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Blue Mackerel

Scomber australasicus

  • Tim Ward (South Australian Research and Development Institute)
  • Andy Moore (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Jeff Norriss (Department of Fisheries, Western Australia)
  • Jeremy Lyle (Institute for Marine and Antarctic Studies, University of Tasmania)
  • John Stewart (Department of Primary Industries, New South Wales)

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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Commonwealth Eastern SESSF (CTS), SPF, VIT Sustainable Catch, effort and CPUE  trends, spawning biomass, ecosystem modelling
Commonwealth Western SESSF (CTS), SESSF (GABTS) Sustainable Catch, effort
SESSF (CTS)
Southern and Eastern Scalefish and Shark Fishery (Commonwealth Trawl Sector) (CTH)
SESSF (GABTS)
Southern and Eastern Scalefish and Shark Fishery (Great Australian Bight Trawl Sector) (CTH)
SPF
Small Pelagic Fishery (CTH)
VIT
Victorian Inshore Trawl Fishery (CTH)
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Stock Structure

For the purpose of fisheries management, Blue Mackerel off southern Australia is currently considered to be comprised of two biological stocks: the Western stock that extends from western Tasmania to southern Western Australia and the Eastern stock, which occurs to the east of Bass Strait1,2. Following a data synthesis undertaken to establish management zones in the Small Pelagic Fishery (Commonwealth)3, Blue Mackerel and other target species are managed in western and eastern sub-areas1,2, which reflect this stock structure.

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

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Stock Status

Western

A preliminary application of the daily egg production method to Blue Mackerel off South Australia during 2005 provided an estimate spawning biomass of 56 228 tonnes (t)4. This estimate of spawning biomass was considered to be conservative as the survey only covered a limited part of the area in which this stock occurs, and there was evidence of spawning activity outside the survey area in the western Great Australian Bight4. Total annual catches of Blue Mackerel from this stock were low in the late-1990s and early-2000s (less than 55 t) and increased to more than 2000 t in 2006–07 and 2008–09. Catches have been mainly taken by purse-seining. For Western Australian licenses commercial fishing for Blue Mackerel was prohibited in 1999, with a boat possession limit of only 10 fish. Most state catches from the Western biological stock have been taken by South Australian licenced vessels. Total annual catches from the Western biological stock decreased to less than 2 t in 2012–13 and have stayed low, with just 0.4 t being taken in 2014–15. Low annual catches in recent years reflect low levels of fishing effort rather than low biomass levels5. Recent catches are less than one per cent of the estimated spawning biomass from 20054, and well below the sustainable exploitation rate of 23 per cent suggested for this stock6. The above evidence indicates that the stock is unlikely to be recruitment overfished5 and that the current level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

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

Eastern

The spawning biomass of Blue Mackerel off eastern Australia during 2014 was estimated to be around 83 300 t (95 per cent confidence interval = 35 100–165 000 t)7, which is higher than the preliminary estimate of 23 009 t8 obtained in 20044. This estimate of spawning biomass for 2014 should be used with caution due to uncertainty in the estimates of adult parameters in the daily egg production model, especially spawning fraction7. The total annual catch off eastern Australia peaked at 1036 t in 2003–04 and decreased to 290 t in 2011–125. There has been a general long-term decline in purse-seine effort in the Small Pelagic Fishery (Commonwealth) and a recent increase in mid-water trawl effort in 2014–155. The total catch in 2014–15 was 442 t5. The recent decline in total catch is considered to reflect reductions in fishing effort rather than a decline in abundance5. Current catches are less than one per cent of the estimated spawning biomass in 20145, and well below the sustainable exploitation rate of 23 per cent suggested for this stock6. The above evidence indicates that the stock is unlikely to be recruitment overfished5, and that the current level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the Eastern biological stock is classified as a sustainable stock.

