The spawning stock biomass (SSB) of the three dominant pelagic stocks in the Norwegian Sea ecoregion - NSS herring, mackerel, and blue whiting - has been above the biomass reference point for the majority of the period since 1980 but with a different temporal pattern between stocks. In 2020 SSB was similar for all three stocks, ranging from 3.2 to 3.7 million tonnes (Figure 11a). Since the late 1980s, combined SSB of the three stocks peaked at 15.6 million tonnes in 2016 and had declined by 34% in 2020. Herring SSB peaked in 2008 and had declined by 53% in 2020. Mackerel SSB peaked in 2014 and had declined by 29% in 2020. Blue whiting SSB last peaked in 2016 and has since declined by 48%.
For herring, the decline during the past decade is associated with below average recruitment (Figure 11b). During the same period, all new year-classes of mackerel have been above average size (Figure 11b). Blue whiting's sharp decline in SSB in most recent years is associated with fishing mortality above FMSY and poor recruitment (Figure 11b).
Since the mid-2000s, the status of mackerel in the ecoregion has been influenced (or characterised) by a westward expansion and subsequent retraction of its summer feeding grounds into Icelandic and Greenland waters.
Cod and haddock SSB shows an increasing trend until 2013/2014, with a decrease in the last few years. However, the mean SSB for cod, haddock, and saithe are at full reproductive capacity above the biomass reference point. Beaked redfish has recovered from low levels in the early 1990s. Biomass levels have been generally stable since the mid-2000s at about four times the early 1990s-levels. The golden redfish remains depleted and is on the Norwegian red list.
There is no analytical assessment for the greater silver smelt for SSB. The acoustic biomass index for the fish was higher in recent years (2014, 2016, and 2018) than in 2009 and 2012.
