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Grey Mackerel (2023)

Scomberomorus semifasciatus

  • Marlee Jesson-Kerr (Department of Agriculture and Fisheries, Queensland)
  • Paul Lewis (Department of Primary Industries and Regional Development, Western Australia)
  • Michael Usher (Department of Industry, Tourism and Trade, Northern Territory)

Date Published: June 2023

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Summary

The five stocks of Grey Mackerel assessed across Australia’s northern waters are all sustainable.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Stock status Indicators
Western Australia Western Australia Sustainable

Catch, indicator species

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Stock Structure

Grey Mackerel (Scomberomorus semifasciatus) are found in southern Papua New Guinea and northern Australia from Shark Bay, Western Australia, to northern New South Wales. At least five Grey Mackerel stocks have been identified for management purposes across northern Australia as determined by otolith stable isotopes chemistry and parasite abundance: Western Australia, North West Northern Territory, Gulf of Carpentaria, East Coast North and East Coast South. Four of these stocks have been confirmed as genetically distinct biological stocks: Western Australia, North West Northern Territory, Gulf of Carpentaria and the East Coast of Queensland. Research suggests that a sixth stock potentially occurs in the north-east Gulf of Carpentaria [Welch et al. 2009; Charters et al. 2010; Newman et al. 2010; Broderick et al. 2011; Welch et al. 2015]. However, the presence of this stock has yet to be confirmed; therefore, it was not included in the assessment.

Here, assessment of stock status is presented at the biological stock level—Western Australia, North West Northern Territory, Gulf of Carpentaria, and at the management unit level for North East Queensland and South East Queensland.

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Stock Status

Western Australia

Grey Mackerel is exploited as a component of the Mackerel Managed Fishery (MMF) in Western Australia. The primary target species of the MMF is Spanish Mackerel (Scomberomorus commerson) and catches of Grey mackerel are low [Newman et al. 2023]. As such there has been no formal higher level stock assessment of Grey Mackerel in Western Australia and the species is assessed on a weight of evidence basis of catch only examining catch and effort data, biological information, biomass and stock reduction analysis [Lewis 2020]. Since significant management changes in 2006, the catch and effort in the MMF have remained stable.  Grey Mackerel are fast growing and attain sexual maturity relatively early in life (less than two years of age) [Cameron and Begg 2002; Welch et al. 2009; GBRMPA 2011]. The minimum legal size limit for Grey Mackerel in Western Australia exceeds length at first maturity, which helps with sustainability by potentially providing some resilience to fishing pressure pending information regarding post-release survival. 

Annual Grey Mackerel catch levels by the MMF from 2000–21 have been low, ranging between 3.5 and 24 tonnes (t), and was only 8.8 t in 2021 with the vast majority of recent catches taken by only two vessels from a small area of their range [Lewis 2020]. This level of catch is well below the TACC; 60 t for each of the three management areas) for Grey Mackerel in WA and very low in comparison with other states. The low levels of catch are likely reflective of the low demand and limited targeting of the species by the MMF line only fishery. In addition, there is low annual charter boat catch of less than 1 t and recreational catch of the species is estimated, with high uncertainty at less than 3 t by the five boat-based surveys between 2011 and 2021 [Ryan et al. 2022] which is also likely due to low targeting and release rates of greater than 50%. Catch-MSY analysis of Grey Mackerel in WA infers that the biomass in 2021 was 60% of the unfished biomass; recent catches were below the MSY and that the harvest rate was at 40% of that required to achieve MSY. Thus, based on the catch history it is likely that the level of stock depletion is minimal and the level of risk is estimated to be low. The above evidence indicates that the biomass of this stock is unlikely to be depleted and 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 Western Australia biological stock is classified as a sustainable stock.

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Biology

Grey Mackerel biology [Cameron and Begg 2002]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Grey Mackerel

14 years, 1,200 mm FL 

Females 2 years, 650–700 mm FL Males 1–2 years, 550–600 mm FL
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Distributions

Distribution of reported commercial catch of Grey Mackerel
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Tables

Fishing methods
Western Australia
Commercial
Hand Line, Hand Reel or Powered Reels
Line
Trolling
Charter
Spearfishing
Hook and Line
Indigenous
Spearfishing
Hook and Line
Unspecified
Recreational
Spearfishing
Hook and Line
Management methods
Method Western Australia
Charter
Bag limits
Limited entry
Passenger restrictions
Possession limit
Size limits
Spatial zoning
Commercial
Gear restrictions
Limited entry
Size limits
Spatial zoning
Total allowable catch
Vessel restrictions
Indigenous
Laws of general application
Recreational
Bag limits
Licence
Possession limit
Size limits
Catch
Western Australia
Commercial 9.11t
Charter < 0.5 t
Indigenous Unknown
Recreational 2.0 t (se +/- 1.2 t; 2020–21)

Western Australian – Recreational (catch). Western Australian boat-based recreational catch survey from 1 Sep 2017–30 Aug 2018 [Ryan et al. 2022]. Shore based recreational catch (if any) largely unknown.

Western Australia – Recreational (Management methods). Western Australian boat-based recreational licence required.

Northern Territory – Charter (management methods). In the Northern Territory, charter operators are regulated through the same management methods as the recreational sector but are subject to additional limits on license and passenger numbers.

Northern Territory - Indigenous (management methods). The Fisheries Act 1988 (NT), specifies that: “Unless expressly provided otherwise, nothing in this Act derogates or limits the right of Aboriginal people who have traditionally used the resources of an area of land or water in a traditional manner to continue to use those resources in that area in that manner.”

