8

Bigeye Tuna

Thunnus obesus

  • Heather Patterson (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Scott Hansen (Australian Bureau of Agricultural and Resource Economics and Sciences)
Toggle content

Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Commonwealth Indian Ocean IOTC, WTBF Sustainable Spawning stock biomass, fishing mortality
Commonwealth Pacific Ocean ETBF, WCPFC Overfished Spawning stock biomass, fishing mortality
ETBF
Eastern Tuna and Billfish Fishery (CTH)
IOTC
Indian Ocean Tuna Commission (CTH)
WCPFC
Western and Central Pacific Fisheries Commission (CTH)
WTBF
Western Tuna Billfish Fishery (CTH)
Toggle content

Stock Structure

Bigeye Tuna in the Indian Ocean and Pacific Ocean are considered to be two distinct biological stocks and are managed by separate regional fisheries management organisations. In the Indian Ocean, tagging and genetic studies have indicated a single biological stock1,2. Genetic studies have also indicated a single biological stock across the Pacific Ocean3. The Indian Ocean biological stock falls under the jurisdiction of the Indian Ocean Tuna Commission; and the Pacific Ocean stock falls under the jurisdiction of the Western and Central Pacific Fisheries Commission. These two commissions are intergovernmental organisations established to manage a number of highly migratory fish species.

Here, assessment of stock status is presented at the biological stock level—Indian Ocean and Pacific Ocean.

Toggle content

Stock Status

The temporal coverage of data used to determine stock status differ, depending on the assessment, because of delays in reporting catch data to the Indian Ocean Tuna Commission and the Western and Central Pacific Fisheries Commission. Data for the Indian Ocean assessment were from 1952–2011, or 1952–20123 (several assessments were undertaken). Data for the Pacific Ocean assessment were from 1952–20121.

Indian Ocean

The Indian Ocean biological stock is fished by Australian fishers endorsed to fish in the Western Tuna and Billfish Fishery (Commonwealth), and numerous international jurisdictions. The assessments undertaken by the Indian Ocean Tuna Commission take into account information from all jurisdictions.

In the Indian Ocean, the most recent assessment1 estimates that biomass in 2012 was 40 per cent of the unfished level. The biological stock is not considered to be recruitment overfished4. This assessment also estimated that the current (2012) fishing mortality was below the level associated with maximum sustaianable yield (MSY) (42 per cent of mortality at MSY). This level of fishing mortality is unlikely to cause the biological stock to become recruitment overfished4.

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

Pacific Ocean

The Pacific Ocean biological stock is fished by Australian fishers endorsed to fish in the Eastern Tuna and Billfish Fishery (Commonwealth) and numerous international jurisdictions. The assessments undertaken for the Western and Central Pacific Fisheries Commission take into account information from all jurisdictions.

In the Pacific Ocean, the most recent assessment5 estimates that biomass in 2012 was 16 per cent of the unfished level. The biological stock is considered to be recruitment overfished6. This assessment also estimated that current fishing mortality was well above the level associated with MSY (157 per cent of fishing mortality at MSY; range 127–195 per cent). This level of fishing mortality is expected to prevent the stock recovering from a recruitment overfished state6.

On the basis of the evidence provided above, the Pacific Ocean biological stock is classified as an overfished stock.

Toggle content

Biology

Bigeye Tuna biology7,8

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Bigeye Tuna ~16 years; 2000 mm FL 3 years; ~1000 mm FL
Toggle content

Distributions

Distribution of reported commercial catch of Bigeye Tuna

Toggle content

Tables

Fishing methods
Commonwealth
Commercial
Hand Line, Hand Reel or Powered Reels
Pelagic Longline
Pole and Line
Trolling
Gillnet
Purse Seine
Various
Recreational
Spearfishing
Hand Line, Hand Reel or Powered Reels
Management methods
Method Commonwealth
Commercial
Area restrictions
Catch limits
Gear restrictions
Individual transferable quota
Limited entry
Recreational
Bag limits
Active vessels
Commonwealth
39 in ETBF, 2 in WTBF
ETBF
Eastern Tuna and Billfish Fishery (CTH)
WTBF
Western Tuna Billfish Fishery (CTH)
Catch
Commonwealth
Commercial 785.00t in ETBF, 92.67Kt in IOTC, 134.68Kt in WCPFC, 109.00t in WTBF
Indigenous Unknown
Recreational Unknown
ETBF
Eastern Tuna and Billfish Fishery (CTH)
IOTC
Indian Ocean Tuna Commission (CTH)
WCPFC
Western and Central Pacific Fisheries Commission (CTH)
WTBF
Western Tuna Billfish Fishery (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 – Recreational Recreational and Indigenous fishing sectors in the Indian Ocean are Western Australia, South Australia and Victoria; recreational sectors in the Pacific Ocean are Queensland, New South Wales and Tasmania. A tick indicates that a measure exists in one of these jurisdictions.
c 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.
d Commonwealth – Commercial (catch) Catches reported for the Indian Ocean Tuna Commission and Western and Central Pacific Fisheries Commission are for 2014 (the most recent year available).