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Biology

Blue Mackerel biology5,8,9

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Blue Mackerel 8 years; 440 mm FL  2 years; 2370–2870 mm FL
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Distributions

Distribution of reported commercial catch of Blue Mackerel

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Tables

Fishing methods
Commonwealth
Commercial
Purse Seine
Otter Trawl
Midwater Trawl
Management methods
Method Commonwealth
Commercial
Catch limits
Limited entry
Mesh size regulations
Spatial closures
Vessel restrictions
Active vessels
Commonwealth
8 in SESSF (CTS), 2 in SESSF (GABTS), 2 in SPF
SESSF (CTS)
Southern and Eastern Scalefish and Shark Fishery (Commonwealth Trawl Sector) (CTH)
SESSF (GABTS)
Southern and Eastern Scalefish and Shark Fishery (Great Australian Bight Trawl Sector) (CTH)
SPF
Small Pelagic Fishery (CTH)
Catch
Commonwealth
Commercial 2.00t in SESSF (CTS)
SESSF (CTS)
Southern and Eastern Scalefish and Shark Fishery (Commonwealth Trawl Sector) (CTH)

a 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.
b Commonwealth – Indigenous 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.
c Commonwealth – Commercial (Management Methods) Historically, no restrictions on vessel hold capacity have been in place in the Small Pelagic Fishery (Commonwealth). However, in 2012, an interim declaration was made to prevent factory trawlers greater than 130 m in length with on-board fish processing facilities, and storage capacity for fish or fish products in excess of 2000 t, from entering this fishery for a two year period.
d Tasmania – Recreational In Tasmania, a recreational licence is required for fishers using dropline or longline gear, along with nets, such as gillnet or beach seine.
e New South Wales – Indigenous (management methods) Aboriginal Cultural Fishing Interim Access Arrangement allows an Indigenous fisher in New South Wales to take in excess of a recreational bag limit in certain circumstances, for example, if they are doing so to provide fish to other community members who cannot harvest themselves.
f New South Wales – Indigenous (management methods) Aboriginal cultural fishing authority - the authority that Indigenous persons can apply to take catches outside the recreational limits under the Fisheries Management Act 1994 (NSW), Section 37 (1)(c1), Aboriginal cultural fishing authority.
g Tasmania – Indigenous (management methods) In Tasmania, aborigines engaged in aboriginal 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. Additionally, recreational bag and possession limits also apply. If using pots, rings, set lines or gillnets, aborigines must obtain a unique identifying code (UIC). The policy document Recognition of Aboriginal Fishing Activities for issuing a Unique Identifying Code (UIC) to a person for Aboriginal Fishing activity explains the steps to take in making an application for a UIC.

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Catch Chart

Commercial catch of Blue Mackerel

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Effects of fishing on the marine environment

  • Purse-seine and mid-water trawl fisheries interact with marine mammals, including seals and dolphins. In Australian waters, some purse-seine fisheries commonly interact with the Short-beaked Common Dolphin11. A Code of Practice has been successful in mitigating but not eliminating interactions with dolphins in one Australia purse-seine fishery11. Mortalities of both seals and dolphins have been recorded during mid-water trawls in the Small Pelagic Fishery (Commonwealth) (SPF)12. Dolphin rarely interact with mid-water trawls, however, seals commonly enter and forage in these nets, with some mortalities12. Seal excluder devices in the trawl nets have reduced, but not eliminated, seal mortalities12.
  • Blue Mackerel are prey for a range of predatory species, including tunas, sharks, marine mammals and seabirds. However, in Australia most predators forage on a wide range of prey are not dependent heavily dependent on one or two species6,13,14. Recent research also indicates that fishing for Blue Mackerel and other small pelagic species has only minor impacts on other parts of the ecosystem, as alternative food sources exist for large predator species6,14. Catch limits in the SPF at set at conservative levels which consider the ecological roles of Blue Mackerel1,2,6.
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Environmental effects on Blue Mackerel

  • Blue Mackerel are associated with relatively warm water and their distributions off the east coast and in the Great Australian Bight are likely to be associated with the strength of intrusion of the warm East Australia Current and Leeuwin Current, respectively8.
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References

