Table 1: Stock status determination for Eastern School Whiting
| Jurisdiction |
Commonwealth, New South Wales, Tasmania, Victoria |
| Stock |
South-eastern Australian
(CTS, ITF, OTF, SESSF, SETF, SF) |
| Stock status |
|
| Sustainable |
| Indicators |
Spawning biomass |
CTS = Commonwealth Trawl Sector; ITF = Inshore Trawl Fishery (Victoria); OTF = Ocean Trawl Fishery (New South Wales); SESSF = Southern and Eastern Scalefish and Shark Fishery (Commonwealth); SETF = South East Trawl Fishery (Victoria); SF = Scalefish Fishery (Tasmania)
Endemic to south-eastern Australia, Eastern School Whiting occurs from southern Queensland to western Victoria and is considered to be a single biological stock. Status is reported at the biological stock level.
South-eastern Australian biological stock
The 2009 assessment of Eastern School Whiting, which includes commercial catch estimates for New South Wales, Victoria, Tasmania and the Commonwealth1–2, estimated that the spawning biomass would be 50 per cent of the unfished level at the beginning of 2010. The spawning biomass was well above the level at which the biological stock would be considered recruitment overfished (20 per cent of the unfished biomass) and, given commercial catch levels in 2010–11, is unlikely to have fallen to this level since the last assessment. The biological stock is not considered to be recruitment overfished.
The recommended biological catch (RBC) for Eastern School Whiting was 1723 tonnes (t) for the 2010–11 fishing season1–2. Total Australian commercial catch of Eastern School Whiting in 2010–11 was about 300 t below the RBC. Commercial catches landed by the Commonwealth Trawl Sector in both the 2009–10 (490 t) and 2010–11 (388 t) fishing seasons were well below the total allowable catches (TACs), with more than 50 per cent of the TAC remaining uncaught3. Total commercial catch is limited to the long-term RBC and has been well below the RBC in recent years. This level of fishing mortality is unlikely to cause the biological stock to become recruitment overfished. The results of the preliminary projections of fixed-catch scenarios1 provide further reassurance of this.
On the basis of the evidence provided above, this biological stock is classified as a sustainable stock.
Table 2: Eastern School Whiting biology1–2,4–5
Longevity and maximum size |
7 years; ~32 cm SL |
Maturity (50%) |
2 years; 14–18 cm FL |
FL = fork length; SL = standard length
Figure 1: Distribution of reported commercial catch of Eastern School Whiting in Australian waters, 2010
- Eastern School Whiting is commercially harvested using Danish-seines, haul seines and otter trawl nets.
- Various management controls are used across the jurisdictions where Eastern School Whiting is targeted:
- Input controls include limited entry to fisheries, gear restrictions, vessel restrictions, temporal closures and area closures.
- Output controls include size limits, and TACs in some jurisdictions.
- Numbers of commercial vessels that caught Eastern School Whiting in 2010 were 15 Danish-seiners and 19 trawlers in the Commonwealth Trawl Sector, 10 vessels in Victorian waters, 239 vessels in New South Wales waters and fewer than 5 vessels in Tasmanian waters.
- Total commercial catch of Eastern School Whiting in 2010 from Australian waters was 1437 t, comprising 388 t from the Commonwealth Trawl Sector (2010–11 fishing season)3, 51 t from Victoria (2010–11 financial year), 965 t from New South Wales and 33 t from Tasmania. Discards in the Commonwealth Trawl Sector have been estimated to be less than 1 per cent of total commercial catch2. Recreational and Indigenous catch is likely to be small. The only available estimate of recreational catch is less than 5 t in Tasmania (2007–08).
Figure 2: Commercial catch of Eastern School Whiting in Australian waters, 2000–10 (calendar year)
Retained commercial catches of Eastern School Whiting from all sectors increased steadily from the late 1970s, peaking at 2423 t in 1995 before declining to about half that level for the 2000s. Over the past 10 years, the commercial catch has varied between 1200 and 1600 t, with no obvious trend. Total removals of Eastern School Whiting during 2009 were the lowest since 2000, but increased again in 2010. Industry continues to emphasise that the limited market for Eastern School Whiting has significantly reduced Danish-seine catches in recent years and is also likely to have influenced targeting and catch rates2. The recent high value of the Australian dollar has all but extinguished the overseas market for Eastern School Whiting, and good recent prices for flathead have seen the Danish-seine fleet target this species in preference to Eastern School Whiting over recent years2.
- The distribution of Australian Fur Seal and, to a lesser extent, New Zealand Fur Seal, overlaps with parts of the Eastern School Whiting fishery. The apparent recovery of some fur seal populations has created the potential for more frequent interactions with trawl and Danish-seine operators. Consequently, the Australian Fisheries Management Authority (AFMA) and industry are focused on minimising seal interactions.
- Seabirds sometimes interact with trawlers (e.g. warp strike), predominantly during hauling of the net. Baker and Finley6 concluded that otter trawl in the Southern and Eastern Scalefish and Shark Fishery (Commonwealth) presents a 'high risk' to seabird populations, whereas Danish-seine in Commonwealth and Tasmanian waters was assessed as 'low risk' (Danish-seine accounts for more than 75 per cent of the Southern and Eastern Scalefish and Shark Fishery catch of Eastern School Whiting). AFMA has been working with otter trawl fishers to develop and implement seabird management plans to address this issue. In 2011, AFMA mandated individual vessel seabird management plans3.
- Danish-seining has the potential to affect seahorses and pipefish (syngnathids) because Danish-seiners operate in relatively shallow waters and use nets with a small mesh size. An AFMA–CSIRO (Commonwealth Scientific and Industrial Research Organisation) Ecological Risk Assessment (ERA) indicated that the Spiny Pipehorse was at low risk because the fishery overlaps with only a small portion of the range of this species7.
- In 2008, demersal trawling in the area of the Southern and Eastern Scalefish and Shark Fishery (Commonwealth) was nominated as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 because of potential damage to marine benthos. However, the ERA for the fishery7 identified no high-risk habitats on the inner shelf (<100 m) where Eastern School Whiting is caught.
- Since Eastern School Whiting is a relatively short-lived species that is caught by the fishery at more than 2 years of age, recruitment is expected to be strongly influenced by environmental conditions, ocean productivity and ecological effects.
a Department of Primary Industries, Victoria
b Institute for Marine and Antarctic Studies, Tasmania
c Department of Primary Industries, New South Wales
d Australian Bureau of Agricultural and Resource Economics and Sciences