Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Critically Endangered
Listing and Conservation Advices Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
 
Commonwealth Listing Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee (TSSC), 2006cm) [Listing Advice].
 
Recovery Plan Decision Recovery Plan not required, included on the Not Commenced List (1/11/2009).
 
Adopted/Made Recovery Plans
Policy Statements and Guidelines Survey guidelines for Australia's threatened fish. EPBC Act survey guidelines 6.4 (Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC), 2011i) [Admin Guideline].
 
Federal Register of
    Legislative Instruments
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (45) (14/08/2006) (Commonwealth of Australia, 2006j) [Legislative Instrument].
 
State Government
    Documents and Websites
WA:Western Trout Minnow (Galaxias truttaceus hesperius) Recovery Plan (Western Australian Department of Environment and Conservation (WA DEC), 2008c) [State Recovery Plan].
State Listing Status
WA: Listed as Endangered (Wildlife Conservation Act 1950 (Western Australia): September 2013 list)
Scientific name Galaxias truttaceus hesperius [81282]
Family Galaxiidae:Salmoniformes:Actinopterygii:Chordata:Animalia
Species author Whitley, 1944
Infraspecies author  
Reference  
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific name: Galaxias truttaceus hesperius

Common name: Western Trout Minnow

Other common names: Trout Minnow, Spotted Minnow, Mountain Trout or Spotted Mountain Trout (Allen et al. 2002; Morgan et al. 1998).

At the species level, Trout Minnow (Galaxias truttaceus) is known from Western Australia, Tasmania, South Australia and Victoria (Allen et al. 2002). However, the degree of separation, reproductive isolation and exposure to differing environmental conditions have produced marked differences in terms of morphology and biology between the western and eastern Australian populations (McDowall & Frankenberg 1981; Morgan 2003).

The Western Australian population of Galaxias truttaceus was originally described as a discrete taxon, Galaxias truttaceus hesperius Whitely 1944, but was revised as a junior synonym by McDowall and Frankenberg (1981). However, preliminary results of molecular studies have demonstrated substantial genetic divergence between the Goodga River population in south-west Australia (using mitochondrial DNA and nuclear genes to obtain a global phylogeny of the Galaxias group) and those in south-east Australia, and suggest that these genetic differences are greater than those between populations of other Australian galaxiids (WA CALM 2005). The Western Australia Threatened Species Scientific Committee recently accepted the subspecies status of Galaxias truttaceus hesperius based on this preliminary genetic data.

The holotype of Galaxias truttaceus hesperius is in the Western Australia Museum.

The Western Trout Minnow is a large, elongate, relatively deep-bodied and scaleless galaxiid reaching a maximum size of 12–14 cm (Allen et al. 2002). The Western Trout Minnow has brown to olive colouring with unmistakable pale-edged dark spots on the upper sides, a dark diagonal stripe below the eye, and reddish-orange median fins and pelvics with a dark posterior margin (Allen et al. 2002; Morgan et al. 1998). Juveniles have a dark bar on each side that fragments with age. There may be 11–15 (usually 12–14) dorsal rays, 14–19 anal rays, and 13–16 (usually 14–15) pectoral rays (Allen et al. 2002; Morgan et al. 1998).

At the species level, the Trout Minnow (Galaxias truttaceus) is known from Western Australia, South Australia, Tasmania and Victoria, and King Island, Flinders Island and Clarke Island in Bass Strait (Allen et al. 2002).

The subspecies, Galaxias truttaceus hesperius, is known only from the relatively small catchments of King River, Kalgan River and Goodga River near Albany in south-west Western Australia. However, recent surveys have failed to locate any Western Trout Minnow in King River or Kalgan River or any other river system of south-west Western Australia. A viable population is believed to currently exist in the Goodga River, however, this population is landlocked and currently restricted to 4 km of the river (Morgan et al. 1998; Morgan 2003). Western Trout Minnow are also known from a 2 km stretch of Angove River (TSSC 2006cm). These populations require repeated surveying to ensure the certainty of these locations (TSSC 2006cm).

The extent of occurrence of the Western Trout Minnow is estimated to be 0.012 km² (calculated as 6 km combined stream length with an average stream width of 2 m) (TSSC 2006cm). This extent of occurrence is severely reduced, as the Western Trout Minnow has historically been known from catchments of King River and Kalgan River.

