© Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia Full citation Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia: Volume 1 - Bony and Cartilaginous Fishes. Report for the South Australian Working Group for Marine Species of Conservation Concern. J. Baker (consultant); Science and Conservation Division, and Coast and Marine Conservation branches of S.A. Department for Environment and Heritage (DEH); Marine and Coastal Community Network of S.A. (MCCN), and Threatened Species Network (TSN). Web version published by Reef Watch, South Australia.

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Australian Grayling

© G.Edgar

Family Name:	Prototroctidae (or Retropinnidae subfamily Prototroctinae)
Scientific Name:	Prototroctes maraena Günther, 1864
Recommended Status:	South Australia: Endangered (B2ab(ii,iii,iv)). South-eastern Australia: Possibly Vulnerable (VU A2c,e)
Rationale:	In South Australia, this species is vulnerable to extirpation, due to its narrow habitat range and continued threats to quantity and quality of critical habitat. In South Australia, it is restricted to the lower South-East (with previous records from several locations such as Ewens Ponds, Piccaninnie Ponds, and Stratman’s Pond); however, it has not been recorded in recent years, despite comprehensive riverine and estuarine surveys. Grayling may no longer be a permanent inhabitant in S.A. (and it is not known whether it ever was), possibly due to reduction in the quantity and quality of riverine / stream and estuarine habitat in south-east S.A., with examples including water diversion, extraction, reduced stream discharge, dredging (and siltation), point and diffuse source water pollution, loss of riparian vegetation, damage to river and stream banks, recreational use / disturbance of ponds, and construction of barriers (e.g. dams, drains) to migration. In S.A., area of occupancy is likely to be less than 500km2 (B2), and the species is (a) known from less than 5 locations, with (b) continuing decline inferred or projected, in the area of occupancy; the area, extent and quality of habitat, and the number of locations or subpopulations (ii, iii, iv). Australian Grayling is listed as Vulnerable under Australian Commonwealth, Victorian and Tasmanian legislation, and is a protected species in New South Wales. In south-eastern Australia (southern N.S.W., Victoria and Tasmania), where Australian Grayling is found in a number of rivers, lakes and estuaries, populations are susceptible to decline because Grayling has a complex life cycle, narrow habitat specificity, specific habitat requirements for both breeding (over a short, environmentally-cued season) and juvenile development, and few larval source habitats. Grayling is considered to be highly sensitive to changes in the environment over space and time. Many freshwater and estuarine habitats in southern Australia in which this species exists are significantly degraded. Threatening processes have been documented in detail, in both State and national reports. Examples include river and stream regulation (e.g. changes in flow patterns caused by dams, weirs and culverts - which prevent dispersal, migrations, and recolonisation of previous habitat; loss of dry-weather stream-flow, suppression of flooding; water extraction for irrigation); habitat loss and disturbance (especially lower reaches of rivers), including dredging, sand and gravel extraction, loss of riparian vegetation, wood removal and channel realignment for flood mitigation; extensive stream siltation from accelerated catchment erosion due to agriculture, coastal development, and forestry practices (which also affects food supply); other pollution of waterways by agriculture, forestry and urban development; and possible predation by (and competition with) introduced fishes, particularly salmonids. Population sizes are not known, but extent of occurrence and area of occupancy are considered to have declined during the past century, and quality of habitat continues to decline. There is a national recovery plan for this species, as well as State action plans / statements, each containing numerous recommended research and management actions to improve conservation of Grayling across the range. Implementation of recovery plans and action plans for this species will be crucial to the long term survival of Australian Grayling.

Page Contents

Current Conservation Status

IUCN Red List 2000 - 2008: Vulnerable (VU A1c) (IUCN, 2009)

Previously, under the Commonwealth’s Endangered Species Protection Act 1992, and currently under the Environment Protection and Biodiversity Conservation Act (EPBC) 1999: Vulnerable

Tasmanian Threatened Species Protection Act 1995: Vulnerable. Also protected under the Tasmanian Inland Fisheries Act, 1995 and not to be taken in Tasmania without a permit (Inland Fisheries Service of Tasmania, 2000).

Listed as a threatened species under Schedule 2 of the Flora and Fauna Guarantee Act 1988 in Victoria, and also classified as Vulnerable in Victoria (CNR, 1995; Victorian Department of Natural Resources and Environment, 2000; Koehn and O’Connor, 2002; DSE, 2007). Under this legislation, the taking, possession or trading of Grayling is prohibited without a permit, licence or Governor-in-Council Order issued under the Act. A Recreational Fishing Licence is not a permit under the Act (DPI Victoria, 1998a). In Victoria, the species was considered endangered in the 1970's and early 1980's, but more recent investigations indicate that while it may be locally rare, it occurs over a wide area (DPI Victoria, 1998a).

Protected Fish in N.S.W. (Fisheries Management Act 1994, and under Clause 6 of the Fisheries Management (General) Regulation 2002, and may not be fished.

The Action Plan for Australian Freshwater Fishes (Wager and Jackson, 1993) listed the species as Vulnerable.
Australian and New Zealand Environment and Conservation Council (ANZECC) List of Threatened Australian Vertebrate Fauna 1995.

Australian Society of Fish Biology 2001 list recommendation: Vulnerable.

Glover (1983) reported the Australian Grayling as being one of Australia’s rarest and most “extinction-threatened” fish species.

Considered rare throughout its natural range (Classon and Booth, 2002).

During the early 2000s, the South Australian National Parks and Wildlife Council and Department for Environment and Heritage (2003) recommended that the species be listed under a schedule of the South Australian National Parks and Wildlife Act 1972, and considered the species to be critically endangered in South Australia. Criteria for listing were CR D (i.e. population estimated to number fewer than 50 mature individuals) (National Parks and Wildlife Council and Department for Environment and Heritage, 2003). In the Action Plan for South Australian Freshwater Fishes (Hammer et al., 2007), this species was recommended for listing as Endangered (EN B2ab(ii,iii)) in South Australia.

Australian Grayling is not a rare species nationally, but its occurrence in South Australia is restricted to limited areas of the South-East, and may therefore be considered rare (or very rare) in this State. One fish authority (J. Pogonoski, Australian Museum, pers. comm., 2003) considers the species to be very rare in South Australia, and another expert (M. Hammer, Adelaide University, pers. comm., 2003), has stated that the species may now be extinct in South Australia.

Distribution

General

The Australian Grayling is the only surviving species in its family, and is now found only in coastal rivers and streams (and some lakes) in Tasmania, Victoria and southern New South Wales (Cadwallader and Backhouse 1983; McDowall, 1996, cited by Morris et al., 2001).
Formerly, the species was reported to have been widespread from the Grose River and Shoalhaven River, throughout New South Wales, Victoria and eastern South Australia (e.g. Ewens Ponds), and also occurred throughout Tasmania, and on King Island in Bass Strait (Lake, 1971; Bell et al., 1980, cited by DEWR, 2007). The Grayling is now patchily distributed throughout the former range, and often only captured in small numbers (less than 10). Larger populations are apparently restricted to a few rivers (e.g. Tambo River in Victoria) (Wager and Jackson, 1993).

