Stout Whiting Sillago robusta

Brad  Zellera, Kevin  Rowlingb, Eddie Jebreena, Michael O'Neilla and Michelle Winninga

Stout Whiting

Table 1: Stock status determination for Stout Whiting


Queensland, New South Wales


Eastern Australian

Stock status




Standardised catch rate, catch-at-age frequencies

ECTF = East Coast Trawl Fishery (Queensland); OTF-PS = Ocean Trawl Fishery–Prawn Sector (New South Wales)

Stock Structure

The geographic distribution of the east coast Stout Whiting biological stock is restricted to southern Queensland and northern New South Wales. Genetic analysis of Stout Whiting catches from southern Queensland locations indicates that biological substocks are unlikely to exist1. Hence, status for this species is reported at the level of the individual biological stock.

Stock Status

Eastern Australian biological stock

On average, 80 per cent of the annual commercial catch is taken in Queensland and 20 per cent in New South Wales. The status of the Stout Whiting biological stock in Queensland waters is adopted as representative of the whole biological stock in any given year2. Long-term size-at-catch and age-at-catch frequency data from commercial landings indicate that the biological stock size structure is relatively stable2.

In Queensland, the annual total allowable catch (TAC) for Stout Whiting is 1500 tonnes (t). The TAC is reassessed before the start of each fishing year using a decision-support model developed from the most recent stock assessment3. Trends in standardised catch per unit effort (CPUE) and catch-at-age frequencies (catch curves) are used as the basis for review and adjustment of the TAC.

The 2010 assessment (DEEDI, unpublished data) estimates that 2009 CPUE was greater than the 75th percentile of historical CPUEs (1991–2009) and that total mortality was below the lower precautionary threshold specified for total mortality in the model. Under a scenario of relatively high CPUE and low total mortality, the model recommended that the TAC for 2010 increase to 1500 t, a 50 t increase from the 2009 TAC.

There have been no declining trends in CPUE over time. In 2009, standardised CPUE was high, and there was no truncation of length and age frequencies, indicating that recruitment was stable. The 2010 total commercial catch was below the Queensland annually adjusted TAC. This evidence indicates that the biological stock is unlikely to be recruitment overfished, and the current level of fishing mortality is unlikely to cause the biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

Table 2: Stout Whiting biology2–3

Longevity and maximum size

8 years; 23 cm FL

Maturity (50%)

2–3 years; 14–18 cm FL

FL = fork length

Figure 1: Distribution of reported commercial catch of Stout Whiting in Australian waters, 2010
Figure 1: Distribution of reported commercial catch of Stout Whiting in Australian waters, 2010

Main features and statistics for Stout Whiting stocks/fisheries in Australia in 2010
  • Stout Whiting is primarily fished using prawn otter trawl and Danish-seine.
  • A range of input and output management controls are in place for Stout Whiting:
    • Input controls in New South Wales include spatial and temporal closures, and gear restrictions. In Queensland, catch of Stout Whiting is limited to five commercial licences.
    • Output controls in New South Wales include a recreational bag limit of 20 whiting (all species). In Queensland, a TAC and individual transferable quotas limit commercial catch of Stout Whiting.
  • In Queensland, 3 commercial fishing vessels caught Stout Whiting in 2010. In New South Wales, 55 commercial vessels reported catch of Stout Whiting in 2010.
  • The total amount of Stout Whiting caught commercially in Australia in 2010 was 1336 t, comprising 1170 t in Queensland and 166 t in New South Wales. Recreational and Indigenous landings of the east coast Stout Whiting biological stock are negligible.

Figure 2: Commercial catch of Stout Whiting in Australian waters, 1991–2010 (calendar year)
Figure 2: Commercial catch of Stout Whiting in Australian waters, 1991–2010 (calendar year)
Note: New South Wales catch is reported by financial year and has been combined with Queensland catch data for the calendar year in which the financial year ends (i.e. 2010 includes the 2009–10 financial year data for New South Wales).

Catch Explanation

Commercial landings from the east coast Stout Whiting biological stock began when an export market was developed in the 1970s2. The fishery in Queensland was restructured in 1991 as a limited-entry fish trawl fishery, with a maximum of five licence holders. The market collapsed in 1991, resulting in significant volumes of unsold catch. This led to a reduction in fishing effort and catch between 1991 and 1993 (Figure 2). Catches increased with effort as the market recovered in the mid-1990s, before a decline in catch and effort in the late 1990s3. In 2000, bycatch reduction devices were introduced to the Ocean Trawl Fishery–Prawn Sector (New South Wales) and may have contributed to the relatively low catch recorded in that year2. Other factors, including a seasonal trawl closure in southern Queensland, a Stout Whiting TAC of 1000 t, and individual transferable quota allocations among Queensland Stout Whiting fishers, may also have been related to changes in catch at the time3. Since 2000, Stout Whiting catches have been relatively stable. In some years, landings have been substantially lower than the predicted sustainable level upon which the TAC is based (median 78 per cent of TAC; range 31–96 per cent). This has been largely attributed to economic drivers (e.g. low demand from export markets)4.

Effects of fishing on the marine environment
  • The seabed where the fishery occurs lacks major reef structures5. Anecdotal information from research trawls and commercial fishers indicates that the seabed in the fishery area is predominantly bare sand6. Consequently, the impact of trawling on benthic habitats in the fishery area is likely to be relatively low6.
  • The fishery has potential for interactions with sea turtles, but these occur infrequently7. Compulsory use of turtle excluder devices in fish trawls minimises the impact of interactions with turtles.
  • Although Danish-seine is legislated as an acceptable method for targeting Stout Whiting in Queensland and New South Wales, it is only used in Queensland. Compared with trawling, Danish-seining harvests Stout Whiting more efficiently, has less physical contact with the seabed, and more effectively reduces some forms of bycatch, including prawns, bugs, squid, sea snakes and pipefish7.
  • Sustainability of Stout Whiting taken as bycatch in the East Coast Otter Trawl Fishery (Queensland) has been assessed. At predicted future levels of effort, there is no more than an intermediate risk that discarding will result in an unacceptable decline in Stout Whiting biological stock abundance (Queensland DAFF, unpublished report).

Environmental effects on Stout Whiting
  • Since Stout Whiting is a shallow-water oceanic species, it is unlikely that land-based events would significantly affect the biological stock. Marine environmental pressures that may affect the biological stock have not been identified.

a Department of Agriculture, Fisheries and Forestry, Queensland
b Department of Primary Industries, New South Wales