© 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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Short-fin Flounder / Short-finned Flounder / Shortfin Flounder

Family Name:	Pleuronectidae
Scientific Name:	Ammotretis brevipinnis Norman, 1926
Recommended Status in S.A:	Data Deficient
Rationale:  The species is included here because (i) A. brevipinnis is a poorly known species of uncertain distribution, with few records in S.A., which is the edge of the geographic range; (ii) the species occurs in the gulfs region of South Australia, in sandy areas, and may thus be vulnerable to nearshore impacts, and fishing mortality in prawn trawls; however, bycatch species identification and quantification are insufficient in S.A. prawn fisheries in Gulf St Vincent and along the West Coast of S.A., hence the previous and current extent of capture of Short-fin Flounder in trawl fisheries in S.A. is not known, and no assessment of potential population impacts has been undertaken; (iii) there is little indication of the total commercial and recreational catch of this species, in relation to its relative abundance and distribution in S.A., and (iv) there is very little existing information about the relative abundance, habitat requirements, depth range, biology and population dynamics of this species across its range.

Page Contents

Current Conservation Status

(No listings known)

Distribution

Southern Australia

Gomon (in Gomon et al. 1994) reported that the species is known only from the south-western side of Australia, extending from Gulf St Vincent and Kangaroo Island in S.A., through to Albany in southern Western Australia.
 

South Australia

The type locality is Gulf St Vincent, and the specimen was collected in 1925 (BMNH specimen, cited by Anonymous, 1999, and Evseenko, 2004).
The species has a limited known distribution within S.A., and there are few published records, none of which have been included in the On-Line Zoological Collections of Australian Museums (OZCAM database, 2008). Other than information about the type locality (Gulf St Vincent), and the presence of this species off Kangaroo I. (Gomon, in Gomon et al., 1994), and Port Giles (1995 fishing record, cited in Australian Anglers Association, 2005), the only other records of A. brevipinnis that could be found for this report relate to bycatch data from Spencer Gulf (Carrick, 1997). 
 

Habitat

The habitat appears not to have been documented, but the Short-fin Flounder presumably occurs on sandy substrates, as do other members of the genus Ammotretis and the family Pleuronectidae.
 

Notes on the Biology

The biology of the species is poorly known (Gomon, in Gomon et al., 1994).
The species grows to at least 38cm (Gomon, in Gomon et al., 1994).
The reported record size of A. brevipinnis 0.83kg, being a specimen taken from Port Giles in S.A., in 1995 (Australian Anglers Association, 2005).   
Flounders live on the sea floor, but are pelagic spawners (Nelson, 2006).
 

Fisheries Information

Commercial

Little species-specific commercial fishing data are available. However, it is noted that flounder species (unspecified) are taken in minor quantities by commercial fishers in S.A. and W.A. (see section above, on Commercial Fishing for flounders as a group).
In S.A., the species has been recorded as a very minor component of bycatch in the Spencer Gulf prawn trawl fishery. For example, 2 Short-fin Flounders were recorded from 32 trawl tows, in a sampling program during the mid 1990s (Carrick, 1997). There are no data available on the bycatch of this species in the prawn fisheries in other parts of South Australia.  
When caught in the bycatch of the South Australian Rock Lobster fishery, flounders are permitted to be retained for sale (Sloan, 20003a).
 

Recreational

Recreational survey catch statistics (e.g. Henry and Lyle, 2003) group recreational catches of flounders with soles and other flatfish, and summary statistics, as well as other State-level data, are provided in the section on Recreational Fishing, at the beginning of this chapter.
The Australian Anglers Association keeps records of the maximum sizes of A. brevipinnis caught by recreational fishing.
In W.A., there is a legal minimum size of 25cm for all flounder species, and a combined daily bag limit of 8 flathead and flounder (all species) in the West Coast, Gascoyne and South Coast regions (Department of Fisheries, 2007c, 2008a, 2008b). For recreational fishers in South Australia, there is a daily bag limit of 20 flounder (all species) and a boat limit of 60. There is no legal minimum size in S.A. (PIRSA, 2008a, 2008b). 
 

