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Mulloway is a widely distributed species in Australian waters. Stock status is sustainable in WA and SA, recovering in NSW and undefined in QLD.

Mulloway has a wide distribution in Australia, from the Gascoyne region on the west coast of Western Australia, around the southern coasts of the continent, and up to the Wide Bay–Burnett region on the east coast of Queensland [Kailola et al. 1993]. 

Biological stock structure for Mulloway in Australia is uncertain. It has been suggested that a single panmictic population occurs in Australia [Archangi 2008]. However, regional differences in genetics, and otolith morphology and chemistry suggest sub-structuring between populations in New South Wales, South Australia and Western Australia [Ferguson et al. 2011; Barnes et al. 2015; Hughes et al. 2022].

Here, assessment of stock status for Mulloway is presented at the jurisdictional level—Western Australia, Queensland, New South Wales and South Australia.

South Australia

The Lakes and Coorong Fishery (LCF) has historically been the most productive of South Australia’s fisheries for Mulloway and contributed 99% of the State’s total commercial catch of the species in 2021–22. Small catches are also taken by the Marine Scalefish Fishery (MSF). The most recent assessment for Mulloway in the LCF was completed in 2023 and used a weight-of-evidence approach that considered fishery data to the end of June 2022 and fishery age structures to the end of June 2023 [Earl 2023]. 

The primary indicators for biomass and fishing mortality are total catch, targeted CPUE using two types of commercial gillnets (large mesh gillnets: 115–150 mm mesh; swinger nets: greater than 150 mm mesh) and fishery age structures. Commercial landings of Mulloway in South Australia peaked at 145 t in 2000–01 and then progressively declined to 22 t in 2010–11. This downward trend was associated with a decline in targeting of Mulloway using gillnets in the LCF during the Millennium Drought in the 2000s and likely reflected a decline in fishable biomass in the Coorong Estuary [Earl 2020]. Since 2010–11, catches have been considerably higher with peaks of 127 t and 123 t in 2017–18 and 2019–20, respectively. These catches were associated with exceptionally high gillnet CPUE. Catch declined to 56 t in 2021–22, reflecting a 55% decline in targeted gillnet effort in the LCF. Nonetheless, high gillnet CPUE in the Coorong Estuary and the adjacent nearshore marine waters in 2021–22 was indicative of high fishable biomass of juvenile and adult Mulloway, respectively. The State-wide recreational catch of Mulloway was estimated at 24 t (± 11) in 2021–22 t [Beckmann et al. 2023], which accounted for around 30% of the State's total annual harvest across all sectors.

Annual age structures for Mulloway from the Coorong Estuary have been stable since 2001–02 (i.e., dominated by juveniles) and are consistent with those for Mulloway from other estuaries around Australia [Silberschneider et al. 2009; Stewart et al. 2020]. The 2022–23 age structure included 2–5-year-old fish and was dominated (80%) by two-year-olds that originated from spawning in 2020–21. The lack of older fish in the age structure likely relates to an ontogenetic migration of individuals from the Coorong Estuary to the adjacent marine environment and the removal of older fish by fishing. Nevertheless, the presence of a strong age class of young fish in the catches from the estuary (i.e., the area that contributes most of the catch) in 2022–23 indicates that relatively strong recruitment occurred in 2020–21. 

Since 2001–02, annual age information for Mulloway from the nearshore marine environment adjacent to the Coorong Estuary has been limited due to the small number of samples and small sample sizes available in most years. The age structure from 2022–23, which was based on a relatively large sample size (n=197), was similar to those from recent years. Specifically, the sample included a wide range of ages (5–22 years), was dominated by 6–10-year-olds and consisted primarily (greater than 70%) of individuals above the age at maturity (5–6 years) for the species. The 2022–23 age structure was dominated by 7-year-olds (i.e., 2015–16 year class), with moderate contributions of 6-year-old fish from the 2016–17 year class. Fish older than 12 years were rare despite the potential for this species to reach 41 years of age in South Australia (Ferguson et al. 2014). The lack of older fish in the age structure likely relates to the removal of older fish by fishing and may also reflect an extended period of relatively poor recruitment during the Millennium Drought (2000s).

