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Yellowfin Whiting (2018)

Sillago schomburgkii

  • Mike Steer (South Australian Research and Development Institute)
  • Kim Smith (Department of Primary Industries and Regional Development, Western Australia)

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Summary

Yellowfin Whiting is found in the coastal waters of south-western Australia. There are two stocks in WA and two in SA. All are assessed as sustainable.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
South Australia Gulf St. Vincent MSF Sustainable Catch, effort, CPUE
South Australia Spencer Gulf MSF Sustainable Catch, effort, CPUE
MSF
Marine Scalefish Fishery (SA)
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Stock Structure

Yellowfin Whiting is endemic to south-western Australia, being found in coastal waters around Exmouth in Western Australia and in and near the gulf waters of South Australia. There is some uncertainty about the continuity of distribution through the remote coastal waters between Western Australia and South Australia. Based on the possible discontinuous distribution between South Australian and Western Australian populations, there is a possibility of separate stocks in these areas [Steer et al. 2018]. Western Australian populations in northern (Gascoyne Coast Bioregion) and southern (West Coast and South Coast Bioregions) regions also appear to have low connectivity. Adults in northern and southern regions have distinctly different size-at-age due to different growth rates, which suggests low levels of movement between regions [DPIRD unpublished data]. Spawning occurs in very shallow (< 5 m) coastal waters, which would limit the alongshore dispersal of eggs and larvae, further restricting movement between regions. Northern and southern regions are therefore assumed to support separate biological stocks. In South Australia, oceanographic separation of the two gulfs during the spawning season in summer must considerably reduce the opportunity for mixing of eggs and larvae. As such, the populations in the gulfs may constitute separate stocks, but more evidence is required to confirm this.

Here, assessment of stock status is presented at the biological stock level–Northern Western Australia, Southern Western Australia, Spencer Gulf (South Australia) and Gulf St. Vincent (South Australia).

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Stock Status

Gulf St. Vincent

Yellowfin Whiting are considered to be a secondary species within South Australia's commercial multispecies, multi-gear and multi-sectoral Marine Scalefish Fishery. The most recent assessment of Yellowfin Whiting was completed in 2018 and used data to the end of December 2017 [Steer et al. 2018]. The primary indicators used for biomass and fishing mortality are catch, effort and targeted CPUE  [Steer et al. 2018]. The Gulf St. Vincent Yellowfin Whiting stock has produced considerably lower catches than the Spencer Gulf stock. Targeted catches by the netting sector have declined in recent years, but these reflect lower effort levels rather than declining CPUE. Targeted hauling net CPUE has remained relatively stable at approximately 60 kg.fisherday-1 over the past decade. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. Furthermore, the above evidence indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

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

Spencer Gulf

The South Australian catches of Yellowfin Whiting are dominated by those from northern Spencer Gulf, although the fishery in this region is characterised by high levels of variability. This may reflect the transient nature of targeted fishing effort, with fishers opportunistically targeting Yellowfin Whiting due to market demands, or when the availability of higher value species is low [Steer et al. 2018]. There has been a long-term declining trend in fishing effort for Yellowfin Whiting. However, this decline has not been reflected in total catch, targeted catch or targeted CPUE. Total catch in 2017 was 134 tonnes (t), 9 per cent less that the peak of 148 t in 2004. The long-term trends in targeted hauling net catch rates have remained relatively stable over the past 30 years fluctuating around an annual average of approximately 85 kg.fisherday-1. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. Furthermore, the above evidence indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

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

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Biology

Yellowfin Whiting biology [Ferguson 2000, Hutchins and Swainston 1986, Hyndes and Potter 1997]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Yellowfin Whiting Western Australia: 12 years, 420 mm TL South Australia: 11 years, 420 mm TL Western Australia: 2 years, 180– 200 mm TL South Australia: 2 years, 220–240 mm TL 
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Distributions

Distribution of reported commercial catch of Yellowfin Whiting
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Tables

Fishing methods
South Australia
Commercial
Unspecified
Handline (hand operated)
Seine Nets
Indigenous
Hook and Line
Recreational
Hook and Line
Management methods
Method South Australia
Commercial
Effort limits
Gear restrictions
Limited entry
Size limit
Spatial closures
Temporal closures
Indigenous
Bag limits
Gear restrictions
Size limit
Recreational
Bag limits
Gear restrictions
Size limit
Active vessels
South Australia
49 in MSF
MSF
Marine Scalefish Fishery (SA)
Catch
South Australia
Commercial 139.14t in MSF
Indigenous Unknown
Recreational 45.3 t (in 2013/14) [Giri and Hall 2015]
MSF
Marine Scalefish Fishery (SA)

Western Australia – Recreational (catch) Recreational catches of Yellowfin Whiting are taken by shore-based fishers. The current recreational catch is unknown due to the absence of any recent surveys of shore-based fishing.

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Catch Chart

Commercial catch of Yellowfin Whiting - note confidential catch not shown
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References

  1. Brown, J 2014, Shark Bay Beach Seine and Mesh Net Managed Fishery Stock Status Report December 2014. Unpublished report. Department of Fisheries, Western Australia. 19pp.
  2. Coulson, PG, Hesp, SA, Potter, IC and Hall, NG 2005, Comparisons between the biology of two co-occurring species of whiting (Sillaginidae) in a large marine embayment. Environmental Biology of Fishes, 73: 125–139.
  3. Department of Fisheries, September 2017, Addendum to: Johnston, DJ, Smith, KA, Brown, JI, Travaille, KL, Crowe, F, Oliver, RK, Fisher, EA 2015, Western Australian Marine Stewardship Council Report Series No. 3: West Coast Estuarine Managed Fishery (Area 2: Peel-Harvey Estuary) and Peel-Harvey Estuary Blue Swimmer Crab Recreational Fishery. Department of Fisheries, Western Australia. 284pp
  4. Ferguson, G 2000, Yellowfin whiting (Sillago schomburgkii). South Australian Fisheries Assessment Series 00/10.
  5. Giri, K and Hall, K 2015, South Australian Recreational Fishing Survey. Fisheries Victoria Internal Report Series No. 62. 
  6. Hutchins, B and Swainston, R 1986, Sea fishes of southern Australia: complete field guide for anglers and divers. Swainston Publishing, Perth.
  7. Hyndes, GA and Potter, IC 1997, Age, growth and reproduction of Sillago schomburgkii in south-western Australian, nearshore waters and comparisons of life history styles of a suite of Sillago species. Environmental Biology of Fishes 49: 435–447.
  8. Jackson, G, Cavali, P and Turner, S 2018, Gascoyne Inner Shark Bay Status Report 2018. In: Status Reports of the Fisheries and Aquatic Resources of Western Australia 2017/18: The State of the Fisheries eds. D.J. Gaughan and K. Santoro. Department of Primary Industries and Regional Development, Western Australia.
  9. Smith, K and Grounds, G, In press West Coast Nearshore and Estuarine Finfish Status Report 2017. In: Status Reports of the Fisheries and Aquatic Resources of Western Australia 2017/18: The State of the Fisheries eds. D.J. Gaughan and K. Santoro. Department of Primary Industries and Regional Development, Western Australia.
  10. Steer, MA, Fowler, AJ, McGarvey, R, Feenstra, J, Smart, J, Roger, PJ, Earl, J, Beckmann, C, Drew, M, Matthews, D 2018, Assessment of the South Australian Marine Scalefish Fishery in 2017. South Australian Research and Development Institute (Aquatic Sciences), Adelaide. SARDI Publication No. F2017/000427-2. SARDI Research Report Series No. 1002. 242pp.