New South Wales

The Clyde River may be important remaining habitat for this species (e.g. West and Jones, 2001; Gehrke et al., 2001) and also the Moruya River (West and Jones, 2001). The Grayling has also been recorded in Yalwal Creek and probably occurs in other tributaries of the Shoalhaven River (New South Wales National Parks and Wildlife Service, 2000). Previously, the Shoalhaven River (below Tallowa Dam) was also a significant habitat, but the abundance in the Shoalhaven area may now be low (R. Faragher, pers. comm. 2000, cited by Morris et al., 2001).
The N.S.W. Rivers Survey recorded 64 specimens from 6 different southern New South Wales coastal rivers (Harris and Gehrke, 1997, cited by Morris et al., 2001), and the Grayling is known to be present in relatively large numbers in several coastal rivers from the Clyde River south to the New South Wales-Victorian border. Examples of rivers in N.S.W. in which Grayling have been recorded include the Clyde River and Macquarie Rivulet (Breen et al., 2005a,b); the Bega River system, such as Bemboka River, Brogo River, Tantawangalo Creek (AWT 1997), the Moruya, and the Tuross (Harris and Gehrke, 1997); the Minnamurra River (Reinfelds, 1999), and a number of rivers in national parks (see Other Information). Some of the lower east-flowing streams in the South East Forest National Park are reported to be important as breeding areas for Australian Grayling (N.S.W. National Parks and Wildlife Service, 2005).
During surveys in the 1990s, the species was found mainly in unregulated rivers along the south coast of N.S.W. (e.g. Gehrke, 1997a,b). The range in N.S.W. now appears to be restricted to the south coast (McDowall, 1996, cited by Morris et al., 2001); however, a decline in populations even along the south coast of New South Wales has been reported (Miles, 2007). The species has not been recorded from the Grose River (part of the Hawkesbury-Nepean River system) since the 1950s (Gehrke and Harris, 1996, cited by Morris et al., 2001).
A single juvenile specimen was collected from Lake Macquarie in 1974 (Australian Fish Collection Records, cited by DEWR, 2007).
Backhouse et al. (2008a,b) summarised important rivers in New South Wales for this species.

Victoria

Once common in all waters of Victoria, particularly the Yarra River, it is still recorded in some localities (DPI Victoria, 1998a), and still considered to have a large geographic range in that State (DAFF, 2004). It is uncertain to what extent presence and abundance has declined in Victoria (Land Victoria, 2007). In that State, the species occurs in coastal drainages, mainly eastwards of the Hopkins River / Warrnambool area, and can occur well inland in streams. DPI Victoria (2005) reported that the Grayling still occurs in the Hopkins River catchment. Grayling has been collected more frequently in the Tambo, Barwon, Mitchell and Tarwin River systems than in other areas (Jackson and Koehn 1988, cited by DEWR, 2007). The Tambo River population may be the largest in Victoria (Wager and Jackson, 1993, cited by Morris et al., 2001). The population of Australian Grayling in the Mitchell River and in most of the tributary rivers is described as being “very large” (Australian Government, 2009).
Populations have been recorded during the past decade in several upstream locations in the Yarra River, including Dight Falls, following the construction of a rock ramp “fishway” to assist upstream migration (DPI Victoria, 1998a, Ryan et al., 2003), as well as immediately downstream of barriers in the Barwon and Yarra Rivers (Wager and Jackson, 1993). The species also occurs in the Highlands – Southern Fall Bioregion of Victoria, which extends from Yan Yean Reservoir in the west to the Tambo River in the east (Mueck et al., 2005). Grayling is also reported from 2 reaches in the Bunyip and Tarago Rivers (Earth Tech, 2006). In 2002, a Grayling was recorded above McNabs Weir, in the upper reaches of the Maribyrnong River, and the distance upstream of the specimen is considered significant (Melbourne Water, 2002).
The species has also been recorded in the Bemm River (Snowy River catchment area) (Land Conservation Council, 1991). The Snowy River area is reported to support a “good resident population” of this species (Australian Government, 2009).
In the East Gippsland region, the species has been recorded in most catchments, although the proportion of the region occupied is calculated to be only 8% (i.e. 22 out of 275 sampled sites) (Raadik 1992a, 1992b, 1995, cited by DAFF, 2004). There are relatively recent records from the East Gippsland River (Harris and Gehrke, 1997), and other areas in Gippsland (Thomson, Macalister and Avon rivers, and Rainbow Creek – Koster and Crook, 2006).
Examples of museum specimens from Victoria include those from the Tambo River and Timbarra River, and Gippsland Lakes (Museum of Victoria records, cited in OZCAM database, 2009).
DSE Victoria (2003) summarised catchments in which this species has been recorded, which includes the following rivers and catchments: Towamba, East Gippsland, Snowy, Tambo, Mitchell, Thomson (a regulated river - Gippel and Stewardson, 1995), La Trobe, South Gippsland, Bunyip, Yarra, Maribyrnong, Werribee, Moorabool, Barwon, Hopkins, and Glenelg (see below), as well as the Otway coast and Portland coast. However, Land Victoria (2007) reported that it is an old (1895) record from the Glenelg River in south-western Victoria but, despite numerous surveys in the Glenelg River over several decades, the species has not been recorded there since (DSE-ARI unpubl. data, cited by Land Victoria, 2007).
Land Victoria (2007) and Backhouse et al. (2008) summarised important rivers in Victoria for this species, which include (in alphabetical order): Agnes River, Aire River, Albert River, Avon River system, Barham River, Barwon River, Bemm River, Bunyip River, Calder River, Cann River system, Cardinia Creek, Carisbrook Creek, Cumberland River, Curdies River, Erskine River, Franklin River, Gellibrand River, Genoa River, Hopkins River, Lang Lang River, Merrimans Creek, Mitchell River system, Roaring Meg Creek, Skenes Creek, Snowy River, St Georges River, Tambo River, Tarra River, Tarwin River, Thomson River, Thurra River, Wild Dog Creek, Wingan River, Wye River, and Yarra River system.

