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Southern Sand Flathead is popular with recreational fishers. It is found in shallow waters around southern Australia. In VIC, one stock is sustainable and one is recovering. The TAS stock is depleted, the SA stock is undefined and the WA stock is negligible.  

Southern Sand Flathead (Platycephalus bassensis) is endemic to Australia and inhabits bays, inlets, estuaries, and shallow coastal waters to a depth of around 100 m from the central New South Wales coast, around Tasmania to South Australia and southern Western Australia [Gomon et al. 2008]. There is some evidence of regional sub-populations with differences in physical characteristics, recruitment dynamics and growth rates. Information from tagging, larval sampling and growth rate studies [Brown 1977; Hamer et al. 2010, 2014], indicate that Southern Sand Flathead in Port Phillip Bay, Victoria, comprise a distinct biological stock that has slower growth, and asymptotic length that is 30% smaller than fish from Bass Strait and 20% smaller than fish from south-east Tasmania [Hirst et al. 2014; Koopman et al. 2009]. However, biological stock structure has not been studied in detail in other areas and each of the State jurisdictions have different management arrangements for Southern Sand Flathead.

Here, assessment of stock status is presented at the biological stock level—Port Phillip Bay (Victoria); at the management unit level—Corner Inlet and Victoria Other (Victoria); and at the jurisdictional level—Western Australia, Tasmania, and South Australia.

Tasmania

In Tasmanian waters, Southern Sand Flathead are targeted primarily by recreational fishers. Commercial catches are comparatively minor. Commercial fishing methods include hook and line gears (primarily), gillnet and Danish seine. Records of commercial landings show peak catches of roughly 10–15 t between 1995–96 and 2008–09 [Krueck et al. 2020]. From then on, annual commercial catches have declined to less than 10 t, amounting to only 3.8 t in 2021–22 [Cresswell et al. 2023]. Recreational catches of Southern Sand Flathead are substantially higher than commercial catches, with an estimated total of almost 300 t landed in the early 2000s and subsequent declines to 184 t in 2017–18 [Krueck et al. 2020; Lyle et al. 2019]. The low commercial catch relative to that taken by the recreational sector means that limited inferences can be made about stock status based on commercial catch and effort data. Thus, fishery-independent surveys were implemented using fishing gear and targeting practices typical of recreational fishers in areas of significant effort [Ewing et al. 2014]. Surveys have been conducted annually since 2012 and provide data on catch rates as well as the age and size composition of Southern Sand Flathead. Survey results indicated low abundances of legal sized fish, particularly in south-eastern Tasmania. In November 2015, recreational daily bag limits were therefore reduced from 30 to 20 and the minimum legal size increased from 300 to 320 mm. Continued monitoring and analysis of survey data indicated that these changes may have benefited populations, but that any potential recovery was short-lived given consistently heavy fishing pressure in the region, particularly on females [Krueck et al. 2020]. From 2020 onwards, independent sampling has been intensified and expanded to more sites along the east coast and north coast. A first in-depth analysis of the expanded survey dataset in 2021–22 indicated that in most regions the spawning biomass of females has likely been depleted below 20% of unfished levels, and that fishing mortality of females remains unsustainable (2–4 times higher than natural mortality) [Fraser et al. 2022]. More comprehensive sampling is needed to corroborate estimates of female stock status in some regions, but current levels of estimated fishing mortality are unlikely to allow for recovery from depletion in most areas where surveys have been conducted to date [Fraser et al. 2022]. These findings indicate that Southern Sand Flathead are likely to be depleted in most regions, which has triggered preliminary management changes, including a reduction of the bag limit from 20 to 10, and an increase of the minimum legal size from 320 to 350 mm.

On the basis of this information, Southern Sand Flathead in Tasmania is classified as a depleted stock.

Southern Sand Flathead biology [Bani and Moltschaniwskyj 2008; Brown 1977; Jordan 1998; Koopman et al. 2004]

Victoria – Indigenous (Management Methods). A person who identifies as Aboriginal or Torres Strait Islander is exempt from the need to obtain a Victorian recreational fishing licence, provided they comply with all other rules that apply to recreational fishers, including rules on equipment, catch limits, size limits and restricted areas. Traditional (non-commercial) fishing activities that are carried out by members of a traditional owner group entity under an agreement pursuant to Victoria’s Traditional Owner Settlement Act 2010 are also exempt from the need to hold a recreational fishing licence, subject to any conditions outlined in the agreement. Native title holders are also exempt from the need to obtain a recreational fishinglicence under the provisions of the Commonwealth’s Native Title Act 1993.

Tasmania – Commercial (Catches). Catches reported for the Tasmanian Scalefish Fishery are for the period 1 July to 30 June the following year. The most recent assessment available is for 2021–22.

Tasmania – Recreational (Management methods). In Tasmania, a recreational licence is required for fishers using dropline or longline gear, along with nets, such as gillnet or beach seine. Due to a recent change in stock status, fishery regulations for the species are currently under review. Until 31 October 2023, the species is subject to a minimum size limit of 350 mm, a bag limit of 10 fish and a possession limit of 30 fish for recreational fishers.

Tasmania – Indigenous (Management methods). In Tasmania, Indigenous persons engaged in traditional fishing activities in marine waters are exempt from holding recreational fishing licences, but must comply with all other fisheries rules as if they were licensed. For details, see the policy document 'Recognition of Aboriginal Fishing Activities” (https://dpipwe.tas.gov.au/Documents/Policy%20for%20Aboriginal%20tags%20and%20alloting%20an%20UIC.pdf).

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4. Brown, IW 1977, Ecology of three sympatric flatheads (Platycephalidae) in Port Phillip Bay, Victoria. PhD thesis, Monash University, Victoria.
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8. Gomon, M, Bray, D and Kuiter, R (ed) 2008, Fishes of Australia's southern coast, Sydney: Reed New Holland.
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19. VFA unpublished, Southern Sand Flathead–Port Phillip Bay stock status indicators update 2018.