© 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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Tamar River Goby / Tamar Goby

Family Name:	Gobiidae
Scientific Name:	Afurcagobius tamarensis (Johnston, 1883) (= Favonigobius tamarensis)
Recommended Status in S.A:	Data Deficient, possibly Near Threatened
Rationale:  Tamar River Goby is included here because (i) although the species has been recorded as abundant in some parts of S.A., it has a limited geographic distribution in this State (mainly known from Gulf St Vincent, and the Murray Mouth); (ii) the species is found over a narrow depth range; (iii) gobies are typically benthic nest spawners and egg guarders, and hence populations may be vulnerable to localised / site specific impacts; (iv) A. tamarensis is found mainly in estuaries, which are few in number in S.A., and most are significantly degraded; and the estuarine systems in S.A. in which this species has been reported to date, are subject to numerous, ongoing threatening processes.

Page Contents

Current Conservation Status

(no listings known)
 

Distribution

Southern Australia

The Tamar River Goby generally occurs in eastern and southern Australia, and has been recorded mainly from N.S.W., Victoria, Tasmania and the Bass Strait islands, and the eastern part of South Australia (Hoese and Larson, in Gomon et al., 1994; Jordan et al., 1998; Edgar et al., 1999; West and Jones, 2001; Allen et al., 2002; Native Fish Australia, 2003d).
The species is considered to be widespread and common in Victorian coastal waters, often locally abundant (Barnham, 1998).
 

South Australia

In S.A., there are records mainly from the central part of the South Australian coast. Gillanders et al. (2008) reported its presence in 15 estuaries in South Australia. Allen et al. (2002) reported that Adelaide (i.e. Gulf St Vincent) is the western limit of this species’ distribution (but see above, for Southern Australia).
The species has been recorded from metropolitan Gulf St Vincent (e.g. Gawler River; Port River – Barker Inlet estuarine area; West Lakes; Torrens river; Patawalonga estuary; Onkaparinga estuary) southern Fleurieu (Myponga River; and the Carrickalinga, Bungala and Yankalilla creeks); southern Kangaroo Island; the Murray Mouth and Lower Lakes region (e.g. Goolwa area – including the Barrage, Tauwitchere Barrage, sites near Sir Richard Peninsula, Hindmarsh Island, Mundoo Channel, Boundary Creek, Lake Albert, and other areas), and the Kingston / Robe area in the upper South-East (Edyvane et al., 1996; Higham et al., 2002, 2005; Hammer, 2002; Classon and Booth, 2002; Ye et al., 2002; Brandle et al., 2002; Wedderburn and Hammer, 2003; Geddes, 2003, 2005; Hammer, 2006a, 2006b; Smith, 2006; SARDI Aquatic Sciences, 2006; South Australian Museum records, Museum of Victoria records, cited in OZCAM database, 2007; Gillanders et al., 2008).
During estuarine fish surveys in 2001-02, Ye et al. (2002) recorded the species as being abundant below the Tauwitchere barrage (Murray Lakes region).
Hammer (2002) reported that the Tamar River Goby is likely to have a wider distribution than that recorded during a recent survey of the South-East of S.A., due to bias in sampling freshwater rather than estuarine / marine areas during that survey.
 