Recent surveys, in 2003 and earlier by Morgan and colleagues (1998), in King River and Kalgan River failed to locate any Western Trout Minnow and the species is presumed locally extinct from these rivers. One estimate suggests that the loss of these populations represents a decline in occurrence of over 238 km of river length (the combined length of the main channels of the two rivers). Thus, the remaining 6 km of river length, where this species is found, represents only 2% of the species former range (TSSC 2006cm).

The current area of occupancy (or approximate total area of remaining habitat) is 0.012 km² (6 km combined stream length in Goodga and Angove Rivers multiplied by 2 m river width) (TSSC 2006cm).

The Western Trout Minnow persists in two isolated locations: a 4 km stretch of the Goodga River; and a 2 km stretch of the Angove River in south-west Western Australia (TSSC 2006cm). The Angove River population was only discovered in 2004 (six individuals) and, like the Goodga River population, is restricted by weirs to the lower 2 km section of the river (TSSC 2006cm).

The risk of further loss of the remaining two populations is high due to their restricted area of occupancy, the risk of deliberate or inadvertent introduction of exotic species such as Rainbow Trout (Oncorhynchus mykiss), Brown Trout (Salmo trutta), European/Redfin Perch (Perca fluviatilis) or competitive fish (such as Mosquitofish, Gambusia holbrooki), increasing salinity, disease and land clearing (Gill et al. 1999; Morgan et al. 1998).

The distribution of the Western Trout Minnow is severely fragmented, with no connection between the two remaining, isolated subpopulations in the Goodga and Angove Rivers. The King River and Kalgan River subpopulations are thought to be extinct due to the lack of specimens in recent, extensive surveys (Morgan 2003).

All rivers in south-west Western Australia have been sampled for the species. In excess of 1300 sites were sampled for fish in Western Australia by staff of the Western Australian Museum (Morgan et al. 1998; TSSC 2006cm).

The total population of Western Trout Minnow has not been accurately determined. However, based on sampling surveys the number of mature individuals (breeding population: individuals two years or older) is estimated to be between 1000 and 2500 (Morgan 2003). The breeding population is estimated to represent approximately 50% of the total population. Thus, the total population of the Western Trout Minnow is likely to be between 2000 and 5000 individuals (Morgan 2003).

Since the extinctions of the King River and Kalgan River subpopulations, the Western Trout Minnow now occurs in three geographically isolated subpopulations between which there is no demographic or genetic exchange: a 4 km stretch of the Goodga River; a 2 km stretch of the Angove River (TSSC 2006cm) and a 1 km stretch of upper Kent River (WA DEC 2008c).

Goodga suite
The Goodga suite population is restricted to a 4 km stretch of the Goodga River, upstream of Moates Lake, Black Cat Creek and Moates Lake, an area of approximately 0.008 km² (Threatened Species Scientific Committee 2008xo). Prior to the construction of the Goodga fishway in 2003, the fish were limited by a weir to only 2 km of the river habitat. The upper reaches of the Goodga River lie within a Water Catchment Reserve managed by the Water Corporation. The main channel of the Goodga River then runs through 10 km of partially cleared farmland, timbered and with some remnant riparian vegetation before entering the Goodga River Reserve, a 300 ha 'A'-class reserve. The Goodga River ends in Moates Lake in the adjacent Two Peoples Bay Nature Reserve (WA DEC 2008c).

Angove suite
The Angove suite population is found a long a 2 km stretch of Angove River, downstream of a gauging station and in Angove Lake, an area of approximately 0.004 km² (Threatened Species Scientific Committee 2008xo). The upper reaches of the Angove River lie within the same Water Catchment Reserve as the Goodga River. The reserve protects the drinking water source which is extracted from a a pipehead on the Angove River above the gauging weir. The Angove River then drains into Angove Lake wwhich is part of the Two Peoples Bay Nature Reserve. A small section of Angove River and Angove Lake are separated form the rest of Two Peoples Nature Reserve by a 3 km stretch of private property. This section of the nature reserved is zoned 'Special Conservation', only allowing public access for appropriate purposes on a permit basis (CALM 1995 in WA DEC 2008c). This population of Western Trout Minnow is landlocked and completely separated form the Goodga suite population.

