Seabass

The sea bass stock in the northern and central Bay of Biscay is harvested sustainable and fully fished.Stock assessments are conducted by the International Council for the Exploration of the Sea (ICES). Following a benchmark in 2025, the latest assessment incorporates catch reallocation across connected ICES divisions and estuary-based recruitment data. These methodological updates have improved the accuracy of the assessment and reduced some uncertainties. However, recreational catches are only based on two years of data, and therefore continue to have a considerable level of uncertainty.The stock assessment defines reference points for fishing pressure (F) and biomass (B). For fishing pressure, there is a target to keep F at or below Maximum Sustainable Yield (MSY). For biomass, there is no target. However, there is a trigger point (MSY Btrigger) and precautionary reference point (Bpa) to ensure reproductive output is maintained. Because BMSY is not defined, the Good Fish Guide applies its own definition of 1.4 x MSY BTrigger.From 1985 to 2002, F fluctuated around 0.18, remaining below FMSY (0.205). However, in 2003, F exceeded MSY, reaching a peak of 0.23 in 2005 before falling back below the threshold in 2008. Since then, total fishing pressure, across both commercial and recreational catches, has steadily declined from 0.2 in 2008 to an estimated 0.088 in 2024. Therefore, F is currently well below FMSY, indicating the stock is harvested sustainably. During the early 2000s, spawning stock biomass (SSB) hovered just above Blim (17,273 tonnes). After 2006, SSB began rising, surpassing MSY Btrigger (21,782 tonnes) from 2010 to 2014, before falling close to Blim again in 2017. In recent years, SSB has gradually increased, exceeding MSY Btrigger again in 2021 and is now estimated at 30,364 tonnes in 2025. Given that the proxy for BMSY is 30,495 tonnes, the 2025 SSB falls just below this level, so we consider the stock fully fished.Despite fishing pressure remaining below FMSY since 2008, SSB declined from 2011 to 2017. This suggests that stock dynamics are not only influence by fishing activity but also by variability in recruitment. Across the time series, annual recruitment has become increasingly variable. The highest recorded recruitment was in 2018, at approximately 179 million individuals. This figure dropped significantly to approximately 31 million in 2021. That said, the 2025 estimate (~89.9 million) exceeds the average for the previous three years (2022-2024), which stood at ~61.6 million.For 2026, ICES advises that under the EU multiannual plan (MAP) for Western Waters and adjacent waters, total catches (commercial and recreational) should be between 6423 and 7618 tonnes. This is a 187-190% increase from the 2025 advice, reflecting an updated assessment of stock status following the benchmark. It is important to note that a portion of this stock is harvested in neighbouring ICES divisions, which should be incorporated into broader management to avoid exceeding advice.

There are management measures in place, which are partly effective in managing the stock.Sea bass in the Bay of Biscay (ICES divisions 8a, 8b) is managed under the European Union’s multiannual management plan (MAP) for Western Waters. Although this stock is not subject to EU Total Allowable Catches (TACs) and quotas, it has been governed by the MAP since 2019. The plan applies to demersal stocks, including sea bass, and sets out conditions for determining fishing opportunities based on stock status and the current FMSY for the stock. It aims to ensure that stocks, particularly sea bass, are fished sustainably, and that management decisions reflect the best available scientific advice. ICES considers the FMSY range used in the MAP to be precautionary for sea bass in this region. Recreational fishing exerts a significant pressure on the stock, and since 2019, these catches, and a 5% post-release mortality rate, have been accounted for in ICES catch advice. Recreational removals are estimates based on observed data in 2010 and 2022, with 2024 recreational activity (kept and dead releases) estimated to have accounted for 26.9% of total removals.As sea bass is a non-TAC species, there is concern about potential displacement of fishing effort from other species with limiting quotas. Management measures are in place to mitigate risk and maintain stocks. A Minimum Landing Size (MLS) of 40cm was introduced for commercial catches in 2020, while recreational catches have been subject to a 42cm MLS since 2013. However, these offer only partial protection, as approximately 50% of females reach maturity at 42.14cm. This means a significant proportion of fish may be removed before the chance of reproducing, which can impact the long-term stock stability.In 2024, the French fleet accounted for 98.7% of sea bass landings in the Bay of Biscay, with the remaining 1.3% landed by Spanish vessels. The discard rate for France has gradually decreased, from 8.80% in 2021 to 7.06% in 2023. While Spanish discards are likely to occur, they are not fully quantified.In France, the dominant fishing party, several national management measures are in place to support the stock. These include a quota system for commercial sea bass fishing licenses (implemented in 2012), a voluntary closed season from February to mid-March for longline and handline fisheries in Brittany, and a recreational daily bag limit of two fish in 2025. Additionally, in January 