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West Atlantic bluefin tuna Executive Summary   
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• Biology
• Continued progress in knowledge of bluefin
  biology, but the complex behaviour of this
  species means that much research still needed
• Recent research in reproductive biology,
  demographic modeling and age determination
  suggests western bluefin may be less resilient to
  fishing than previously thought
• WG remains concerned about issues of mixing, and
  in particular, the inability to quantify the kind
  and extent of mixing for use in assessments
• Need to integrate recent and anticipated
  advances in otolith microconstituent analyses,
  archival tagging and genetics into assessment and
  management evaluation processes.

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Fishery indicators catch
QUOTAS
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Fishery indicators catch
2002 landings (3,319 t) highest since
1981 Canadian and Japanese landings stable at
500-600 t U.S. did not catch its quota in
2004-2006 with landings of 899, 717 , and 468 t
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Fishery indicators abundance indices
No consistent changes in CPUE
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State of the stock (review)
Consistent with 2002 SA Less optimistic
estimates of 1994 and 1997 year classes More
optimistic view of recent Fs
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• State of stock low U.S. catches
• Plausible explanations
• (1) that availability of fish to the United
  States fishery was low
• (2) the overall size of population in the west
  declined substantially
• Evidence (SCRS/2007/171)
• (1) Canada and Japan did not have abnormally low
  catches
• CPUE series from Gulf of St. Lawrence at high
  levels since 2004
• CPUE series from GOM do not show consistent
  decline
• (2) some abundance indices suggest decline
• declining size composition in some areas
• small changes in F suggested by tag data
  despite declining catches
• Conclusion
• (1) No strong evidence to favor either
  explanation over the other
• (2) However, the failure of a fishery to take
  half of its TAC for several years, and other new
  evidence reviewed by the committee, heightened
  concern that the estimate of stock status from
  the 2006 assessment may be optimistic

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Outlook

• Short-term (5-year) projections to cover time
  until next assessment
• assume future recruitment will fluctuate around
  recent levels

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Outlook
FMSY 2,100 MT
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• Current (2006) Catch (including discards) 1,929
  t
• Short-term Sustainable Yield 2,300 t
• Maximum Sustainable Yield (MSYR) 3,200
  (3,000-3,400)
• Relative Spawning Stock Biomass
• B2004/B1975 0.18
• B2004/BMSYR 0.41 (0.29-0.54)
• Relative Fishing Mortality3
• F2004/FMSYR 1.7
• F2004/F0.1 3.1
• F2004/Fmax 1.7
• Management Measures
• 2,100 t TAC from 2007 inc. dead disc Rec.
  06-06
• 2,700 t TAC from 2003 inc. dead discards Rec.
  02-07
• 30 kg (115 cm FL) min. size with 8 tol. Rec.
  98-07
• No directed fisheries in Gulf of Mexico Rec.
  98-07

BFTW summary table
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• Effect of current regulations
• Recommendation 06-06 expected to result in
  rebuilding stock towards convention objective
  with fishing mortality rates at about the
  estimated MSY level
• New evidence suggests that current regulations
  may be insufficient to achieve the objectives
  (cannot evaluate until next assessment)
• Ability to achieve the convention objectives
  would be further hampered by future use of
  accumulated unused quota (large amount involved
  for WBFT

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• Management recommendations
• Commission responded positively, making Rec.
  06-06,
• which establishes a quota of 2,100 MT
• However, the Committee is even more concerned
  about
• status of west stock than it was a year ago.
  Further
• advice provided after the next assessment
  (2008).
• Evidence accumulating that both productivity of
  west
• stock and west bluefin fisheries linked to the
  east stock.
• One plausible explanation for failure of west
  fishery to
• take TAC in recent years is that it is partly
  dependent on
• east fish, and east fish now less available to
  the west
• Therefore, management actions taken in the
  eastern
• Atlantic and Mediterranean are likely to impact
  recovery

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