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 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, Mulloway in South Australia is classified as a sustainable stock.

Mulloway biology [Farmer 2008; Silberschneider and Gray 2008; Ferguson et al. 2014]

Western Australia – Recreational (Catch totals). Shore based catches are unknown, thus landings are likely to be underestimated.

Western Australia – Indigenous (Management Methods). Subject to the defence that applies under Section 211 of the Native Title Act 1993 (Cth), and the exemption from a requirement to hold a recreational fishing licence, the non-commercial take by Indigenous fishers is covered by the same arrangements as that for recreational fishing.

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

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

Queensland – Recreational Fishing (Catch). Data with high uncertainty (Residual Error >50 %) has been excluded and listed as unknown. More information available at: https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/monitoring-reporting/statewide-recreational-fishing-surveys 

New South Wales – Commercial (Management Methods). Fishers using haul nets in the New South Wales commercial Ocean Hauling Fishery are permitted a bycatch allowance of 500 kg of Mulloway per day.

New South Wales – Recreational (Catch). Murphy et al. [2020], includes charter catch. 

New South Wales – Indigenous (Management Methods).  https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing

Commercial catch of Mulloway - note confidential catch not shown

1. Archangi, B 2008, Levels and patterns of genetic diversity in wild and cultured populations of mulloway (Argyrosomus japonicus) using mitochondrial DNA and microsatellites, PhD thesis, School of Natural Resource Sciences, Queensland University of Technology.
2. Barnes, TC, Junge, C, Myers, SA, Taylor, MD, Rogers, PJ, Ferguson, GJ, Lieschke, JA, Donnellan, SC and Gillanders, BM 2015, Population structure in a wide-ranging coastal teleost (Argyrosomus japonicus, Sciaenidae) reflects marine biogeography across southern Australia, Marine and Freshwater Research, 67: 1103–1113.
3. 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. 185pp.
4. Earl, J 2020, Assessment of the South Australian Lakes and Coorong Fishery in 2018/19. Report to PIRSA Fisheries and Aquaculture. South Australian Research and Development Institute (Aquatic Sciences), Adelaide. SARDI Publication No. F2020/000208-01, SARDI Research Report Series No. 1059. 81pp.
5. Earl, J 2023, Assessment of the South Australian Lakes and Coorong Fishery in 2021/22. Report to PIRSA Fisheries and Aquaculture. South Australian Research and Development Institute (Aquatic Sciences), Adelaide. SARDI Publication No. F2020/000208-04. SARDI Research Report Series No. 1176. 94pp.
6. Farmer, BM 2008, Comparisons of the biological and genetic characteristics of the mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia, PhD thesis, Centre for Fish and Fisheries Research, Murdoch University, Perth.
7. Ferguson, GJ, Ward, TM and Gillanders, BM 2011, Otolith shape and elemental composition: complimentary tools for stock discrimination of mulloway (Argyrosomus japonicus) in southern Australia, Fisheries Research, 110: 75–83.
8. Ferguson, GJ, Ward, TM, Ivey, A and Barnes, T 2014, Life history of Argyrosomus japonicus, a large sciaenid at the southern part of its global distribution: implications for fisheries management, Fisheries Research, 151: 148–157.
9. Froese, R, Winker, H, Coro, G, Palomares, MLD, Tsikliras, AC, Dimarchopoulou, D, Touloumis, K, Demirel, N, Scarcella, G, de Souza Vianna, GM, Liang, C and Pauly, D 2021, Catch time series as the basis for fish stock assessments: the CMSY++ method. Frontiers in Marine Science
