STATUS OF AUSTRALIAN FISH STOCKS REPORT
Eastern School Whiting (2020)
1
Eastern School Whiting (2020)
Sillago flindersi
Karina Hall: NSW Department of Primary Industry, Timothy Emery: Australian Bureau of
Agricultural and Resource Economics and Sciences (ABARES), Nils Krueck: Institute for
Marine and Antarctic Studies, University of Tasmania, Victorian Fisheries Authority:
Victorian Fisheries Authority
STOCK STATUS OVERVIEW
Jurisdiction
Stock
Stock status
Indicators
Commonwealth,
Victoria, Tasmania
Southern
Australia
Sustainable
Catches, standardised CPUE, lengths,
ages, discards, biomass depletion
estimates (stock synthesis)
New South Wales
New South
Wales
Sustainable
Catches, standardised CPUE, lengths,
ages, discards, biomass depletion
estimates (stock synthesis)
STOCK STRUCTURE
Eastern School Whiting is endemic to south-eastern Australia and occurs from southern
Queensland to western Victoria. Some historical genetic and growth data suggests there may
be separate northern and southern stocks of Eastern School Whiting, with a division around
Forster [Dixon et al. 1987]. However, the power of the methods used to detect a difference was
limited and the results were difficult to interpret, with no clear geographic pattern in the genetic
variation detected [Dixon et al. 1987]. Overall, the hypothesis of a single, genetically diverse
panmictic stock could not be rejected, and the species has been assessed as a single biological
stock [Day 2010, Day 2017, Conron et al. 2018]. However, due to divergent fishing effort and
assessment results between the northern and southern parts of the stock in recent years and
the ongoing uncertainty regarding the stock structure, stock status is reported according to
management units in the current report.
Here, the assessment of the stock status is presented for two management units—Southern
Australia (Commonwealth, Victoria and Tasmania) and New South Wales.
STOCK STATUS
STATUS OF AUSTRALIAN FISH STOCKS REPORT
Eastern School Whiting (2020)
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New South
Wales
An annual basket total allowable catch (TAC) for combined Eastern School
Whiting and Stout Whiting (
Sillago robusta
) was introduced for the New South
Wales Ocean Trawl Fishery (OTF) in May 2019, and was initially set at 1 189 t
for the 2019–20 fishing season [Hall 2020]. A harvest strategy is currently being
developed for trawl whiting in New South Wales and a cross-jurisdictional
research project funded by the Fisheries Research and Development Corporation
is underway to clarify the stock structure of the species using modern genetic
and otolith chemistry methods.
To support quota determination, a quantitative stock assessment of the entire
biological Eastern School Whiting stock has been undertaken by Commonwealth
agencies every 3-5 years [e.g., Day 2017]. Previous assessments have included
State catch data, but were otherwise based largely on Commonwealth fisheries
data, particularly from the Lakes Entrance Danish-seine fleet. Nevertheless, the
biological parameters selected, especially in more recent assessments that have
included age data from sectioned otoliths, are considered appropriate for New
South Wales and these stock assessments, together with complimentary
fisheries data analyses from New South Wales, provide the most reliable source
of information on stock status for TAC determination [Gray et al. 2014a,b, Hall
2018].
Historically, approximately 60 per cent of the total catch of Eastern School
Whiting has come from New South Wales State waters. However, New South
Wales catches decreased between 2011 and 2014 from historical levels of
around 700–1 000 t per year to 492 t in 2014 [Hall 2015] and Commonwealth
catches increased to take approximately 50 per cent of the total catch [Day
2017]. Since 2014, the New South Wales State catch has increased significantly
and, in the three years prior to quota introduction, was 1 188 t in 2017, 1 155 t
in 2018 and 1 196 t in 2019 [Hall 2020].
The increased catches in New South Wales over the last three years have been
mostly taken by the fish trawl fleet from a single ocean zone (OZ5, covering one
degree of latitude near Newcastle). While standardised mean catch rates for the
entire fish trawl fleet have recently increased from below the long-term average
in 2013 and 2014 to near the long-term average over the last three years, catch
rates from the ocean zone near Newcastle decreased by over 50 per cent
between 2011 and 2014 to below the long-
term average and have remained low
since [Hall 2020]. While there is some evidence of localised depletion and that
total biomass has recently decreased to near 35% of unfished spawning
biomass, the stock is not considered to be recruitment impaired.
