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Jackass Morwong (2020)

Nemadactylus macropterus

  • Timothy Emery (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Geoffrey Liggins (New South Wales Department of Primary Industries)
  • Nils Krueck (Institute for Marine and Antarctic Studies, University of Tasmania)
  • Victorian Fisheries Authority (Victorian Fisheries Authority)

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Summary

Jackass Morwong is a sustainable species distributed around southern Australia from the Great Australian Bight to northern NSW. The eastern and western biological stocks are assessed separately.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Stock status Indicators
South Australia Western Sustainable Estimated biomass, fishing mortality
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Stock Structure

Jackass Morwong (Nemadactylus macropterus) are distributed around southern Australia including Tasmania [Jordan 2001]. Genetic studies have found no differences between the stocks and although otolith microstructure analyses have shown some differences between fish in southern Tasmania, New South Wales and Victoria [Elliott and Ward 1994, Morison et al. 2011, Thresher et al. 1994], a recent review of stock structure found limited evidence in support of the existence of separate stocks east and west of Tasmania [Bessell-Browne et al. 2020]. To maintain consistency with the approach taken for SAFS 2018 in which the species was considered to comprise biological stocks (Eastern and Western), and to maintain consistency with the current stock assessment and management approach within the SESSF, the species is assessed here as two management units (Eastern and Western).

Here, assessment of stock status is presented at the management unit level—Eastern and Western.

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Stock Status

Western

Western Jackass Morwong is primarily caught by the Commonwealth managed Southern and Eastern Scalefish and Shark Fishery (SESSF) with negligible catches from State jurisdictions. Stock status classification reported here is based on stock assessments conducted for the SESSF, which include reported State catches.

In Tasmanian waters, commercial catches of the Western stock account for a small share of total commercial catches, averaging 0.6 t per year over the recorded history of the fishery. The maximum recorded catch was 1.6 t in 1997/98. In the most recent assessment year (2018/19), catches of the Western stock were below 100 kg. 

There have been no catches of Jackass Morwong reported in South Australia’s commercial multi-species, multi-gear and multi-sectoral Marine Scalefish Fishery since at least 1984. Small quantities (<5 t per yr) of undifferentiated 'Morwong' species have been recorded in the past 20 years. There is no information available on the catch of Jackass Morwong by Aboriginal and Torres Strait Islander people in South Australian waters. The most recent recreational fishing survey in South Australia in 2013–14 indicated that the annual catch of Jackass Morwong was zero.

For Victoria, commercial catch from the 2017 calendar year onwards was zero. Although recreational catch has occurred it is believed to be small compared to other sources of fishing mortality. As the majority of catch is taken in the Commonwealth, catch from Victoria is unlikely influence the biomass of the stock.

Western Jackass Morwong in Commonwealth fisheries is managed as a Tier 1 stock under the SESSF Harvest Strategy Framework [AFMA, 2019]. The 2018 Tier 1 stock assessment [Day and Castillo-Jordán 2018a] informed the management of the stock for the 2019–20 fishing season.

The latest Tier 1 stock assessment in 2018 [Day & Castillo-Jordán 2018a] estimated the spawning stock biomass at the start of 2018 was 0.66% (0.66 SB0). This led to an RBC of 235 t for the 2019–20 fishing season. There is some underlying uncertainty in the Western Jackass Morwong assessment resulting from sporadic age data, length compositions based on a very low number of sampled fish and relatively poor fits to the CPUE data, however the assessment was accepted by the South East Resource Assessment Group. The stock is therefore unlikely to be depleted and recruitment is unlikely to be impaired.

Commonwealth logbook-reported catch for Western Jackass Morwong in the CTS and GHAT sectors of the SESSF was 12.1 t in the 2019–20 fishing season (61.4 t in 2018–19 fishing season). Discards have been estimated to be 3.8 t based on the weighted average of the previous four calendar years (2015 to 2018) [Burch et al., 2019]. When estimated discards are combined with average state catch and Commonwealth logbook catch for 2019–20, the total fishing mortality is below 235 t per year. This level of fishing pressure is unlikely to cause the stock to become recruitment impaired.

On the basis of the evidence provided above, the Western management unit is classified as a sustainable stock.

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Biology

Jackass Morwong biology [Stobutzki et al. 2009]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Jackass Morwong 20–35 years, ~700 mm TL 3 years, 230–270 mm FL  
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Distributions

Distribution of reported commercial catch of Jackass Morwong

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Tables

Fishing methods
South Australia
Commercial
Unspecified
Management methods
Method South Australia
Charter
Fishing gear and method restrictions
Licence
Limited entry
Commercial
Fishing gear and method restrictions
Limited entry
Spatial restrictions
Indigenous
Fishing gear and method restrictions
Recreational
Fishing gear and method restrictions
Catch
South Australia
Indigenous Unknown
Recreational 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 Commonwealth waters is managed by the state or territory immediately adjacent to those waters

New South Wales – Recreational catch and Indigenous catch New South Wales Indigenous and Recreational catch estimates of Negligible are based on zero catches of Jackass morwong recorded during the 2017-18 survey of the catch of NSW  1-3 year recreational licence holders [Murphy et al. 2020]

New South Wales – (Indigenous management methods)  Customary Fishing Management Arrangements. See 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 – Commercial (catch) Catches reported for the Tasmanian Scalefish Fishery are for the period 1 July to 30 June the following year. The most recent assessment available is for 2018/19.

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 10 individuals and possession limit of 20 individuals (all morwong species combined excluding Banded Morwong) is in place for recreational fishers.

