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The ICES Workshop on ICES reference points (WKREF2) was tasked review the WKREF1 report and based on the outcome develop updated guidelines for the ICES reference points system and recommendations for ACOM consideration. The WKREF1 report has suggested 5 key recom- mendations to simplify and harmonise the ICES reference points framework representing a ma- jor change to the current guidelines. At WKREF2, we detailed discussions and four key concerns were raised about the proposed approach. The first related to the simplification of rules to define Blim. Around two thirds of category 1 stocks would end up as WKREF1 “Blim Type 2” where Blim would be set as a fraction of B0. The Allee effect or “depensation” maybe more important than previously thought and should be furthered explored for ICES stocks since it has important consequences for Blim. A number of challenges and issues around defining Blim using the current guidelines were documented. Some suggestions on improvement criteria were discussed including using classifiers to define spas- modic stocks and using change point algorithms to address non-stationary productivity regimes. However, further work is need to make these approaches operational and there was no consen- sus that the WKREF1 Blim types should replace the current guidelines. WKREF1 recommended that the FMSY proxy should be based on a biological proxies and should be less than the deterministic FMSY. It was pointed out that the stochastic FMSY estimated in EqSim for example, is lower than the deterministic FMSY and that the current guidelines ensure that the FMSY should not pose a more than 5% risk to Blim. A large amount of work described in WD 1 was carried out to develop an MSE framework to consistency and robustness test a candidate refer- ence point system for North East Atlantic stocks. However, WKREF2 recommended that further work needs to be carried out to condition and test the simulation framework before the conclu- sions could be adopted by ICES and incorporated into the guidelines. A number of considerations for defining MSY related reference points were discussed including using model validation and prediction skill to ensure that ICES provide robust and credible ad- vice. There is evidence that density dependence (DD) is important in the majority of ICES stocks (68% in recruitment and 54% in growth). The correct prediction of the shape and strength of density-dependence in productivity is key to predicting future stock development and providing the best possible long-term fisheries management advice. A suggested approach to use surplus production models (SPMs) to account for DD in FMSY was suggested and discussed but there was no consensus on whether that approach was appropriate. There was consensus that the FECO approach as a means of adapting target fishing mortality to medium-term changes in productiv- ity should be included in the guidelines subject to a benchmark and ACOM approval. While WKREF1 and 2 focused mainly on Category 1 stocks ToR c) called for a “simplified and harmonised set of guidelines for estimating MSY and precautionary reference points applicable in the advice framework across various ICES stock categories.” Ideally the ICES assessment cat- egories should provide equivalent risk across all stocks. This issue was discussed but no recom- mendations emerged. There was no consensus a revised reference point framework was proposed at WKREF2. How- ever, it was agreed that it should be presented here for further discussion at ACOM and other fora. The key feature of the suggested approach is that the stock status evaluation is treated in- dependent of the Advice Rule (AR). The main feature of the system is that the biomass trigger is not linked to a stock status evaluation, it is linked to the expected biomass when fishing at the target fishing mortality, in contrast to the current ICES approach. It also entailed that FMSY would also become an upper limit of fishing mortality and that the advised fishing mortality would be set at or lower than that level. WKREF2 did not discuss what to do in situations where SSB< Blim or alternative forms of HCR for the advice rule. Building community understanding and con- sensus around simplified and harmonised guidelines has yet to be achieved. A further workshop WKREF3 will be required to achieve that aim. The report includes 6 recommendations for ACOM consideration. ICES The main objective of the workshop was to review the recommendations of WKREF1 and con- sider how these might feed into a new reference points framework and guidelines for ICES. There were a number of presentations on the wider issues of best practice for reference points, the Allee effect, density dependence and the WKIRISH approach. The starting point was to try and develop a set of simplified and harmonised guidelines based on the WKREF1 report rather than evolving the current guidelines to include the WKREF1 conclusions. A key aspect of the meeting was to allow for discussions in order to build a shared understanding of the strengths and weakness of the current framework and of the new framework emerging from WKREF1. Published Non Refereed

– De visserijsector, wetenschap en maatschappelijke organisaties werken in onderzoeksprojecten samen aan duurzaam visserijbeheer,zoals innovaties om selectiever te vissen en verbetering van de bestandsschattingen. De projecten worden gefinancierd uit het Europees Fonds voorMaritieme Zaken en Visserij. Over de onderzoekssamenwerking publiceren de projectpartners in een eigen column in Visserijnieuws. Deze weekschrijven Martin Pastoors (Pelagic Freezer-trawler Association) en Niels Hintzen (Wageningen Marine Research) over onderzoek naar grote zilversmelt.

