© 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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BOTHIDAE: LEFT-EYE FLOUNDERS
PARALICHTHYIDAE: LARGE-TOOTH FLOUNDERS
PLEURONECTIDAE: RIGHT-EYE FLOUNDERS

© MLSSA

 

Bothidae

Left-eye flounders are found in all tropical and temperate seas. During the 2000s, at least 161 named species were known, including several species of commercial importance (Froese and Pauly, 2008). Some species previously included in the Bothidae have now been placed in the family of large-tooth flounders, the Paralichthyidae. The left-eye flounders are extremely compressed benthic fishes, with two eyes on the left side of the head. Species in the family lie on the sea bottom (usually sand), with their unpigmented right side down, and both eyes directed upward (Gomon, in Gomon et al., 1994). Members of the Bothidae prey on benthic invertebrates and fishes. They are pelagic spawners (Nelson, 2006). The left-eye flounders are separated from the Tongue Soles (a family of fishes which also have two eyes on the left side), in having pectoral fins, and separated dorsal, anal and caudal fins (Gomon, in Gomon et al., 1994).
There are about 20 left-eye flounder genera worldwide. Several of these genera are found in southern Australian coastal waters (Gomon, in Gomon et al., 1994; Kuiter, 2000), and of those, Arnoglossus contains the most species. Flounders in southern Australia are usually small species (from 10cm - 25cm). Most are considered to be excellent eating (Kuiter, 2000), despite their relatively low commercial importance. Example of Bothid flounders found in southern Australia include Bass Strait Flounder Arnoglossus bassensis; the Small-eye Flounder Arnoglossus micrommatus; Mueller’s Flounder Arnoglossus muelleri; and Crested Flounder Lophonectes gallus (Gomon, in Gomon et al., 1994; Kuiter, 1996a; CSIRO, 2007). Within Bothidae, two species in Arnoglossus, as well as Lophonectes gallus, are described in synopses below, as species of conservation concern in S.A..

Paralichthyidae

Like members of the Bothidae, fishes in Paralichthyidae have both eyes on the left side, and a number of species were previously included in Bothidae (e.g. Gomon, in Gomon et al., 1994). Differences between fishes in Bothidae and Paralichthyidae are minor – e.g. differences in pelvic fins, and extent of development of the lateral line on the underside (Hensley, 1995; Hensley and Amaoka, 1997; Amaoka and Hensley, 2001). Globally, there are at least 116 species in the family, distributed through the Atlantic, Indian and Pacific oceans, mostly in marine and estuarine waters, and rarely in fresh water (Froese and Pauly, 2008).  In southern Australia, two of the most commonly known and caught species in the Paralichthydiae, are Largetooth Flounder Pseudorhombus arsius and Small-tooth Flounder Pseudorhombus jenynsii. Despite their broad distribution in Australia, both of these flounder species are discussed in synopses below, due to their high vulnerability to capture in various fisheries. Some flounder species, including the Small-tooth Flounder P. jenynsii, are susceptible to capture in prawn trawls in South Australia, as discussed below in the synopsis for that species.

Pleuronectidae

Like members of the Bothidae and Paralichthyidae, right-eye flounders are extremely compressed benthic fishes. Adult fishes in this family have two eyes on the right side of the head, and lie on the usually unpigmented left side, with the camouflaged right side directed upwards (Gomon, in Gomon et al., 1994). The pigmented side is capable of remarkable colour changes in order to match the bottom habitat (Nelson, 2006). Species in the right-eye flounder families are benthic, and prey on benthic invertebrates and fishes. They are pelagic spawners (Nelson, 2006). Evseenko (2004) reviewed the family Pleuronectidae, and included 40 genera and around 100 species. In recent years, some right-eye flounders (including genera such as Ammotretis, Taratretis and Rhombosolea) have been grouped into a separate family, the Rhombosoleidae, but that family is not currently recognised in CSIRO’s Codes for Australian Aquatic Biota (2007) or in the Australian Faunal Directory (Hoese et al., 2006).  
Several Right-eye Flounder species have a broad distribution across southern Australia. These include the Greenback Flounder Rhombosolea tapirina, the Elongate Flounder Ammotretis elongatus (for which Investigator Strait in S.A. is the type locality), and the Long-snouted Flounder A. rostratus. Another species, A. lituratus, occurs in S.A., Victoria and Tasmania, and is found from the shallows down to around 80m.
A few right-eye flounder species occur in brackish water, and occurrence in fresh water is even rarer. Flounders feed by digging for polychaete worms and small crustaceans in the benthic sand and mud they inhabit (DPIWE Tasmania, 2004h). Most flounder species are important to fisheries. 
The potential vulnerability of all sedentary benthic, sand-dwelling fishes to trawling impacts (particularly prawn trawling in upper continental shelf waters) is noted here, and that would include the majority of the flounders.  Most flounders in southern Australia (but see Hourston et al., 2004) have been little studied, and for most species there is very little known about their biology and life history (N.S.W. Department of Primary Industries, 2004).
Several species in the Pleuronectidae are discussed in synopses below, including species for which South Australia is the edge of the geographic range; species with a narrow depth range (including those whose habitat is subject to numerous impacts); poorly known species for which there are currently few records in S.A., and species which are caught in large numbers in trawl bycatch in South Australia.

