Stock assessment is based on a Bayesian version of a surplus-production model that includes two survey indices and one commercial index; discards are not included. Uncertainties in the assessment are related to model insensitiveness to yearly changes and if rapid and large changes in recruitment happens; prey function of the Northern shrimp in the ecosystem especially by cod predation – that had recently increased (ICES, 2011b) – and alternative predators as capelin are still poorly known and may affect analysis (ICES, 2011a).
ICES/NAFO analyzed the short-term risk scenarios for the stock and recommended that a TAC equal to or less than 60,000 tonnes be established for 2012, in order to ensure with a high probability, that F remains below Flim and B above Blim (ICES, 2011a).
The following reference points have been defined for the stock:
|Precautionary approach||Blim||0.3||30% of Bmsy ; relative value|
|Flim||1.7||1.7 of Fmsy ; relative value|
|Targets||Not defined||Not defined|
Source : ICES (2011a)
Both biomass and fishing mortality for this stock are expressed as a ratio of their maximum sustainable yield value.
The stock is being sustainably harvested and in full reproductive capacity; is considered to be close to the carrying capacity (ICES/NAFO, 2011) and 2010 survey results demonstrated that the stock increased comparing with the last year (ICES, 2011c). As in previous years, stock biomass is above BMSY and fishing mortality below FMSY. Biomass is estimated to be well above Btrigger at the end of 2011 (ICES/NAFO, 2011). After a declining trend within 2004-2008, recruitment has been higher in 2009 and 2011 (ICES/NAFO, 2011).
Several countries joined Norway in the fishery since 1970s, contributing to a maximum of 128,000 tonnes in 1984. Catches have meanwhile varied within 21,000-61,000 tonnes, being around 75-93% of the total taken by the Norwegian fleet, with the rest by Russian, Icelandic, Greenlandic and EU vessels (NAFO/ICES, 2011). Since catches of 83,000 tonnes in 2000, values have been declining close to the lowest levels since the fishery developed, related to the reduced profitability of the fishery. Since 1995 the fleet has undergone major restructuring, existing nowadays fewer but larger and powerful factory trawlers (ICES, 2011a).