WKRPChange was tasked with examining how ICES handles the estimation of target and limit reference points in the face of changing environmental conditions. In particular, the meeting participants were asked to review the robustness of the current ICES procedures and to suggest specific improvements that could be made, especially relating to changes in stock productivity arising from environmental conditions, species interactions, and density-dependent effects. Part of the work involved reviewing the basis of the ICES reference points and contrasting the ICES procedures with those in the USA and Canada, and part on providing specific guidance for future reference point estimation within ICES. One common approach to changing environmental conditions is to truncate data series. WKRPChange agreed that this may be necessary in some cases, but several studies were presented showing that the estimation of reference points becomes unreliable (both noisy and potentially biased) as the time series is reduced, and therefore recommended that modelling the specific process involved is generally a better approach than truncation. The meeting noted several examples within the current ICES management system for which reference points are allowed to vary (e.g. F in the case of NEA cod, Blim in the case of Iberian Sardine) according the prevailing conditions. WKRPChange noted that this was only required if conditions were expected to change significantly over the lifespan of the reference points, and that where it was implemented the status determination (the “traffic lights”) should be made accordingly.The key recommendation of WKRPChange is consistent with the conclusions of WKGMSE2, namely that a scoping exercise should be undertaken for each stock to identify any key drivers. Where there is good evidence for ecosystem-driven changes in stock productivity that process should be accounted for in setting reference points. The meeting highlighted that reference points have a finite lifespan, generally related to the benchmark cycle, and the estimation of the reference point should predominantly take into account processes likely to be important over that lifespan. WKRChange noted that many ICES stocks are managed by Harvest Controls which are evaluated through a MSE process. In this case there is considerable scope for including such environmentally driven processes in the Operating Model. However, many stocks are managed through the standard ICES HCR with reference points derived through the EqSim program. There is therefore a specific recommendation that the possibility to include density-dependentgrowth be incorporated into EqSim, to allow more realism to be included in the estimation of reference points where the evidence indicates that this is important within the reference point life span. The meeting also highlighted the recent work at WKRISH 6, which gave scope to “fine tune” the Ftarget to account for small changes in environmental drivers without requiring full reestimation of the reference points.

The ICES herring assessment working group (HAWG) met on an interactive virtual platform for eight days in March 2020 to assess the state of five herring stocks and three sprat stocks. HAWG also provided advice for four sandeel stocks but reported on those prior to this meeting in February. The working group conducted update assessments for the five herring stocks. An analytical assessment was performed for the combined North Sea and Division 3.a sprat, and a data limited assessment (ICES category 3) was conducted for English Channel sprat (spr.27.7de). The North Sea autumn spawning herring (her.27.3a47d) SSB in 2019 was estimated at 1.7 mill tonnes while F2–6 in 2019 was estimated at 0.18, which is below FMSY. Recruitment in 2019 is comparable to the 2018 value and remains within the low recruitment regime observed since 2015. Year classes since 2002 are estimated to be consistently weak with year classes 2014 and 2016 some of the weakest on record. ICES considers that the stock is still in a low productivity phase.The Western Baltic spring-spawning herring (her.27.20-24) assessment was updated. The SSB and recruitment in 2019 are record low. SSB is estimated to be around 56 600 tonnes which is below both Bpa and Blim. Recruitment has been low since 2006 and it has been further deteriorating with time. Fishing mortality has decrease in 2019 to 0.382 but is still well above FMSY (0.31). The stock has decreased consistently during the second half of the 2000s and given the continued low recruitments the stock is not able to recover above Blim unless a drastic reduction in fishing effort is applied.The Celtic Sea autumn and winter spawning stock (her.27.irls) is estimated to be at a very low level. SSB is currently estimated to be at the lowest level in the time-series and has been below Blim (34 000 t) since 2016. Mean F(2–5 rings) was estimated at 0.49 in 2019, having decreased from the peak of 1.15 in 2017. Recruitment has been consistently below average from 2013-2018. Recruitment in 2019 is estimated to be above average. The assessment of the combined stocks of herring in 6.aN and 6.aS/7.b, c (her.27.6a7bc) went through an interbenchmark procedure in 2019 and the advice is based on trends from an analytical assessment. SSB and recruitment have been declining since around 2000 and are currently at the lowest level in the time-series. Fishing mortality has reduced since 2016 when catches have been limited to a scientific monitoring TAC but recovery of the stock is hampered by the very low recruitment.Irish Sea autumn spawning herring (her.27.nirs) assessment shows a stable SSB in 2019 compared to previous years at around 24 700 tonnes. The stock has experienced large incoming year classes in recent years. Fishing mortality (F4–6) is estimated at 0.18, one of the lowest in the timeseries and below FMSY (0.266). Catches have been relatively stable since the 1980s, and close to the TAC in recent years. North Sea and 3.a Sprat (spr.27.3a4) were combined into a single assessment unit during the 2018 benchmark. Perception of the status of the stock is dominated by the dynamics in Subarea 4 where most of the catches occur. Despite the fact that fishing mortality in the last years has fluctuated at high levels between 0.6–2.2, recruitments slightly but consistently above the average during recent years have contributed to an increase in SSB well above MSY Bescapement. The estimates for 2020 show an SSB of 266 000 t which is more than double of Bpa (125 000 t).Catch advice for sprat in the English Channel (7.d, e) (spr.27.7de) was based on criteria for an ICES category 3-based method. Data available are landings and a short time-series of acoustic biomass (2013–2019). The acoustic biomass has fluctuated over time and the 2019 biomass has increased from the 2018 estimate. The HAWG reviewed the assessments performed on four sandeel stocks and the related advice of these stocks. Section 9 of this report contains the assessments of sandeel in Division 3.a and Subarea 4. Standard issues such as the quality and availability of data, estimating the amounts of discarded fish, availability of data through industry surveys and scientific advances particularly with respect to stock discrimination relevant to small pelagic fish were discussed. All data and scripts used to perform the assessments and the forecast calculations are available at https://github.com/ICES-dk/wg_HAWG and accessible to anyone.