Commercial Fishing

Flounder species (unspecified) are taken in small quantities by commercial fishers in southern Australia, including N.S.W., Victoria, Tasmania, South Australia and Western Australia. Most commercial fishing data aggregate all flounders as a group, and therefore, there are few family-specific or species-specific fishing data. During the 1990s, the total catch of flounder species from south-eastern Australia was about 140 tonnes per annum (Kailola et al., 1993, cited by Morton et al., 2005). Much of the flounder catch in south-eastern Australia and Tasmania is Greenback Flounder Rhombosolea tapirina.
In N.S.W., flounders are taken in a number of fisheries, including the Ocean Trawl (fish and prawn sectors) Fishery, and the estuarine (fish and prawn sector) hauling fisheries. Catches in the estuarine fisheries are low (less than 10% of the total State catch of flounder), compared with the ocean trawl fishery. In the Ocean Trawl Fishery, flounders as a group are listed as a key secondary species, and there was a substantial increase in catches from late 1980s to mid 1990s; then more stable, but large annual variability (N.S.W. Department of Primary Industries, 2004). Between 1997 and 2003, the average annual catch of flounders was reported to be 10.6t in the ocean fish trawl sector, and 18.5t in the ocean prawn trawl sector. During one year of the early 2000s, the total commercial catch of flounder in N.S.W. was 32t, and 28.6t of that came from the Ocean Trawl Fishery. There are reference levels and trigger points (in terms of catch fluctuation) in the Ocean Trawl Fishery that will determine management response (N.S.W. Department of Primary Industries, 2004). Catches of Pseudorhombus arsius (Large-tooth Flounder), Pseudorhombus jenynsii (Small-tooth Flounder) and Ammotretis species (“Bay flounder”) in N.S.W. are discussed in synopses below.  
In Victoria, Greenback Flounder is one of the most common flounder species taken by recreational fishers. Annual catches of flounders (all species combined, but mostly comprising R. tapirina) throughout the 1980s were mostly in the range 30t – 70t (BRR 1991). The annual commercial catch of Greenback Flounder between 1997 and the early 2000s ranged between ~ 15t and 41t per annum (NRE Victoria, 2003), with 18t caught in 2003/04 and 26t in 2004/05 (Department of Primary Industries, Victoria, 2006b).
Flounders (mainly in the Pleuronectidae) are amongst the top 10 scalefish species landed in Tasmania’s commercial fishery for scalefish, and are sold for the table fish market (Jordan et al., 1998; Lyle and Jordan, 1999; DPIWE Tasmania, 2004b). Flounders are taken using gillnets (including graball nets), spearing, inshore trawl, and seine nets (Lyle and Jordan, 1999; Smith and Heran, 2001; Morton et al., 2005; Ziegler et al., 2006). In the Tamar estuary, flounder is one of the top commercial fish catches, in terms of numbers. The reported flounder catch in Tasmania from the 1970s to the early 2000s is shown below (Figure 1).
 

Figure 1 Reported Catches of Flounder species (unspecified) from Tasmania, 1969-70 to 2004/05

(from tables in Lyle and Jordan, 1999, and Ziegler et al., 2006)

In Tasmania, there was reported to be a declining trend in catch throughout the 1990s and early 2000s (see Lyle and Jordan, 1999; Smith and Heran, 2001, Ziegler et al., 2006, and table above), partly related to a significant decline in graball net effort during the latter half of the 1990s (Lyle and Jordan, 1999), but also likely due to a decline in stocks (Ziegler et al., 2006). 
In W.A., flounders are caught commercially in low tonnages per annum in a number of fisheries. During the 1980s, catches were in the range of 5t – 10t for 6 years of that decade (BRR, 1991), but decreased to less than 5t in most years of the 990s and early 2000s. Combined catch of Flounder species (unspecified) from all commercial fisheries in W.A. is provided below, according to fishers’ statutory monthly returns. The figures presented below may slightly underestimate the total catch, because additional data from research logbooks and processors are not included (W.A. State of the Fisheries report, 2002-2003). It is possible that the catch figures include species from the Pleuronectidae as well as the Bothidae. Ammotretis rostratus is one of the few flounder species in W.A. for which statistics are separated in the catch reporting. During the past 7 years for which data on combined flounder species are available, between 96% and 100% of the live catch by weight was landed, indicating a very low proportion of discards (Table 2). 
 

