Tuna, Pacific bluefin
Method of production - Caught at sea
Capture method - All applicable methods
Capture area - Worldwide (FAO All Areas)
Stock area - Pacific Ocean
Stock detail - All Areas
Fish type - Oily fish
Pacific bluefin is a relatively slow growing and long-lived predator that is both a very important commercial and artisanal species. The majority of the catch in the Pacific is taken by purse seiners with much of the catch now fattened in pens before being sold on the sashimi market. Approximately 90% of fish is captured before it has had a chance to breed and is seriously contributing to the overfishing on this Pacific-wide stock. The latest stock assessment was undertaken in 2014 and, similar to previous assessments, indicated that the stock is still heavily overfished the biomass is estimated to be at historical low levels, with the spawning biomass near historical low levels, and is also still subject to heavy overfishing. Recently bolstered catch and effort limits are a positive sign, yet it remains to be seen whether or not these will be sufficient to reduce fishing mortality to sustainable levels and to recover the biomass. Pacific bluefin is best avoided until considerable improvement is seen in the stock.
Tuna belong to the family Scombridae. They are large, oceanic fish and are seasonally migratory, some making trans-oceanic journeys. Bluefin tuna are the largest of the tuna species, reaching upwards of 680 kg. There are three species in each of the Pacific, Atlantic and Southern Oceans. In all oceans bluefins are known for their impressive migrations, routinely crossing ocean basins. Pacific bluefin tuna are generally smaller than their Atlantic cousins, reaching a maximum length of 3m and a maximum weight of 540kg. Not only do they have a hydrodynamic shape, their pectoral (side) fins can be retracted and, unlike other fish, their eyes are set flush to their body. Pacific bluefin tuna is capable of swimming at speeds of 12 to 18 miles per hour (20-30 km per hour) for brief periods. In the Pacific, tagging studies indicate there is only one stock with a spawning ground off southern Japan. Pacific bluefin tuna spawn between Okinawa (Japan) and the Philippines, in April and August, then migrate over 6,000 nautical miles to the eastern Pacific, eventually returning to their birth waters to spawn. They reach reproductive maturity at around 5 years and 60kg.
Pacific bluefin is assessed by the International Scientific Committee for Tuna and Tuna-like species in the North Pacific (ISC). Historical Pacific bluefin tuna (PBF) catch records are scant yet landing records from coastal Japan date back to as early as 1804 and to the early 1900s for U.S. fisheries. Catches appear to have peaked before WWII at about 59,000t, after which, catches fluctuated widely without trend before stabilising over the last 20years between 5,800 and 10,000t. In 2013, total catch was approximately 12,000t, representing a 22% decrease from 2012. Since the early 1990s the Western Pacific Ocean purse seine fleet has increased its impact, and the effect of this fleet on the stock is currently greater than any of the other fishery groups. This is due to the very high proportion of juvenile bluefin caught in these purse seine fisheries. The latest stock assessment was carried out in 2014 and, similar to the previous assessment in 2012, indicated that the stock was still heavily overfished, with spawning biomass levels at approximately 4% of unfished levels (near the historical low), and continues to be subject to heavy overfishing, with fishing mortality exceeding all commonly used Fmsy proxy reference points (e.g. F is about 1.8Fmax).
Pacific bluefin tuna has a single Pacific-wide stock managed by both the Western and Central Pacific Fisheries Commission (WCPFC) and the Inter-American Tropical Tuna Commission (IATTC). Bluefin tunas have been badly managed in the past with a lack of regulation and enforcement across their range. Contributing to this has been its extremely high market value adding plenty of incentive for Illegal, Unreported and Unregulated (IUU) fisheries. In recent years, decreased catches and fish sizes and concerns over the stock status led to increased management measures, yet there remained concern that such measures were insufficient to have a positive impact on the stock, particularly if recruitment remained below average.
In December 2014 additional measures were developed by the WCPFC, including a multiannual rebuilding plan for stock tuna starting in 2015, with the initial goal of rebuilding the spawning biomass (SB) to the historical median (42,592 t) within 10 years with at least 60% probability (Current SB is approximately 26,324t). Reference points and harvest control rules are to be established and reviewed in 2015 and in 2016. All WCPFC members are to ensure that: total fishing effort by their vessel fishing for Pacific bluefin tuna in the area north of the 20degrees N shall stay below the 2002 to 2004 annual average levels; all catches of Pacific bluefin tuna less than 30 kg shall be reduced to 50% of the 2002 to 2004 levels; and any overage of the catch limit shall be deducted from the catch limit for the following year.
Similarly, the IATTC has further reduced its Total Allowable Catch (TAC) from: 5,600t in 2012; and 5,000t in 2014; down to 3,300t a year for 2015 and 2016 (Or a maximum total of 6,600t over the two years).
The IATTC require 100% regional observer coverage on large purse seiners. In the WCPFC 100% coverage is required for all purse seine vessels fishing on the high seas and in waters under the jurisdiction of one or more coastal States, or vessels fishing in waters under the jurisdiction of two or more coastal States during the same trip; and on all purse seiners fishing between 20N and 20S. Both the IATTC and WCPFC require 5% observer coverage on longline vessels over 20m in length.
To help address IUU, both the IATTC and the WCPFC maintain an IUU Vessel list as well as a register of large longliners that are authorised to target albacore; it is also prohibited to undertake transhipments at sea between purse seiners (Some exemptions apply) and all other transhipments need to be documented and 100% observed as part of the regional observer programme.
Approximately 68% of Pacific bluefin is captured in purse seine fisheries that target free schooling fish. During recent years, most of the catches have been transported to holding pens, where the fish are held for fattening and later sale to sashimi markets. These fisheries catch a very high proportion of juvenile fish. Approximately 90% of the total catch is made on juvenile fish, aged 0-3yr. The ISC recommend that fishing effort be reduced to below 2002-2004 levels, particularly for juvenile fish. Lesser amounts of bluefin are caught via trolling, gillnet, trap, pole-and-line and longline gear.
Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below . Click on a name to show the sustainable options available.
Froese, R. and Pauly, D. Editors, 2013. FishBase. World Wide Web electronic publication. Available at www.fishbase.org [Accessed Nov 2013].
ISC, 2014. Stock assessment of Pacific bluefin tuna. Available at http://isc.ac.affrc.go.jp/pdf/2014_Intercessional/Annex4_Pacific%20Bluefin%20Assmt%20Report%202014-%20June1-Final-Posting.pdf [Accessed Dec 2014].
ISSF, 2014. ISSF Tuna Stock Status Update, 2014: Status of the world fisheries for tuna. ISSF Technical Report 2014-09. International Seafood Sustainability Foundation, Washington, D.C., USA. Available at http://iss-foundation.org/wp-content/uploads/downloads/2014/09/ISSF-2014-09-Status-of-the-Stocks-Sept-11-BYCATCH-APPENDIX.pdf [Accessed Nov 2014].
IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2.
WCPFC, 2015. Conservation and management measures. Available at https://www.wcpfc.int/conservation-and-management-measures [Accessed Jan 2015].
WCPFC, 2014. Scientific committee tenth regular session: summary report. 6 to 14 August 2014. Majuro, Republic of the Marshall Islands. Available at https://www.wcpfc.int/system/files/SC10%20-%20final_posted_1.docx [Accessed Jan 2015].
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