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.

Some sea bass is caught using otter trawls, which causes seabed disturbance and has bycatch of ETP species, including marine mammals, sharks, and rays.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.Bycatch data in many EU fisheries remains limited due to generally low monitoring coverage. However, available evidence shows that demersal trawls, including otter trawls, are associated with bycatch of non-target fish species, marine mammals, sharks and rays, including endangered, threatened, and protected (ETP) species. In 2023, bottom otter trawls in the Bay of Biscay and Iberian Coast ecoregion were estimated to have caught 33 spiny butterfly rays – an endangered species on the IUCN Red List. Other elasmobranchs frequently caught include small-eyed rays, sandy rays, undulate rays, skates (Dipturus spp.), and Spurdog.Cetacean bycatch is another significant concern. In 2023, an estimated 312 short-beaked common dolphins were caught in otter trawls across the ecoregion. These bycatch levels are of significant ecological concern as populations now at unfavourable conservation status in the Bay of Biscay. Dolphin Deterrent Devices (DDDs) have shown strong potential for mitigating cetacean bycatch, with trials demonstrating up to a 95.6% reduction in common dolphin captures in bottom trawls.Otter trawls also have substantial physical impacts on the seabed due to the penetration and abrasion caused by gear contact. The impact of trawling on the seabed depends on the where trawling happens, and on what scale. Habitats naturally exposed to tidal and wave disturbances tend to be more resilient, whereas previously untrawled or sensitive areas are more vulnerable to new disturbance. Otter trawls are the most commonly used gear type in the region, with effort concentrated on the continental shelf of the Bay of Biscay. While trawling has occurred over only 22% of the region’s total area, this is largely due to depth constraints and underwater topography. In effect, the majority of areas accessible to trawling have already been fished.To improve monitoring and reporting of fishing activity, MCS would like to see remote electronic monitoring (REM) with cameras implemented, used and enforced.

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