Table 2 Reported Catches of Flounder species (unspecified) from W.A. waters, 1994-95 to 2004-05
Year	Live weight (kg)
1994/95	3,559
1995/96	2,802
1996/97	4,279
1997/98	3,274
1998/99	3,465
1999/00	2,630
2000/01	2,991
2001/02	2,576
2002/03	2,357
2003/04	2,327
2004/05	4,944
(W.A. Fisheries Research Services Division statistics 1994-2002, extracted from W.A. Fisheries website, 2003, and W.A. State of the Fisheries reports, 2000/01 - 2005/06)

According to BRR (1991) catches of flounder and sole (combined) from South Australia have been very high in years, particularly during the 1970s. For example, in 1976/77 and 1977/78, annual catches in both years were as high as 232 tonnes, but catches during most years of the following decades were one to two orders of magnitude lower, and the record catches of the mid 1970s have never been repeated. In South Australia, much of the flounder catch is from the Lakes and Coorong fishery, and comprises Greenback Flounder (Rhombosolea tapirina). The reported commercial catch of flounder from inland (including estuarine) waters in S.A. was 28t in 1998/99; 40t in 1999/2000; 19t in 2000/01, 26t in 2001/02; 6t in 2002/03, 6t in 2003/04, 9t in 2004/05 and 7t in 2005/06  (Knight et al., 2005, 2007). Variations in flow of fresh water into the Murray Lakes region and out of the Murray Mouth directly affects the life cycle of estuarine dependent species such as Greenback Flounder (Higham et al., 2002), and annual catch fluctuations reflect this variation. Flounder species are also caught, in lower numbers, in the Marine Scalefish Fishery. Examples of locations in S.A. where flounder species are caught commercially in minor quantities include Venus Bay on western Eyre Peninsula, northern Gulf St Vincent, and the bays of north-eastern Kangaroo Island. In South Australia, one of the main fishing-induced sources of mortality of flounders may be due to by-capture in prawn trawl fisheries, as discussed below, in synopses for several species, including Pseudorhombus jenynsii. Flounder bycatch is very minor in other fisheries, such as the Blue Crab Pot Fishery (e.g. Svane and Hooper, 2004; Currie and Hooper, 2006).  
Flounders such as Greenback (R. tapirina) Banded-fin (Azygopus pinnifasciatus), Crested (Lophonectes gallus), Long-snout (Ammotretis rostratus), Small-tooth (Pseudorhombus jenynsii) and Spotted (Ammotretis lituratus) are also a minor part of the bycatch in the Commonwealth-managed SESSF (Southern and Eastern Scalefish and Shark Fisheries) (AFMA, 2002a), including the trawl sector of the South East Fishery. There are low catches (e.g. 1 – 2t per annum during the early 2000s) in the part of the Commonwealth-managed South East Fishery that operates near N.S.W. waters, and these statistics are included in compilations of total commercial catches in New South Wales (e.g. N.S.W. Department of Primary Industries, 2004).

Recreational Fishing

Flounders of various species in the Bothidae and Pleuronectidae families are taken in large quantities by recreational fishers in some of the southern States, particularly New South Wales and Tasmania.  The National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) reported that 246,620 “Flounder / Sole / Flatfish” were caught and kept by recreational fishers in southern Australian states during the survey time period (May 2000 to April 2001), comprising the following State catches (Table 3).

Table 3 Recreational Catches of Flounder (all species combined) 2000-01
State	No. of Flounder, Sole and other flatfish caught
Queensland	43,031
New South Wales	92,303
Victoria	27,521
Tasmania	64,590
South Australia	3,616
Western Australia	15,559
(from Henry and Lyle, 2003)