Tasmania

The species occurs widely in Tasmania, although it is uncommon across that range, and in low to very low abundance compared with historical records. It is mainly found in northern and eastern rivers, at lower elevations (Inland Fisheries Service of Tasmania, 2000). It also occurs less frequently in the southern coastal river drainages, with occasional reports from the west coast (McDowall, 1980). Rivers such as the Duck, Arthur, Pieman, Detention, Weld, Picton, several in the Mersey catchment, Tamar (including sightings in the Cataract Gorge), Tomahawk, Leven, Boobyalla, Georges, North West Bay, and Huon (south-west Tasmania) are known or considered highly likely to contain P. maraena (Green, 1999, 2001; Edgar et al., 1999; Pinto and Graham, 2000; Forestry Tasmania, 2000; Davies et al., 2001; Pinto, 2002; Hydro Tasmania, 2003; Aquenal Pty Ltd, 2004; CSIRO Australian National Fish Collection records, cited in OZCAM database, 2009).
Australian Grayling is reported to be native to the Derwent (Davies, 2001).
This species has been sighted at Swanston (Little Swanport River), one location in the lower Little Swanport catchment (Deep Hole), and one location in Lisdillon Rivulet (DPIWE and IFS data, 1998, 2003, 2004). The species has also been recorded at Emu River (Krasnicki, 2001) and Cox’s Rivulet (Davies and Cook, 2006) in northern Tasmania, and the North Esk River (Krasnicki, 2003), in north-eastern Tasmania.
During surveys conducted on King Island in 2001, the species was not recorded (Davies et al., 2001), but this species was recorded on King Island during a mid-late 1990s survey, below the gauging weir in the Ettrick River (Edgar et al., 1999; also cited by Davies et al., 2002).
Backhouse et al. (2008) summarised currently important rivers in Tasmania for this species.

South Australia

The lower South-East of South Australia is the western edge of the distribution (Hammer et al., 2007).
In S.A., Grayling have previously been reported from Eight Mile Creek (Ewens Ponds) (photographic evidence, cited in Glover, 1983; Cadwallader and Backhouse 1983), Ellards Creek (Piccaninnie Ponds) (unverified record, cited in Hallam and Thurgate, 1992), and Stratman’s Pond (Deep Creek system) (anecdotal report, cited by Hammer et al., 2007). No Grayling have been found recently in South Australia, following comprehensive estuarine surveys (M. Hammer, Adelaide University, pers. comm., 2003; Hammer et al., 2007).
It is unknown whether the Australian Grayling was a permanent inhabitant in South Australia, or whether juveniles occasionally moved there (to the lower South-East) from source habitat in western Victoria (Hammer et al., 2007).
One fish authority (J. Pogonoski, ex-Australian Museum, pers. comm., 2003) considers the species to be very rare in South Australia, and another expert (M. Hammer, Adelaide University, pers. comm., 2003), has stated that the species may now be extinct in South Australia.
There are no records from South Australia listed in the On-line Zoological Collections of Australian Museums’ database (OZCAM, 2004, 2007, 2009).

Habitat

Australian Grayling is a freshwater fish, but has a marine stage in its life cycle. Little is known of the marine phase, compared with its freshwater and estuarine existence, and the precise habitats are not known (Crook et al., in prep., cited by Land Victoria, 2007).
In general, the species occurs in estuarine creeks, coastal rivers, and marine waters (Paxton et al. 1989). The species is mainly associated with coastal drainages of south-eastern Australia and inhabits large and small coastal rivers, creeks and streams for most of the life cycle. Grayling prefer deep, slow flowing pools and other still fresh waters (of high water quality) with good riparian vegetation and macrophyte cover, and the species is often found mid-water, over gravel bottoms in cool, clear waters of moderate or slow flow, in sections alternating between pools and rapids / riffles (Berra, 1982; Allen, 1989; Wager and Jackson, 1993; McDowall, 1996; DPI Victoria, 1998a; Inland Fisheries Service of Tasmania, 2000; Pinto, 2002).
In the Tambo River, this species inhabits a clear, gravel-bottomed stream with alternating pools and riffles, and granite outcrops (Berra, 1982). It has also been associated with clear, gravel-bottomed habitats in the Mitchell and Wonnangatta Rivers (Victoria) but was present in a muddy-bottomed, heavily silted habitat in the Tarwin River (Jackson, 1980). Hall and Harrington (1989) located a population of adult Grayling in consecutive years in the lower, urban reaches of the highly turbid Barwon River, with a salinity of about 1.5 parts per thousand.
Grayling is mainly a mid-water species, and it is not known whether the species has a preference for structural habitat (Wager and Jackson, 1993).
In South Australia, potential habitat includes streams with coastal access (e.g. from rising spring habitat), in the lower South-East (Hammer et al., 2007).
The species can penetrate well inland, and has been reported from over 100 km upstream from the sea (Jackson and Koehn, 1988, cited by Land Victoria, 2007).
Reported depth range is 0 – 4m (Edgar, 2000).

Notes on Biology and Behaviour

Compared to many other rare (and threatened) fish, a considerable amount is known about the biology and ecology of the Australian Grayling (DAFF, 2004).

Age and Growth

This species is known to reach 30 - 33cm in length (Lake, 1971; Allen, 1989; Inland Fisheries Service of Tasmania, 2000), but the most common size is between (15cm)17cm - 18cm(20cm) (McDowall, 1976; Koehn and O'Connor 1990b; DPI Victoria, 1998a; Inland Fisheries Service of Tasmania, 2000; Prokop, 2000; DEWR, 2007; Hammer et al., 2007). Fish reach about 80mm at 1 year of age, 150mm at 2 years of age, and 190mm at 3 years of age (McDowall, 1996, cited by Morris et al., 2001).
One of the longest specimens known in recent decades was taken in the Barwon River in Victoria, and measured 262 mm FL (Hall and Harrington, 1989, cited by DEWR, 2007).
Grayling reportedly reaches 0.3 - 0.5kg (Bryant and Jackson, 1999; Land Victoria, 2007). The maximum size recorded by the Australian Anglers Association Records Authority is 0.12kg, being a specimen caught in 1990, from the Ford River in Glenaire, Victoria (Australian Anglers Association, 2003). A specimen of 100g was caught in 1987, by a member of the Gerringong Hotel Fishing Club (NSW Fishing Clubs Association record).
Maximum reported age is 6 years (Berra, 1982; Berra and Cadwallader, 1983); however evidence indicates that the majority of Grayling die before or during their third year (DPI Victoria, 1998a), and Koehn and O’Connor (1990b, cited by DAFF, 2004) reported an average life span of 4 years. During a study in the Shoalhaven River in N.S.W., longevity of individuals was about three years and heaviest adult mortality appeared to occur after spawning at two years of age (Bishop and Bell, 1978b, cited by DEWR, 2007). During a study of 1,203 individuals in the Tambo River, the majority (88%) were in the 1+ and 2+ age class; 11% were in the 3+ and 4+ age class, and less than 1% in the 5+ age class (Berra and Cadwallader, 1983).
In the Tambo River, a study of the Grayling population indicated that the size of individuals increased from January to May, then growth ceased during winter and resumed in September. There was no difference in growth between the sexes (Berra and Cadwallader, 1983).

Behaviour

The species often forms large schools, especially prior to spawning (Allen, 1989).
In Tasmania, Grayling occurs in fast-moving schools (Inland Fisheries Service of Tasmania, 2000).
Grayling is described as “a shy fish” that flees when disturbed (Inland Fisheries Service of Tasmania, 2000).