The Commonwealth stock assessment in 2017 estimated an average
recommended biological catch (RBC) of 1 615 t for the whole stock for the three
years 2018 to 2020 [Day 2017]. The total combined catches over this period
were 1 701 t in 2017, 1 916 t in 2018 and 1 743 t in 2019 (catch chart). When
combined with the weighted average discards (estimated as 103.92 t for the
2018-19 year, ABARES 2019) the total removals has exceeded the estimated
RBC over the last three years. Furthermore, a partial update of the assessment
in 2019 revised the predicated RBC under an average recruitment scenario to 1
165 t for 2020 [Day 2019].
Given the uncertain stock structure, decrease in biomass estimates to 35% of
unfished levels in 2020 under average recruitment and total removals in excess
of the estimated RBC over three years that was concentrated in New South
Wales waters, the level of fishing mortality was considered sufficient to cause
recruitment impairment, and the New South Wales part of the South Eastern
Australia biological stock was classified as a depleting stock in 2019. The New
South Wales basket TAC was reduced from 1 189 t in 2019–20 to 898 t for the
2020–21 fishing season, of which on average approximately 668 t is likely to be
Eastern School Whiting.
A full update of the Commonwealth stock assessment using data up to 2019 and
STATUS OF AUSTRALIAN FISH STOCKS REPORT
Eastern School Whiting (2020)
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including an increased amount of data from New South Wales, comprising two
standardised CPUE series, historical length and age data and discard rate
estimates, was completed using a new five-fleet model in late 2020, to inform
TAC setting for the 2021–22 fishing season [Day et al. 2020, cited in AFMA
2021]. The results estimated that the stock level had increased from 33% of
unfished spawning biomass in 2019 to 41% in 2021, assuming average
recruitment into the future, and that the estimated RBC in 2020 had increased
to 2 140 t [AFMA 2021]. While this includes a larger amount of total discards
than previous RBCs, the overall productivity of the stock had increased and the
certainty in the parameter estimates improved. Consequently, the current level
of fishing mortality is considered unlikely to cause the stock to become
recruitment impaired.
On the basis of the above evidence, the New South Wales part of the stock is
classified as a sustainable stock.
Southern
Australia
Stock status classification reported here for the Southern (Commonwealth,
Victoria and Tasmania) management unit is based on stock assessments
conducted for the Commonwealth’s Southern and Eastern Scalefish and Shark
Fishery (SESSF). This assessment includes reported state catches. Eastern
School Whiting in the SESSF is managed as a Tier 1 stock under the
SESSF Harvest Strategy Framework [AFMA, 2019]. The 2017 Tier 1 stock
assessment [Day 2017] informed the management of the stock for the 2019–20
fishing season, however an update to the assessment was undertaken in 2019
[Day, 2019].
The last full assessment, which was undertaken in 2017 [Day 2017] predicted
the spawning stock biomass at the start of 2018 would be 47% of the
unexploited spawning stock biomass (0.47SB0), below the target reference point
of 48% (0.48SB0) but above the limit reference point of 20% (0.20SB0). In
2019, this assessment was updated with catch data for the Commonwealth and
New South Wales for 2017 and 2018 and CPUE data for the Commonwealth
[Day 2019]. This led to a revised estimated spawning stock biomass of 36%
(0.36SB0) at the start of 2018. This reduction in the estimate of spawning stock
biomass, when compared with the 2017 assessment, was driven by declining
Commonwealth CPUE in 2018 and revisions to the New South Wales catch data
for 2017 and 2018 (actual catches were substantially higher than those used for
projections in the 2017 assessment). This led to a revised RBC of 1 165 t for
2020–21, and a 3-year-average RBC of 1 318 t [AFMA 2019]. The stock is
therefore unlikely to be depleted and recruitment is unlikely to be impaired.
Projections published in the 2019 update of stock response to various fixed-
catch scenarios (RBC, 1 600 t, 1 800 t and 1 900 t), when assuming average
recruitment, indicated that if the RBC was caught in 2020 and 2021 the stock
would recover to 44% (0.44SB0) at the start of 2022. If 1 800 or 1 900 t was
caught, then the spawning stock biomass would remain relatively stable at 36%
and 34%, respectively, at the start of 2022.
