Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)

Section 4 on North Sea cod stocks was added September 2023.

Section 12 on Norway pout was added October 2023.

Sections 10 and 11 on Nephrops, Annex 10, and other corrections were added December 2023.

[note: executive summary abridged]

The summary of stock status is as follows:

Category 1:

• Cod (cod.27.46a7d20): Spawning-stock biomass of the Northwestern substock has been fluctuating above MSY B_trigger for most of the time-series and is well above it in 2023. Spawning-stock biomass of the Viking substock has been fluctuating between MSY B_trigger and B_lim for most of the time-series and is just below MSY B_trigger in 2023. Spawning-stock biomass of the Southern substock has been fluctuating around MSY B_trigger for most of the time-series until 2016 and has been below B_lim since 2017. Fishing pressure has been high throughout the time-series but decreased sharply from 2018 and is currently above F_MSY for all three substocks. Recruitment has been low for all three substocks, with the lowest recruitment in the Southern substock.
• Haddock (had.27.46a20): Spawning-stock biomass has been low since the mid of the 2000s but has increased sharply since 2019 and is now well above MSY B_trigger, B_pa and B_lim. Fishing pressure has declined since the beginning of the 2000s, but it has been above F_MSY for most of the entire time-series. Since 2021, fishing pressure has been below F_MSY. Recruitment (age 0) since 2000 has been low with occasional larger year classes. The last four year classes have all been above the recent mean.
• Nephrops FU 3–4 (nep.fu.3-4): Fishing pressure is slowly increasing from 2017–2022, but is still below F_MSY. Stock size is decreasing over that period. No reference point for stock size has been defined for this stock..
• Nephrops FU 6 (nep.fu.6): Fishing pressure has been fluctuating above F_MSY (with the exception of 2008). Stock size was below MSY B_trigger in 2009, 2010 and from 2012–2016, but is above this reference point in the most recent years.
• Nephrops FU 7 (nep.fu.7): Over the last seven years, fishing pressure is well below F_MSY and stock size is well above MSY B_trigger.
• Nephrops FU 8 (nep.fu.8): Stock size has been above MSY B_trigger for the entire time-series, while fishing pressure has been fluctuating around F_MSY. In 2022, fishing pressure is below F_MSY.
• Nephrops FU 9 (nep.fu.9): Fishing pressure has been fluctuating around F_MSY, and is below the reference point in 2022. Stock size was estimated to be largely above MSY B_trigger, and this was also the case in 2022.
• Norway pout (nop.27.3a4): Spawning-stock biomass has been fluctuating over the time-series, with periods of higher biomass in the 1990s and late 2000s, as well as in the late 2010s. In the most recent years, SSB decreased, but is still above B_pa and B_lim. No reference points for fishing pressure or for MSY B_trigger have been defined for this stock.
• Plaice (ple.27.420): The spawning-stock biomass is well-above MSY B_trigger and has markedly increased since 2008, following a substantial reduction in fishing pressure since 1999. Currently, fishing pressure on the stock is below F_MSY. After a strong recruitment (age 1) in 2019, the recruitment in 2020 and 2021 is estimated to be on an average level. Recruitment in 2022 is the second highest in the time-series.
• Plaice (ple.27.7d): The spawning-stock biomass has increased rapidly from 2010 following a period of higher recruitment between 2009 and 2019. However, since 2016, SSB has declined and is now at a level just above B_lim. Higher fishing pressure from 2015 onwards and lower recruitment from 2020 onwards contributed to this decrease in SSB. Fishing pressure on the stock is currently situated between F_MSY and F_pa. Recruitment (age 1) in 2020 is estimated to be the lowest value in the time-series. The 2021 recruitment was slightly higher. The lack of the UK-BTS survey in Division 7.d in 2022 resulted in high uncertainty for the 2022 recruitment estimate.
• Saithe (pok.27.3a46): Spawning-stock biomass has mostly decreased since the early 2000s and is currently above MSY B_trigger, B_pa and B_lim. Fishing pressure has decreased and stabilized above F_MSY since 2000. Currently, fishing pressure on the stock is below F_MSY. Recruitment (age 3) has shown an overall decreasing trend over time but slightly increasing in 2022.
• Sole (sol.27.4): The spawning-stock biomass has fluctuated around B_lim since 1996. Currently, SSB is estimated to be between B_lim and MSY B_trigger ( = B_pa). Fishing pressure has been fluctuating above F_lim for a large part of the time-series. In 2022, it declined to levels below F_MSY. Recruitment (age 1) in the most recent years has been lower than the long-term average.
• Sole (sol.27.7d): The spawning-stock biomass has decreased since 2014 and is estimated to be fluctuating around B_lim since 2017. Currently, SSB is estimated to be between B_lim and MSY B_trigger (= B_pa). Fishing pressure has decreased since 2007 and is currently estimated around F_MSY. Recruitment (age 1) is estimated to be on a relatively low level since 2012 and the 2022 recruitment is the lowest of the time-series.
• Turbot (tur.27.4): The spawning-stock biomass has increased since 2005 and has been above MSY B_trigger since 2013. Currently, spawning stock size is above MSY B_trigger, B_pa and B_lim. Fishing pressure has decreased since the mid-1990s, and has been around F_MSY since 2012. Currently, fishing pressure on the stock is below F_MSY. Recruitment is variable without a trend. In 2021, recruitment (age 1) is estimated to be the lowest of the time-series.
• Whiting (whg.27.47d): Spawning-stock biomass has increased substantially in recent years and is now well above MSY B_trigger, B_pa and B_lim. Fishing pressure has been below F_MSY since the early 2000s. Currently, fishing pressure on the stock is below F_MSY. Recruitment (age 0) has been fluctuating without trend, but the 2019 and 2020 year classes are estimated to be the largest since 2002.
• Witch (wit.27.3a47d): Spawning-stock biomass is now just above B_lim but below MSY B_trigger and B_pa. Fishing pressure has been above F_MSY since the beginning of the time-series. Currently, fishing pressure on the stock is above F_MSY but below F_pa and F_lim. Recruitment (age 1) has increased since 2016.