Various flounder species are also taken by spear fishers. It is noted that record sizes of several flounder species, such as Ammotretis lituratus, A. rostratus, and Rhombosolea tapirina, have been taken by spear fishers in south-eastern Australia (New South Wales, Victoria, Tasmania) (e.g. Australian Underwater Federation Inc., 2003).
In N.S.W., larger flounder species are caught by recreational fishers and the total recreational catch of flounder (species combined) in NSW was estimated to be about 5t per annum during the early and mid 2000s (N.S.W. Department of Primary Industries, 2004).
In Victoria, there is a minimum legal size of 23cm for all flounder species taken by recreational fishers, and a bag limit / possession limit of 20 flounder (DPI Victoria, 2007b). 
In Tasmania, flounders are significant species for recreational fishers (Jordan et al., 1998; Lyle and Jordan, 1999). They are commonly caught on shallow coastal sandy flats, using spears and lights at night, or dip nets, or specially designed bottom-set gillnets (graball nets). They are rarely caught on lines. Although there are some 12 species of flounder and 1 species of sole found in Tasmanian waters, the most commonly found (and taken by recreational fishers) in Tasmanian coastal estuaries and bays, are the Greenback Flounder and the Long-snouted Flounder, the latter frequently (and incorrectly) referred to as “sole”. During 2000/01 an estimated 75,000 flounder were caught by recreational fishers in Tasmania, and over 71,000 (95%) were retained (Morton et al., 2005). Catches were concentrated in Derwent – Channel region (35%) and Fredrick Henry - Norfolk Bay region (24%), followed by the eastern north coast (17%), west coast (11%) and south-east (9%). Fishing with spears (from the surface and generally at night using lights) was the dominant capture method, accounting for over 80% of the recreational catch during the 2000/01 survey period. Gillnets contributed a further 15% and beach seine nets the bulk of the remainder. During the 2000/01 survey, fishing was largely conducted from the shore (63% of the catch), reflecting the common practice of wading and using hand spears to target the species (Morton et al., 2005). As indicated by the survey figures above, gillnets are also a significant method of capture. The graball gillnet catch of flounders was about 4.6t in 1997 (Lyle and Jordan, 1999). During the early 2000s, the gillnet catch was about 5.2t per annum. Flounders are the third most important group of fish taken by gillnets (Smith and Heran, 2001). The minimum legal size for flounders (and sole) taken recreationally in Tasmania is 25cm. During the early 2000s, there was a daily bag limit of 30 flounder and sole, and a possession limit of 45 (Smith and Heran, 2001; DPIWE Tasmania, 2004h); however during the mid to late 2000s, the daily bag limit was removed, and replaced by a personal possession limit of 30 (DPIW, 2008).
In W.A. there is a minimum legal length of 25cm for flounder. The combined daily bag limit is currently 8 flathead and flounder (all species) in the West Coast, Gascoyne and South Coast regions, but was previoulsy 20 in the South Coast region (Department of Fisheries, 2003b, 2007c, 2008a, 2008b). Some recreational catch statistics for particular species are included in several of the synopses below. It is noted that during a 12-month survey of coastal recreational boat fishing between Augusta and Kalbarri (west coast of W.A.) in 1996-97, a total of 2,553 flounder (SE = 476) were reported to have been caught and kept, and 459 released (Sumner and Williamson, 1999).
In S.A., there is no minimum legal size for flounder species taken by recreational fishing, but there is a daily bag limit of 20 flounder, and a boat limit of 60 (PIRSA, 2008a, 2008b). In the charter boat fishery, there is an individual passenger catch limit of 20 flounder (for boats of up to 3 passengers) or 10 flounder (if more than 6 passengers), and a charter boat limit of 60 (for boats up to 6 passengers) (Presser and Mavrakis, 2005). Flounders are also taken by spear fishers. For example, flounder (specimens over 0.4kg) were listed targets in the 54^th Australian Spearfishing Titles 2006, held on northern Kangaroo Island (Australian Underwater Federation Inc., 2006).  In South Australia, examples of locations where flounder are taken include bays of the eastern Great Australian Bight (e.g. Ceduna and Streaky Bay area), Coffin Bay; Port Lincoln area, Tumby Bay, Port Broughton, Port Augusta and other locations in Spencer Gulf; Marion Bay, Edithburgh and other locations along southern Yorke Peninsula.

Associated taxa

Small-eye Flounder / Smalleye Flounder / Flimsy Flounder	Arnoglossus micrommatus Amaoka, Arai and Gomon, 1997
Bass Strait Flounder	Arnoglossus bassensis Norman, 1926
Crested Flounder	Lophonectes gallus Günther, 1880
Small-tooth Flounder / Smalltooth Flounder	Pseudorhombus jenynsii (Bleeker, 1855)
Large-tooth Flounder	Pseudorhombus arsius (Hamilton-Buchanan, 1822)
Derwent Flounder	Taratretis derwentensis Last, 1978
Short-fin Flounder / Short-finned Flounder / Shortfin Flounder	Ammotretis brevipinnis Norman, 1926
Large-scale Flounder / Largescale Flounder / Bay Flounder	Ammotretis macrolepis McCulloch, 1914
Long-snout Flounder / Long-snouted Flounder	Ammotretis rostratus Günther, 1862
Elongate Flounder / Elongated Flounder	Ammotretis elongatus McCulloch, 1914
Spotted Flounder	Ammotretis lituratus (Richardson, 1843)
Greenback Flounder	Rhombosolea tapirina Günther, 1862