Last updated on 1 March 2014
An age-based analytical (TASACS) assessment is conducted, taking into consideration catch at age data, acoustic surveys of adults and juveniles, a larval survey, and a 0-group survey. A benchmark assessment in 2008 opted for a VPA based model from the TASACS toolbox for use with the most recent data. There has been some uncertainty around the assessment estimates. A retrospective pattern has revealed overestimated spawning stock biomass (SSB) and underestimated fishing mortality (F) in previous assessments and recruitment estimates are uncertain (ICES, 2012a, 2012b). This was also observed in the most recent assessment (2013), but to a much smaller extent (ICES, 2013a).
Discarding is thought to be low. Slippage is known to occur but has not been quantified and could not be considered in the assessment (ICES, 2013a).
Last updated on 9 January 2013
In 2010, ICES started a transition to a Maximum Sustainable Yield (MSY) approach for scientific advice (ICES 2010b). During the transition, catch options are presented under the ICES MSY approach, the precautionary approach (PA), and the management plan.
As for previous years, ICES advice is based on the management plan (MP). As the spawning biomass for 2014 is projected below the target of 5 million tonnes, the agreed management plan anticipates a reduction of the fishing mortality to F=0.099, meaning catches should be limited to 418,487 tonnes. This is expected to lead to decrease of 16% in SSB in 2015 (compared to 2014), to 3.54 million tonnes, below the management plan Btrigger (=Bpa). ICES’ MSY approach also implies a reduction in fishing mortality to 0.124 in 2014, resulting in landings of 519 thousand tonnes. According to the projections, this would also result in a decrease in SSB in 2015, to 3.5 million tonnes. Following the precautionary approach, at SSB levels below Bpa F should be reduced to allow a quick recovery of the stock. But even the absence of any fishing in 2014 is expected to lead to a decrease of SSB to below Bpa in 2015 (ICES, 2013a).
The recent lack of agreement by all parties on their share for the 2013 TAC has led to quotas being unilaterally set, and resulted in a global TAC higher than the anticipated in the management plan. ICES has advised that, if the situation persists, it may lead to overfishing and accelerate the present decline of the stock (ICES, 2013a). The Pelagic Regional Advisory Council has recommended “a return to the international agreement by all parties", and the 2014 TAC to be set according to the management plan (i.e., at 418,000 tonnes) (Pelagic RAC, 2013).
Last updated on 09 Jan 2013
The reference points for this fishery have remained unchanged since 2010 and are as follows (ICES, 2012a):
|Management plan:||MSY Approach:||Precautionary Approach:|
|SSBMP = 5.0 million tons|
FMP = 0.125*
|MSY Btrigger = 5.0 million tons|
FMSY = 0. 15 million tons
|Blim = 2.5 million tons |
Bpa = 5.0 million tons
Flim = not defined
Fpa = 0.15
*According to the agreed management plan for this fishery, target F will drop linearly from 0.125 at Bpa to 0.05 at Blim if the SSB is below Bpa (ICES, 2010c).
Last updated on 7 March 2014
The state of the stock was revised in 2012, with SSB revised downwards and F upwards. This was also observed in the most recent assessment (2013), but to a much smaller extent compared to previous years (ICES, 2013a).
Spawning stock biomass has been decreasing since 2009 and is currently estimated at 5 million tonnes, i.e., at Bpa. Fishing mortality has been fluctuating around Fpa (=FMSY) since 2003 and in 2011 and 2012 was estimated as just below Fpa but above the target F from the management plan (Ftarget = 0.125). The last strong recruitment was in 2004; since 2005 all cohorts have been small (ICES, 2013a).
Last updated on 07 Mar 2014
Fishing mortality has oscillated between Ftarget and Fpa since the mid-2000s, and in 2011-2012 has been just below Fpa. After an historical peak in 2009, when it was estimated at 8.5 million tonnes, SSB has been declining since due to the lack of strong year classes in the past decade, and is is currently at Bpa. Projections suggest that even under a no fishing scenario (F=0), the declining trend is expected to continue on the short-term. If the target fishing mortality defined in the management plan is followed, SSB is expected to decrease to 3.54 million tonnes in 2015 (ICES, 2013a).