Category 2:

• Brill (bll.27.3a47de): Catches declined sharply in recent years. The relative exploitable biomass (B/B_MSY) has been above reference point since the beginning of the time-series. Relative fishing pressure (F/F_MSY) has decreased since 2000 and is currently below F_MSY.
• Turbot (tur.27.3a): Catches peaked in the late 1970s and early 1990s and have been more stable in recent years. The relative exploitable biomass (B/B_MSY) has been above reference point since the beginning of the time-series. Relative fishing pressure (F/F_MSY) peaked in the late 1970s and early 1990s, and has been relatively low without a trend in more recent years. Currently, fishing pressure on the stock is below F_MSY.

Category 3:

• Dab (dab.27.3a4): rollover advice.
• Flounder (fle.27.3a4): The stock size indicator has been fluctuating below I_trigger for the past six years. Currently, fishing pressure on the stock is below the F_{MSY proxy}.
• Grey gurnard (gug.27.3a47d): rollover advice.
• Lemon sole (lem.27.3a47d): The stock size indicator has decreased since 2016, but is still above I_trigger. Currently, fishing pressure on the stock is below the F_{MSY proxy}.
• Striped red mullet (mur.27.3a47d): The stock size indicator is well-above the I_trigger. Currently the fishing pressure on the stock is above the F_{MSY proxy}.
• Whiting (whg.27.3a): rollover advice.

Category 4:

• Nephrops FU 32 (nep.fu.32): rollover advice.
• Nephrops FU 33 (nep.fu.33): rollover advice.
• Nephrops FU 34 (nep.fu.34): rollover advice.
• Nephrops FU 10 (nep.fu.10): rollover advice.

Category 5:

• Nephrops FU 5 (nep.fu.5): rollover advice.
• Nephrops out of FU (nep.27.4outFU): rollover advice.
• Pollack (pol.27.3a4): rollover advice.