Kent River suite
In 2005, specimens from a private property off the upper Kent River were identified as Western Trout Minnow (D. Morgan, pers.comm. 2007 in WA DEC 2008c). The available habitat for this Kent Rvier population has been estimated to be 0.001 km ² (a 1 km stretch approximately 1 m wide), though surveys are still required to determine the actual extent of this population (WA DEC 2008c).

In 2004, 25 individuals of Western Trout Minnow were collected form the Goodga River and translocated into a wetland on private property in the upper Goodga catchment. This translocation is thought to have been unsuccesful (D. Morgan pers. comm. 2008 in WA DEC 2008c).

The largest population of Western Trout Minnow occurs within a 4 km stretch of the Goodga River system. This population, however, has decreased in numbers by more than 50% in recent years. Further population reductions may occur in the future if threatening processes are not managed (Morgan 2003).

The generation length of the Western Trout Minnow is greater than two years, the age at which breeding commences. Sexual maturity is reached by the age of two years, and the age class with the greatest sampled frequency fell within the 0–3 year age cohort (Morgan 2003).

The recovery plan developed for this species (WA DEC 2008c) has identified the following as critical habitat:

  • The area of occupancy of the known populations and similar habitat within 200 m of the known populations.
  • Additional occurrences of similar habitat that do not currently contain the species but may have done so in the past (i.e. King and Kalgan Rivers).

Goodga River and Angove River, which contain the only remaining known viable populations of Western Trout Minnow, are both partly located within the Two Peoples Bay Nature Reserve (TSSC 2006cm).

Museum records show that the Western Trout Minnow is usually found around plants, rocks or logs on the shore margins of still or flowing rivers, streams and lakes where they feed on aquatic and terrestrial insects (Morgan et al. 1998). The streams are generally shallow (< 1.5 m) and are between 0.5 and 5 m wide. The species is most common at lower elevations close to the coast (Allen et al. 2002).

The Western Trout Minnow is confined to cooler climate rivers. Mean water temperatures of the Goodga River follow a seasonal pattern, reaching 20–23 °C in summer and dropping to 11.7 °C in mid-winter (Morgan 2003). It is thought that the restricted distribution of the Western Trout Minnow is due to its sensitivity to the higher water temperatures encountered in most of the inland rivers of south-west Western Australia (Morgan et al. 1998). The waters of Goodga River, where a viable population of Western Trout Minnow exists, are acidic and non-saline (Morgan 2003; TSSC 2006cm).

The juveniles and adults of the Goodga suite population occur in the narrow riverine environments of the Goodga River and Black Cat Creek, while the larval fish use Moates Lake as a nursery (Morgan 2003 in WA DEC 2008c).
The Western Trout Minnow is not known to associate with any listed threatened ecological communities, however, Balston's Pygmy Perch (Nannatherina balstoni), listed as vulnerable under the EPBC Act, occurs in a similar area.

Compared to the south-east Australia Trout Minnow population, Western Trout Minnow in the Goodga River are characterised by:

  • A greater proportion of the population attain sexual maturity in their first year (Humphries 1989; Morgan 2003).
  • There is a smaller larvae size at hatching: around 6.5 mm with Tasmanian larvae at 7.5–9.0 mm (TSSC 2006cm).
  • There is a greater frequency of individuals in younger age classes: 53% belonged to the 0–1 age class, 34% of 1–2 age class, 10% of 2–3 age class and the remaining 3% of fish belonged to the 3–7+ age classes (Morgan 2003); compared to > 50% and > 30% of fish in the Tasmanian populations found in streams and lakes respectively that were older than three (Humphries 1989).
  • A much smaller proportion of the population reach a size greater than 140 mm total length: only one fish of this length has been recorded at Goodga River whereas in Tasmania a substantial proportion of individuals are > 140 mm total length (Morgan 2003).
  • In the Goodga River population, nine of the 25 morphometric characters measured by McDowall and Frankenberg (1981) represent the extremes of the ranges exhibited by all populations (Morgan 2003). Godga River populations also exhibit a higher mean number of gill rakers and a lower mean number of anal rays and vertebra (except for the landlocked Great Lake population in Tasmania) than the eastern population.