Diet

Generally, Grayling is an opportunistic omnivore that feeds on small crustaceans (e.g. cladocerans), terrestrial insects that fall to the water surface, aquatic insects and their larvae (e.g. chironomids, trichopterans, and ephemeropterans), and also small gastropods, macrophytes, filamentous algae and diatoms (Jackson, 1976; Berra, 1982; Bishop and Bell, 1978b, and Berra et al., 1987, cited by DEWR, 2007; Michaelis, 1985; Allen, 1989; McDowall, 1996).
Adaptation to the consumption of algae is facilitated by a double loop in the intestine, an unusual feature in salmoniform fishes (McDowall, 1996, cited by Morris et al., 2001).
During one study, green algae Stigeoclonium sp. occurred only in the stomachs of the largest size group of Grayling in summer, where it made up 25% of the volume (Berra et al. 1987, cited by DEWR, 2007).

Reproduction

Grayling mature at 1-2 years of age (around 15 cm TL) (Inland Fisheries Service of Tasmania, 2000). Males mature earlier, at age 1, and females appear to mature after 2 years in fresh water (Berra 1982, cited by DEWR, 2007; Koehn and O’Connor, 1990; Classon and Booth, 2002).
A study in the Barwon River in Victoria indicated that (i) males were fertile more than two months earlier than females, and (ii) the dominance of 3+ and 2+ year old fish in that river may reflect geographical or temporal variation in recruitment, or differential survival of year classes (Hall and Harrington 1989, cited by DEWR, 2007). In south-eastern Australia, gonad development begins in mid March, peaks in late April and declines by mid May. There are increasingly large mortality rates amongst spawning adults after 2 years (Koehn and O’Connor, 1990, cited by Morris et al., 2001). Some males may spawn in their first year, but most males and females do not spawn until their second year. This means that most individuals probably spawn only once before dying (Land Victoria, 2007, citing research by Koehn and O’Connor).
Spawning is likely to take place in the freshwater mid-reaches of streams (Lake, 1971; McDowall 1976; DPI Victoria, 1998a; Classon and Booth, 2000), usually in the same place that the adults inhabit (Cadwallader and Backhouse, 1983; Inland Fisheries Service of Tasmania, 2000). Australian Grayling are thought to spawn in freshwater on rising flows (O’Connor and Mahoney, 2004, cited by Koster and Crook, 2006).
Grayling is a diadromous species, which spawns annually during spring, summer or autumn (Koehn and O’Connor, 1990b; DEWR, 2007). Different rivers at different latitudes (with varying temperature regimes or other environmental influences) may produce different spawning seasons (Berra, 1982), and spawning time may also vary between years. South-eastern Australian examples include February to March in Shoalhaven River in N.S.W.; April to May in the Tambo River in Victoria; and mid-May in the Barwon River (Victoria) (Bishop and Bell, 1978b; Berra, 1982; Hall and Harrington, 1989, all cited by DEWR, 2007). In Tasmania, spawning may take place from late spring to early summer (Fulton, 1990).
Various spawning cues have been suggested, including a drop in water temperature, flow events (increase in river flows from seasonal rains, possibly coupled with a decrease in water temperatures), reduction in day length, moon phase, a rise in water levels, and an increase in river water discharge to a critical level (Jackson and Koehn, 1988; Hall and Harrington, 1989; O'Connor and Mahoney, 2000, all cited by DEWR, 2007; Land Victoria, 2007).
During a study in the Tambo River, the spawning season was reported to be short and highly synchronised (Berra, 1982). About 25,000-68,000 eggs (average reported is 47,000) are released (Berra, 1982; Cadwallader and Backhouse, 1983).
Exact spawning sites and behaviour are poorly known, but eggs are scattered over the substrate, and sink to the bottom, downstream of the spawning site. Berra (1982, cited by DEWR, 2007) speculated that eggs settle in the crevices of the gravel bottom.
Eggs hatch after 10-20 days, and the actively swimming larvae, which are around 6-7 mm TL, are swept downstream to estuaries / brackish water near the sea. They remain in estuarine and nearshore waters for around 6 months before returning to freshwater to complete the life cycle (Berra, 1982). Newly-hatched fish are known to react strongly to light, preferring shady areas (DPI Victoria, 1998a). Larvae probably commence feeding in estuarine waters where the food supply is more diverse and abundant than in rivers (Bacher and O'Brien, 1989). Marine larval stages probably disperse widely and have the ability to recolonise suitable habitat (Wager and Jackson, 1993). The young fish (approximately 55-75mm long) return upstream (e.g. in the “whitebait run”, in Tasmania) to fresh water during late spring / early summer, where they spend the rest of their lives (Berra, 1982; Allen 1989, Paxton et al. 1989, Koehn and O’Connor, 1990b; Wager and Jackson, 1993; DPI Victoria, 1998a; Inland Fisheries Service of Tasmania, 2000).
In the Tambo River (Victoria), young-of-the-year fish return to fresh water in about November; they attain 73–142 mm in length at one year, 113–200 mm in length after two years and 183–234 mm in length after three years. However, most fish die after their second year, probably soon after spawning, although a small proportion may reach four or five years of age (Land Victoria, 2007).
It is not known whether there are discrete stocks of Grayling that ascend their own natal streams, or whether there is mingling in coastal areas and ascension of any convenient river (Berra 1982, cited by DEWR, 2007).

Other Information

Grayling migrate between freshwater streams and the ocean (Lake, 1971; Bishop and Bell, 1978a) and as such it is generally accepted to be a diadromous (migratory between fresh and salt waters) species (Bishop and Bell 1978a).
Grayling can form large schools (possibly spawning aggregations), and are fast swimmers, darting away from danger very quickly (Land Victoria, 2007).

Fisheries Information

The species is not fished commercially, but it is noted that Wayte et al. (2004) reported a minor quantity (0.5kg) being caught in one otter trawl shot in the South East Trawl Fishery, as part of a monitoring program during 2000/01. The validity of the record cannot be ascertained for this report.
• Recent Australian Fishing Network Guides (Prokop, 2000 and Classon and Booth, 2002) recognise the conservation status of the species. Grayling is reported to be rarely taken by recreational anglers, and not specifically targeted, due to its small size and recognition of its vulnerable status (Prokop, 2000). Previously, the Australian Grayling was regarded as an excellent table fish, but would not be eaten today due to its conservation status (Prokop, 2000). In Victoria, Grayling has been described as previously being a highly esteemed sporting fish, renowned for its table qualities, but seldom taken in recent years, and now of little significance as an angling or food species (DPI Victoria, 1998a). Previously, in both Victoria and New South Wales, there were records of capture by anglers. For example, a specimen of 100g was caught in 1987, by a member of the Gerringong Hotel Fishing Club (NSW Fishing Clubs Association record). In Victoria, the record specimen is 0.12kg, caught in the Ford River in Glenaire, in 1990 (Australian Anglers Association, 2003).
Australian Grayling is one of the species caught in the bycatch of the commercial eel fishery in Victoria (DPI Victoria, 2003), but data are not available for this report.

