Past stock status and conservation advice
(From ISC11 Plenary Report)
Concern was raised that the last point in the ALBWG's list of proposed conservation recommendations strayed too closely into management advice, which is not in the competence of ISC, rather than being strictly science-based conservation advice. It was noted that F2006-2008 is significantly below F2002-2004. The ISC accepts the WG recommendation with a modification to bullet 5 as shown below:
- The stock is considered to be healthy at average historical recruitment levels and fishing mortality (F2006-2008).
- Sustainability is not threatened by overfishing as the F2006-2008 level (current F) is about 71% of FSSB-ATHL and the stock is expected to fluctuate around the long-term median SSB (~400,000 t) in the short- and long-term future.
- If future recruitment declines by about 25% below average historical recruitment levels, then the risk of SSB falling below the SSB-ATHL threshold with 2006-2008 F levels increases to 54% indicating that the impact on the stock is unlikely to be sustainable.
- Increasing F beyond F2006-2008 levels (current F) will not result in proportional increases in yield as a result of the population dynamics of this stock.
- The current assessment results confirm that F has declined relative to the 2006 assessment, which is consistent with the intent of the previous (2006) WG recommendation.
Pacific Bluefin Tuna
Given the conclusions of the July 2010 PBFWG workshop (ISC/10/Annex/07), the current (2004- 2006) level of F relative to potential biological reference points, and the increasing trend of F, it is important that the level of F is decreased below the 2002-2004 levels, particularly on juvenile age classes.
A striped marlin stock assessment is scheduled for completion in 2012. Until this time the fishing mortality rate should not be increased above the current reference years (2001-2003) as specified in the latest assessment.
The WCPO and EPO stocks of swordfish are healthy and above the level required to sustain recent catches.