The Workshop on guidelines and methods for the evaluation of rebuilding plans (WKREBUILD) chaired by Vanessa Trijoulet (Denmark) and Martin Pastoors (Netherlands) met from 24 to 28 February 2020. The workshop attracted 27 participants from the US, Canada, Europe and FAO. When stocks are estimated to be below Blim1 and there is no perceived possibility of rebuilding above Blim within the time-frame of a short-term forecast, ICES has regularly recommended zero catch in combination with the development of a rebuilding plan. A review was carried out on the international experience on the development, evaluation and implementation of rebuilding plans for fisheries management in the Northeast Atlantic and in other fora around the world. In the Northeast Atlantic, rebuilding plans have been implemented in the past (e.g. the cod recovery plans of the early 2000s) but ICES has played a limited role in evaluating the performance of such recovery plans and does not have the tools or criteria to evaluate such plans. Recently, when a rebuilding plan for herring in 6.a 7.bc was submitted to ICES for evaluation, ICES refrained from providing such an evaluation. In the US and Canadian approaches, the legal framework determines the triggering and required elements of rebuilding plans. Such a legal imperative does not exist in the Northeast Atlantic. Nevertheless, the US and Canadian experiences provided useful elements that could be included in establishing ICES approach to rebuilding plans. Several case studies were presented on potential tools for the evaluation of rebuilding plans. Particular attention was given to evaluating options for harvest control rule options of such a plan. The tools focused mostly on short to medium term explorations of the probability of achieving a rebuilding of stocks. Because rebuilding plan evaluations need to be ready and available at short-notice when required, it was concluded that relatively standardized tools (i.e. packages or compiled code) to carry out such evaluations would be preferable over custommade evaluation tools. In addition, certain modelling considerations were highlighted as important such as realistic assumptions of productivity, uncertainty, bias in assessments and implementation error and the possibility of estimating the probability of achieving a rebuilding of stocks.Criteria for the acceptability of rebuilding plans will require an agreed Limit Reference Point (LRP) for initiating a rebuilding plan, definition of targets for fishing mortality or stock biomass, time-frames and the acceptable probabilities whether the rebuilding targets have been achieved. All of these should take into account realistic levels of uncertainty and being consistent with international best (scientific) practices. Although it was recognized that Blim would be the most likely candidate LRP triggering a rebuilding plan, the current approach in ICES for the determination of Blim was questioned during the workshop because it requires a more or less subjective classification of the stock-recruitment pairs into different types. In other regions, the LRP is often set as a certain proportion of the SSB at maximum sustainable yield (BMSY), e.g. 40% BMSY. If changes in productivity have been experienced in recent years at these are taken into account when estimating MSY reference points, the proportion of BMSY approach would likely lead to greater changes in the estimated value of LRP than the current ICES procedures used to estimate Blim, which rely on stock-recruitment pairs or definition of the lowest observed biomass (Bloss). This could have a large impact on the rebuilding target for stocks that experience changes in productivity regimes. Some concerns were raised regarding the often small distance between Blim and MSY Btrigger2 reference points for ICES stocks in comparison to the distance between trigger and limit in other jurisdictions. MSY Btrigger could therefore represent a late trigger to start decreasing fishing mortality when SSB is decreasing. The workshop recommended a future workshop on the revision of the procedure to estimate reference points within the ICES framework.An estimate of the minimum time (TMIN) by which rebuilding may be expected to be achieved, could be calculated by assuming zero catch and should be used as baseline for comparison with other rebuilding scenarios. The maximum time for rebuilding in the US and New Zealand is set to TMAX = 2 * TMIN or to TMIN plus one generation time1 (average length of time between when an individual is born and the birth of its offspring NRC (2014)). While the workshop did not arrive at an overall agreement on a default value for TMAX, it was suggested that TMAX = 2 * TMIN could be explored as a potential bounding on the rebuilding period, even though this should be subject to scientific analysis of potential effects on the stock in question. The workshop generated a guidance table summarizing the best practices for evaluation of rebuilding plans against the potential criteria of acceptability. The guidance table includes elements such as estimation of reference points, time-frames for rebuilding, rebuilding targets, handling uncertainties and bias, probability of achieving rebuilding targets and visualizing results. The workshop recommended that a follow-up workshop (WKREBUILD2) be organized for testing the guidelines with actual test cases, with the aim of defining more specific criteria and guidelines, i.e. learning by doing. Some of the elements that were discussed in the workshop but that have not (yet) entered the guidelines for evaluation of rebuilding plans are socio-economic trade-offs (e.g. between fast and slow rebuilding), mixed fisheries aspects (e.g. unavoidable bycatch due to mixed fisheries) and elements in rebuilding plans other than the HCR part (e.g. monitoring to improve the knowledge base). Most of the discussion at WKREBUILD was centred on stocks with analytical assessments (Category 1+2). Identifying when a data limited stock is in need of rebuilding (or has rebuilt) and how to evaluate rebuilding plan options for such stocks would likely require a separate process.