2024, a one-month fishing ban was introduced in part of the Bay of Biscay for certain vessels and gear types, aiming to reduce cetacean bycatch. Although not designed for sea bass, the ban overlaps with their spawning period and may offer indirect benefits by reducing fishing pressure during their reproductive window. The closure is set to reoccur in January/February of 2025 and 2026.Despite these management measures, there are some limitations relating to data for recreational fisheries. Continued monitoring and research are essential to improve data quality and ensue effective management of the sea bass stock in this region.The EU and UK both have fishery management measures, which can include catch limits, population targets, and gear restrictions. However, compliance in the EU and UK has been inconsistent, with ongoing challenges in implementing some regulations. The goal of reaching Maximum Sustainable Yield (MSY) by 2020 was missed, with less than half of UK TACs in 2024 following ICES advice. In 2024, the EU and UK reaffirmed their commitment to sustainable fisheries by aligning management with scientific advice to gradually approach MSY. However, no new target date has been set for achieving MSY across all fisheries. The Landing Obligation (LO), an EU law retained by the UK post-Brexit, requires all quota fish to be landed, even if unwanted (over-quota or below minimum size). It aims to encourage more selective fishing methods, reduce bycatch, and improve catch reporting. However, compliance is poor, and accurate discard levels are hard to quantify with current monitoring programmes. The UK is in the process of replacing the LO with country-specific Catching Policies. The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras is one of the most cost-effective tools for providing reliable fisheries data and aiding informed management decisions. Fully monitored fisheries enhance collaboration, data accuracy, stock recovery, and reduce impacts on marine wildlife and habitats. However, the full potential of REM may only be achieved when it tracks fishing location and documents catch and bycatch, particularly where vulnerable species and habitats are at risk. As of January 2024, the EU is introducing a Remote Electronic Monitoring (REM) mandate for EU vessels, including CCTV cameras on vessels 18m or more that pose a potential risk of non-compliance, within the next 4 years. Across the UK, different approaches to REM are being taken and legislation is expected to be in place across all 4 countries within the next few years.

Around a third of sea bass in areas 8a and b in the Bay of Biscay is caught using lines, which should have limited contact with the seabed. The gear can catch non-target species, with particularly high risk to seabirds and marine reptiles.In 2024, sea bass was primarily caught using lines (35%), nets (27%), and bottom trawling (16%). The French fleet dominated landings, accounting for 98.7% of total catch, with Spanish vessels contributing the remaining 1.3%. An estimated 864 tonnes were also removed through recreational fishing, making up 26.9% of total removals.Longlining involves setting hundreds of baited hooks along a main fishing line, and while this method can have generally low bycatch of non-target fish species, it poses notable risks to seabirds, marine reptiles, and deep-water species of sharks and rays. In 2023, longlines were responsible for an estimated 1890 bycaught Northern gannets and 18 Balearic shearwaters in the Bay of Biscay and Iberian Coast ecoregion. This coincides with ongoing population declines of these species, especially along the western Iberian and Portuguese coasts.The Agreement on the Conservation of Albatrosses and Petrels (ACAP) outlines best practice mitigation measures for seabird bycatch, including the use of weighted lines, bird-scaring devices, and night setting, ideally in combination. Alternatives such as hook-shielding or underwater bait-setting devices may also be effective. However, it is current unknown whether these methods are adopted in the sea bass longline fishery as there is limited monitoring.Marine reptiles are also at risk. In 2023, an estimated 166 loggerhead turtles were bycaught on longlines. This is largely attributed to the use of J-hooks, which cause problems when swallowed and are often fatal. Circle hooks have been shown to reduce turtle bycatch, but may increase shark catches. It is unclear whether circle hooks are currently used in the sea bass longline fishery as there is limited robust data and a lack of observer coverage.Sea bass is also part of a mixed fishery in the Bay of Biscay, where under current fishing patterns, it is not possible to meet all single stock catch advice. Pollack, primarily caught by nets (52%) and lines (39%), is currently the most limiting species. As such, the sea bass net fishery may amplify the exploitation risks for pollack in the region. While Blim for sea bass is projected to be achievable by 2026, Bpa is not, indicating continued sustainability concerns.Longlining is considered to have minimal physical impact on the seabed, especially when gear is properly anchored and does not drag. However, longlining requires large quantities of bait fish, which may put additional pressure on bait fish populations.To improve monitoring and reporting of fishing activity, The Marine Conservation Society would like to see remote electronic monitoring (REM) with cameras implemented, used and enforced.