Morgan and Beatty (2005) found that there are distinct differences in the population demographics of the Goodga and Angove River suites, with the Angove River either supporting faster growth of fish or earlier spawning. Given these differences, the two populations are considered genetically distinct (WA DEC 2008c).


Sexual maturity in Western Trout Minnows is reached from two years of age (Morgan 2003). It is thought likely that the onset of gonadal development is triggered by the photoperiod (day length), and the cue for spawning is most likely a decrease in water temperature with a concomitant increase in water level (Humphries 1989; Morgan 2003).

It is possible that the diadromous (migrating from sea to freshwater) populations of Western Trout Minnow followed a similar pattern to that seen in the Tasmania Trout Minnow, with spawning in late autumn to winter (compared to spring in the landlocked form), amongst aquatic vegetation. The adults of the diadromous form move from their freshwater habitats downstream into estuaries to spawn and the resultant larvae move into the ocean, returning to fresh water in summer after approximately six months of growth. Adults of the Tasmanian landlocked form moved into upstream tributaries to spawn, with the larvae hatching approximately one month after spawning when they are swept downstream into the lakes, in a similar manner to the Western Trout Minnow (Allen et al. 2002; Morgan et al. 1998).

Fecundity is thought to range from > 1000 eggs in a 72 mm diadromous fish to almost 16 000 in a 142 mm landlocked fish (Allen et al. 2002; Morgan et al. 1998).

Larval fish feed exclusively on surface plankton (copepods) in their nursery-lakes, and then migrate back to the river system where the predominant prey species are terrestrial insects, such as coleopterans and hymenopterans, that fall on the water surface. Other items consumed include dipterans, arachnids, orthopterans, aphids, decapods (Palaemonetes australis), amphipods and fish (Pseudogobius olorum) (Morgan et al. 1998).

Historically, Western Trout Minnow occured in both landlocked and diadromous (migrating between the sea and freshwater) populations. The remaining Two Peoples Bay populations appear to be landlocked (TSSC 2006cm).

Goodga River Western Trout Minnow populations are largely confined to riverine environments with narrow breadth, with newly-hatched larvae found in the upper reaches of the River below the spawning populations, which aggregate below the weir. Gonadal development for males in this population commences in early summer with spawning occurring in mid to late autumn and completed by early winter, which is marginally earlier than other freshwater species in south-west Australia (Morgan 2003). Larval fish move from spawning grounds to Moates Lake, where they spend the next 2–3 months feeding on surface plankton (copepods) and use the lake area as a nursery. At 25 mm total length, juveniles move back to Goodga River where they remain (Morgan 2003).

The landlocked populations of Western Trout Minnow utilise the lacustrine (lake) environment as a nursery area, then migrate back into the river system where they remain (Morgan et al. 1998). In contrast, diadromous populations (currently extinct in Western Australia) migrate from fresh water to estuaries to spawn, with the larvae moving to the sea, returning to fresh water after approximately six months (Morgan 2003). Juvenile stages of Galaxias truttaceus were observed 'climbing' and 'jumping' to successfully negotiate a low, vertical weir wall during their upstream recruitment migrations in south-western Australia, however, further research is required to use this knowledge to help improve the management of instream barriers in this species habitat (Close et al. 2014).

Western Trout Minnow possess unmistakable pale-edged dark spots on their upper sides and a dark diagonal stripe below their eye, accompanied by brown to orange fins (Allen et al. 2002; Morgan et al. 1998). Juveniles have a dark bar on their sides which fragment with age. The sympatric G. maculatus is of a similar length but has different colouration, with irregular greenish-grey spots, blotches or bands on the dorsal and dorso-lateral surface, and largely unpigmented fins (Morgan et al. 1998).

Morgan (2003) surveyed for Western Trout Minnow using seine nets, larval tow nets and sweep nets. The seine nets used were 1, 5, 10 and 26 m long, and were each made of 3 mm woven mesh and fished to a depth of 1.5 m, except the 26 m long net, which consisted of a 10 m pocket of 3 mm mesh and two 8 m wings of 6 mm mesh. The conical larval tow net had a diameter of 800 mm and consisted of 500 mm mesh.

There are a number of threats to the Western Trout Minnow including physical barriers restricting the species' spawning movements upstream; predation and competition from introduced fish species; the impact of a parasite and subsequent bird predation; and hydrological changes such as elevated water temperatures and increasing water salinity levels.