Vulnerable Characteristics of the Species

The Grayling is vulnerable to decline, due to its having a narrow habitat range in South Australia, being dependent upon a small number of estuaries, particularly in cool temperate regions. The species also has specific habitat requirements for breeding and juvenile development. The situation is similar in Victoria, where the species is described as having a “narrow habitat specificity”, thus occupying only a small proportion of available river and stream habitat (Koehn and O'Connor, 1990b; Raadik, 1992a and 1995, cited by DAFF, 2004).
It is suspected that only a few rivers may act as sources of larvae for the total population (Wager and Jackson, 1993).
Grayling is considered to be “highly sensitive to changes in the environment” (New South Wales Fisheries, 2006c). Grayling have a short, highly synchronised reproductive season, and although this species is considered to be relatively fecund, its complex life cycle and reliance on rivers means that a succession of environmentally “difficult” years (which result in poor reproductive output), could decimate populations until conditions improve (Berra, 1982).
Because the Australian Grayling is a diadromous species, migrating between rivers, their estuaries and coastal seas, it relies on free access to a range of freshwater, estuarine and marine habitats for its survival, but many of the freshwater and estuarine habitats in southern Australia are significantly degraded (see Threatening Processes).
Although the species has a relatively high fecundity, the decline in Grayling abundances (which may be cyclical), possibly reflect the species’ complex life cycle. Several difficult environmental years in succession, which is typical of Australia's drought-flood cycles, could have serious effects on Grayling populations; however it is reported that survivors could “explosively” repopulate some areas during favourable years (DPI Victoria, 1998a).

Threatening Processes

General

In the latter half of the twentieth century, the Australian Grayling was believed to have suffered a severe decline in distribution throughout most of its range (Ingram et al., 1990, cited by Morris et al., 2001), due to habitat modification and destruction (Wager and Jackson, 1993).
Reduction in the quality and extent of critical riverine and estuarine habitat is a major threatening process for Grayling populations, especially the construction of dams and weirs in rivers and estuaries (Prokop, 2000; Morris et al., 2001; Classon and Booth, 2002). Barriers such as dams, weirs, culverts and levee banks prevent dispersal, and also the diadromous migrations and the re-colonisation of the previous generations’ upstream habitats (Morris et al., 2001). It has been suggested that the construction of impoundments (Bell et al., 1980) and river regulation (T. Raadik, pers. comm. 2001, cited by Morris et al., 2001) have been the main contributors to the decline of the Australian Grayling in New South Wales and Victorian coastal streams. The upstream migration of this species has been effectively terminated in some rivers by dams (e.g. Tallowa Dam, thought to be responsible for the virtual disappearance of this species from the Shoalhaven River) (Bishop and Bell 1978a, cited by DEWR, 2007; Gehrke et al., 2002). Many rivers within the natural range of the Australian Grayling have been affected by barriers (Inland Fisheries Service, 2000; DSE unpubl. data, cited by Land Victoria, 2007). The blocking of upstream migration, and interference with downstream migration, can cause local extinction in the section of river upstream from the barrier. If barriers block access to breeding habitat, then reproductive output is reduced, placing pressure on the population. Barriers also limit the ability to colonise or recolonise suitable habitat, and can reduce gene flow by fragmenting populations (Land Victoria, 2007). River regulation and extraction reduces the frequency and extent of natural flooding in winter and spring, and often increasing flows in summer, when stored water is released for irrigation. Reducing and altering the seasonality of river flow (either through retention in dams and weirs, diversions or from direct pumping), can directly affect adult Grayling as well as reducing reproductive potential and recruitment (Land Victoria, 2007).
For a short-lived species such as the Australian Grayling, several reduced or missed spawning opportunities in quick succession (such as could occur in regulated rivers) could have important consequences, leading to decline or local extinction, especially of small populations (Backhouse et al., 2008b).
Reduction in river flow, and increases in water temperature may be detrimental to this species. In areas where rivers or streams have been reduced to a series of pools during drier periods of the year, the increased temperature of such small pools may have lethal effects. In Victoria, for example, during a drought year in 1982/3, a school of Australian Grayling in the Dargo River was observed dying in a pool of water with a surface temperature of 26oC and a bottom temperature of 24oC. Dissolved oxygen readings were 4 mg/L at the bottom and 6 mg/L at the surface (B. O’Connor, DNRE, pers. comm., 1999, cited by Clunie and Koehn, 2001). This observation may indicate that increased water temperatures are detrimental to this species, but further research is required (Clunie and Koehn, 2001). Over the longer term, the decline in overall rainfall, and consequent increasing dryness caused by climate change, is expected to result in further reduced river flows and higher demand for water use (Land Victoria, 2007). For Australian Grayling, reduced flows mean reduced habitat, reduced spawning opportunities and interference with upstream migration. Reduced flows may also cause increased blockage of river mouths by sand bars, which prevent both upstream migration and movement of larvae and juveniles to the sea. This decreases chances of recolonisation and may possibly cause local extinction of populations (Land Victoria, 2007).
Siltation is another significant component of the degradation of rivers, streams and estuaries, and another potential impact upon Grayling populations, particularly spawning habitat (Morris et al., 2001). Increased siltation of rivers can result from catchment disturbance including vegetation clearing, degradation of riparian zones, burning, and making roads. Increased siltation reduces water quality, can promote plankton blooms and smother river substrate used by Grayling for feeding and spawning. High turbidity from suspended sediment erodes fish gills and has been shown to affect feeding in riverine fish species (Rowe et al. 2002, cited by Backhouse et al., 2008a). Sediments can remain deep in river substrates for several years and altered flows may reduce sediment removal. Whilst subsequent flooding would usually flush excessive siltation downstream, reduced flooding (e.g. from drought, river regulation) possibly means less effective flushing of sediment from gravel beds (Backhouse et al., 2008a).
Poor water quality (such as thermal pollution, reduced dissolved oxygen, increased nutrients and toxins) can also affect Grayling populations. Causes include reduced flows due to water diversion (discussed above), impoundment or sustained dry periods. Heavy rainfall can cause sediment and ash run-off from areas laid bare from over-grazing, vegetation clearance, drought and wild fires. Nutrient run-off from urban and agricultural areas can cause result in plankton blooms and reducing oxygen levels. Fish kills can result from these conditions, and species such as Australian Grayling may avoid or not recolonise areas of sustained poor water quality (Land Victoria, 2007).
The possible impact of salmonids on Australian Grayling was included as one of a suite of justifications for a nomination (in the early 2000s) under the EPBC Act 1999 to list as a threatening process: The introduction of live native or non-native fish into Australian watercourses that are outside their natural geographic distribution. As at 2007, the introduction of introduced fishes (such as salmonids) has not been listed yet under legislation as a threatening process. However, the potential impacts of introduced fishes has been highlighted as one of the significant issues for Australian grayling populations, in the national recovery plan for Australian Grayling. Examples of introduced fishes which may cause impacts include Common Carp Cyprinus carpio, Goldfish Carrasius auratus, Redfin Perch Perca fluviatilis, Eastern Gambusia Gambusia holbrooki, Oriental Weatherloach Misgurnis anguillicaudatus, Brown Trout Salmo trutta and Rainbow Trout Oncorhynchus mykiss. Introduced species can pose a threat to native fish species and their habitats through predation, competition, disease transmission and other effects such as physical habitat degradation, often through the very high densities some introduced fish species may reach. Trout are known to prey on small grayling (T. Raadik DSE-ARI pers. comm., cited by Backhouse et al., 2008a) and are also likely to compete for habitat, especially as Grayling and trout occur in similar habitats (Jackson and Koehn, 1988). Larvae and juveniles may be highly susceptible to predation by trout (and other piscivorous species), especially during their migration from marine waters through estuaries and then upstream to the adult habitats, where they may need to pass through areas occupied by trout. Barriers and areas of low flow may also exacerbate susceptibility to predation, causing large aggregations of migrating fish to gather at blockages (Backhouse et al., 2008a).
Historically, spread of disease from introduced salmonids is considered to have been responsible for significant mortality in Australian Grayling in Tasmania. For example, Saville-Kent (1888) reported that the fungus Saprolegnia is associated with Brown Trout and Tasmanian Salmon hatcheries in Tasmanian rivers (e.g. River Plenty). On some occasions, it was said to be "so abundantly developed as to constitute a veritable epidemic which may be communicated to apparently healthy fish". Saville-Kent reported a significant episode which caused the demise of Australian Grayling in the area. The grayling were said to "have been seen floating down the rivers in thousands, covered more or less extensively with a cottony fungoid growth. So virulent and exhaustive was this epidemic that many, more especially of the southern rivers, were more or less completely denuded of their stock of this species and have so remained up to the present date". "The approximate date of the appearance of this epidemic would appear to be about the year 1869 or 1870, periods it maybe remarked of great activity in association with the distribution of the fry of the newly acclimatised Salmonidae in the rivers of this colony. Is it possible ...that the fungus, Saprolegnia, was hitherto unknown to Tasmania and was introduced with the ova of these Salmonidae, or more probably in the moss wherein they were packed? Under such conditions, the germs or spores, like the microbes of measles or smallpox, arriving on a virgin and congenial soil, might be expected to spread with devastating virulence among the aboriginal inhabitants” (Saville-Kent, 1888, cited by Cadwallader, 1996). According to Low (cited by Coyne, 2001), the population recovered, yet there is no evidence that Grayling currently persists in Tasmanian rivers in the thousands, as was the case during the 19th century.
Angling and whitebait collecting can result in accidental catches, especially where aggregations of grayling occur below instream barriers (Land Victoria, 2007).

