*

Spanish Mackerel are widely distributed across several fisheries in WA, NT, Qld, NSW and the Torres Strait. Three of the five stocks are sustainable, the Gulf of Carpentaria stock is depleting, and the East Coast stock is depleted.

Genetic evidence indicates that there are three biological stocks of Spanish Mackerel across northern Australia [Moore et al. 2003]; however, evidence from otolith microchemistry, parasite analysis and limited adult movement (at scales greater than 100 km) indicates that there are likely to be a number of smaller biological stocks with limited interaction [Buckworth et al. 2007, Lester et al. 2001, Moore et al. 2003]. Each jurisdiction is likely to have multiple biological stocks within its boundaries; however, the difficulty in obtaining relevant biological, and catch and effort, information to assess each stock individually has meant that not all assessments are undertaken at the biological stock level. Those that are, are based on the populations that receive the highest harvest rates; their status can be assumed to be representative of the highest level of exploitation that occurs on any population within each management unit or jurisdiction.

Here, assessment of stock status is presented at the biological stock level—Torres Strait Spanish Mackerel Fishery and East Coast (Queensland and New South Wales); management unit level—Mackerel Managed Fishery (Western Australia), Gulf of Carpentaria (Queensland); and jurisdictional level—Northern Territory.

Mackerel Managed Fishery

The most recent full assessment of Spanish Mackerel in Western Australia was during 1999–2002 [Mackie et al. 2003]. The assessment, conducted when catches were higher than current levels, used catch and effort, biological information, age structure and yield-per-recruit modelling, and indicated the stock was sustainable. Recent Catch-MSY analysis (SimpleSA package) indicated the Western Australia stock is likely to be above the target biomass and is stable at current catch levels. Catch and fishing effort throughout the Mackerel Managed Fishery (Western Australia) have been relatively stable since 2006, following the introduction of quotas and reductions in vessels due to management changes, with total catches within the target range (246–430 t) [Gaughan and Santoro 2018]. The catch rates for the two main northern fishery areas (Kimberley and Pilbara, covering Onslow to the Northern Territory border), have declined over recent years but remain above historical levels, indicating a relatively high abundance of Spanish Mackerel in these management areas. Catch rates in the southern (Gascoyne–West Coast) area have declined in recent years, after the influence of the 2011 'heatwave' apparently increased abundance of Spanish mackerel for a period in southern WA [Pearce et al. 2011]. Thus, based on the available information the weight of evidence assessment [DPIRD 2020] determined it is possible that there is an acceptable moderate depletion of the stock. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired.

The total commercial catch of Spanish Mackerel in Western Australia for 2019 was 291 t, and, apart from a low catch in 2018, has been within target range of 246-430 t since management changes in 2006. However, the estimated boat based recreational fishing harvest weights of Spanish Mackerel have declined from 62–86 t to 35–54 t (95 per cent confidence intervals), between the 2011–12 to 2017–18 boat based surveys, respectively [Ryan et al. 2019]. The charter catch has been stable between 14–20 t since 2008. The lower recent recreational catch estimate can be attributed in part to declining recreational effort levels in the northern bioregions and also to a likely lower abundance associated with lower water temperatures in the West Coast Bioregion, as is reflected in the lower commercial catches and catch rates. The minimum size limit for Spanish Mackerel in Western Australia (900 mm TL) is similar to the size at maturity for this species [Mackie et al. 2003], which helps with sustainability as commercial line fishers avoid areas with undersize fish and means the spawning stock is essentially the same as the exploited stock. Thus, the weight of evidence assessment concluded the current management settings are maintaining risk to the stock at acceptable, medium levels. 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 Mackerel Managed Fishery (Western Australia) management unit is classified as a sustainable stock.

Spanish Mackerel biology [McPherson 1992, McPherson 1993, QDAFF 2013]

Commonwealth – Commercial (active vessels) Total number of TIB licences; this is not an indicator of licence activity.

Commonwealth – Recreational The Australian Government does not manage recreational fishing, including charter fishing, in Commonwealth waters. Recreational and charter fishing in Commonwealth waters is managed by the state or territory immediately adjacent to those waters, under its management regulations.