Introduced Species
The deliberate or inadvertent introduction of species such as Rainbow Trout, Brown Trout, European/Redfin Perch or competitive fish (such as Mosquitofish) pose a significant threat to the Western Trout Minnow (Morgan 2003). Unlike King River and Kalgan River, Goodga River and Angove River are currently free from introduced fishes, particularly Mosquitofish, which is a known aggressor towards native fishes in south-west Western Australia (Gill et al. 1999). However, Mosquitofish are known to occur within the catchment area of the Goodga River in dams on private properties (Morgan et al. 1998). It is possible that these species could be introduced to the Goodga and Angove Rivers in the near future, which would likely result in the elimination of the remaining Western Trout Minnow populations (TSSC 2006cm).

The Department of Fisheries have reviewed proposals to introduce three other native fish from the Murray-Darling (Golden Perch, Macquaria ambigua, Murray Cod, Maccullochella peelii peelii and Australian Bass, Macquaria novemaculeata) into Western Australian river systems for the purposes of recreational stocking, domestic stocking and commercial and non-commercial aquaculture (Department of Fisheries 2003). As these three species are top-order predators, they are likely to compete with, or prey on, existing native fishes (Department of Fisheries 2003; TSSC 2006cm). This review does not state what rivers translocated fish would be released in, the time frame in which such a program would occur or the management precautions that would be undertaken to protect threatened fish in south-west Western Australia (Department of Fisheries 2003).

There is concern that the introduced aquatic plant Typha orientalis, present in the Goodga River, may block water flow, thereby affecting water levels, food availability and movement of the Western Trout Minnow (WA DEC 2008c).

Impediments to spawning and susbsequent predation
A biological study conducted by Morgan (2003) showed that the Goodga River population of Western Trout Minnow had its upstream spawning migration impeded by a weir (Goodga River gauging station). Weirs restrict the upstream movements of Western Trout Minnows and prevent them from spawning in their traditional freshwater spawning grounds (Morgan 2003). Large numbers (and a high proportion of the total population) of Western Trout Minnow congregated below the weir where they were at increased risk from avian predation (Morgan 2003). This threat of predation was further increased when they became infected with the parasite Ligula intestinalis, a Northern Hemisphere species of cestode. To prevent such obstruction, a fish ladder was constructed at the Goodga River weir in 2003 to facilitate migration of the Western Trout Minnow, effectively doubling the species' range (previously only 2 km downstream of the weir, now includes a further 2 km of upstream habitat) (TSSC 2006cm).

The Goodga River has been considered as a possible water source for the City of Albany (Water and Rivers Commission 1997): no current information is available regarding whether or not authorities are still considering this project.

Disease
The population of Western Trout Minnow in the Goodga River has recently been found to be infected with Pseudophyllidea cestode Ligula intestinalis. The parasite has been found in the body cavity of approximately 7% of juvenile Western Trout Minnow (Morgan 2003). The cestode is known to infect numerous freshwater fish species in the Northern Hemisphere but has only recently been recorded in the Southern Hemisphere. This parasite causes gonadal retardation, gross morphological deformities and reduced swimming ability (Morgan 2003; Owen & Arme 1965; Pollard 1974). It is likely that Western Trout Minnows are infected during their larval phase in Moates Lake as no fish bigger than 80 mm total length have been found to be infected. It is likely that infection with the parasite and subsequent disfiguration makes them vulnerable to avian predation (Morgan 2003). Birds are a significant part of the lifecycle of L. intestinalis, acting as an additional host. The introduction of a parasite into the Moates lake system may have occurred during the unsuccessful Brown and Rainbow Trout releases in the 1950s and 1960s, or by an avian host migrating from south-east (or south-west) Australia (Morgan 2003).

Altered hydrology and salinity
It is unknown whether water extraction, flow alteration and increased salinity are impacting the Western Trout Minnow (WA DEC 2008c).

Water extraction from Angove River increased in 2001, removing 67–82 % of mean annual flow (WA DEC 2008c). The Kent River catchment has also been identified as a possible source of potable water, in which case the impact of water extraction on the Western Trout Minnow should be considered (WA DEC 2008c).

