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

The main terms of reference for the ICES Working Group for the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK) were to update, quality check, and report relevant data for the working group, to update and audit the assessment and forecasts of the stocks, to produce a first draft of the advice on the fish stocks, and to prepare planning for benchmarks in future years. Ecosystem changes have been analytically considered in the assessments for cod, haddock, and whiting in the form of varying natural mortalities estimated by the ICES Working Group on Multispecies Assessment Methods (WGSAM). Conservation status advice was considered but WGNSSK did not identify any conservation aspects for its stocks. The summary of stock status is as follows:

Category 1 stocks

• 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 2024. 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 above MSY B_trigger in 2024. 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 (age 1) in recent years has been low for all three substocks, with 2024 being the lowest recruitment in the time-series for both the Northwestern and Viking substocks.
• 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. 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. Four recent year classes (2019-2022) have all been above the recent mean. Recruitment in 2023 is estimated to be low.
• Nephrops FU 3–4 (nep.fu.3-4): advice in autumn.
• Nephrops FU 6 (nep.fu.6): advice in autumn.
• Nephrops FU 7 (nep.fu.7): advice in autumn.
• Nephrops FU 8 (nep.fu.8): advice in autumn.
• Nephrops FU 9 (nep.fu.9): advice in autumn.
• Norway pout (nop.27.3a4): advice in autumn.
• 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. Recruitment (age 1) in 2022 is the second highest in the time-series, while recruitment in 2023 is above average.
• 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 just below F_MSY. Recruitment (age 1) 2022 appears to be above average.
• Saithe (pok.27.3a46): Spawning-stock biomass has mostly decreased since the early 2000s and is currently above MSY B_trigger. Fishing pressure has decreased and stabilized above F_MSY since 2000. Currently, fishing pressure on the stock is just above F_MSY. Recruitment (age 3) has shown an overall decreasing trend over time but slightly increasing in 2022. Recruitment in 2023 is low.
• Sole (sol.27.4): The spawning-stock biomass has fluctuated around MSY B_trigger since 1996. Currently, SSB is estimated to be above MSY B_trigger. Fishing pressure has been fluctuating above F_lim for a large part of the time-series, but sharply decreased from the beginning of the 2000s. In 2023, fishing pressure is below F_MSY. Recruitment (age 0) in 2018 was the 5^th highest of the time-series, but decreased sharply in the following years. Recruitment in 2023 is low.
• 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 below B_lim. Fishing pressure has decreased since 2007 and is currently estimated below F_MSY. Recruitment (age 1) is estimated to be on a relatively low level since 2012 and the 2023 recruitment is low.
• 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. Fishing pressure has decreased since the mid-1990s and has been around F_MSY since 2011. Currently, fishing pressure on the stock is below F_MSY. Recruitment (age 1) is variable without a trend. In 2021, recruitment is estimated to be the lowest of the time-series, while in 2022 and 2023, it is around the long-term mean.
• Whiting (whg.27.47d): Spawning-stock biomass has increased substantially in recent years and is now well above MSY B_trigger. Fishing pressure has been below F_MSY since the early 1990s. Currently, fishing pressure on the stock is well 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. Recruitment in 2023 is one of the lowest of the time-series.
• Witch (wit.27.3a47d): Spawning-stock biomass has decreased and been below MSY B_trigger since the end of the 1990s, but is above MSY B_trigger in 2024. 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 decreased since 2019 and is low in 2023.

Category 2 stocks

• 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.
• Nephrops FU 32 (nep.fu.32): advice in autumn.
• 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 stocks

• Dab (dab.27.3a4): rollover advice.
• Flounder (fle.27.3a4): rollover advice.
• Grey gurnard (gug.27.3a47d): The stock size indicator has decreased since 2017, but is still above I_trigger.
• Lemon sole (lem.27.3a47d): The stock size indicator has decreased since 2016, but is still just above I_trigger. Currently, fishing pressure on the stock is below the F_{MSY proxy}.
• Striped red mullet (mur.27.3a47d): rollover advice.
• Whiting (whg.27.3a): The stock size indicator has decreased since 2015, but is still just above I_trigger.

Category 4 stocks

• Nephrops FU 33 (nep.fu.33): advice in autumn.
• Nephrops FU 34 (nep.fu.34): advice in autumn.
• Nephrops FU 10 (nep.fu.10): advice in autumn.

Category 5 stocks

• Nephrops FU 5 (nep.fu.5): advice in autumn.
• Nephrops out of FU (nep.27.4outFU): advice in autumn.
• Pollack (pol.27.3a4): Catches in the last two years have slightly increased from a low level.

Note: this is an abridged version of the executive summary. Please see the report for the full version.