State Summaries

Wager and Jackson (1993) and Bryant and Jackson (1999) summarised the following specific reasons for decline of Australian Grayling populations in south-eastern Australian states: (i) dams, weirs and culverts, which prevent dispersal, diadromous migrations, and recolonisation of previous habitat; (ii) river regulation with loss of dry-weather stream-flow, suppression of minor flooding, and changes in flow patterns caused by dams and water extraction for irrigation; (iii) habitat loss and disturbance (especially the lower reaches of rivers); loss of riparian vegetation, and other habitat alterations such as wood removal and channel realignment for flood mitigation; (iv) extensive stream siltation from accelerated catchment erosion due to agriculture and forestry practices; (v) other pollution of waterways by agriculture, forestry and urban development; (vi) stream channel damage from sand and gravel extraction; (vii) alteration, particularly through siltation, of stream macro-invertebrate communities that provide food; and (viii) possible predation by salmonids (e.g. Brown Trout Salmo trutta) on the whitebait stage of the life cycle, and competition between salmonids and Grayling (also cited by McDowall, 1996; Arthington and McKenzie, 1997; and Morris et al., 2001).
In N.S.W., populations of Grayling have greatly declined because of construction of dams, siltation and other changes to coastal streams (New South Wales National Parks and Wildlife Service, 2000). River regulation may be a significant factor in the decline of populations. For example, during a study of regulated and unregulated rivers in N.S.W., no Grayling were recorded in rivers along the north coast, and in the south coast, numbers were an order of magnitude higher in unregulated compared with regulated rivers (Gehrke, 1997b).
In Victoria, Australia Grayling was a very common species a century ago, but populations declined dramatically during the last half of the 19th century, probably as the result of the human impact on habitat, stream regulation and siltation of stream beds, and possible impact of introduced species such as trout (DPI Victoria, 1998a).
In Tasmania, it is thought that over-fishing and habitat loss have caused a reduction in numbers to the point of Grayling being uncommon, although they are still quite widespread (Inland Fisheries Service of Tasmania, 2000). Recognised threats in Tasmania are mainly associated with the freshwater phase of the life cycle, and include loss of riparian and in-stream habitat (including wood removal); construction of dams and weirs (obstructing migration paths and changing flow patterns); in-stream barriers preventing dispersal; high water temperatures during low flow periods; river regulation and channel realignment, with loss of dry weather flow and suppression of minor flooding; extensive stream siltation from erosion; other forms of water pollution; stream channel damage from sand and gravel extraction; and possible predation by salmonids on the whitebait stage of their life cycle (Inland Fisheries Service of Tasmania, 2000; Pinto, 2002).
In South Australia some of the concerns for freshwater and estuarine species (including Grayling) include the construction of dams, weirs, barrages (and drains) along watercourses, which (i) changes the rate, volume and direction of water flow; (ii) restricts access of native fish species to existing habitat and new areas for colonisation, and (iii) also interrupts patterns of migration (e.g. during spawning). Widespread residential and/or agricultural development adversely affects the habitat of native freshwater fish, through water extraction and diversion, point source and diffuse source water pollution, and loss or degradation of essential habitat such as riparian vegetation (resulting in reduced habitat for feeding and sheltering; stream and river bank instability; changes to channel morphology; increased siltation, and reduced capacity of streams and channels to filter agricultural and urban pollutants). Further, the introduction of exotic fish has resulted in increased competition and predation for native river- and stream-dwelling species in S.A. (Urban Forest Biodiversity Program, undated). Hammer et al. (2007) summarised threatening processes for Grayling in South Australia, which mirror most of those in south-eastern Australia. Examples include reduction in habitat condition and suitability, due to continued stream modification (e.g. dredging in Eight Mile Creek), human activity and disturbance to a “shy” species (e.g. heavy recreational use of Ewens Ponds), and reduced stream discharge noted in the Lower South East springs. Other general threats include the construction of migration barriers without adequate fish passage, and potential for predation from introduced fish species (NB trout are not currently present in south-eastern south Australia) (Hammer et al., 2007).

Research Notes

In southern Victoria, mitochondrial sequences and microsatellite loci have been used to investigate the genetic structure of Australian Grayling populations. The study aimed to determine if populations comprise a single genetic stock with a common marine recruitment source or each river hosts a discrete fish population genetically differentiated from the others with the fish displaying a homing behaviour. A total of 81 samples were collected from four Victorian coastal rivers. Based on data from 505 base pair fragments of mitochondrial ATPase and 6 microsatellite loci, it was suggested that populations of the Australian graylings are not genetically differentiated across the four rivers. The fish larvae must mix during the time that they spend in the ocean and then return to any river to complete their life in freshwater without displaying a homing behaviour (Carini, 2009).

