© 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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 Lagoon Goby / Scary’s Tasmangoby

Family Name:	Gobiidae
Scientific Name:	Tasmanogobius lasti Hoese, 1991
Recommended Status in S.A:	Data Deficient, possibly Near Threatened (S.A.)
Rationale:  The Lagoon Goby is included here because (i) South Australia is the western edge of the geographic range; (ii) the species is found over a narrow depth range; (iii) the species is associated with estuaries, which are few in number in S.A., and many are significantly degraded, and /or subjected to significant and ongoing threats; and (iv) gobies are typically benthic nest spawners and egg guarders, and hence populations may be vulnerable to localised impacts. Although the species has been regularly recorded in recent year in the Murray Mouth and Lakes region (as well as  a number of other locations), and there are no specific data on the impacts of estuarine degradation in S.A. on Lagoon Goby populations, possible threats to populations due to reduced water quantity and quality in that region have not been ameliorated, and are likely to continue in future.

Page Contents

Current Conservation Status

No listings known, but Tasmanogobius lasti is considered to be of conservation significance at State level (S.A.), due to its limited geographic range in the Murray –Darling Basin (Smith and Hammer, 2006).
 
In the Action Plan for South Australian Freshwater Fishes (Hammer, 2007), T. lasti was classified as Near Threatened, due to the limited number of known locations in which the species occurs, within a limited area of occupancy in South Australia (Hammer, 2007).

Distribution

South-Eastern Australia

The species occurs in rivers and estuaries around Tasmania (including the north, east, south and west coasts); across Victoria; Bass Strait islands (e.g. King, Flinders), and south-eastern South Australia (Hoese and Larson, in Gomon et al., 1994; O’Connor et al., 1996, cited by DPIWE Tasmania, 1998; Jordan et al., 1998; Edgar et al., 1999; Museum of Victoria records, cited in OZCAM database, 2007; CSIRO Marine Research records, and CSIRO, 2007).
 

South Australia

Most records in S.A. are from the Lower Murray and Murray Mouth region; and the upper and lower South-East, to the Victorian border (see below). There are also records of Lagoon Goby T. lasti from rivers and near river mouths around Kangaroo I. (CSIRO, 2007; OZCAM database, 2007), including river mouths along southern and south-western coast of Kangaroo I. (paratype specimens - Australian Museum records, cited in OZCAM database, 2007), and an unverified record from Patawalonga estuary, in metropolitan GSV (SARDI Aquatic Sciences, 2006).
Lagoon Goby has also been recorded regularly in the Murray Mouth area and associated lakes (Higham et al., 2002; Ye et al., 2002; Geddes, 2005; Smith, 2006; S.A. Museum records, cited in OZCAM database, 2007). Generally, in the Murray Mouth and Lakes region, the species has been found at various sites around lakes Alexandrina and Albert, and in associated drainages into Lake Alexandrina, to the north, north-west and west (S.A. Museum records, cited in OZCAM database, 2007; Wedderburn and Hammer 2003; Smith and Hammer, 2006). During sampling in December / January 2001 and March / April 2002, small numbers of T. lasti individuals were recorded below Goolwa and Tauwitchere Barrages, and the species is considered to be resident in the estuarine area (Ye et al., 2002). During a survey in December 2003, 57 T. lasti individuals were recorded at Teringie, 82 at Lake Alexandrina, 91 at Narrung, and 239 at Lake Albert (Wedderburn and Hammer, 2003, cited by Bjornsson, 2006a,b). Geddes (2005) also recorded the species at the Goolwa Barrage (in 2003), and at the Mundoo Channel and Boundary Creek (in 2004). In 2003 and 2004, Lagoon Goby was recorded in the low hundreds (using standardised gear, with numbers pooled over 4 sampling occasions) at various habitats in the lower lakes and swamps region near the Murray Mouth (Higham et al., 2005). Examples of locations in that area in which T. lasti has been recorded in low numbers include Younghusband, and Rocky Gully; and in much higher numbers at Pelican Lagoon, Poltalloch Station, and Hindmarsh I. (Smith, 2006; Smith and Hammer, 2006). The species has been recorded in low numbers further upstream, for example at Reedy Creek (near Mannum) (Smith, 2006, and map in Smith and Hammer, 2006).   
In S.A., the species has been recorded from the Lake Bonney floodplain, in the Millicent area, but may have a wider range than that detected in the South-East region during a survey in 2000-01 (Hammer, 2002), due to sampling in freshwater rather than estuarine locations. The recent record of 4 specimens of Lagoon Goby from the Lake Bonney floodplain in the south-east of S.A. (recorded during sampling in 2000 and 2001) represent the first official South Australian Museum record for the South-East S.A. region (Hammer, 2002). The species has also been recorded from fresh water (Lake Mombeong) in the lower reaches of the Glenelg River, near the Victorian / South Australian border (Museum of Victoria record A3568, cited in OZCAM database, 2007). Other recent records from the south-east of S.A. include Lake George; Lake Battye (one of the lakes near Robe), Eight Mile Creek and Deep Creek (part of the Eight Mile Creek system), and the S.A. section of the Glenelg River (M. Hammer, unpubl. data, cited by M. Hammer, pers. comm., 2007).
 