Queensland – Indigenous (management methods). For more information see: https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing

Queensland – Recreational Fishing (Catch). Data based at the whole of Queensland level and derived from state-wide recreational fishing surveys. Where possible, estimates have been converted to weight (tonnes) using best known conversion multipliers. Conversion factors may display regional or temporal variability. In the absence of an adequate conversion factor, data presented as number of fish. 

Queensland – Commercial (Catch). Queensland commercial and charter data has been sourced from the commercial fisheries logbook program. Further information available through the Queensland Fisheries Summary Report at: https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/data/queensland-fisheries-summary-report

Queensland – Commercial (Management Methods). Harvest strategies are available at: https://www.daf.qld.gov.au/business-priorities/fisheries/sustainable/harvest-strategy  

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Catch Chart

Commercial catch of Grey Mackerel - note confidential catch not shown
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References

  1. Bessell-Browne, P, Lovett, R, Leigh, G, O'Neill, MF and Campbell, A, 2019, Stock assessment of the Australian east coast grey mackerel (Scomberomorus semifasciatus) fishery, Technical Report, State of Queensland.
  2. Broderick, D, Ovenden, J, Buckworth, R, Newman, S, Lester, R and Welch, D 2011, Genetic population structure of grey mackerel Scomberomorus semifasciatus in northern Australia, Journal of Fish Biology, 79: 633–661.
  3. Cameron, D and Begg, G 2002, Fisheries biology and interaction in the northern Australian small mackerel fishery, final report to Fisheries Research and Development Corporation, projects 92/144 and 92/144.02, Department of Primary Industries, Queensland.
  4. Charters, R, Lester, R, Buckworth, R, Newman, S, Ovenden, J, Broderick, D, Kravchuk, O, Ballagh, A and Welch, D 2010, The stock structure of grey mackerel Scomberomorus semifasciatus in Australia as inferred from its parasite fauna, Fisheries Research, 101: 94–99.
  5. Great Barrier Reef Marine Park Authority, 2011, A vulnerability assessment for the Great Barrier Reef - Grey mackerel.
  6. Great Barrier Reef Marine Park Authority, 2012, A vulnerability assessment for the Great Barrier Reef: Grey Mackerel, Vulnerability Assessments for the Great Barrier Reef, Ecosystems, Great Barrier Reef Marine Park Authority.
  7. Lewis PD, 2020, Statewide Large Pelagic Resource in Western Australia, Resource Assessment Report No 19, Department of Primary Industries and Regional Development Western Australia, 145pp.
  8. Martell, S and Froese, R, 2013, A simple method for estimating MSY from catch and resilience, Fish and Fisheries, 14(4), pp 504-514.
  9. Newman, S, Wright, I, Rome, B, Mackie, M, Lewis, P, Buckworth, R, Ballagh, A, Garrett, R, Stapley, J, Broderick, D, Ovenden, J and Welch, D 2010, Stock structure of grey mackerel, Scomberomorus semifasciatus (Pisces: Scombridae) across northern Australia, based on otolith isotope chemistry, Environmental Biology of Fishes, 89: 357–367.
  10. Newman, SJ, Wise, BS, Santoro, KG and Gaughan, DJ (eds) 2023, Status Reports of the Fisheries and Aquatic Resources of Western Australia 2021/22: The State of the Fisheries, Department of Primary Industries and Regional Development, Western Australia.
  11. Northern Territory Government 2012, Fishery Status Reports 2011, Fishery Report 111, Northern Territory Government.
  12. Northern Territory Government 2017, Fishery Status Reports 2015, Fishery Report 118, Northern Territory Government Department of Resources, Darwin, Northern Territory.
  13. Parks Australia 2018, Gulf of Carpentaria Marine Park, Commonwealth of Australia.
  14. Pidd, A, Jacobsen, I, Walton, L and Lawson, A 2021, East Coast Inshore Large Mesh Net Fishery Level 2 Ecological Risk Assessment, Target & Byproduct Species, Technical Report, State of Queensland, Brisbane, Queensland.
  15. Queensland Department of Agriculture and Fisheries 2016. Grey Mackerel Update.
  16. Queensland Department of Agriculture and Fisheries 2022, Harvest Strategies.
  17. Ryan, KL, Lai, EK and Smallwood, CB 2022, Boat-based recreational fishing in Western Australia 2020/21, Fisheries Research Report 327, Department of Primary Industries and Regional Development, Western Australia.
  18. Teixeira, D, Janes, R and Webley, J, 2021, 2019–20 statewide recreational fishing survey - Social and attitudinal results, Department of Agriculture and Fisheries, Queensland
  19. Welch, D, Buckworth, R, Ovenden, J, Newman, S, Broderick, D, Lester, R, Ballagh, A, Stapley, J, Charters, R and Gribble, N 2009, Determination of management units for grey mackerel fisheries in northern Australia, Fisheries Research and Development Corporation project 2005/010, Fishing and Fisheries Research Centre Technical Report 4, Fishing and Fisheries Research Centre, James Cook University, Townsville, Australia.
  20. Welch, D, Newman, S, Buckworth, R, Ovenden, J, Broderick, D, Lester, R, Gribble, N, Ballagh, A, Charters, R, Stapley, J, Street, R, Garrett, R and Begg, G 2015, Integrating different approaches in the definition of biological stocks: A northern Australian multi-jurisdictional fisheries example using grey mackerel Scomberomorus semifasciatus, Marine Policy, 55:73-80.

Downloadable reports

Click the links below to view reports from other years for this fish.