© 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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Southern Tongue Sole / Broadhurst’s Tongue Sole

Family Name:	Cynoglossidae
Scientific Name:	Cynoglossus broadhursti Waite, 1905
Recommended Status in S.A:	Data Deficient
Rationale:  The species is included here because C. broadhursti (i) is a south-western species that may have a limited geographic distribution within South Australia; (ii) is a little known species, with few published records in S.A., and the species may be less abundant here than in W.A.; (iii) the species occurs in estuaries and shallow coastal waters, and in the S.A. part of the range, such habitats are subject to numerous impacts which have reduced habitat quality over many decades; (iv) the species is vulnerable to bycatch in trawls;  and (v) very little is known of the relative abundance, biology, and population dynamics of this species.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

The species occurs in south-western and southern Australia, from Carnarvon area in W.A. (Hutchins and Swainston, 1986), through to Kangaroo Island and Gulf St Vincent in South Australia (Gomon, in Gomon et al., 1994).
The Southern Tongue Sole is considered common on sandy bottoms in waters of south-western Australia (Hutchins and Thompson, 1983; Hutchins and Swainston, 1986).

South Australia

Examples of locations in S.A. where the species occurs, include the Murray Mouth / Goolwa area; Port River – Barker Inlet estuary; and other parts of Gulf St Vincent, including the central area (N.B. old records from 1909, prior to the commencement of trawling in GSV); eastern Investigator Strait / “heel” of Yorke Peninsula area; northern and eastern Kangaroo Island; and northern and central Spencer Gulf, and southern Spencer Gulf / lower Eyre Peninsula (Gomon, in Gomon et al., 1994; Jones et al., 1996; Carrick, 1997; Anonymous, 1999; SARDI data by P. Jennings, unpublished; Australian Museum records; S.A. Museum records, Museum of Victoria records, cited in OZCAM database, 2007; Currie and Sorokin, 2010).

Habitat

The Southern Tongue Sole lives on / in sandy sediments, in estuarine and coastal marine areas (Hutchins and Swainston, 1986; Gomon, in Gomon et al., 1994).
The soft-bottom habitat of this species’ ranges in exposure from sheltered estuarine areas (e.g. Gaughan et al., 1990; Jones et al., 1996) to more wave-exposed surf zones (e.g. Ayvazian and Hyndes, 1995).
Cynoglossus broadhursti is recorded from shallow waters, to around 45m deep (Gomon, in Gomon et al., 1994; Edgar, 2000).
Some specimens have been recorded from the mouth of the River Murray (Gomon, in Gomon et al., 1994).

Notes on the Biology

Growth

The species grows to between 27cm (Gomon, in Gomon et al., 1994) and 31cm (Hutchins and Swainston, 1986). The reported record size of Southern Tongue Sole is 0.150kg, being a specimen taken from Preston Beach in W.A., in 1976 (Hutchins and Swainston, 1986; Australian Anglers Association Inc. W.A. Division, 2005).

Diet

The diet of Tongue Soles is likely to be similar to that of Soles (Soleidae), which eat benthic invertebrates and small fishes (Ayvazian and Hyndes, 1995; Kuiter, 2000).
During a survey in Spencer Gulf in 2007, the gut contents of 7 specimens were examined, and found to contain 35% squillid crustaceans; 20% unspecified crustaceans; 17% polychaete worms; 12% prawns; 6% galatheid crustaceans and 6% brachyurid crustaceans (Currie and Sorokin, 2010).

Fisheries Information

Commercial

The Southern Tongue Sole is occasionally taken by trawlers (Gomon, in Gomon et al., 1994).
In S.A., the species has been recorded as a minor component of bycatch in the Spencer Gulf prawn trawl fishery. For example, 21 Southern Tongue Soles were recorded from 32 trawl tows, in a sampling program during the mid 1990s (Carrick, 1997). During a more recent research survey in trawl grounds of Spencer Gulf, this species was recorded at 27 of 120 trawl stations, mainly south of the Franklin Harbour - Wallaroo line, through to the "toes" of Yorke Peninsula (Currie and Sorokin, 2010).
Tongue soles are caught commercially in W.A. in low numbers. Species-specific information is not available for this report. During 2001 to 2005, the annual catch of soles (in both Cynoglossidae and Soleidae families) from fisheries in W.A., ranged between ~ 800 kg and 1.1 tonnes (Fisheries Research Division, W.A. Department of Fisheries, 2002, 2004f, 2005c, 2006c).