Habitat

Lagoon Goby is found in muddy estuaries and bays (Hoese and Larson, in Gomon et al., 1994; Museum of Victoria records, cited in OZCAM database, 2007), but can also inhabit fresh water (Hammer, 2002; Museum of Victoria records, S.A. Museum records, cited in OZCAM database, 2007). In S.A., the species has recently been recorded at Younghusband, a shallow, ephemeral wetland, and at a number of permanent wetlands in the Lower Murray lakes and wetlands region, such as Reedy Creek, Rocky Gully, Pelican Lagoon, Poltalloch Station, and Hindmarsh I. (Smith, 2006).  Sampling in the Lower Lakes region near the Murray Mouth has shown that Lagoon Goby is found in higher numbers in drainage channels (the “inner” habitat) during spring and summer, but moves to open water (“outside” habitat) during winter (Higham et al., 2005).
In Victoria, the species has been recorded in estuaries and shallow bays burrows, in silty sand and mud (Barnham, 1998); and also in shallow freshwater marshes (e.g. Centre for Environmental Management, 2005).
Along the east and south-east coats of Tasmania, the species has been recorded in Heterozostera tasmanica habitat, off beaches and in estuaries (the latter including the Derwent, Huon, Arthur, and other estuaries) (Jordan et al., 1998; Edgar et al., 1999).  
Using Whitfield’s (1999) classification, the species has been described as an estuarine resident (Higham et al., 2002).
 

Notes on the Biology

During surveys in the Murray Mouth region of S.A., Ye et al. (2002) reported specimens in the range 2cm – 9.5cm from below the Goolwa Barrage in December 2001 – January 2002; also specimens in the range 1.6cm – 6.5cm,  from below the Tauwichere Barrage, in March – April, 2002. Geddes (2005) reported specimens of the Lagoon Goby T. lasti in the range 7cm – 8.3cm at Boundary Creek and the Mundoo Channel (Murray lower lakes region of S.A.). It is therefore assumed that, if the species identification in these samples were correct, then Lagoon Goby can grow to larger than the 5.5cm previously published (e.g. Hoese and Larson, in Gomon et al., 1994).
Members of the family are typically nest spawners, with males guarding the eggs (Hoese, 1998).
 

Vulnerable Characteristics of the Species and Threatening Processes

Tasmanogobius lasti is considered to be of conservation significance at State level (S.A.), due to its limited geographic range in the Murray–Darling Basin (Smith and Hammer, 2006).
The Lagoon Goby species has been found in and around lakes and small wetlands in the Murray Mouth region. Reduction in freshwater input to this system is likely to have significant impacts on estuarine resident fish species. Higham et al. (2002) reported that changes to the volume and flow rate of the Murray Mouth area (including periodic closure) is likely to indirectly affect Lagoon Goby, due to degraded water quality and salinity impacts. It is likely that further reduction in freshwater inflows will occur 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.
Estuaries are often subject to many pollutants, and other impacts that degrade water quality and habitat. Polluted estuarine areas can take a long time to recover as toxicants accumulate in their sediments (Pogonoski et al., 2002). The fact that most population centres in Australia are located within close proximity to coastal and/or estuarine environments means that estuarine habitats and their associated communities are often vulnerable to the effects of habitat degradation, and overexploitation by humans (Pogonoski et al., 2002). There are few pristine or near pristine estuaries remaining in South Australia, and most are subject to numerous impacts, with the Murray Mouth being a prime example (see Bucher and Saenger, 1989; Edyvane et al., 1996; Lewis et al., 1998; Barnett, 2001; GeoScience Australia, 2001; Baker, 2004).
Gobies are benthic nest spawners and egg guarders, a population characteristic that increases their vulnerability to site-specific habitat impacts.
 

Research Requirements

There is little information on the distribution and relative abundance of this species in parts of S.A. other than the Murray Mouth region. The relative abundance of this species in the south-east of S.A. is not well defined, nor is the westernmost extent of the distribution in S.A., considering that this State is at the edge of the geographic range. Those undertaking future surveys of estuaries, lakes and channels in other parts of S.A. should be conscious of the potential presence of goby species such as T. lasti, and such species should be recorded when found.    
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 Lagoon 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 small, site-associated estuarine species such as Lagoon Goby.