Recent surveys failed to capture any Western Trout Minnow in King River or Kalgan River. The increasing salinity of these rivers may have caused local extinction of the species. Most of the larger river systems in the Albany Coast Basin are brackish to saline, attributed to hinterland salt lakes, saline groundwater and clearing in the upper catchments. Clearing in the upper catchments has contributed to erosion problems and increased sedimentation of many river channels, pools and in some cases the filling of coastal lagoons (TSSC 2006cm). It is thought unlikely that salinity would be having a considerable impact on the Western Trout MInnow in the Goodga and Angove Rivers as these rivers naturally experience seasonal variation in salinity (WA DEC 2008c). The impact of increasing salinity in the Kent River on the Western Trout Minnow population is unknown (WA DEC 2008c).

Changes in hydrology can also affect water temperature. There may be alterations to the groundwater recharge of the Goodga and Angove Rivers due to the Blue Gum plantations in the upper Goodga catchment. Groundwater-fed rivers are cooler and a change in the groundwater input may lead to changes in river water termperature. This is potentially a significant issue for the Western Trout Minnow which is sensitive to change in water temperature (WA DEC 2008c).

Land Clearing
The upper lethal temperature tolerance for the Western Trout Minnow is 30 °C (Morgan 2003). Land clearing in the Albany Coast Basin has led to elevated water temperatures and salinity, which may pose a threat to the persistence of the Western Trout Minnow should water temperatures exceed their tolerance limits over the summer months (TSSC 2006cm).

Livestock access to riparian habitat
While much of the Two Peoples Bay Reserve is protected from cattle access, some stock access to riparian habitat is still available in some stretches of the Western Minnow Trout habitat (WA DEC 2008c). Protection of Western Trout Minnow habitat from stock access is considered vital (WA DEC 2008c).

The Threatened Species Scientific Committee (2006cw, 2008xo) recommended the following recovery actions be undertaken to address the threats to the Western Trout Minnow:

  • Secure the viability of the population at Angrove River.
  • Develop strategies to prevent the introduction of non-indigenous fish species (especially Mosquitofish and fish for recreation and aquaculture purposes) from catchments surrounding the Goodga and Angrove Rivers.
  • Design and implement a monitoring program.
  • Investigate extending Two Peoples Bay Nature Reserve to incorporate more of the important habitat for this species.
  • Investigate improving habitat suitability in appropriate areas for the Western Trout Minnow.
  • Re-assess the status in the King and Kalgan Rivers as recent surveys failed to locate Western Trout Minnow in these rivers. If salinity is a significant factor in the decline in distribution of this taxon in Western Australia it will be difficult to reverse the trend.
  • Investigate options for linking, enhancing or establishing additional populations, especially in Angove River, or other suitable sites, to provide an additional population as security against a catastrophic event on the Goodga River.
  • Investigate measures (eg. fish ladders) to facilitate migration of Western Trout Minnow upstream, particularly where there are physical barriers (eg. weirs) to the species' spawning migration.
  • Investigate ways to minimise the impacts of the parasite, Ligula intestinalia, on the Western Trout Minnow.
  • Investigate the salinity tolerance of the species and determine to what degree increasing salinity, sedimentation and water temperature levels are contributing to the decline of the Western Trout Minnow.

The Western Trout Minnow (Galaxias truttaceus hesperius) Recovery Plan (WA DEC 2008c) aims to abate the identified threats to the Western Trout Minnow and maintain or enhance in situ populations and distribution to ensure the long-term preservation of the Western Trout Minnow in the wild. Included in its actions are:

  • Define and map critical habitat and survey for additional populations.
  • Implement a monitoring program for the known populations.
  • Develop and implement strategies to prevent the introduction of invasive fish species.
  • Research the cause of the deaths of the fish from the drop-off of the Goodga River Gauging Station.
  • Maintain and improve the Goodga fishway.
  • . Investigate and implement measures to facilitate upstream movement of the Angove suite population.
  • Investigate and implement strategies to cease recreational fishing in the Angove and Goodga catchments.
  • Obtain biological and ecological information for the separate populations.
  • Investigate the potential for ex situ populations.
  • Investigate the tolerances of the Western Trout Minnow to factors such as water temperature, salinity, turbidity and nutrients.
  • Fence off access of livestock to riparian habitat and revegetate where necessary.
  • Promote awareness of threatened aquatic species.

