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

The main impression in recent years is that fishing pressure has been reduced substantially for many North Sea stocks of roundfish and flatfish compared to the beginning of the century. Five stocks with agreed reference points (Category 1 stocks) have SSB higher than MSY Btrigger (haddock in 4, 6.a, and 20; plaice in 4 and 20; saithe in 3.a, 4, and 6; turbot in 4; whiting in 4 and 7.d), while the SSB of sole in 4, sole in 7.d, plaice in 7.d, and witch in 3.a, 4, and 7.d is just above Blim. Northern shelf cod (cod in 4, 6a, 7d, and 20) has one substock (Northwestern) with SSB above MSY Btrigger, one substock (Viking) between MSY Btrigger and Blim and one substock (Southern) below Blim. Several North Sea stocks are exploited at or below FMSY levels (haddock in 4, 6.a, and 20; plaice in 4 and 20; saithe in 3.a, 4, and 6; sole in 4; sole in 7.d; turbot in 4; whiting in 4 and 7.d); however, two stocks are being fished above FMSY (plaice in 7.d; witch in 3.a, 4, and 7.d). All substocks of Northern shelf cod (cod in 4, 6a, 7d, and 20) are fished above FMSY. An important feature is that recruitment remains poor compared to historic average levels for most gadoids, although there are signs of strong recruitment for haddock and whiting in most recent years. Recruitment in 2022 for flatfish stocks continues on a high level only for witch in 3.a, 4, and 7d, and for plaice in 4 and 20.WGNSSK is also responsible for the assessment of several data-limited species (Category 2+ stocks) that are mainly bycatch in demersal fisheries. 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 Btrigger 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 Btrigger and Blim for most of the time-series and is just below MSY Btrigger in 2023. Spawning-stock biomass of the Southern substock has been fluctuating around MSY Btrigger for most of the time-series until 2016 and has been below Blim since 2017. Fishing pressure has been high throughout the time series but decreased sharply from 2018 and is currently above FMSY for all three substocks. Recruitment has been low for all 3 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 Btrigger, Bpa and Blim. Fishing pressure has declined since the beginning of the 2000s, but it has been above FMSY for most of the entire time-series. Since 2021, fishing pressure has been below FMSY. Recruitment (age 0) since 2000 has been low with occasional larger year classes. The last 4 year-classes have all been above the recent mean. 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 Btrigger and has markedly increased since 2008, following a substantial reduction in fishing pressure since 1999. Currently, fishing pressure on the stock is below FMSY. 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 Blim. 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 FMSY and Fpa. 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 Btrigger, Bpa and Blim. Fishing pressure has decreased and stabilized above FMSY since 2000. Currently, fishing pressure on the stock is below FMSY. Recruitment (age 3) has shown an overall decreasing trend over time but slightly increas-ing in 2022. Sole (sol.27.4): The spawning-stock biomass has fluctuated around Blim since 1996. Currently, SSB is estimated to be between Blim and MSY Btrigger (= Bpa). Fishing pressure has been fluctuating above Flim for a large part of the time series. In 2022, it declined to levels below FMSY. 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 Blim since 2017. Currently, SSB is estimated to be between Blim and MSY Btrigger (= Bpa). Fishing pressure has decreased since 2007 and is currently estimated around FMSY. 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 Btrigger since 2013. Currently, spawning stock size is above MSY Btrigger, Bpa and Blim. Fishing pressure has decreased since the mid-1990s, and has been around FMSY since 2012. Currently, fishing pressure on the stock is below FMSY. 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 Btrigger, Bpa and Blim. Fishing pressure has been below FMSY since the early 2000s. Currently, fishing pressure on the stock is below FMSY. 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 Blim but below MSY Btrigger and Bpa. Fishing pressure has been above Fyear classes since the beginning of the time-series. Currently, fishing pressure on the stock is above FMSY but below Fpa and Flim. Recruitment (age 1) has increased since 2016. Category 2: Brill (bll.27.3a47de): Catches declined sharply in recent years. The relative exploitable biomass (B/BMSY) has been above reference point since the beginning of the time series. Relative fishing pressure (F/FMSY) has decreased since 2000 and is currently below FMSY. 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/BMSY) has been above reference point since the beginning of the time series. Relative fishing pressure (F/FMSY) 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 FMSY. Category 3: Dab (dab.27.3a4): rollover advice. Flounder (fle.27.3a4): The stock size indicator has been fluctuating below Itrigger for the past 6 years. Currently, fishing pressure on the stock is below the FMSY 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 Itrigger. Currently, fishing pressure on the stock is below the FMSY proxy. Striped red mullet (mur.27.3a47d): The stock size indicator is well above the Itrigger. Cur-rently the fishing pressure on the stock is above the FMSY 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.