Habitat

The Tamar River Goby is found on sand, silt or mud bottoms, near the freshwater/estuarine interface, in quiet (and often brackish) estuarine waters (e.g. Western Port Bay, where the species is common on intertidal mudflats – Edgar and Shaw, 1995a; Environmental Protection Authority of Victoria, 1996), tidal creeks, coastal estuarine lakes (e.g. in southern N.S.W.), and the lower parts of rivers and freshwater streams (Hoese and Larson, 1980, cited by Koehn and O’Connor, 2002; Hoese and Larson, in Gomon et al., 1994; Pollard, 1994; West and Jones, 2001; Allen et al., 2002). Tamar River Goby prefers still or slow-flowing water with mud or silt substrate and cover provided by aquatic plants, rocks or fallen logs (Barnham, 1998).
Although the species is classified as an “estuarine resident” species (Whitfield classification, cited in Ye et al., 2002), it occasionally enters lower reaches of rivers and streams, and also occurs also in coastal sand dune lakes (Barnham, 1998). In the Clarence river in N.S.W., Tamar River Goby has been found in freshwater, brackish and marine parts of the river, near both sand bottom and vegetated bottom, in all three salinity regimes (West and King, 1996). In Tasmania, it is found mainly on soft sediments in estuaries with a barrier to the sea (Edgar et al., 1999).
In N.S.W., in saline coastal lagoons, the species has been recorded in Zostera seagrass interspersed with the green macroalga Enteromorpha (Pollard, 1994). It is also commonly found in nearshore seagrass beds, such as Zostera capricorni in N.S.W. (Griffiths, 2001) and Heterozostera tasmanica, in south-eastern Australia (e.g. Jordan et al., 1998; Rotherham and West, 2002). This species has also been reported from habitat with freshwater / brackish eelgrass Vallisneria, and from freshwater habitat with the South American waterweed Egeria densa (West, 1993). The species has also been recorded in mangroves and/or mangrove channels in N.S.W. (Jelbart et al., 2006) and in the Barwon River estuary in Victoria (Smith and Hindell, 2005).
 

Notes on the Biology

Growth

Tamar River Goby grows to around 10cm – 11cm (Hoese and Larson, in Gomon et al., 1994; Koehn and O’Connor, 2002), but more commonly, is about 8cm (Native Fish Australia, 2003d).
In late 2001 and early 2002, during a survey below the Goolwa Barrage (Murray Mouth) in S.A., Tamar River gobies in the size range 29mm – 100mm were recorded (Ye et al., 2002). 
 

Diet

The species probably feeds on small burrowing invertebrates (Barnham,1998; Native Fish Australia, 2003d).  In W.A., small benthic crustaceans are an important part of the diet of the related goby species Afurcagobius suppositus (Platell and Hall, 2006). Tamar River Goby frequently feeds by taking a mouthful of mud and forcing it through the gills, presumably to extract food items (Barnham, 1998).
 

Reproduction

Tamar River Goby spawns in spring (Cadwallader and Backhouse, 1983, cited by Koehn and O’Connor, 2002; Classon and Booth, 2002).
Males become territorial during the spring courtship period and select a burrow site, often beneath a rock or root (Barnham, 1998). The female lays the eggs on the underside of a solid object that forms the roof of the burrow, and the male guards the eggs (Cadwallader and Backhouse, 1983, cited by Koehn and O’Connor, 2002).
 

Behaviour

Tamar River Goby is a benthic and burrowing species, which may construct a burrow beneath a rock or tree root (Cadwallader and Backhouse, 1983, cited by Koehn and O’Connor, 2002).
The species is often found in small aggregations, in its preferred habitat (Kuiter, 1993; Allen et al., 2002).
Tamar River Goby depends upon migration to and from estuaries (Koehn and O’Connor, 2002).
 

Other Information

Pseudaphritis urvillii (Congolli) preys upon Tamar River Goby (Hortle and White, 1980). This goby is a prey species for a number of larger predatory fishes, including those in estuaries (Smith and Hindell, 2005).
Although A. tamarensis is a small, benthic species, it has a swim bladder (Gee and Gee, 1995).
 

Fisheries and Trade Information

The species is not targeted, but has been recorded in the bycatch of prawn trawlers in New South Wales (e.g. Liggins et al., 1996; New South Wales Fisheries, 2002).
Tamar River Goby is described as “an unusual aquarium fish” (Native Fish Australia, 2003d). The species is listed in a number of international web sites on aquarium fish.  
 