Commonwealth – Indigenous (a) The Australian Government does not manage non-commercial Indigenous fishing in Commonwealth waters, with the exception of the Torres Strait. In general, non-commercial Indigenous fishing in Commonwealth waters is managed by the state or territory immediately adjacent to those waters. In the Torres Strait, both commercial and non-commercial Indigenous fishing is managed by the Torres Strait Protected Zone Joint Authority (PZJA) through the Australian Fisheries Management Authority (Commonwealth); the Department of Agriculture, Fisheries and Forestry (Queensland); and the Torres Strait Regional Authority. The PZJA also manages non-Indigenous commercial fishing in the Torres Strait; and (b) 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.

Western Australia – Recreational (catch) Western Australian boat-based recreational catch surveys from 1 Sept 2017–30 Aug 2018 [Ryan et al 2019]. Shore-based recreational catches are largely unknown.

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

Western Australia – Charter (catch) is an estimate based on numbers of fish caught multiplied by their average weight.

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 “…without derogating from any other law in force in the Territory, nothing in a provision of this Act or an instrument of a judicial or administrative character made under it limits the right of Aboriginals who have traditionally used the resources of an area of land or water in a traditional manner from continuing 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

New South Wales – Recreational (Catch) Murphy et al. [2020].

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

Commercial catch of Spanish Mackerel - note confidential catch not shown. Years shown on this graph are Australian financial years (e.g. 2015 refers to the financial year beginning 01 July 2014 and ending 30 June 2015).

