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Jackass Morwong (2023)

Nemadactylus macropterus

  • Timothy Emery (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Geoffrey Liggins (New South Wales Department of Primary Industries)
  • Stephen Bradshaw (Institute for Marine and Antarctic Studies, University of Tasmania)
  • Justin Bell (Victorian Fisheries Authority)
  • Jason Earl (South Australian Research and Development Institute)

Date Published: June 2023

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Summary

Jackass Morwong is distributed around southern Australia from the Great Australian Bight to northern NSW. The eastern and western biological stocks are assessed separately. The eastern stock Is classifed as depleted and the western stock Is sustainable.

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Stock Status Overview

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

Spawning stock biomass, fishing mortality

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Stock Structure

Jackass Morwong (Nemadactylus macropterus) is distributed around southern Australia including Tasmania [Jordan 2001]. Genetic studies have found no evidence of separate stocks, 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 support 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 and 2020 in which the species was considered to comprise two biological stocks (Eastern and Western), and 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 assessment conducted for the SESSF, which include reported State catches.

As stated above, Commonwealth catches of Jackass Morwong (Eastern and Western) peaked at more than 2 500 t in the mid-1960s and have declined since the 1980s.

In Tasmanian waters, commercial catches of the Western stock account for a small share of total commercial catches, averaging 0.4 t per year over the recorded history of the fishery. The maximum recorded catch was 1.3 t in 1995–96. With the exception of 2012–13 and 2018–19 landings, annual catches of the Western stock have been below 100 kg for the last decade.

There have been no commercial catches of Jackass Morwong reported by South Australia's commercial fisheries since at least 1984. Small quantities (less than 5 t per annum) of undifferentiated 'Morwong' species have been taken by the commercial Marine Scalefish Fishery 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 2021–22 indicated that the annual catch of Jackass Morwong was zero [Beckmann et al. 2023].

For Victoria, commercial Jackass Morwong catch from has been less than 1 t for over 25 years, being zero in many years. Although recreational catch has occurred it is believed to be small compared to other sources of fishing mortality and is unlikely to 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 2021a]. The 2018 Tier 1 stock assessment [Day and Castillo-Jordán 2018b] informed the management of the stock for the 2021–22 fishing season.

The 2018 Tier 1 stock assessment [Day and Castillo-Jordán 2018b] estimated the spawning stock biomass at the start of 2018 to be 66% of the unfished level. This led to a 3-year average RBC of 223 t. It is important to note that this assessment was uncertain because only sporadic age data were available, length compositions were based on very low numbers of sampled fish, and the quality of the CPUE data was questionable [Day and Castillo-Jordán 2018b]. 

Since 2018, catches have declined to the point that there were concerns about the adequacy of the CPUE series as a reliable index of abundance, meaning the assessment was not updated (along with the Eastern management unit) in 2021 [AFMA 2021b]. Consequently, an RBC was determined using a weight-of-evidence approach for the 2021–22 fishing season. In a review of all available indicators and noting the very low levels of catch in recent years (for example, 29 t in 2019 and 11 t in 2020 calendar years), the South-East Resource Assessment Group (SERAG) found that there was no reason to deviate from their previous management advice and recommended maintaining the previous RBC [AFMA 2021b].

Commonwealth logbook-reported catch for Western Jackass Morwong in the CTS and GHAT sectors of the SESSF was 18.6 t in the 2021–22 fishing season based on the percentage split east/west from logbook data [Emery et al. 2022]. The 4-year weighted average of recent (2017 to 2020) discards was 19.8 t and state catch was 0.6 t [Althaus et al. 2021]. When combined, the total fishing mortality for Western Jackass Morwong was 39.0 t for the 2021–22 fishing season. Total fishing mortality was therefore below the RBC of 223 t calculated in the 2018 assessment [Day and Castillo-Jordán 2018b].  

The above evidence indicates that the Western management unit is not considered to be recruitment impaired, 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 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
Indigenous
Unspecified
Charter
Rod and reel
Recreational
Rod and reel
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 None (2021–22)

Commonwealth – Commercial (Management Methods/Catch). Data provided for the Commonwealth align with the Commonwealth Southern and Eastern Scalefish and Shark Fishery for the 2021–22 financial year.

Commonwealth – Recreational. The Australian government 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). New South Wales Recreational catch estimate of Negligible is based on zero catches of Jackass morwong recorded during the 2019–20 survey of the catch of NSW 1–3 year recreational licence holders [Murphy et al. 2022].

New South Wales – Indigenous (Management Methods). Cultural 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 2021–22.

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). 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://fishing.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 2021a, Harvest strategy framework for the Southern and Eastern Scalefish and Shark Fishery 2009 (amended 2021), Australian Fisheries Management Authority, Canberra.
  2. AFMA 2021b, Southern and Eastern Scalefish and Shark Fishery South East Resource Assessment Group (SERAG) meeting 3, minutes, 29 November – 1 December 2021, Australian Fisheries Management Authority, Canberra.
  3. AFMA 2022a, Concession holder letter, ref: AFMADMW-1932364602-40082, Australian Fisheries Management Authority, Canberra.
  4. AFMA 2022b, Southern and Eastern Scalefish and Shark Fishery total allowable catches and management arrangements for the 2022–23 fishing year, Australian Fisheries Management Authority, Canberra.
  5. Althaus, F, Thomson, R and Sutton, C 2021, Southern and Eastern Scalefish and Shark Fishery catches and discards for TAC purposes using data until 2020, CSIRO Oceans and Atmosphere, Hobart.
  6. Beckmann, CL, Durante, LM, Graba-Landry, A, Stark, KE and Tracey, SR 2023, Survey of Recreational Fishing in South Australia 2021-22, Report to PIRSA Fisheries and Aquaculture. South Australian Research and Development Institute (Aquatic and Livestock Sciences), Adelaide, SARDI Publication No. F2022/000385-1, SARDI Research Report Series No. 1161, 185 pp.
  7. 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.
  8. Day, J and Castillo-Jordan, C 2018a, Eastern jackass morwong (Nemadactylus macropterus) stock assessment based on data up to 2017, CSIRO Oceans and Atmosphere, Hobart.
  9. Day, J and Castillo-Jordan, C 2018b, Western jackass morwong (Nemadactylus macropterus) stock assessment based on data up to 2017, CSIRO Oceans and Atmosphere, Hobart.
  10. Day, J, Bessell-Browne, P and Curin Osorio, S 2021, Eastern jackass morwong (Nemadactylus macropterus) stock assessment based on data up to 2020, CSIRO Oceans and Atmosphere, Hobart.
  11. 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: 51–67.
  12. Emery, T, Wright, D, Davis, K, Keller, K, Woodhams, J and Curtotti, R, 2022, Commonwealth Trawl and Scalefish Hook sectors, in Patterson, Bromhead, D, Galeano, D, Larcombe, J, Timmiss, T, Woodhams, J and Curtotti, R (eds), Fishery status reports 2022, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra.
  13. 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.
  14. 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.
  15. 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, Australian Fisheries Management Authority.
  16. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE, Hughes, JM, Taylor, MD 2022, Survey of recreational fishing in NSW, 2019/20 – Key Results, NSW DPI – Fisheries Final Report Series No. 161, ISSN 2204-8669.
  17. Sharples, R, Cresswell, K, Hartmann, K and Krueck, N, 2023, Tasmanian Scalefish Fishery Assessment 2021/22, Institute for Marine and Antarctic Studies, University of Tasmania.
  18. 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 (eds) Fishery status reports, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, pp 184–186.
  19. 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.

Downloadable reports

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