Vulnerable Characteristics of the Species, and Threatening Processes

Gobies are benthic nest spawners and egg guarders, population characteristics that increases their vulnerability to site-specific habitat impacts.
Tamar River Goby is an estuarine resident species. Ongoing degradation of benthic habitat and  water quality, and reduced flow rates in some estuarine areas may have negative impacts on populations of this species (see discussion above, for Lagoon Goby Tasmanogobius lasti). It is noted however, that the species may have the ability to survive in some degraded waterways, as evidenced by its presence in polluted creeks, such as the Kororoit Creek in the Werribee Catchment, metropolitan Victoria (DPI Victoria, 2004).   
In N.S.W., during a comparison of fish assemblages in an area with a tidal floodgate, and an un-gated reference area, Kroon and Ansell (2006) reported significantly higher numbers of Tamar River Goby in the un-gated area, indicating that flood mitigation structures may have an impact on estuarine fish populations in some areas.  
Tamar River Goby is associated with estuaries, and there are few such habitats in South Australia. At least half of the estuarine areas in S.A. are significantly degraded, including those in which the species has been recorded to date, such as the Port River – Barker Inlet estuary and surrounds; Patawalonga; Onkaparinga; and Murray Mouth (e.g. Bucher and Saenger, 1989; Lewis et al., 1998; GeoScience Australia, 2001; Barnett, 2001; Bryars, 2003; Baker, 2004; DEH, 2005; EPA – SA, 2006; Gillanders et al., 2008). A more recent and equally significant stress on estuaries in S.A. (and therefore on estuarine inhabitants) is likely further reduction in freshwater inflows in the coming years, due to expansion of urban populations and rural developments in some areas, and also due to the effects of climate change in South Australia.
Populations of estuarine goby species in degraded areas such as the Port River – Barker Inlet system may be vulnerable to extirpation from further habitat loss, fish kill events, and/or treatment methods to control introduced organisms (Hammer, 2006b).
Ye et al. (2002, Table 22) listed Tamar River Goby as a potential migratory species. If so, then barriers to migration within estuarine systems such as the Murray may interrupt the life cycle of this species. Period closure of the Murray River mouth could have similar detrimental impacts (Higham et al., 2002).  For estuarine species that utilise the Coorong, Murray Mouth and Lower Lakes region, freshwater inflows during spring/summer are believed to stimulate estuarine species to spawn. A protracted period of estuarine condition extending to late summer with a gradual tail-off of freshwater flows to the Coorong, and a gradual change of salinity, is believed to be critical to enhance the survival of larval and juvenile fish (AWE, 2003).
 

Research Requirements

In S.A., surveys are required to better determine the distribution and relative abundance of this species in estuarine areas in GSV; also around Kangaroo I., south-eastern S.A. (to the Victorian border) and the western part of the State, including the western extent of the distribution in S.A..
When the less commonly known goby species are recorded in surveys, fish taxonomy experts should be sought to provide species-specific determinations. Voucher specimens and/or photographs should be taken.
 

Management Requirements

An assessment of the possible impacts of estuarine degradation in S.A. on Tamar River Goby populations is required. Determination of the impacts of reduced water quantity and quality on goby populations will help to better determine the conservation status of these species in S.A., and will assist with the development of recovery plans for small estuarine fish species.
Ongoing programs to protect and restore estuarine function may benefit site-associated estuarine species such as A. tamarensis. For example, for estuarine species that utilise the Coorong, Murray Mouth and Lower Lakes region, freshwater inflows during spring/summer are believed to stimulate estuarine species to spawn. A protracted period of estuarine condition extending to late summer with a gradual tail-off of freshwater flows to the Coorong, and a gradual change of salinity, is believed to be critical to enhance the survival of larval and juvenile fish (AWE, 2003).
 

Other Information

In S.A., the species has been recorded in various protected areas, such as Port River – Barker Inlet Aquatic Reserve (Hammer, 2006a), Onkaparinga Estuary (Hammer, 2006a); Wyndgate on Hindmarsh Island (Hammer et al, in Brandle et al., 2002), and parts of the Coorong National Park.
The species has been recorded in a number of protected areas in Victoria, including the Yaringa Marine National Park (MNP) and French Island MNP (Plummer et al., 2003).