1. AFMA 2019, PZJA Torres Strait Finfish Resource Assessment Group meeting number 6, 27–28 November 2019, Australian Fisheries Management Authority, Canberra.
2. Begg, GA, Chen, CM, O’Neill, MF and Rose, DB 2006, Stock assessment of the Torres Strait Spanish Mackerel Fishery, technical report 66, CRC Reef Research Centre, Townsville.
3. Benthuysen, JA, Oliver, ECJ, Feng, M and Marshall, AG 2018, Extreme marine warming across tropical Australia during austral summer 2015–2016. Journal of Geophysical Research: Oceans, 123: 1301–1326
4. Bessell-Browne, P, O'Neill, MF, and Langstreth, J 2020, Stock assessment of the Queensland Gulf of Carpentaria Spanish mackerel (Scomberomorus commerson) fishery, Technical Report, State of Queensland, Brisbane.
5. Buckley, SM, Thurstan, RH, Tobin, A and Pandolfi, JM 2017, Historical spatial reconstruction of a spawning-aggregation fishery, Conservation Biology 31, pp. 1322–1332 https://doi.org/10.1111/cobi.12940.
6. Buckworth, R, Newman, S, Ovenden, J, Lester, R and McPherson, G 2007, The stock structure of northern and western Australian Spanish Mackerel, Fishery report 88, final report, Fisheries Research and Development Corporation Project 1998/159, Fisheries Group, Northern Territory Department of Business, Industry and Resource Development, Darwin.
7. DPIRD 2020, Statewide Large Pelagic Scalefish Resource in Western Australia, Resource Assessment Report 19 , Department of Primary Industries and Regional Development WA.
8. Gaughan, DJ and Santoro, K (eds) 2018, Status Reports of the Fisheries and Aquatic Resources of Western Australia 2016/17: The State of the Fisheries. Department of Primary Industries and Regional Development, Western Australia.
9. Grubert, M, Saunders, T and Usher, M unpublished, Spanish Mackerel Stock Status Summary: Spanish Mackerel (Scomberomorus commerson) Northern Territory stock.
10. Langstreth, J, Williams, A, Stewart, J, Marton, N, Lewis, P and Saunders,T 2018, Spanish Mackerel Scomberomorus commerson, in Carolyn Stewardson, James Andrews, Crispian Ashby, Malcolm Haddon, Klaas Hartmann, Patrick Hone, Peter Horvat, Stephen Mayfield, Anthony Roelofs, Keith Sainsbury, Thor Saunders, John Stewart, Simon Nicol and Brent Wise (eds) 2018, Status of Australian fish stocks reports 2018, Fisheries Research and Development Corporation, Canberra.
11. Lester, RJG, Thompson, C, Moss, H and Barker, SC 2001, Movement and stock structure of narrow-barred Spanish Mackerel as indicated by parasites, Journal of Fish Biology, 59: 833–842.
12. Mackie, M, Gaughan, DJ and Buckworth, RC 2003, Stock assessment of narrow-barred Spanish Mackerel (Scomberomorus commerson) in Western Australia, final report, Fisheries Research and Development Corporation project 1999/151, Western Australian Department of Fisheries, Perth.
13. Marton, N, Williams, A and Mazur, K 2017, Torres Strait Finfish Fishery, in H Patterson, R Noreiga, L Georgeson, J Larcombe and R Curtotti (eds), Fishery status reports 2017, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, 305–315.
14. McPherson, GR 1992, Age and growth of the narrow-barred Spanish Mackerel (Scomberomorus commerson Lacepede, 1800) in north-eastern Queensland waters, Australian Journal of Marine and Freshwater Research, 43: 1269–1282.
15. McPherson, GR 1993, Reproductive biology of the narrow-barred Spanish Mackerel (Scomberomorus commerson Lacepede, 1800) in Queensland waters, Asian Fisheries Science, 6: 169–182.
16. Moore, BR, Buckworth, RC, Moss, H and Lester, RJG 2003, Stock discrimination and movements of narrow-barred Spanish Mackerel across northern Australia as indicated by parasites, Journal of Fish Biology, 63: 765–779.
17. Murphy, JJ, Ochwada-Doyle, FA, 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.
18. Northern Territory Government (NTG) 2009, Fishery Status Reports 2008, Northern Territory Department of Resources. Fishery Report No. 101.
19. O’Neill, MF and Tobin, A (unpublished), Torres Strait Spanish mackerel stock assessment II, 2015. Torres Strait AFMA Project Number: RR2014/0823, Department of Agriculture and Fisheries, Queensland Government.
20. O’Neill, MF, Langstreth, JC, and Buckley, SM 2018. Stock assessment of Australian east coast Spanish mackerel: predictions of stock status and reference points. Department of Agriculture and Fisheries, Brisbane. 107 pp.
21. Ovenden, JR and Street, R 2007, Genetic population structure of Spanish Mackerel, in R Buckworth, S Newman, JR Ovenden, RJ Lester and G McPherson (eds), The stock structure of Northern and Western Australian Spanish Mackerel, Fishery report 88, Fisheries Research and Development Corporation project 98/159, Northern Territory Government, Darwin.
22. Pankhurst, NW and Munday, PL 2011, Effects of climate change on fish reproduction and early life history stages, Mar Freshw Res 62: 1015–1026.
23. Pearce, A, Lenanton, R, Jackson, G, Moore, J, Feng, M and Gaughan, D 2011, The ‘marine heat wave’ off Western Australia during the summer of 2010/11, Fisheries research report 222, Western Australian Department of Fisheries, Perth.
24. QFish, Department of Agriculture and Fisheries, www.qfish.gov.au
25. Queensland Department of Agriculture, Fisheries and Forestry 2013, Stock status of Queensland’s fisheries resources 2012, Queensland DAFF, Brisbane.
26. Ryan, KL, Hall, NG, Lai, EK, Smallwood, CB, Tate, A, Taylor, SM, Wise, BS 2019, State-wide survey of boat based recreational fishing in Western Australia 2017/18, Fisheries Research Report 297, Department of Primary Industries and Regional Development, Western Australia.
27. Sainsbury, K 2008, Best practice reference points for Australian Fisheries. Australian Fisheries Management Authority Report R2001/0999, 169pp.
28. Stewart, J, Hegarty, A, Young, C, Fowler, AM and Craig, J 2015, Status of Fisheries Resources in NSW 2013–14, NSW Department of Primary Industries, Mosman: 391pp.
29. Tanimoto, M, Fox, AR, O'Neill, MF and Langstreth, JC 2021, Stock assessment of Australian east coast Spanish mackerel (Scomberomorus commerson), Queensland Department of Agriculture and Fisheries, Brisbane.
30. Teixeira, D, Janes, R, and Webley, J 2021, 2019–20 Statewide Recreational Fishing Survey Key Results. Project Report. State of Queensland, Brisbane
31. Tobin A, Currey L and Simpfendorfer, C 2013, Informing the vulnerability of species to spawning aggregation fishing using commercial catch data, Fisheries Research, 143: 47–56.
32. Tobin, A, Heupel, M, Simpfendorfer, C, Buckley, S, Thurstan, R and Pandolfi, J 2014, Utilising innovative technology to better understand Spanish Mackerel spawning aggregations and the protection offered by Marine Protected Areas, Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville.
33. Webley, J, McInnes, K, Teixeira, D, Lawson, A, Quinn, R 2015, Statewide Recreational Fishing Survey 2013–14, Queensland Department of Agriculture and Fisheries, Brisbane.
34. West, LD, Stark, KE, Murphy, JJ, Lyle JM and Doyle, FA 2015, Survey of recreational fishing in New South Wales and the ACT, 2013/14. Fisheries Final Report Series.