8.6 BLUE MARLIN AND WHITE MARLIN

1
8.6 BLUE MARLIN AND WHITE MARLIN

• One summary for both marlin species, as reported
  in 2006

2
BUM/WHM-1. Biology

• New information on the timing and location of
  spawning for blue and white marlin, the size at
  first maturity and the fecundity for different
  size fish, has been recently made available.

SCRS 2007/100
3
Identification of Round scale spearfish vs White
marlin and Atlantic spearfish

• The significance of this misidentification is
  still to be evaluated, but more effort is been
  made to train observers to separate the two
  species in the catches.

4
Includes only updates of new information
5
BUM/WHM 2. Catch

• In recent years large catches of billfish
  continue to be reported as unclassified billfish
• BUM/WHM-Figure 1

6
BUM/WHM 2. Catch

• Catches in 2005 and 2006 have not yet been
  evaluated to the extent done for catches for
  1990-2004 during the 2006 marlin assessment

2004 2005 2006
BUM 2117 3451 2060
WHM 573 598 342
7
Only changes are updates of values for 2005 and
2006 catch from task I
8
BUM/WHM-3. Fishery indices
No updates of abundance indices have been
obtained since the 2006 assessment. No changes
to the text
9
BUM/WHM-4. State of the stocks

• No new information on stock status has been
  provided since the 2006 assessment.

WHM BUM
B2004gtBmsy Yes Yes
Recent Abundance trend 2001-2004 Slightly upward Possibly stabilizing
F2004gtFreplacement Yes Possibly
F2004gtFmsy Possibly Yes
10
No changes to the text except references to the
2006 assessment
11
BUM/WHM-5. Recovery/Outlook

• No new information on the recovery/outlook for
  marlins has been provided since the 2006
  assessment.

WHM BUM
Longline and purse seine Catchrecent/Catch1996 0.47 0.52
Catch2004 610 2,916
MSY 600-1,300 1,000-2,400
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No changes to the text except references to the
2006 assessment
13
BUM/WHM-6. Effect of current regulations

• More countries have started reporting live
  releases in 2006. Additionally, more information
  has come about, for some fleets, on the potential
  for using gear modifications to reduce the
  bycatch and increase the survival of marlins.

Photo courtesy of SCRS/2007/113
Such studies have also provided information on
the rates of live releases for those fleets.
However there is not enough information on the
proportion of fish being released alive for all
fleets, to evaluate the effectiveness of the
ICCAT recommendation relating to the live release
of marlins.
14
Only changes are reference to studies of effects
of gear modifications
15
BUM/WHM-7. Management recommendations

• Should the Commission wish to increase the
  likelihood of success of the current management
  measures of the marlin rebuilding plan, further
  reduction in mortality would be needed, for
  example by
• encouraging the use of alternative gear
  configurations, including certain types of circle
  hooks, hook/bait combinations etcin fisheries
  where its use has been shown to be beneficial,

16
Only changes are reference to studies of effects
of gear modifications
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WHM BUM Summary TableNo changes except to
footnote 3 2006 catches