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Bigeye Tuna (2018)

Thunnus obesus

  • Heather Patterson (Australian Bureau of Agricultural and Resource Economics and Sciences)

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Summary

Australia’s Bigeye Tuna stocks in both the Indian and Pacific Oceans are sustainable. The separate biological stocks are managed by international commissions as a resource shared by many countries, including Australia.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Commonwealth Pacific Ocean ETBF, WCPFC Sustainable Spawning stock biomass, fishing mortality
Commonwealth Indian Ocean IOTC, WTBF Sustainable 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)
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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 not resulted in evidence of more than a single biological stock [Chiang et al. 2008, IOTC 2017]. Genetic studies have also indicated a single biological stock across the Pacific Ocean [Grewe and Hampton 1998]. The Indian Ocean biological stock falls under the intergovernmental organisations established to manage a number of highly migratory fish species.

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

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Stock Status

Indian Ocean

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

In the Indian Ocean, the most recent assessment [IOTC 2017] estimates that spawning stock biomass in 2015 was 38 per cent of the unfished level. The biological stock is not considered to be recruitment impaired [Williams et al. 2018]. This assessment also estimated that the current fishing mortality was below the level associated with maximum sustainable yield (MSY) (76 per cent of fishing mortality at MSY). This level of fishing mortality is unlikely to cause the biological stock to become recruitment impaired [Williams et al. 2018].

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 members of the Western and Central Pacific Fisheries Commission. 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 assessment in 2017 [McKechnie et al. 2017] estimates that the recent median spawning biomass was 32 per cent of the unfished level (range 15–41 per cent). There was a roughly 16 per cent probability that the recent spawning biomass breached the limit reference point [WCPFC 2017]. The biological stock is not considered to be recruitment impaired [WCPFC 2017, Larcombe et al. 2018]. This assessment also estimated that the median recent fishing mortality was 83 per cent of the level associated with MSY (80 per cent confidence interval 61–131 per cent). This level of fishing mortality is unlikely to cause the biological stock to become recruitment impaired [Larcombe et al. 2018, WCPFC 2017].

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

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Biology

Bigeye Tuna biology [Farley et al. 2006, 2017, 2018, Froese and Pauly 2009]
Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Bigeye Tuna ~16 years, ~2000 mm FL ~3 years, ~1000 mm FL 
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Distributions

Distribution of reported commercial catch of Bigeye Tuna
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Tables

Fishing methods
Commonwealth
Commercial
Hand Line, Hand Reel or Powered Reels
Pelagic Longline
Pole and Line
Trolling
Gillnet
Beach Seine
Purse Seine
Unspecified
Various
Rod and reel
Trawl
Handline
Recreational
Spearfishing
Handline
Management methods
Method Commonwealth
Commercial
Area restrictions
Catch limits
Gear restrictions
Individual transferable quota
Limited entry
Recreational
Bag limits
Active vessels
Commonwealth
38 in ETBF, 3 in WTBF
ETBF
Eastern Tuna and Billfish Fishery (CTH)
WTBF
Western Tuna Billfish Fishery (CTH)
Catch
Commonwealth
Commercial 449.00t in ETBF, 88.26Kt in IOTC, 213.59Kt in WCPFC, 67.00t 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)

Commonwealth – Commercial (catch) Catches reported for the Indian Ocean Tuna Commission and Western and Central Pacific Fisheries Commission are for 2016, the most recent year available; data for the Eastern Tuna and Billfish Fishery and Western Tuna Billfish Fishery are for 2017.

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 – Recreational and Indigenous 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. Measures listed here exist in one of these jurisdictions.

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.

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Catch Chart

Commercial catch of Bigeye Tuna - note confidential catch not shown
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References

  1. 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.
  2. Farley, J, Eveson, P, Krusic-Golub, K, Clear, N, Sanchez, C, Roupsard, F, Satoh, K, Smith, N and Hampton, J 2018, ‘Update on age and growth of bigeye tuna in the WCPO WCPFC Project 81, working paper WCPFC-SC14-2018/SA-WP-01, WCPFC Scientific Committee fourteenth regular session, Busan, Republic of Korea, 8–16 August 2018.
  3. Farley, J, Eveson, P, Krusic-Golub, K, Sanchez, C, Roupsard, F, McKechnie, S, Nicol, S, Leroy, B, Smith, N and Chang, S-K 2017, ‘Project 35: Age, growth and maturity of bigeye tuna in the western and central Pacific Ocean’, working paper WCPFC-SC13-2017/SA-WP-01, WCPFC Scientific Committee thirteenth regular session, Rarotonga, Cook Islands, 9–7 August 2017.
  4. 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.
  5. Froese, R and Pauly DE 2009, FishBase, version 02/2014, FishBase Consortium.
  6. 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. 
  7. Indian Ocean Tuna Commission 2017, Report of the twentieth session of the Scientific Committee, Mahe, Seychelles, 30 November–4 December 2017.
  8. Larcombe, J, Patterson, H and Mobsby, D 2018, Eastern Tuna and Billfish Fishery, in H Patterson, J Larcombe, S Nicol and R Curtotti (eds), Fishery status reports 2018, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra.
  9. McKechnie, S, Pilling, G and Hampton, J 2017, ‘Stock assessment of bigeye tuna in the western and central Pacific Ocean’, working paper WCPFC-SC13-2017/SA-WP-05, WCPFC Scientific Committee thirteenth regular session, Rarotonga, Cook Islands, 9–17 August 2017.
  10. Western and Central Pacific Fisheries Commission 2017, Summary report of the thirteenth regular session of the Scientific Committee for the Western and Central Pacific Fisheries Commission, Rarotonga, Cook Islands, 9–17 August 2017.
  11. Williams, A, Patterson, H and Mobsby, D 2018, Western Tuna and Billfish Fishery, in H Patterson, J Larcombe, S Nicol and R Curtotti (eds), Fishery status reports 2018, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra.

Archived reports

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