In Tasmania, commercial catches of Eastern School Whiting recorded for the
Tasmanian Scalefish Fishery (TSF) fluctuate strongly and in close agreement
with the level of effort recorded for a limited number of operators. Commercial
catches vary between a few kg and up to about 50 t per year. In 2018–19, the
total recorded TSF catch was 41.5 t [Krueck et al. 2020]. Recreational catches in
Tasmanian waters are comparatively low [Lyle et al. 2019]. The total landed
catch from the Victorian ITF and GLF sectors was less than 5 t in 2018–19.
Commonwealth landed catch in the trawl and scalefish hook sectors of the
SESSF was 526 t in the 2019–20 fishing season (538 t in 2018–19 fishing
season). Discards and state catches have been estimated to be 191.8 t and 1
153.5 t, respectively, based on the weighted average of the previous four fishing
seasons (2015–16 to 2018–19) [Burch et al. 2019]. Combined, total
landings are
estimated to be above the revised RBC of 1 165 t but below 1 900 t. This level
STATUS OF AUSTRALIAN FISH STOCKS REPORT
Eastern School Whiting (2020)
4
of fishing mortality is unlikely to cause Eastern School Whiting to become
recruitment impaired.
Based on the evidence provided above, the Southern management unit is
classified as a sustainable stock.
BIOLOGY
Eastern School Whiting biology [Day 2017, Dixon et al. 1987, Gray et al. 2014a]
Species
Longevity / Maximum Size
Maturity (50 per cent)
Eastern School Whiting
9 years, 320 mm FL 2 years, 140–180 mm FL
DISTRIBUTION
Distribution of reported commercial catch of Eastern School Whiting
TABLES
Fishing methods
Commonwealth
New South
Wales
Tasmania
Victoria
Commercial
Danish Seine
Net
Otter Trawl
Trawl
Unspecified
Recreational
Gillnet
Hook and Line
STATUS OF AUSTRALIAN FISH STOCKS REPORT
Eastern School Whiting (2020)
5
Management
Methods
Commonwealth
New South
Wales
Tasmania
Victoria
Commercial
Effort limits
Gear
restrictions
Licence
Limited entry
Spatial
closures
Total allowable
catch
Vessel
restrictions
Recreational
Bag and
possession
limits
Bag limits
Gear
restrictions
Licence
Spatial
closures
Catch
Commonwealth
New South
Wales
Tasmania
Victoria
Commercial
538.188 t
1201.56 t
0 t
3.912 t
Indigenous
Unknown
Unknown
Unknown (No
catch under
permit)
Recreational
10 933 fish or
1.54 t (in
2017/18)
2.1 t (2012/13)
Unknown
Commonwealth – Commercial (Management Methods/Catch) Data provided for the Commonwealth align with
the Commonwealth Southern and Eastern Scalefish and Shark Fishery for the 2018-19 financial year.
Commonwealth – Recreational The Commonwealth does not manage recreational fishing in Commonwealth
waters. Recreational fishing in Commonwealth waters is managed by the state or territory immediately adjacent to
those waters, under its management regulations.
Commonwealth – Indigenous The Australian government does not manage non-commercial Indigenous fishing in
Commonwealth waters, with the exception of Torres Strait. In general, non-commercial Indigenous fishing in
STATUS OF AUSTRALIAN FISH STOCKS REPORT
Eastern School Whiting (2020)
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Commonwealth waters is managed by the state or territory immediately adjacent to those waters.
New South Wales, Victoria and Tasmania State data are for the 2018/19 fiscal year. Reported landings from
northern New South Wales waters have been adjusted to account for estimated species misreporting with Stout
Whiting, Sillago robusta [Hall 2020].
New South Wales – Recreational (catch totals) Estimate from Murphy et al. [2020], based on a survey of
Recreational Fishing Licence households.
New South Wales – Indigenous (Management Methods) https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing).
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 fishing licence under the provisions of the Commonwealth’s Native
Title Act 1993.
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. A bag limit of 15 individuals and
possession limit of 30 individuals (combined total for all whiting species except King George Whiting) is in place 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
).
CATCH CHART
Commercial catch of Eastern School Whiting - note confidential catch not shown
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Eastern School Whiting (2020)
7
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