The Working Group on Widely Distributed Stocks (WGWIDE) reports on the status and considerations for management of Northeast-Atlantic mackerel, blue whiting, Western and North Sea horse mackerel, Northeast-Atlantic boarfish, Norwegian spring-spawning herring, striped red mullet (Subareas 6, 8 and Divisions 7.a-c, e-k and 9.a), and red gurnard (Subareas 3, 4, 5, 6, 7, and 8) stocks. Northeast-Atlantic (NEA) Mackerel. This species is widely distributed throughout the ICES area and currently supports one of the most valuable European fisheries. Mackerel is fished by a variety of fleets from many countries (ranging from open boats using handlines on the Iberian coasts to large freezer trawlers and Refrigerated Sea Water (RSW) vessels in the Northern Area). The assessment methodology was modified during the 2019 inter-benchmark process. The 2019 WGWIDE assessment was an update of the benchmarked assessment incorporating a new year for the catch information, for all surveys (egg survey, IESSNS survey and recruitment index) and for the RFID tagging recapture. After a strong increase from the late 2000s to 2014, the SSB has been declining since 2015, but remains at high levels (well above MSY Btrigger), The estimated fishing mortality has been steadily declining since the mid-2000s, and is now estimated to be close to FMSY. This decrease of the fishing mortality, while the stock has been sustaining high catches (consistently in excess to ICES advice) is explained by a succession of good recruitments, indicating a current high productivity for this stock. Blue Whiting. This pelagic gadoid is widely distributed in the eastern part of the North Atlantic. The assessment this year followed the Stock Annex based the conclusions from the Inter-Benchmark Protocol of Blue Whiting (IBPBLW 2016). The method for calculating mean weight at age for the preliminary (2019) was however changed, such that the observed values were used. Previously, a three year average was used. Most of the annual catches are taken in the first halfyear, which makes it possible to use preliminary catches for 2019 in the assessment. This is done to reduce the effect of potential biases from the single survey used for this assessment. The SSB of the stock is large but declining since 2018. F has been reduced in recent years, but is still above FMSY. Recruitments in 2017–2019 are estimated to be low, following a period of high recruitments. Western Horse Mackerel. This species is widely distributed throughout the Northeast Atlantic: it spawns in the Bay of Biscay, and in UK and Irish waters; after spawning, parts of the stock migrate northwards into the Norwegian Sea and the North Sea. The stock is assessed using the Stock Synthesis integrated assessment model. The 2019 assessment is an update of the benchmark assessment with the inclusion of the 2018 data. According to the assessment results, the 20154-2018 recruitment estimates are the highest observed since 2008 (and higher than the geometric mean estimated over the years 1983–2018). Fishing mortality since 2012 has been decreasing overall, dropping to low values in 2015–2018 due to lower catches and a reduced proportion of fraction of the adult population in the exploited stock; it is however currently above FMSY. SSB in 2017 was estimated as the lowest in the time-series, below the limit reference point and is just above in 2018. The updated assessment shows the same trend as the previous ones, but rescales the absolute level of SSB and F over the most recent decade and, although this years’ revision is smaller, this indicates that there is still considerable uncertainty associated with it. An interbenchmark workshop occurred prior to the 2019 assessment working group: the workshop revised the biomass reference points from 911587t to 1168272t for MSYBtrigger and 0.108 to 0.074 for FMSY, hence the significant drop in adviceNorth Sea Horse Mackerel. After being benchmarked in January 2017, the CGFS and NS-IBTS survey indices were modelled with a zero-inflated model to produce a combined index. The observed trend in the last decade suggests that the stock is still at a low level in comparison with values earlier in the time-series. In 2017, the survey index showed a declining trend, and the stock remained at a low level in 2018. The result of the Length-Based Methods to estimate proxy MSY reference points for North Sea Horse Mackerel indicated that in 2018 fishing mortality was slightly above FMSY. Northeast Atlantic Boarfish. This is a small, pelagic, planktivorous, shoaling species, found at depths of 0 to 600 m. The species is widely distributed from Norway to Senegal. The directed fishery for boarfish in the NEA is a relatively new one with large catches during the early 2000s when the fishery was unregulated. Catches have reduced significantly since 2012 to the current level. Annual catch advice is provided using the data limited category 3 approach based on output from an exploratory Bayesian surplus production assessment model. The assessment model utilises catch data, an acoustic survey estimate of stock size and indices from a number of bottom-trawl surveys. The current assessment indicates that biomass peaked in 2012 at twice the historic mean before a rapid decline until 2014. Since this time the biomass level has been relatively stable. Norwegian Spring Spawning Herring. This is one of the largest herring stocks in the world. It is highly migratory and distributed throughout large parts of the NE Atlantic. This stock was benchmarked in 2016 (WKPELA). The assessment model introduced in the benchmark (XSAM), incorporates uncertainty in the input data, and has