Vulnerable Characteristics of the Species and Threatening Processes

South Australian waters are considered to be at the edge of the species’ range.
Benthic fishes in general have limited mobility, more localised reproduction than most pelagic species, and limited opportunity for population dispersal, all of which can increase the vulnerability of populations to decline.
Short-fin Flounder has been recorded in few parts of South Australia, the most notable being the type locality, Gulf St Vincent, and the population in that gulf may be vulnerable to decline, because Gulf St Vincent has been subject to numerous habitat impacts over many decades (see Tanner, 2003 and 2005 on specific prawn trawling impacts in GSV and Investigator Strait, and Baker, 2004, for general summary of multiple physical, chemical and ecological impacts in GSV).
Flounders are vulnerable to capture in prawn trawls, due to their benthic nature, existence in the same habitats as prawns are found, and their poor swimming ability (PIRSA, 2003). The species is recorded as a minor component of the prawn trawl bycatch in Spencer Gulf, and, given the distribution and habitat of this species, it is likely present in trawl bycatch in other parts of south Australia. Mortality due to trawling may be a threatening process for some of the flounder species of lesser abundance in S.A., but no species-specific data are available, and there are no available data on the prawn trawling bycatch composition or abundance in Gulf St Vincent, or in the eastern Great Australian Bight / western Eyre Peninsula. Therefore, it is not possible to comment on the extent to which trawling may be a threatening process for Short-fin Flounder populations in South Australia.
Tanner (2003 and 2005) discussed the impacts of prawn trawling on habitats and benthos in Gulf St Vincent, and this species is likely to occur in these trawl grounds, given the known distribution to date. 
Flounder species are defined as “Category 2” fish species in Western Australia, with a “medium risk” of over-exploitation. Category 2 fish species generally mature at two to three years old, are of moderate abundance, are highly targeted, and/or often utilise estuarine and inshore habitats extensively (Department of Fisheries, 2004).
 

Research Requirements

The species is little known in this State, with few published records. More information is required on the current geographical distribution and relative abundance of this species in S.A., which is at the edge of the geographic range. In particular, surveys are required, in conjunction with analysis of bycatch data, to determine whether the range of Short-fin Flounder extends eastwards into Victoria.
More information is required on the depth distribution and habitat requirements of Short-fin Flounder, which appear to have not been adequately determined or documented.
There is very little information on the biology, and population dynamics of this species.
Where possible. prawn trawling bycatch data from Gulf St Vincent (the type locality of Short-fin Flounder), Spencer Gulf, and the West Coast of S.A. should be recorded, analysed and monitored to determine the presence and relative abundance of this species over time.  
 

Management Requirements

Documentation and quantification of flounder bycatch in fisheries across the geographic range is required (see above).
As indicated in Research Requirements above, 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; Dixon et al., 2005).
Measures (such as improvements in net design) to reduce the bycatch of benthic fish species in all trawl fisheries should be implemented (see Management Notes, below).
Protection of shallow coastal bays from land-based discharges, and, where possible, from coastal activities (such as dredging, and aquaculture developments) that can reduce benthic habitat quality in such bays.  
 

Management Notes

It is noted that prawn fisheries in southern Australia have made significant efforts during the past decades to reduce the bycatch of finfish species. Examples for Spencer Gulf and Gulf St Vincent include the spatial and temporal organisation and “real time” management of the fishing fleet in some areas (e.g. Spencer Gulf) to minimise capture of undersized prawns and bycatch species, and developments in gear design to reduce bycatch, such as square-mesh cod-ends, bycatch chutes, hopper/conveyor systems, and the fitting of exclusion devices (e.g. MacDonald, 1998; Carrick, 1997; Broadhurst et al., 1999; South Australian Prawn Industry Association web site, 2000; PIRSA, 2003). PIRSA (2003) reported that field studies have indicated that survival of flounders (e.g. the commonly caught species Pseudorhombus jenynsii) is higher with hopper/conveyors systems, compared with the previously used sorting equipment. However, Australian Government DEH (2004b) reported that further work is required to confirm this assumption.