Toggle content

Catch Chart

Commercial catch of Bigeye Tuna - note confidential catch not shown

Toggle content

Effects of fishing on the marine environment

  • Following completion of environmental risk assessments (levels 1–3) in the Western Tuna and Billfish Fishery (Commonwealth) (WTBF), no species were identified as high risk9. In the Eastern Tuna and Billfish Fishery (Commonwealth) (ETBF), nine species were identified as high risk or precautionary high risk. This is the priority list of species for attention under the Eastern Tuna and Billfish Fishery ecological risk management strategy; it includes two species of sunfish, four species of shark, two species of cetacean and one species of marine turtle10,11.
  • No target species, ecological communities or habitats were assessed to be at high risk from the effects of fishing in the ETBF or the WTBF9,10,11.
  • Australia implements regulations to minimise the environmental impact of fisheries for tuna and tuna-like species on pelagic ecosystems; specifically on seabirds, sea turtles and sharks12,13.
  • Australia has prohibited shark finning in longline fisheries managed by the Commonwealth, and has also prohibited the use of wire leaders in these fisheries, to reduce fishery impacts on sharks12,13.
  • Both the Indian Ocean Tuna Commission14 and the Western and Central Pacific Fisheries Commission15 have passed conservation and management measures that are broadly consistent with each other and with Australia’s domestic requirements.
Toggle content

Environmental effects on Bigeye Tuna

  • The distribution and abundance of tuna can be affected by environmental factors16,17. For example, seasonal changes in the abundance of Bigeye and Yellowfin Tuna on the east coast of Australia are linked to the expansion and contraction of the East Australian Current18.
Toggle content

References

  1. 1 Indian Ocean Tuna Commission 2015, Report of the eighteenth session of the Scientific Committee, Bali, Indonesia, 23–27 November 2015.
  2. 2 Chiang, H-C, Hsu, C-C, Wu, GC-C, Chang, S-K and Yang, H-Y 2008, Population structure of Bigeye Tuna (Thunnus obesus) in the Indian Ocean inferred from mitochondrial DNA, Fisheries Research, 90: 305–312.
  3. 3 Grewe, PM and Hampton, J 1998, An assessment of bigeye (Thunnus obesus) population structure in the Pacific Ocean, based on mitochondrial DNA and DNA microsatellite analysis, SOEST 98-05, JIMAR Contribution 98–320, Joint Institute for Marine and Atmospheric Research, University of Hawaii, Honolulu.
     
  4. 4 Williams, A, Patterson, H and Bath, A 2016, Western Tuna and Billfish Fishery, in H Patterson, R Noriega, L Georgeson, I Stobutzki and R Curtotti (eds), Fishery status reports 2016, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, 404–420.
  5. 5 Harley, S, Davies, N, Hampton, J and McKechnie, S 2014, Stock assessment of Bigeye Tuna in the Western and Central Pacific Ocean, working paper WCPFC-SC10-2014/SA-WP-01_Rev1, Western and Central Pacific Fisheries Commission Scientific Committee 10th regular session, Republic of the Marshall Islands, 6–14 August 2014.
  6. 6 Larcombe, J, Williams, A and Savage, J 2016, Eastern Tuna and Billfish Fishery, in H Patterson, R Noriega, L Georgeson, I Stobutzki and R Curtotti (eds), Fishery status reports 2016, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, 359–3681.
  7. 7 Farley, JH, Clear, NP, Leroy, B, Davis, TLO and McPherson G 2006, Age, growth and preliminary estimates of maturity of Bigeye Tuna, Thunnus obesus, in the Australian region, Marine and Freshwater Research, 57: 713–724.
  8. 8 Froese, R and Pauly DE 2009, FishBase, version 02/2014, FishBase Consortium.
    www.fishbase.org
  9. 9 Zhou, S, Smith, T and Fuller, M 2007, Rapid quantitative risk assessment for fish species in selected Commonwealth fisheries, report for the Australian Fisheries Management Authority, CSIRO Marine and Atmospheric Research, Cleveland.
  10. 10 Zhou, S, Fuller, M and Smith, T 2009, Rapid quantitative risk assessment for fish species in seven Commonwealth fisheries, report for the Australian Fisheries Management Authority, CSIRO Marine and Atmospheric Research, Cleveland.
  11. 11 Australian Fisheries Management Authority 2009, Residual risk assessment of the level 2 ecological risk assessment: species results, report for the Eastern Tuna and Billfish Fishery, AFMA, Canberra.
  12. 12 Australian Fisheries Management Authority 2016, Eastern Tuna and Billfish Fishery Management Arrangements Booklet: 2016 Fishing Season, AFMA, Canberra.
  13. 13 Australian Fisheries Management Authority 2016, Western Tuna and Billfish Fishery Managements Arrangements Booklet: 2016 Fishing Season, AFMA, Canberra.
  14. 14 Indian Ocean Tuna Commission 2015, Compendium of Active Conservation and Management Measures for the Indian Ocean Tuna Commission, IOTC Seychelles.
  15. 15 Western and Central Pacific Fisheries Commission 2016, Conservation and Management Measures (CMMs) and Resolutions of the Western and Central Pacific Fisheries Commission (WCPFC), WCPFC, Federated States of Micronesia.
  16. 16 Hobday, AJ and Young, J 2007, Pelagic fisheries, in AJ Hobday, ES Poloczanska and RJ Matear (eds), Climate impacts on Australian fisheries and aquaculture: implications for the effects of climate change, report for the Australian Greenhouse Office, Canberra.
  17. 17 Lehodey, P, Hampton, J, Brill, RW, Nicol, S, Senina, I, Calmettes, B, Portner, HO, Bopp, L, Ilyina, T, Bell, JD and Sibert, J 2011, Vulnerability of oceanic fisheries in the tropical Pacific to climate change, in JD Bell, AJ Johnson, and AJ Hobday (eds), Vulnerability of tropical Pacific fisheries and aquaculture to climate change, Secretariat of the Pacific Community, Noumea, New Caledonia, 433–492.
  18. 18 Campbell, RA 1998, Long term trends in yellowfin tuna abundance in the south-west Pacific: with an emphasis on the eastern Australian Fishing Zone, Paper presented at the 11th meeting of the Standing Committee on Tunas and Billfish, 30 May–6 June 1998, Honolulu, USA.

Archived reports

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