As a result of a Natural Heritage Trust grant, in April 2003 a fish ladder was constructed at the weir on the Goodga River, with the aim of allowing migration around the weir and allowing more habitat to be accessed by the species. The weir had limited the distribution of the Western Trout Minnow to about a 2 km stretch of the Goodga River. Observations on the effectiveness of the fish ladder at the weir have noted that it is accessible to a range of age classes, with 100–200 fish using the ladder a day (sometimes as many as 300) (TSSC 2006cm). This ladder has effectively doubled the habitat available to the species from a 2 km stretch of the Goodga River to 4 km. However, only some parts of this total river length are suitable habitat for the fish, with some sections as narrow as 1 m wide, and the river passes through agricultural land north of the weir.

Protection of riparian habitat is also achieved through the provisions of the Two Peoples Bay Nature Reserve Management Plan (Orr et al. 1995) which zones the lower Angove River and Angove Lake as 'Special Conservation' under the Plan and which restricts public access to the area only under permit. Moates Lake is zoned as 'Natural Environment' under the Plan, which restricts public access to "by foot" only (WA DEC 2008c).

The conservation and protection of fish and their environment is the legislative responsibility of the Department of Fisheries, Western Australia under the Fish Resources Management Act 1994. The Recovery Plan will be reviewed by a Southern Freshwater Fauna Recovery Team, in consultation with both the Department of Fisheries and the WA Department of Environment and Conservation (WA DEC 2008c).

A recent study on the distribution and biology of Galaxias truttaceus hesperius in south-west Western Australia, including evidence of parasitism, was conducted by Morgan (2003).

A Western Trout Minnow (Galaxias truttaceus hesperius) Recovery Plan (WA DEC 2008c) has been prepared. The Action Plan for Australian Freshwater Fishes (Wager & Jackson 1993) does not list this species, however this Plan discusses management issues for threatened Australian freshwater fishes.

The Two Peoples Bay Nature Reserve Management Plan (Orr et al. 1995) provides an overview of management priorities for the section of habitat, and associated catchment, that passes through this Nature Reserve.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Climate Change and Severe Weather:Temperature Extremes:Elevated water temperatures NON-APPROVED Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee (TSSC), 2006cw) [Conservation Advice].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Loss and/or fragmentation of habitat and/or subpopulations Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Gambusia holbrooki (Eastern Gambusia, Mosquitofish) Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Oncorhynchus mykiss (Rainbow Trout) Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Perca fluviatilis (Redfin, Redfin Perch) Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Salmo trutta (Brown Trout) Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Infection by parasites NON-APPROVED Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee (TSSC), 2006cw) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Problematic Native Species:Competition, predation and/or habitat degradation by fish Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Natural System Modifications:Dams and Water Management/Use:Changes to hydrology including construction of dams/barriers Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Pollution:Pollution:Changes to water and sediment flows leading to erosion, siltation and pollution Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].
Pollution:Pollution:Declining water quality (salinity, nutrient and/or turbitity) Commonwealth Conservation Advice on Galaxias truttaceus hesperius (Threatened Species Scientific Committee, 2008xo) [Conservation Advice].

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

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Threatened Species Scientific Committee (2008xo). Commonwealth Conservation Advice on Galaxias truttaceus hesperius. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/81282-conservation-advice.pdf.

Threatened Species Scientific Committee (TSSC) (2006cm). Commonwealth Listing Advice on Galaxias truttaceus hesperius. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/galaxias-truttaceus-hesperius-listing.pdf.

Threatened Species Scientific Committee (TSSC) (2006cw). NON-APPROVED Commonwealth Conservation Advice on Galaxias truttaceus hesperius. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/galaxias-truttaceus-hesperius-conservation.pdf.

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Western Australian Department of Environment and Conservation (WA DEC) (2008c). Western Trout Minnow (Galaxias truttaceus hesperius) Recovery Plan. [Online]. Western Australia: WA DEC. Available from: http://www.dec.wa.gov.au/pdf/plants_animals/threatened_species/frps/47-western-trout-minnow-2010-03-17.pdf.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Galaxias truttaceus hesperius in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Tue, 16 Sep 2014 18:08:54 +1000.