton 1996; TSS 2006). Adults seem to prefer the shelter of aquatic vegetation, rocks and boulders around the margins of the lakes (Fulton 1990; McDowall & Fulton 1996; TSS 2006).

The saddled galaxias feeds mainly on crustaceans, (benthic and planktonic) and some aquatic insects (McDowall & Fulton 1996; TSS 2006). Larvae are likely to feed on planktonic species (IFS 2014).

Breeding has been observed to occur year round, as larvae have been found in the lakes year round (McDowall & Fulton 1996; TSS 2006). However, there seems to be a breeding peak in spring-summer (Fulton 1990; McDowall & Fulton 1996; TSS 2006). Females produce 800 - 5400 small eggs (1.5 mm in diameter) which are not strongly adhesive compared those of other galaxiid species (TSS 2006). Artificially fertilised eggs took 19 - 24 days to begin hatching at 10°C (Jackson 2002, cited in TSS 2006). Most of the individuals in the wild are less than two years old, with few older and larger individuals found (TSS 2006).

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Threats

Competition and predation by the alien fish species, brown trout ( Salmo trutta ), and a barrier to movement between the two lakes where the saddled galaxias 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).

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

Threat factor Threat Evidence base type and status

Invasive species

Competition known While populations of saddled galaxias continue to coexist with and predation current brown trout in Arthurs Lake and Woods Lake, it is highly likely by alien fish that the alien brown trout (Salmo trutta ) are generally species negatively impacting on the species given that there is evidence of predation from analysis of trout gut contents in Woods Lake (IFC 1989). Saddled galaxias are less abundant in Arthurs Lake, and it is possible that given the water of this lake is far less turbid than that of Woods Lake, levels of trout predation may be higher as the galaxias are easier to hunt (TSS 2006).

The chance of introduction of other alien fish species poses an ongoing threat to the saddled galaxias. 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 saddled galaxias 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). Because of Arthurs Dam, fish from Arthurs Lake could not supplement the population in Woods Lake by any natural movement via Upper Lake River.

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Habitat loss, disturbance and modifications

Deterioration suspected Since it is 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). While Stuart-Smith et al. (2007) suggest that it is possible that increased turbidities may benefit the closely related golden galaxias in avoiding brown trout predation, high turbidities may damage fish gills (TSS 2006) and affect the algal-based food chain (TSS 2006).

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 saddled galaxias 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 rainbow trout, redfin perch and European carp.

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

Fragmentation

o Consider translocating saddled galaxias from the Woods Lake population to Arthurs Lake to overcome effects of fragmentation caused by the Arthurs Dam wall.

Habitat loss, disturbance and modifications

o Manage water fluctuations in Arthurs Lake and Woods Lake to avoid sudden changes in water levels, especially in spring and summer when peak breeding occurs for the saddled galaxias.

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.

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Information and research priorities

• Investigate why the saddled galaxias, in comparison to some Tasmanian galaxiid species, is relatively successful in its ability to co-exist with brown trout in Arthurs Lakes and Woods Lake. Such findings could be used to better manage situations where the impacts on other galaxiid species by brown trout are more drastic.

• 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.

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. (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.

Jackson, J.E. (2002). Report on captive breeding trials conducted under the Tasmanian Galaxias Recovery Plan: Swan galaxias ( Galaxias fontanus ), Clarence galaxias ( G. johnstoni ) and saddled galaxias (G. tanycephalus ). Unpublished report to Environment Australia. Inland Fisheries Service, Hobart.

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, R.M. (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.

Stuart-Smith, R.D., Stuart-Smith, J.F., White, R.W.G., & Barmuta, L.A. (2007). The effects of turbidity and complex habitats on the feeding of a galaxiid fish are clear and simple. Marine and Freshwater Research 58 , 429 – 435.

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

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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) (2014). Saddled galaxias – Inland Fisheries Service – Managing trout fishing in Tasmania . Inland Fisheries Service, Tasmanian Government. Last modified: 19 January 2014. Viewed: 2 March 2016 Available on the Internet at: http://www.ifs.tas.gov.au/publications/fish-fact-sheets/saddled-galaxias

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.

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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