© 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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Crested Flounder

Family Name:	Bothidae
Scientific Name:	Lophonectes gallus Günther, 1880
Recommended Status in S.A:	Data Deficient
Rationale:  The species is included here because (i) South Australia is at the edge of geographic range of this mainly south-eastern species; (ii) there are few records of Crested Flounder in S.A., and the distribution and relative abundance within S.A. are both poorly known; (iii) in the eastern part of the range, Crested Flounder is highly vulnerable to capture in coastal prawn trawls and fish trawls, and a recent assessment in N.S.W. highlighted the vulnerability of this species to fishery-induced population decline; (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., including insufficient information about the extent of capture in prawn trawl fisheries in Gulf St Vincent and eastern Great Australian Bight, and no assessment of potential population impacts has been undertaken; and (v) there is very 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

The species (or two closely related ones) occurs in New Zealand and the Kermadec Islands, and also along the south-eastern coast of Australia, from southern Queensland through to south-eastern South Australia, and including Tasmania (May and Maxwell, 1986; Kendrick, 1988; Kendrick and Francis, 2002; Gomon, in Gomon et al., 1994).
There are various museum records and fisheries bycatch records from N.S.W. and eastern Victoria, and several museum specimens from northern and eastern Tasmania (CSIRO Marine Research records, cited in CSIRO, 2007; South Australian Museum records; CSIRO Marine Research records, in Australian National Fish Collection, cited in OZCAM database, 2008).

South Australia

South Australia is the western edge of the geographic range. There are few published records, compared with the eastern States. Examples of locations in S.A. where the species has been recorded include central GSV (old records from 1909, prior to the development of trawling in that area) (Australian Museum records, cited in OZCAM database, 2008), central and southern Spencer Gulf (Currie and Sorokin, 2010), and the GAB Marine Park (S.A. Museum specimen F10247, cited by R. Foster, South Australian Museum, 2006). SARDI records (2002, cited by R. Foster, S.A. Museum, pers. comm., 2006) from the central coast of the Great Australian Bight represent a westerly extension of the previously known range.

Habitat

L. gallus is usually found on sandy bottoms. One published depth range is 26m – 240m (Hensley and Amaoka, 1997). CSIRO et al. (2001) reported the overall depth range to be 26m – 311m.

Notes on the Biology

The species grows to around 20cm (Gomon, in Gomon et al., 1994; Hensley and Amaoka, 1997).
The Crested Flounder feeds on benthic invertebrates (Hensley and Amaoka, 1997). During a survey in Spencer Gulf, the gut contents of 4 specimens were examined, and found to contain about 80% polychaete worms, and 20% gammarid crustaceans (Currie and Sorokin, 2010).
Flounders live on the sea floor, but are pelagic spawners (Nelson, 2006). In New Zealand, larvae of L. gallus have been found in coastal waters during most months of the year (i.e. 9 months or more) (Kingsford, 1988).
The larvae of L. gallus are relatively small at metamorphosis (15-18 mm BL), compared with other flounders in the Bothidae (Fukui et al., 2002).

Fisheries Information

Commercial

Lophonectes gallus is part of the bycatch in the Commonwealth-managed SESSF (Southern and Eastern Scalefish and Shark Fisheries) (AFMA, 2002a). Bromhead and Bolton (2005), reported that L. gallus is a discarded bycatch species in the South East Trawl Fishery. It is noted that the species was not recorded during a bycatch monitoring program in the SETF during the early 2000s (Knuckey et al., 2002; Wayte et al., 2004). There appear to be no data on the bycatch of this species in the Great Australian Bight Trawl fishery, and it was not listed in a number of bycatch survey reports (e.g. Brown and Knuckey, 2002; Daley et al., 2006).
In N.S.W., L. gallus is a commonly recorded part of the bycatch in the shelf sector of the ocean prawn trawl and ocean fish trawl fisheries, with a recorded frequency of occurrence across all trawls of 84% in ocean prawn trawl shelf sector (hence the species was ranked number 2 in the top 10 finfish bycatch species for that sector), 25% in the ocean fish trawl (shelf sector), and 16% in the Wreck Bay and Tathra inshore grounds of the ocean fish trawl shelf sector (N.S.W. Department of Primary Industries, 2004). Information about the catches of flounders as a group in N.S.W. are provided at the beginning of this chapter, in the section on Commercial Fishing. 
Previously, L. gallus was part of the bycatch in the Bass Strait Central Zone Scallop Fishery, caught in variable numbers per annum. Examples are shown in the table below (Table 4, from Haddon and Semmens 2001, 2002, 2003, and Haddon et al., 2004). This fishery has a zero TAC for 3 years from the start of 2006 (so is currently closed) (J. Pogonoski, pers. comm., 2007).
 

