© 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.

---

Large-scale Flounder / Largescale Flounder / Bay Flounder

Family Name:	Pleuronectidae
Scientific Name:	Ammotretis macrolepis McCulloch, 1914
Recommended Status in S.A:	Data Deficient
Rationale:  The species is included here because A. macrolepis (i) is a poorly known species, with few records in S.A., which is the edge of the geographic range; (ii) is reported to have a narrow depth range; (iii) is subject to mortality due to bycatch in prawn trawling; 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 Large-scale Flounder in trawl fisheries in S.A. is not known, and no assessment of potential population impacts has been undertaken; (iv) 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 (v) there is little existing information about the relative abundance, habitat requirements, biology and population dynamics of this species across its range.

Page Contents

Current Conservation Status

(No listings known)
 

Distribution

Southern Australia

The species is reported to range from eastern Bass Strait (including Tasmania), through to the eastern reaches of the Great Australian Bight (Gomon, in Gomon et al., 1994).
Flinders I. in Bass Strait is the type locality (McCulloch, 1914).
 

South Australia

There are few published records of the species in South Australia. Examples of locations in S.A. where A. macrolepis is reported to have been recorded include the eastern Great Australian Bight, and deeper waters west of the Coorong and south of Encounter Bay (Gomon, in Gomon et al., 1994; Museum of Victoria record, cited in OZCAM database, 2008).
 

Habitat

The full depth range is not known, but during the 1990s, the species was reported to have a narrow depth range, between 40m and 80m (Gomon, in Gomon et al., 1994).
The Large-scale Flounder presumably occurs on sandy substrates, as do other members of the genus Ammotretis and the family Pleuronectidae.
 

Notes on the Biology

The smallest member of the genus, A. macrolepis grows to at least 10m (Gomon, in Gomon et al., 1994).
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 southern Australian States (see section above, on Commercial Fishing for flounders as a group).
The species is reported to be “frequently taken” by prawn trawlers in the South Australian prawn grounds (Gomon, in Gomon et al., 1994).
 

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.
In southern States of Australia, legal minimum sizes for flounder are all larger than the maximum size of this species, which would preclude it from being taken as a recreational species. 
 

Vulnerable Characteristics of the Species and Threatening Processes

South Australian waters are considered to be the edge of the species range.
To date, Large-scale Flounder has been recorded over a narrow depth range (of 20m).
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.
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 taken as bycatch by prawn trawlers (“frequently”, according to Gomon, in Gomon et al., 1994).
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 Large-scale Flounder populations in South Australia.
 

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, habitat requirements and depth range of Large-scale Flounder in South Australia, which is at the edge of the geographic range. The species is little known in this State, with few published records.
There is very little information on the biology and population dynamics of this species.  
Where possible, prawn trawling bycatch data from Gulf St Vincent, 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 GSV 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)
 

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.