ACAP (2024) ACAP Review of mitigation measures and Best Practice Advice for Reducing the Impact of Pelagic Longline Fisheries on Seabirds [2024]. In: ACAP - 14th Meeting of the Advisory Committee. Lima, Peru Available at: https://www.bmis-bycatch.org/references/b8w4f6bn [Accessed on 23.04.2025].Almeida, A., Alonso, H., Oliveira, N., Silva, E., and Andrade, J. 2023. Using a visual deterrent to reduce seabird interactions with gillnets. Biological Conservation, 285: 110236. https://doi.org/10.1016/j.biocon.2023.110236Bycatch Management Information System (2020). Purse seine. Available at https://www.bmis-bycatch.org/fishing-gear/purse-seine [Accessed 24.04.2025]Conseil d’État (2024) Protection of dolphins and porpoises: the Conseil d’État confirms the need for a fishing ban in the Bay of Biscay for four weeks in winter. Available at: https://www.conseil-etat.fr/en/news/protection-of-dolphins-and-porpoises-the-conseil-d-etat-confirms-the-need-for-a-fishing-ban-in-the-bay-of-biscay-for-four-weeks-in-winter [Accessed on 10.04.2025]Earth.org (2024) Why Did France Introduce a One-Month Ban on Commercial Fishing in the Bay of Biscay? Available at: https://earth.org/france-ban-on-commercial-fishing-bay-of-biscay/ [Accessed on 10.04.2025]Eigaard, O. R., Bastardie, F., Breen, M., Dinesen, G. E., Hintzen, N. T., Laffargue, P., Mortensen, L. O., Nielsen, J. R., Nilsson, H. C., O- Neill, F. G., Polet, H., Reid, D. G., Sala, A., Skold, M., Smith, C., Sorensen, T. K., Tully, O., Zengin, M. and Rijnsdorp, A. D., 2016. Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions. ICES Journal of Marine Science, 73:1, pp. i27- i43. https://doi.org/10.1093/icesjms/fsv099.European Commission, 2020. Nature and Fisheries: Commission urges FRANCE, SPAIN and SWEDEN to take action to reduce bycatch. Available at: https://ec.europa.eu/commission/presscorner/detail/en/inf_20_1212 [Accessed on 17.04.2025]Hiddink, J., Jennings, S., Sciberras, M., Szostek, C.L., Hughes, K.M., Ellis, N., Rijnsdorp, A.D., McConnaughey, R.A., Mazor, T., Hilborn, R., Collie, J.S., Pitcher, C.R., Amoroso, R.O., Parma, A.M., Suuronen, P. and Kaiser, M.J. 2017. Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance. PNAS. 114:31, pp. 8301-8306. https://doi.org/10.1073/pnas.1618858114.ICES. 2025. Seabass (Dicentrarchus labrax) in divisions 8.a-b (northern and central Bay of Biscay). In Report of the ICES Advisory Committee, 2025. ICES Advice 2025, bss.27.8ab. https://doi.org/10.17895/ices.advice.27202530 ICES. 2024. Bay of Biscay and the Iberian Coast ecoregion – Ecosystem overview. In Report of the ICES Advisory Committee, 2024. ICES Advice 2024, Section 6.1, https://doi.org/10.17895/ices.advice.27899889 [Accessed on 16.04.2025]ICES. 2024. Bay of Biscay mixed fisheries considerations. In Report of the ICES Advisory Committee, 2024. ICES Advice 2024. https://doi.org/10.17895/ices.advice.26763901 [Accessed on 17.04.2025]ICES. 2024. Bycatch of endangered, threatened and protected species of marine mammals, seabirds and marine turtles, and selected fish species of bycatch relevance. In Report of the ICES Advisory Committee, 2024. ICES Advice 2024, byc.eu. https://doi.org/10.17895/ices.advice.27999401 [Accessed on 17.04.2025]ICES. 2024. Sea bass (Dicentrarchus labrax) in divisions 8.a-b (northern and central Bay of Biscay). In Report of the ICES Advisory Committee, 2024. ICES Advice 2024, bss.27.8ab. https://doi.org/10.17895/ices.advice.25019186 [Accessed on 08.04.2025]ICES. 2024. Working Group for the Bay of Biscay and Iberian Waters Ecoregion (WGBIE). ICES Scientific Reports. 