Tasmania – Indigenous (management methods) https://dpipwe.tas.gov.au/Documents/Policy%20for%20Aboriginal%20tags%20and%20alloting%20an%20UIC.pdf

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Catch Chart

Commercial catch of Jackass Morwong - note confidential catch not shown

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References

  1. AFMA 2019, Harvest strategy framework for the Southern and Eastern Scalefish and Shark Fishery 2009 (amended 2019), Australian Fisheries Management Authority, Canberra.
  2. Bessell-Browne P, Day J, Sporcic M and Appleyard S 2020, SESSF species stock structure review: Jackass Morwong, Pink Ling and Blue Warehou. Technical report presented at SERAG #2 Meeting, 23-25 November 2020. CSIRO Oceans and Atmosphere, Hobart. 74p.
  3. Burch, P, Althaus, F & Thomson, R 2019, Southern and Eastern Scalefish and Shark Fishery (SESSF) catches and discards for TAC purposes using data until 2018, Prepared for the SERAG Meeting, 3-4 December 2019, Hobart, CSIRO Oceans and Atmosphere, Hobart, Tasmania.
  4. Day, J & Castillo-Jordan, C 2018, Eastern jackass morwong (Nemadactylus macropterus) stock assessment based on data up to 2017, CSIRO Oceans and Atmosphere, Hobart.
  5. Day, J & Castillo-Jordan, C 2018a, Western jackass morwong (Nemadactylus macropterus) stock assessment based on data up to 2017, CSIRO Oceans and Atmosphere, Hobart.
  6. Elliott, N and Ward, R 1994, Enzyme variation in jackass morwong, Nemadactylus macropterus (Schneider, 1801) (Teleostei: Cheilodactylidae), from Australian and New Zealand waters. Marine and Freshwater Research, 45(1), 51–67.
  7. Helidoniotis, F, Koduah, A, Moore, A, Mazloumi, N and Nicol, S 2017, Commonwealth Trawl and Scalefish Hook sector, In: Patterson, H, Georgeson , L, Noriega , R, Koduah, A, Helidoniotis, F, Larcombe, J, Nicol, S, and Williams, A(ed.) Fishery status reports, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, pp 173–175.
  8. Jordan, AR 2001, Age, growth and spatial and interannual trends in age composition of jackass morwong, Nemadactylus macropterus, in Tasmania. Marine and Freshwater Research, 52(4), 641–660.
  9. Krueck N, Hartmann, K and Lyle J 2020, Tasmanian Scalefish Fishery Assessment 2018/19. Institute for Marine and Antarctic Studies, University of Tasmania.
  10. Lyle, JM, Stark, KE, Ewing, GP and Tracey, SR 2019, 2017-18 Survey of recreational fishing in Tasmania. Institute for Marine and Antarctic Studies, Hobart, Tasmania.
  11. Morison, A, Knuckey, I, Simpfendorfer, C and Buckworth, R 2011, Stock assessment summaries for the South East Scalefish and Shark Fishery. Southern and Eastern Scalefish and Shark Fishery Assessment Group, AFMA.
  12. Murphy, JJ, Ochwada-Doyle, West, LD, Stark, KE and Hughes, JM, 2020, The NSW Recreational Fisheries Monitoring Program - Survey of recreational fishing, 2017/18. NSW DPI - Fisheries Final Report Series No. 158.
  13. Proctor, C.H., Thresher, R.E., and D.J. Mills. 1992. Stock delineation in jackass morwong, 1. Otolith chemistry results. Newsletter of the Australian Society for Fish Biology 22(2): 47-48.
  14. Stobutzki, H, Patterson, H, Ward, P, Sampaklis, A Sahlqvist, P, Moore, A and Vieira, S 2009, Commonwealth Trawl and Scalefish Hook sector, In: Wilson, DT, Curtotti, R and Begg, GA (ed.) Fishery status reports, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, pp 184–186.
  15. Thresher, RE, Proctor, CH, Gunn, JS and Harrowfield, IR 1994, An evaluation of electron-probe microanalysis of otoliths for stock identification of nursery areas in a southern temperate groundfish, Nemadactylus macropterus (Cheilodactylidae). Fishery Bulletin (US), 92: 817–840.
  16. Tuck, GN (ed.) 2015, Stock Assessment for the Southern and Eastern Scalefish and Shark Fishery 2014. Part 2. Australian Fisheries Management Authority and CSIRO Oceans and Atmosphere Flagship, Hobart. 432 p
  17. Tuck, GN, Day, J and Wayte, S 2015, Assessment of the eastern stock of Jackass Morwong (Nemadactylus macropterus) based on data up to 2014. Paper to Shelf Resource Assessment Group, 27 October 2015, Retrieved from CSIRO Oceans and Atmosphere, Hobart, Tasmania
  18. Tuck, GN, Day, J and Wayte, S. Assessment of the western stock of Jackass Morwong (Nemadactylus macropterus) based on data up to 2014 2015, Paper to Shelf Resource Assessment Group, 27 October 2015, Retrieved from CSIRO Oceans and Atmosphere, Hobart, Tasmania.
  19. Wayte, S and Fay, G 2010, Jackass Morwong (Nemadactylus macropterus) stock assessment based on data up to 2009. Tuck, GN (ed).
  20. Wayte, SE 2013, Management implications of including a climate-induced recruitment shift in the stock assessment for jackass morwong (Nemadactylus macropterus) in south-eastern Australia. Fisheries Research, 142, 47–55.

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