been used to provide advice after the benchmark. The SSB on 1 January 2019 is estimated by XSAM to be above Bpa (3.184 million t). The stock is declining and there is an upward revision of SSB for later years in this year’s assessment. The revision is, however, within the confidence limits of the model. Fishing mortality in 2018 is estimated to be below the management plan F that was used to give advice for 2018. A new management plan was implemented for the 2019 advisory year. Striped Red Mullet in North Sea, Bay of Biscay, Southern Celtic Seas, Atlantic Iberian Waters. This stock has been considered by WGWIDE since 2016. It is a category 5 stock without information on abundance or exploitation in relation to proxy reference points and indicators, and the evaluation is based on commercial landings. A time series of biological sampling of catches is being developed, and it may be possible to produce an analytical assessment in the near future, The advice for this stock, following the ICES precautionary approach, was given in 2017 for 2018, 2019 and 2020. Northeast-Atlantic Red Gurnard. This stock was first considered by WGWIDE in 2016, and this represents the second time the group has advised upon it. This is a category 6 stock, with large uncertainties in landings data due to poor resolution at the species level. Landings have fluctuated without trend since 2006, and discards remain significant –over 90% of catch in some cases. There remains no indication of where fishing mortality is relative to proxies and no stock indicators, and the evaluation is based on commercial landings, given the caveat that they will be incomplete. Advice for this stock is provided on the basis of the ICES precautionary approach for 2020 and 2021.

The purpose of the meeting was to bring up to date the methodologies and technical specifications that should be incorporated in Management Strategy Evaluation (MSE) work in ICES. The workshop was tasked with reviewing recent methodological and practical MSE work conducted in ICES and around the world, as well as the guidelines provided by the 2013 ICES Workshop on Guidelines for Management Strategy Evaluations (WKGMSE). The Terms of Reference indicated that the revision should include all aspects involved in MSE, while paying specific attention to several issues that had been identified through ICES practice. The Terms of Reference also requested WKGMSE 2 to consider how best to disseminate the guidelines to experts within the ICES community and the need for training courses. The workshop addressed all its Terms of Reference. The main results of the workshop are the revised MSE guidelines, as well as recommendations in relation to the ICES criterion for defining a management strategy as precautionary and in relation to the evaluation and advice on rebuilding strategies.

WKNSMSE (Workshop on North Sea stocks Management Strategy Evaluation) took place over two physical meetings (19-21 November 2018 and 26-28 February 2019, but at ICES HQ, Copenhagen) and several WebEx meetings, was chaired by José De Oliveira (UK) and included 30 participants from Denmark, Germany, Netherlands, Norway, Sweden, UK and the European Commission, and two reviewers from South African and New Zealand. The purpose of this work was to evaluate long-term management strategies for jointly-managed stocks in the North Sea (cod, haddock, whiting, saithe and autumn-spawning herring) between the European Union and Norway, following a request from EU-Norway. The first physical meeting provided an ICES interpretation of the EU-Norway request, agreed the specifications of the MSE, decided on the tools and approaches to use, and developed a work plan, while the second meeting (and subsequent follow-up WebEx meetings) discussed results, developed conclusions, ensured the minimum requirements for conducting MSEs (developed by WKGMSE2) were met, and finalised the report. ICES were tasked to find “optimal” combinations of harvest control rule parameters (Ftarget and Btrigger) for management strategies with or without stability mechanisms (TAC constraints and banking and borrowing scenarios). “Optimal” combinations were defined as those combinations of Ftarget and Btrigger that simultaneously maximised long-term yield while being precautionary (long-term risk3≤5%). The request also asked for sensitivity tests once the management strategies were “optimised”. The approach adopted for all stocks was to include the assessment and forecast in a full-feedback MSE simulation, and to condition the baseline operating model on the benchmarked ICES assessment. The one exception was haddock, where it was not possible to include TSA in the full-feedback simulation because it was too slow to converge and requires manual intervention; SAM was used instead as a reasonable approximation. The approach also considered alternative operating models to capture a broader range of uncertainties. Full-feedback simulations were computationally challenging and required the use of parallelisation and high-performance computing; it also meant that the time-frame for the work was extremely tight, and in some cases, analyses were restricted. Nonetheless, the work was completed for all stocks, and “optimal” combinations for most management strategies were found. There were some notable issues that arose through this suite of MSEs, including that some management strategies that were precautionary in the long-term could have unsavoury and avoidable features in the short term (depending on the management strategy), and that reference points estimated by EqSim were, in many cases, no longer found to be precautionary in the MSE.