10. Goodyear, CP 1993, Spawning stock biomass per recruit in fisheries management: foundation and current use, in SJ Smith, JJ Hunt and D Rivard (ed.s), Risk evaluation and biological reference points for fisheries management, Canadian Special Publication of Fisheries and Aquatic Sciences 120, NRC Research Press, pp 67–81.
11. Henry, GW and Lyle, JM 2003, The national recreational and Indigenous fishing survey, final report to the Fisheries Research and Development Corporation and the Fisheries Action Program Project FRDC, project 1999/158, New South Wales Fisheries final report series 48, NSW Fisheries, Cronulla.
12. Hughes, JM 2020, Status of Australian Fish Stocks 2020 – NSW Stock status summary – Mulloway (Argyrosomus japonicus).
13. Hughes, JM 2023, Status of Australian Fish Stocks 2023—NSW Stock Status Summary – Mulloway (Argyrosomus japonicus).
14. Hughes, JM, Meadows, NM, Stewart, J, Booth, DJ and Fowler, AM 2022, Movement patterns of an iconic recreational fish species, mulloway (Argyrosomus japonicus), revealed by cooperative citizen-science tagging programs in coastal eastern Australia. Fisheries Research, 247, 106179.
15. Kailola, P, Williams, MJ, Stewart, PC, Reichelt, RE, McNee, A and Grieve, C 1993, Australian fisheries resources, Bureau of Resource Sciences and Fisheries Research and Development Corporation, Canberra. 
16. Mace, PM and Sissenwine, MP 1993, How much spawning per recruit is enough?, in SJ Smith, JJ Hunt and D Rivard (ed.s), Risk evaluation and biological reference points for fisheries management, Canadian Special Publication of Fisheries and Aquatic Sciences 120, NRC Research Press, pp 101–118.
17. Methot, RD and Wetzel, CR 2013, Stock synthesis: A biological and statistical framework for fish stock assessment and fishery management. Fisheries Research 142: 86-99.
18. Murphy, JJ, Ochwada-Doyle, FA, Hughes JM, West, LD and Stark, KE 2020, The Recreational Fisheries Monitoring Program. Survey of recreational fishing in 2017–18, Fisheries final report series 158, NSW Department of Primary Industries, Wollongong.
19. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE, Hughes, JM and Taylor, MD 2022, Survey of recreational fishing in NSW, 2019/20. NSW Department of Primary Industries, Nelson Bay, Fisheries Final Report Series No. 161. 80p.
20. 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.
21. Ryan, KL, Lai, EKM and Smallwood, CB 2022, Boat-based recreational fishing in Western Australia 2020/21. Fisheries Research Report No. 327, Department of Primary Industries and Regional Development, Western Australia.
22. Silberschneider, V and Gray CA 2005, Arresting the decline of the commercial and recreational fisheries for Mulloway (Argyrosomus japonicus), Fisheries Research and Development Corporation project 2001/027, final report series 82, New South Wales Department of Primary Industries, Cronulla.
23. Silberschneider, V and Gray, CA 2008, Synopsis of biological, fisheries and aquaculture-related information on mulloway Argyrosomus japonicus (Pisces: Sciaenidae), with particular reference to Australia, Journal of Applied Ichthyology, 24(1): 7–17.
24. Silberschneider, V, Gray, CA and Stewart, J 2009, Age, growth, maturity and the overfishing of the iconic sciaenid, Argyrosomus japonicus, in south-eastern Australia, Fisheries Research, 95(2–3): 220–229.
25. Stewart, J, Hughes, JM, Stanley, C and Fowler, AM 2020, The influence of rainfall on recruitment success and commercial catch for the large sciaenid, Argyrosomus japonicus, in eastern Australia. Marine Environmental Research, 157, 104924.
26. Teixeira, D, Janes, R, and Webley, J 2021, 2019–20 Statewide Recreational Fishing Survey Key Results. Project Report. State of Queensland, Brisbane.
27. West, LD, Stark, KE, Murphy, JJ, Lyle, JM and Ochwada-Doyle, FA 2015, Survey of recreational fishing in New South Wales and the ACT, 2013–14, Fisheries final report series 149, NSW Department of Primary Industries, Wollongong.