Recreational

Recent recreational survey catch statistics (Henry and Lyle, 2003) group recreational catches of tongue soles with flounders and other flatfish, and summary statistics are provided in the section on Bothidae, Paralichthyidae and Pleuronectidae.
The species is taken by some recreational fishers. Angling clubs in W.A. record maximum sizes of Southern Tongue Soles caught (e.g. Australian Anglers Association Inc., W.A. Division, 2002a).

Vulnerable Characteristics of the Species and Threatening Processes

The Southern Tongue Sole occurs in shallow coastal waters and estuaries. There are few pristine or near pristine estuaries remaining in South Australia (and southern W.A.), and most are subject to numerous impacts, particularly two of the S.A. estuarine areas where this species has been recorded, namely the Murray Mouth, and the Port River-Barker Inlet estuary (see Bucher and Saenger, 1989; Edyvane et al., 1996; Lewis et al., 1998; Barnett, 2001; GeoScience Australia, 2001; Murray Darling Basin Commission and Department of Water, Land and Biodiversity SA, 2002; Baker, 2004). The species has also been recorded in the Swan Estuary in W.A. (Loneragan et al., 1989; Neira et al., 1992), which has also been subject to numerous polluting influences and modification during the past several decades. Coastal impacts that degrade habitat quality in shallow sandy bays might also be a threat to nearshore populations of this species.
Southern Tongue Sole occurs within a relatively narrow depth range in coastal waters, and, in addition to estuaries (see above), populations in some other coastal areas may be vulnerable to impacts - for example, in the gulfs region of S.A. where habitats have been degraded, due to trawling (e.g. see Tanner, 2003, 2005).
Bycatch in trawling operations may be a threatening process for this species; however there is no specific information on population impacts. The Southern Tongue Sole is recorded as bycatch in the Spencer Gulf prawn trawl fishery in S.A., and in some other trawl fisheries across its range. There are also records of the species being present in central Gulf St Vincent, in the trawl grounds; however the museum records for that area are old (1909), and the specimens were collected prior to the commencement of trawling in that gulf. The section on Bothidae, Paralichthyidae and Pleuronectidae flounders provides some information on the likely impact of prawn trawling on populations of flatfish species; soles have similar morphology, habitat requirements and life history to flounders, hence the impact of bycatch mortality on specific populations of Southern Tongue Sole might be similar.  
The central coast of South Australia is at the edge of the species’ range, and although the species is considered common in south-western Australian, it may not be as abundant in South Australia, and appears to be found mainly in the gulfs region.
The species is taken by some recreational fishers; however the extent to which these practices impact upon Southern Tongue Sole populations is not known for this report.

Research and Management Recommendations

More information is required on the distribution, relative abundance and habitat requirements of the Southern Tongue Sole in South Australia. In particular, surveys and bycatch data should be assessed to determine whether or not the species is confined to the gulfs region.
There is very little information on the biology, ecology and population dynamics of this species.
Documentation and quantification of tongue sole bycatch in fisheries across the geographic range is required.
The potential impacts on sole (and other flatfish) populations of degradation of estuarine habitats should be investigated.
In S.A., a system should be developed for the ongoing collection and monitoring of bycatch data from the Gulf St Vincent Prawn Fishery and the West Coast Prawn Fishery (as currently occurs in the Spencer Gulf Prawn Trawl Fishery), sufficient to enable identification of long-term trends in bycatch (Australian Government DEH, 2004b).
Measures (such as improvements in net design) to reduce the bycatch of benthic fish species in all trawl fisheries should be implemented.
Recreational fishing limits for flounder in S.A. should be amended to include tongue soles, if those bag and boat limits do not presently include the latter group.

Other Information

A related species of Cynoglossus in south-eastern Australia, C. maculipinnis, is a bycatch species in the shelf sector of the N.S.W. ocean prawn trawl fishery (recorded in 11% of shots, according to a recent survey – see N.S.W. Department of Primary Industries, 2004). C. maculipinnis is also caught incidentally in the Bass Strait Scallop fishery (Haddon and Semmens, 2002).