About this document Deliverable: D5.16 Case Study Nr.4 Report on Marine Fisheries Climate Services Workshop Work package in charge: WP5 Developing and Valuing Climate Services Actual delivery date for this deliverable: Project‐month 12 Dissemination level: The general public (PU) Lead authors Technical University of Denmark (DTU‐Aqua): Mark R. Payne Pelagic Freezer Trawler Association (PFA): Martin Pastoors Other contributing author Danish Pelagic Producers’ Organisation (DPPO): Claus Sparrevohn Reviewer Danish Meteorological Institute (DMI): Chiara Bearzotti

The ICES herring assessment working group (HAWG) met for seven days in March 2018 to assess the state of five herring stocks and four sprat stocks. HAWG also provided advice for seven sandeel stocks but reported on those prior to this meeting. The working group conducted update assessments for five of the herring stocks. An analytical assessment was performed for North Sea sprat, and data limited assessments (ICES category 3 and 5) were conducted for English Channel sprat and Division 3.a sprat. The assessment of sprat in the Celtic Sea (spr.27.67a–cf–k) was not updated this year.The North Sea autumn spawning herring (her.27.3a47d) SSB in 2017 was estimated at 1.9 mill tonnes while F2–6 in 2017 was estimated at 0.21, which is below the management plan target F2–6 and below FMSY. Fishing mortality on juveniles, mean F0–1 is 0.032, below the agreed ceiling. Recruitment in 2017 is estimated to be very low. The estimate of 0-wr fish in 2017 (2016 year class) is estimated to be at approximately 18 billion, which is very low even compared to other recent low recruitments. Year classes since 2002 are estimated to be consistently weak with year classes 2015 to 2017 some of the weakest on record. ICES considers that the stock is still in a low productivity phase.The Western Baltic spring spawning herring (her.27.20-24) assessment was updated. The SSB in 2017 was relatively stable compared to recent years and is estimated to be around 104 000 tonnes. Fishing mortality has been estimated at 0.33 which is is above the estimate of FMSY (0.31). Recruitment has been low since 2006 and 2017 is the lowest observed in the time-series. Under a historical perspective the estimate of SSB of 104 170 tonnes in 2017 is considered low, below both Bpa and Blim, The stock has decreased consistently during the second half of the 2000s and given the continued low recruitments the stock seems not to be able to recover to these higher biomass levels.The Celtic Sea autumn and winter spawning stock (her.27.irls) is estimated to be at a low level, declining from a recent high biomass that peaked in 2011. SSB is currently estimated at 36 000 tonnes in 2017, coming down from 136 000 tonnes in 2011. Mean F(2–5 rings) was estimated at 0.4 in 2017, having increased from 0.06 in 2009. Recruitment has been good in recent years with several strong cohorts (2004, 2008, 2009, 2010 and 2013) entering the fishery but has come down substantially in the most recent years with the poorest year class in 2015.The 2017 SSB estimate of 6.a/7.b, c herring (Her.27.6a7bc) the combined stock of 6.aN and 6.aS/7.b, c was 113 000 tonnes, well below Bpa. Continued low recruitment has caused a decline of the stock which is expected to continue in the near future although fishing mortality is low at 0.05–0.1 in recent years.Irish Sea autumn spawning herring (her.27.nirs) assessment shows a stable SSB in 2017 compared to previous years at around 27 000 tonnes. The stock has experienced large incoming year classes in most recent years. Fishing mortality is estimated at the lowest level in the time series at 0.15, below FMSY. Catches have been relatively stable since the 1980s, and close to TAC levels in recent years.North Sea sprat (spr.27.4) is an ICES category 1 stock with a fully accepted analytical assessment. The stock is estimated to be at the highest level since the 1970s in 2018, driven by relatively high recruitment in 2017. The stock appears to be well above Bpa (142 000 tonnes) in 2018 at 408 808 tonnes. Fishing mortality in the last years has fluctuated between 0.4–2.3. A recent management strategy evaluation (WKMSYREF2) suggested that the Bescapement management strategy is not precautionary.Sprat in Division 3.a (spr.27.3a) was benchmarked in 2013 (WKSPRAT), however, it is an ICES category 3 stock that uses three survey series, from which an abundance index is derived, and landings data. ). The surveys show variability over time without a clear trend. The most recent annual change is positive compared to the 4 years before.Catch advice for sprat in the English Channel (7.d, e) (spr.27.7de) was based on criteria for an ICES category 3-based method. Data available are landings and a short time series of acoustic biomass (2013–2017). The acoustic biomass indicates an overall decline in the stock size. Quantitative advice was provided for Sprat in the Celtic Sea (spr.27.67a–cf–k) in 2017 using an ICES category 5-based method where only data on landings are available; this assessment was not updated this year as the advice is still valid and the perception of the stock has not changed. A sprat benchmark is taking place in the summer/autumn of 2018.The HAWG reviewed the assessments performed on seven sandeel stocks and the related advice of these stocks. Section 11 of this report contains the assessments of sandeel in Division 3.a and Subarea 4. Standard issues such as the quality and availability of data, estimating the amounts of discarded fish, availability of data through industry surveys and scientific advances relevant for small pelagic fish were discussed. All data and scripts used to perform the assessment and perform the forecast calculations are available on GitHub and accessible to anyone.