6:59. 762 pp. https://doi.org/10.17895/ices.pub.25908130 [Accessed on 08.04.2025]ICES. 2023. EU additional request on mitigation measures to reduce by-catches of common dolphin (Delphinus delphis) in the Bay of Biscay and Iberian Coast. In Report of the ICES Advisory Committee, 2023. ICES Advice 2023, sr.2023.01. https://doi.org/10.17895/ices.advice.21946634 [Accessed on 17.04.2025]ICES. 2023. Pollack (Pollachius pollachius) in Subarea 8 and Division 9.a (Bay of Biscay and Atlantic Iberian waters). In Report of the ICES Advisory Committee, 2023. ICES Advice 2023, pol.27.89a. https://doi.org/10.17895/ices.advice.21841014 [Accessed 23.04.2025]ICES. 2023. Workshop on mitigation measures to reduce bycatch of short-beaked common dolphins in the Bay of Biscay (WKEMBYC2). ICES Scientific Reports. 5:3. 96 pp. https://doi.org/10.17895/ices.pub.21940337 [Accessed on 22.04.2025]ICES. 2022. Bay of Biscay and the Iberian Coast ecoregion – Fisheries Overview. In Report of the ICES Advisory Committee, 2022. ICES Advice 2022, section 6.2. https://doi.org/10.17895/ices.advice.21641396 [Accessed 17.04.2025]ICES. 2020. Workshop on fisheries Emergency Measures to minimize BYCatch of short-beaked common dolphins in the Bay of Biscay and harbour porpoise in the Baltic Sea (WKEMBYC). ICES Scientific Reports. 2:43. 295 pp. https://doi.org/10.17895/ices.pub.7472 [Accessed on 16.04.2025]ICES (2018): Stock Annex: Sea bass (Dicentrarchus labrax) in division 8.a–b (northern and central Bay of Biscay). ICES Stock Annexes. Report. https://doi.org/10.17895/ices.pub.18623219.v1 [Accessed 09.04.2025]Kennelly, S. J. & Broadhurst, M. K., 2021. A review of bycatch reduction in demersal fish trawls. Rev Fish Biol Fisheries 31, 289–318. https://doi.org/10.1007/s11160-021-09644-0.Kynoch, R., Fryer, R. & Neat, F., 2015. A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries. ICES J Mar Sci,72(6):1861.Peltier, H., Authier, M., Deaville, R., Dabin, W., Jepson, P. D., van Canneyt, O., Daniel, P., and Ridoux, V., 2016. Small cetacean bycatch as estimated from stranding schemes: The common dolphin case in the northeast Atlantic. Environmental Science & Policy, 63 : 7–18. https://doi.org/10.1016/j.envsci.2016.05.004 Seafish, 2025. Fishing Gear Database: Pelagic trawl & Gill nets & Long line. Available at https://www.seafish.org/responsible-sourcing/fishing-gear-database/?t=docGear [Accessed on 22.04.2025]Silva, F., Ellis, J. & Catchpole, T., 2012. Species composition of skates (Rajidae) in commercial fisheries around the British Isles and their discarding patterns. J Fish Biol., 80:1678–1703Spitz, J., Chouvelon, T., Cardinaud, M., Kostecki, C., and Lorance, P. 2013. Prey preferences of adult sea bass Dicentrarchus labrax in the northeastern Atlantic: implications for bycatch of common dolphin Delphinus delphis – ICES Journal of Marine Science, 70: 452–461.van Denderen, P. Bolam, S., Hiddink, J.G., Jennings, S., Kenny, A., Rijnsdorp, A., and van Kooten, T., 2015. Similar effects of bottom trawling and natural disturbance on composition and function of benthic communities across habitats. Mar Ecol Prog Ser. 2015;541:31–43. https://doi.org/10.3354/meps11550.