Table 4 Bycatch of Crested Flounder in Bass Strait Central Zone Scallop Fishery
Year	No. Random Tows	No. L. gallus recorded
2001	35	3
2002	59	34
2003	17	1
2004	36	5
(Haddon and Semmens 2001, 2002, 2003, and Haddon et al., 2004)

It is noted that flounder species (unspecified) are taken in minor quantities by commercial fishers in south-eastern Australian States, including N.S.W., Victoria, Tasmania and S.A., and the Crested Flounder occurs in all of these States (see sections on Bothidae and Pleuronectidae).
this species is likely to be part of the bycathc in the Spencer gulf prawn trawl fishery, and perhaps in other prawn trawl fisheries in south australia. During a research survey using otter trawl in Spencer Gulf in 2007, this species was reported from 29 locations in central and southern Spencer Gulf, ranging from outside of the Franklin Harbour area, through to the "toes" of Yorke Peninsula (Currie and Sorokin, 2010). The total area in which the species was recorded contains various sites worked periodically by prawn trawlers.
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.
In N.S.W., larger flounder species are caught by recreational fishers and the total recreational catch of flounder (species combined) in NSW is estimated to be about 5t per annum (N.S.W. Department of Primary Industries, 2004).
In Tasmania, there is a minimum legal size of 25cm for all flounder species taken by recreational fishers (Morton et al., 2005) and a personal possession limit of 30 (DPIW Tasmania, 2008). The estimated recreational catch of flounder (all species) in 2000/01 of 21 tonnes was double the size of the commercial catch, indicating the importance of recreational fishing of this species (Henry and Lyle 2003, cited by Lyle et al., 2004). In Victoria, the minimum legal size is 23cm, with a bag limit / possession limit of 20 flounder (DPI Victoria, 2007b).
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

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.
The combined effects of commercial (including bycatch) and recreational fishing, in areas where these are high (e.g. N.S.W.), may be a threatening process.
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 (Carrick, 1997; PIRSA, 2003). Studies of trawl bycatch in New South Wales reported that L. gallus suffers trawl trauma when hauled in trawls, and that the species has a high “fishery impact profile” The species was classified overall as being of moderate resilience, but of “high risk” in terms of potential population impacts from trawl fishing (see N.S.W. Department of Primary Industries, 2004). It is quite likely that this species forms part of the prawn trawl bycatch in Spencer Gulf, give its presence in grounds worked periodically by trawlers (e.g. research trawl data of Currie and Sorokin, 2010). 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. There are old records of Crested Flounder from early 20^th century survey in Gulf St Vincent, prior to the development of the prawn trawl fishery in that gulf. No information is available on the prawn trawling bycatch composition or abundance in Gulf St Vincent, or in the eastern Great Australian Bight / western Eyre Peninsula, and the species is not routinely recorded in the prawn trawl bycatch in Spencer Gulf, even though it occurs there and is highly likely to be caught. Therefore, it is not possible to comment on the extent to which trawling may be a threatening process for Crested 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 has been previously recorded in these trawl grounds.
There is insufficient information on the extent of capture of this species in Commonwealth-managed fish trawl fisheries.
 

Research Recommendations

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. The species is little known in this State, apart from isolated records from Gulf St Vincent and the GAB, and recent trawl bycatch in Spencer gulf.
There is little existing information about biology and population dynamics of this species.
Where possible, flounders in prawn trawling bycatch from Gulf St Vincent, Spencer Gulf and the West Coast of S.A. should be recorded, with data analysed and monitored to determine the presence and relative abundance of this species over time (see Management Requirements). 
Where possible, the presence or absence of this species in the bycatch in the Great Australian Bight Trawl fishery should be ascertained. Bycatch of flounders in the Commonwealth-managed fish trawl fisheries (e.g. SETF and GABTF) should be recorded, analysed and monitored over space and time. 
 

Management Recommendations

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 further improvements in net design) to reduce the bycatch of benthic fish species in all trawl fisheries are recommended (see Management Notes). This is particularly required in areas where bycatch is high (e.g. New South Wales).
Further recreational fishing controls (e.g. legal minimum sizes, and possession limits) are required in areas where these do not yet exist, and enforcement is also required.
 

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.