The ICES herring assessment working group (HAWG) met for seven days in March 2017 to assess the state of five herring stocks and four sprat stocks. HAWG also provided advice for seven sandeel stocks but reported on those prior to this meeting. The working group conducted update assessments for five of the herring stocks. An analytical assessment was performed for North Sea sprat and data limited assessments were conducted for English Channel sprat, Celtic Sea sprat and 3.a sprat.The North Sea autumn spawning herring SSB in 2016 was estimated at 2.20 m tonnes while F2–6 in 2016 was estimated at 0.26, at the management plan target F2-6 and below Fmsy. Fishing mortality on juveniles, mean F0-1 is 0.05, just below the agreed ceiling. Recruitment in 2017 is estimated to be very low. The estimate of 0-wr fish in 2016 (2015 year class) is estimated to be at approximately 29 billion, being low but in line with recent recruitment. Year classes since 2002 are estimated to be consistently week with year classes 2002 to 2007 to be among the weakest. ICES considers that the stock is still in a low productivity phase. The Western Baltic spring spawning herring assessment was updated. The SSB in 2016 was relatively stable compared to recent years and is estimated to be around 97 000 tonnes. Fishing mortality has been estimated at 0.41 and seems to have increased again after a period of reductions. It is above the estimate of Fmsy (0.32). Recruitment in 2016 is very low and potentially the lowest in the time-series. Under an historical perspective the estimates of SSB are considered still low, and the stock seems not to be able to recover to these higher biomass levels. The Celtic Sea autumn and winter spawning stock is estimated to be at a low level, declining from a recent high biomass that peaked in 2011. SSB is currently estimated at 46 000 tonnes in 2016, coming down from 140 000 tonnes in 2011. Mean F (2–5 rings) was estimated at 0.4 in 2016, having increased from 0.07 in 2009. Recruitment has been good in recent years with several strong cohorts (2003, 2005, 2007, 2011, 2012) entering the fishery but has come down substantially in the most recent years with the poorest year class in 2015. The 2016 SSB estimate of 6.a/7.b, c herring (the combined stock of 6.aN and 6.aS/7.b, c) was 151 000 tonnes, well below Bpa. Low recruitment has caused a decline of the stock while fishing mortality is low at 0.05-0.1 in recent years. Advice has been drafted to setup a monitoring fishery to ensure data relevant for the assessment and genetic studies are secured. Irish Sea autumn spawning herring was benchmarked in 2017 and the assessment shows a stable SSB in 2016 compared to previous years at around 26 000 tonnes, estimated substantially higher than pre-benchmark. The stock increased owing to large incoming year classes in most recent years. Fishing mortality is estimated at the lowest level in the time series at 0.17, below Fmsy. Catches have been relatively stable since the 1980s, and close to TAC levels in recent years. North Sea sprat came down from a time-series high since the early ’80, driven by high recruitment in 2014 and shows another increase owing to the 2016 year class. The stock appears to be well above Bpa (142 000 t) in 2016 at 246 170t. Fishing mortality in the last years has fluctuated between 0.4–1.6. Expected recruitment for 2017 is estimated to be in line with long-term recruitment. Sprat in Division 3.a was benchmarked in 2013 (WKSPRAT) but an analytical assessment is not presented. Short term projections are to be based on a combination of indices providing in year advice for 3.a based on the ICES approach for data limited stocks (Category 3 / 4). (Category 3/4). The surveys show variability over time without a clear trend. The most recent change is negative compared to the 4 years before. Catch advice for sprat in the English Channel (7.d, e) was based on criteria for data limited stocks. Data available are landings and a short time series of acoustic biomass (2013–2016). The acoustic biomass indicates a decline in the stock. Quantitative advice was provided for Sprat in the Celtic Sea (spr-irls) based on criteria for data limited stocks where only data on landings are available. The HAWG reviewed the assessments performed on seven sandeel stocks and the related advice of these stocks. Section 11 of this report contains the assessment of sandeel in Division 3.a and Subarea 4.Standard issues such as the quality and availability of data, estimating the amounts of discarded fish, availability of data through industry surveys and scientific advances relevant for small pelagic fish were discussed.All data and scripts used to perform the assessment and perform the forecast calculations are available on GitHub and accessible to anyone.