  1. 1 Australian Fisheries Management Authority 2008, Small Pelagic Fishery harvest strategy (last revised April 2015). AFMA, Canberra.
  2. 2 Australian Fisheries Management Authority 2009, Small Pelagic Fishery management plan 2009, Federal Register of Legislative Instruments F2010L00081, AFMA, Canberra.
  3. 3 Bulman, C, Condie, S, Findlay, J, Ward, B and Young, J 2008, Management zones from small pelagic fish species stock structure in southern Australian waters, Final report to the Fisheries Research and Development Corporation and Australian Fisheries Management Authority, FRDC Project No 2006/076, Commonwealth Scientific and Industrial Research Organisation, Hobart.
  4. 4 Ward, TM, Rogers, PJ, McLeay, LJ and McGarvey, R 2009, Evaluating the use of the daily egg production method for stock assessment of blue mackerel, Scomber australasicus, Marine and Freshwater Research, 62:112-128.
  5. 5 Ward, TM and Grammer, GL 2016, Commonwealth Small Pelagic Fishery: Fishery assessment report 2015, Report to the Australian Fisheries Management Authority, SARDI Publication No. F2010/000270-7. SARDI Research Report Series No. 900, South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
  6. 6 Smith, ADM, Ward, TM, Hurtado, F, Klaer, N, Fulton, E and Punt, AE 2015, Review and update of harvest strategy settings for the Commonwealth Small Pelagic Fishery: Single species and ecosystem considerations. Final Report of FRDC Project No. 2013/028. Commonwealth Scientific and Industrial Research Organisation Oceans and Atmosphere Flagship, Hobart.
  7. 7 Ward, TM, Grammer, GL, Ivey, AR, Carroll, JR, Keane, JP, Stewart, J and Litherland, L 2015, Egg distribution, reproductive parameters and spawning biomass of Blue Mackerel, Australian Sardine and Tailor off the East Coast during late winter and early spring, FRDC Project No. 2014/033, South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
  8. 8 Ward, TM and Rogers, PJ 2007, Development and evaluation of egg-based stock assessment methods for blue mackerel Scomber australasicus in southern Australia. Final report to the Fisheries Research and Development Corporation Project No 2002/061. South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
  9. 9 Stevens, JD, Hausfeld, HF and Davenport, SR 1984, Observations on the biology, distribution and abundance of Trachurus declivis, Sardinops neopilchardus and Scomber australasicus in the Great Australian Bight. Commonwealth Scientific and Industrial Research Organisation Marine Laboratories, Cronulla.
  10. 10 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 No 149,.NSW Department of Primary Industries, Wollongong.
  11. 11 Hamer, DJ, Ward, TM and McGarvey, R 2008, Measurement, management and mitigation of operational interactions between the South Australian Sardine Fishery and short-beaked common dolphins (Delphinus delphis) Biological Conservation 141: 2865–2878
  12. 12 Lyle, JM and Willcox, ST 2008, Dolphin and seal interactions with mid-water trawling in the Commonwealth Small Pelagic Fishery, including an assessment of bycatch mitigation, Final Report to the Australian Fisheries Management Authority, Project R05/0996, Australian Fisheries Management Authority, Canberra.
  13. 13 Bulman, C, Condie, SA, Neira, FJ, Goldsworthy, SD, Fulton, EA 2010, Trophodynamics of small pelagic fishes in the southern Australian ecosystems and the implications for ecosystem modelling of southern temperate fisheries. Final Report to the Fisheries Research and Development Corporation (FRDC2008/023). Commonwealth Scientific and Industrial Research Organisation Marine and Atmospheric Research, Hobart.
  14. 14 Goldsworthy, SD, Page, B, Rogers, PJ, Bulman, C, Wiebkin, A, McLeay, L, Einoder, L, Baylis, A, Braley, M, Caines, R, Daly, K, Huveneers, C, Peters, K, Lowther, AD and Ward, T 2013, Trophodynamics of the eastern Great Australian Bight ecosystem: ecological change associated with the growth of Australia's largest fishery. Ecological Modelling, 255, 38–57.