Research Recommendations

The Action Plan for Australian Freshwater Fishes (Wager and Jackson, 1993) stated that knowledge about Grayling is inadequate, and recommended research into basic biology; distribution and determination of genetic diversity, and identification of breeding populations. In particular, recommendations for biological research included habitat requirements of various life history stages (especially in-stream flow rates); migratory behaviour; spawning locations; reproductive biology, and recruitment processes, including determination of the most important river systems for recruitment, which would require an investigation of genetic diversity. The resolution of distribution and genetic diversity would require a major co-operative project between authorities in the south-eastern States (Wager and Jackson, 1993).
The New South Wales Department of Primary Industries (2008), has recommended a number of research requirements, such as (i) an assessment of the distribution of P. maraena within catchments where it is known to occur, to help quantify the extent to which barriers are affecting the distribution of the species; (ii) population genetics assessment, to determine if the Australian grayling population on the east coast of Australia is a single panmictic population or whether each catchment supports its own independent population. It is also unknown how the NSW population/s interact with those in Victoria and Tasmania.; and (iii) catchment level analysis of the inter-annual population dynamics of Australian grayling populations. This is considered particularly important given the typically highly variable nature of Australian grayling abundance in any one catchment.
In the south-eastern highlands of the Australian Capital Territory, the Australian Government (2007) listed recommended conservation actions for this species, which included fencing (to exclude grazing), visitor management / control of human disturbance, and weed control near rivers, and reinstating hydrology / enhancing flow regimes.
Morris et al. (2001) and Land Victoria (2007) recommended that conservation of Australian Grayling requires further study of the species’ population genetics throughout the range, and should especially address the question whether populations in individual rivers are discrete or part of a single, larger homogeneous population that should be managed as a single unit. Such work is now being undertaken in some areas (see Research Notes)

Conservation / Management Recommendations

The implementation of the national recovery plan (Backhouse et al., 2008) is required, in accordance with the Commonwealth listing of this species under the EPBC Act 1999 (see DEWR, 2007), and State listings. At a State level, implementing the recommendations in conservation plans / action plans will assist with protecting and recovering Australian Grayling populations. Examples include plans for Tasmania (Bryant and Jackson, 1999), Victoria (Land Victoria, 2007), and South Australia (Hammer et al., 2007).
Increased freshwater flows through the mouths of rivers into the marine environment act as a cue for migration upstream and so it is important that flooding events (or “freshes”) occur within coastal river systems, to ensure recruitment of this species.
Unobstructed migration corridors within rivers are essential to this species’ survival, making improved fish passage an integral component of any recovery program (Morris et al., 2001).
Improved land use practices and the re-establishment of riparian vegetation could be achieved via further education of landholders, and would result in further improvement of water quality. Habitat restoration at localities where Australian Grayling populations are known to occur may also significantly benefit this species (Morris et al., 2001).
Previously, the Action Plan for Australian Freshwater Fishes (Wager and Jackson, 1993) recommended that existing major populations and their habitats be protected, especially those populations from which recruitment is greatest; and that free passage for Grayling between estuaries and freshwater habitats must be ensured. Other important management requirements include the need for adult fish to have access to freshwater habitats.
Previously, Wager and Jackson (1993) reported that a number of management actions had been initiated in New South Wales, including liaison within and between State and local government authorities, in order to manage Grayling habitat more effectively; research and management to maintain free passage for fish in streams; a survey of the status of New South Wales populations of Grayling; feral animal controls, such as restricting the stocking of salmonids in known Grayling habitats, and controlling salmonid populations in known habitats.
More recently, similar recommendations have been made in Tasmania (Bryant and Jackson, 1999; DPIWE, 2004p) for the protection of Grayling. Examples include (i) avoiding the construction of dams, weirs and culverts wherever possible. Structures such as culverts channel the water flow over a smooth concrete surface and increase flow velocity, but some freshwater fish are unable to navigate through such structures, and the Grayling requires free movement between fresh water and marine habitats in order to complete the life cycle; (ii) not removing gravel or large quantities of rock from streambeds (because gravel beds contain aquatic fauna, provide cover, and disperse water flow; also, the removal of shingle from river beds can alter the stream hydrology and lead to erosion of the streambed and channel); (iii) not clearing native vegetation from stream side zones or stream banks, because vegetation provides shelter, shade (maintains water temperature) and essential food for Grayling and other aquatic fauna, and also filters surface runoff (reducing nutrients and sediments), limits light levels and maintains slope and bank stability; (iv) maintaining a mix of native understorey and overstorey plants in stream zones, including reeds, grasses, shrubs and trees, because trees, shrubs and ground cover all play different and important roles in stream bank stability; (v) removing non-native vegetation such as willows, cumbungi, and dense weed mats, and replacing with native species; (vi) establishing vegetation as far down the base of stream banks as possible; and providing as wide a native vegetation buffer as possible; (vii) ensuring that snags and other woody debris are maintained in rivers and streams (or reintroduced into degraded systems), because snags are essential for maintaining natural flow conditions, and creating shade and shelter; also, their gradual decay and trapping of leaf litter provides the food for Australian Grayling and many other aquatic animals. Other recommendations include reduction of the use and run-off of farm chemicals in waterways, because some native fish (including grayling and its eggs) are considered to be sensitive to even light dosages of chemicals. Reduction of stock access to stream and river banks may also reduce pollution / water fouling, and help control degradation of stream / river banks.
Protection of this species in South Australia would require similar actions to those recommended in New South Wales and Tasmania, with protection of water quality and flow, and in-stream habitat, being key requirements. The Action Plan for South Australian Freshwater Fishes (Hammer et al., 2007) recommended the following recovery objectives: (i) conditions be improved in potential habitat; (ii) continual monitoring for presence, and assessment of status in the wild; (iii) better understanding of biology and habitat, if species is recorded again in South Australia; and (iv) increased awareness, and reporting on the species’ presence. Actions required to meet these objectives include: (i) protecting and restoring groundwater discharge to rising springs in the lower south-east of South Australia; (ii) undertaking riparian habitat restoration along eight Mile Creek and Deep Creek, to improve stream-side shelter and bank stability; (iii) determine the current presence of Grayling in S.A. through ongoing surveys and movement studies, to detect if juvenile migration is occurring (and hence recruitment to adult habitat is an issue); (iv) reporting any past or present sightings to Native Fish Australia (South Australian branch) (Hammer et al., 2007).