Stakeholder involvement is perceived as an important development in the European Common Fisheries Policy. But how can uncertain fisheries science be linked with good governance processes, thereby increasing fisheries management legitimacy and effectiveness? Reducing the uncertainties around scientific models has long been perceived as the cure of the fisheries management problem. There is however increasing recognition that uncertainty in the numbers will remain. A lack of transparency with respect to these uncertainties can damage the credibility of science. The project Judgement and Knowledge in Fisheries Involving Stakeholders (JAKFISH) was a 3 year project with 10 partners from the EU and Norway. It provided an integrated approach to stakeholder involvement into fisheries management and examined the institutions, practices and tools that allow complexity, uncertainty and ambiguity to be dealt with. The JAKFISH project reviewed the general literature on participatory modelling in natural resource management and derived a number of key recommendations from that review. The project also developed a fisheries management simulation game that was successfully applied in a number of occasions. In four different case studies, the JAKFISH project invited fisheries stakeholders to participate in the process of framing the management problem, and to give input and evaluate the scientific models that are used to provide fisheries management advice. JAKFISH investigated various tools to assess and communicate uncertainty around fish stock assessments and fisheries management. We conclude that participatory modelling has the potential to facilitate and structure discussions between scientists and stakeholders about uncertainties and the quality of the knowledge base. It can also contribute to collective learning, increase legitimacy, and advance scientific understanding. Modelling should not be seen as the priority objective. The crucial step in a science-stakeholder collaboration is the joint problem framing. The JAKFISH project also carried out social network analyses of the institutions and networks involved in six fisheries management systems (four in Europe, one in Australia and one in the USA). The results suggest that management systems with high participation in decision-making tended to have more disagreement about facts and values. When experts discuss matters more with colleagues from other stakeholder groups, their values, interests, opinions, and knowledge tend to differ. Consensus within a stakeholder group seems to be higher if the most important discussion partners are selected within the group. The discussion about the role of uncertainty in natural resource management and decision-making often assumes that it is the scientists that help other stakeholder better understand uncertainties and that this happens after the uncertainties have been identified. Our research refuted both assumption. Communication about uncertainty is clearly a two-way process and it already is happening during the problem framing and research process. An important difference has been identified between scientific proof-making and scientific justification. Scientific proof-making is evaluated against set of internal scientific criteria. Scientific justification is evaluated by a broader community consisting of scientific peers, government officials, industry stakeholders and environmental NGOs. Whether scientific uncertainty becomes an issue in a policy making context, not only depends on the amount of uncertainty, but also on the stakes involved and the burden of proof placed on the science. The claim in the EU Habitats Directive that site designation is an exclusively scientific exercise places all the burden of proof on the science which then triggers disproportionate attention to scientific complexity and uncertainty, particularly where stakes are high. The JAKFISH project has shown that participatory modelling requires an effective facilitation strategy where scientists, stakeholders and policy-makers actively connect and discuss. There is a need to train the participants in these process. It needs the realization that participatory modelling both builds trust and is built on trust, that it takes time and effort and that the outcome is more than the individual parts.

How can uncertain fisheries science be linked with good governance processes, thereby increasing fisheries management legitimacy and effectiveness? Reducing the uncertainties around scientific models has long been perceived as the cure of the fisheries management problem. There is however increasing recognition that uncertainty in the numbers will remain. A lack of transparency with respect to these uncertainties can damage the credibility of science. The EU Commission’s proposal for a reformed Common Fisheries Policy calls for more self-management for the fishing industry by increasing fishers’ involvement in the planning and execution of policies and boosting the role of fishers’ organisations. One way of higher transparency and improved participation is to include stakeholders in the modelling process itself. The JAKFISH project (Judgment And Knowledge in Fisheries Involving StakeHolders) invited fisheries stakeholders to participate in the process of framing the management problem, and to give input and evaluate the scientific models that are used to provide fisheries management advice. JAKFISH investigated various tools to assess and communicate uncertainty around fish stock assessments and fisheries management. Here, a synthesis is presented of the participatory work carried out in four European fishery case studies (Western Baltic herring, North Sea Nephrops, Central Baltic Herring and Mediterranean swordfish), focussing on the uncertainty tools used, the stakeholders’ responses to these, and the lessons learnt. We conclude that participatory modelling has the potential to facilitate and structure discussions between scientists and stakeholders about uncertainties and the quality of the knowledge base. It can also contribute to collective learning, increase legitimacy, and advance scientific understanding. However, when approaching real-life situations, modelling should not be seen as the priority objective. Rather, the crucial step in a sciencestakeholder collaboration is the joint problem framing in an open, transparent way.