Management Notes

A national recovery plan for Prototroctes maraena has been prepared (Backhouse et al., 2008a,b). The main aim is to ensure that the Australian Grayling can survive, flourish and retain its potential for evolutionary development in the wild (Land Victoria, 2007). The national recovery plan builds upon the previous national review of conservation status, threats and recovery actions for Australian Grayling, included in The Action Plan for Australian Freshwater Fishes (Wager and Jackson 1993). At a State level, conservation plans / action plans with management advice for protecting and recovering Australian Grayling populations include those for Tasmania (Bryant and Jackson, 1999), Victoria (Land Victoria, 2007), and South Australia (Hammer et al., 2007).
According to Land Victoria (2007), important populations, that will be high priority for recovery actions to ensure their long-term survival, are those at the limits of the species’ range, and those known to contain large breeding populations or occur in areas with extensive spawning habitat. Such populations are likely to act as ‘source’ populations for other areas containing less suitable habitat for the species. Identification of additional important populations, such as any that are genetically distinct, will be undertaken as a recovery action.
There are programs to improve rivers in southern Australia, including river health strategies, stream flow management plans and restoration of riparian vegetation for many rivers within the range of the Australian Grayling (Land Victoria, 2007).
Various programs in Victoria include the following: (i) a catchment management program for improved water quality in the Gippsland lakes; (ii) stocking of trout has ceased in the Barwon River, because of the presence of several threatened fish species including Australian Grayling; (iii) a program to increase environmental flows to the Snowy River, the catchment of which contains some of the most important populations of Australian Grayling in Victoria; and (iv) investigation has been undertaken into the effects of 2003 wildfires (e.g. increased sedimentation) on the upper catchments of two of the most important rivers for Australian Grayling in Victoria, the Tambo and Snowy River systems (Land Victoria, 2007).
In South Australia, conservation actions that have been initiated include (i) surveys on historic habitat; (ii) review of dredging procedures at Eight Mile creek (a potentially significant habitat for this species); hydrological and groundwater investigations in the South-East; and (iv) installation of a fish ladder at the weir at Piccaninnie Ponds (Hammer et al., 2007). Other fishways that have been constructed in S.A. (e.g. Stuart et al., 2002, 2005), may be of limited benefit for Grayling in S.A., because this species is (or was) found mainly in the south-east of South Australia.
Since 1999, more than 20 “fishways” that permit upstream passage of migrating fish species (including Grayling), have been constructed in various rivers around Victoria (e.g. Maribyrnong River, which feeds into the Yarra). The devices are like curved, rocky ramps, or in some cases, gentle cascades, with water tumbling down. The fishways are designed to enable fish to “climb” past barriers such as dams, weirs and road culverts (Melbourne Water, 2002). These fishways have facilitated access to over 3,000 km of rivers that were previously blocked (DSE-ARI unpubl. data, cited by Land Victoria, 2007).
There are also programs to facilitate fish passage past barriers in New South Wales and Tasmania.
At a national scale, recovery plans that support the objective of identifying important populations of Australian Grayling include: (i) collating existing data on distribution, abundance and population parameters; (ii) determining gaps in distribution data and undertake surveys to determine presence and significance of grayling populations in areas poorly surveyed (for example, in Victoria, some rivers in the Otway ranges and South Gippsland have been identified and targeted for surveys, due to apparent gaps in Grayling distribution); (iii) undertaking a genetic assessment of population structure throughout its range; (iv) identifying populations and locations for long-term monitoring, especially to determine population trends and responses in locations where recovery actions are occurring (e.g. fishway installation, catchment protection); (v) acquiring baseline data on selected populations by conducting surveys including identification of the area and extent of populations; estimates of the size and structure of populations; inference or estimation of population change, and habitat quality (Backhouse et al., 2008b). Identification and mapping of important habitat (rivers/locations) are especially important to identify key sites for recruitment (Land Victoria, 2007). Baseline data must be acquired for selected populations by conducting surveys to (a) identify the area and extent of populations; (b) estimate the size and structure of populations; (c) infer or estimate population change and (d) determine habitat quality (Land Victoria, 2007).
Recovery plans to support the objective of protecting and restoring habitat for Australian Grayling include: (i) identifying and mapping important habitat (rivers/locations), particularly for recruitment and as potential drought refuge habitat; (ii) identifying rivers where flow regulation or water abstraction potentially impacts on important populations and habitats of Australian Grayling, and ensure conservation requirements are included in river management processes; (iii) ensuring Australian Grayling conservation requirements are included in fishway programs (Backhouse et al., 2008b); (iv) protecting and restoring riparian vegetation in catchments supporting Australian Grayling populations, with priority to those catchments supporting important habitats or populations (Backhouse et al., 2008b).
Recovery plans to support the objective of investigating important life history attributes to acquire targeted information for management include: (i) investigating spawning cues, particularly the influence of river flows; (ii) investigating larval and juvenile distribution, habitat and movements; and (iii) investigating adult distribution, habitat and movements (Backhouse et al., 2008b).
Recovery plans to support the objective of investigating and managing threats to populations and habitats include: (i) investigating the potential for predation on larvae/juveniles in estuarine environments; (ii) investigating the impact of trout on Australian Grayling; (iii) ensuring that important populations and locations are protected from stocking of trout; and (iv) investigating the impact of increased sedimentation on Australian Grayling and habitats in catchments (e.g. such as areas in Victoria affected by wildfires in 2003) (Backhouse et al., 2008b).
Recovery plans to support the objective of increasing awareness of Australian Grayling conservation with resource managers and the public, include (i) ensuring that research findings are publicised and incorporated into catchment management and river health programs where appropriate; and (ii) promoting angler awareness of conservation of Australian Grayling where incidental capture is likely to be an issue.

Other Information

In some parts of south-eastern Australia, the distribution and abundance of Australian Grayling is reported to be relatively stable at this time, especially in places where there is a high degree of catchment protection in national parks and native forest reserves (Morris et al., 2001). Australian Grayling occurs in a number of National Parks, State conservation parks, or other protected river parks in south-eastern Australia, such as the Snowy River National Park (which has a reduced and highly regulated flow), Kosciuszko National Park, and various tributaries of the Snowy River draining the slopes of Mt Kosciuszko; Wilsons Promontory National Park (though Grayling has rarely been recorded there), Otway National Park, Croajingolong National Park, Moondara state Park and Tyers Park, Lorne-Anglesea State Park, and Aire River (listed as a Heritage River) in Victoria; South-West National Park and Arthur-Pieman Conservation Area in Tasmania; Morton National Park and South East Forests National Park in New South Wales (Morris et al., 2001).
In some areas, conservation parks offer little protection, because riverine habitat is dependent on processes occurring throughout the catchment, and also, the species is migratory and in many parts of the range must pass through large sections of unprotected rivers (Wager and Johnson, 1993).
A closely related species Prototroctes oxyrhynchus, endemic to New Zealand, has been extinct in that country since the 1930s, possibly due to a combination of the effects of introduced trout, and the deterioration of the freshwater habitat through the clearance of forest cover, resulting in increased light penetration and raised water temperature (McDowall 1978, 1996b; IUCN, 2003).

Support for S.A. Listing: In addition to the recommendations by the National Parks and Wildlife Council and Department for Environment and Heritage (2003) and Hammer et al. (2007), John Pogonoski (ex-Australian Museum) and Graham Edgar (University of Tasmania), both considered that the species should be listed, the former citing the very rare status of Grayling as the primary justification. Barry Hutchins (ex-WA Museum) recommended that the species should possibly be listed.