Essential coastal habitats for fish in the Baltic Sea

Many coastal and offshore fish species are highly dependent on specific habitat types for population maintenance. In the Baltic Sea, shallow productive habitats in the coastal zone such as wetlands, vegetated flads/lagoons and sheltered bays as well as more exposed rocky and sandy areas are utilized by fish across many life history stages including spawning, juvenile development, feeding and migration. Although there is general consensus about the critical importance of these essential fish habitats (EFH) for fish production along the coast, direct quantitative evidence for their specific roles in population growth and maintenance is still scarce. Nevertheless, for some coastal species, indirect evidence exists, and in many cases, sufficient data are also available to carry out further quantitative analyses. As coastal EFH in the Baltic Sea are often found in areas that are highly utilized and valued by humans, they are subjected to many different pressures. While cumulative pressures, such as eutrophication, coastal construction and development, climate change, invasive species and fisheries, impact fish in coastal areas, the conservation coverage for EFH in these areas remains poor. This is mainly due to the fact that historically, fisheries management and nature conservation are not integrated neither in research nor in management in Baltic Sea countries. Setting joint objectives for fisheries management and nature conservation would hence be pivotal for improved protection of EFH in the Baltic Sea. To properly inform management, improvements in the development of monitoring strategies and mapping methodology for EFH are also needed. Stronger international cooperation between Baltic Sea states will facilitate improved management outcomes across ecologically arbitrary boundaries. This is especially important for successful implementation of international agreements and legislative directives such as the Baltic Sea Action Plan, the Marine Strategy Framework Directive, the Habitats Directive, and the Maritime Spatial Planning Directive, but also for improving the communication of information related to coastal EFH among researchers, stakeholders, managers and decision makers. In this paper, efforts are made to characterize coastal EFH in the Baltic Sea, their importance and the threats/pressures they face, as well as their current conservation status, while highlighting knowledge gaps and outlining perspectives for future work in an ecosystem-based management framework. (C) 2018 Elsevier Ltd. All rights reserved.Peer reviewe

A pan-Baltic assessment of temporal trends in coastal pike populations

The northern pike (Esox lucius) is an iconic predatory fish species of significant recreational value and ecological role in the Baltic Sea. Some earlier studies indicate local declines of pike in the region, but a thorough spatial evaluation of regional population trends of pike in the Baltic Sea is lacking. In this study, we collate data from 59 unique time-series from fisheries landings and fishery-independent monitoring programs to address temporal trends in pike populations since the mid-2000 ' s in eight countries surrounding the Baltic Sea. In a common analysis considering all time-series in concert, we found indications of an overall regional temporal decline of pike in the Baltic Sea, but trends differed among countries. Individual negative trends in time-series were moreover found in several regions of the Baltic Sea, but predominantly so in the central and southern parts, while positive trends were only found in Estonia and northern Finland. The mix of data used in this study is inherently noisy and to some extent of uncertain quality, but as a result of the overall negative trends, together with the socioeconomic and ecological importance of pike in coastal areas of the Baltic Sea, we suggest that actions should be taken to protect and restore pike populations. Management measures should be performed in combination with improved fishery-independent monitoring programs to provide data of better quality and development of citizen-science approaches as a data source for population estimates. Possible measures that could strengthen pike populations include harvest regulations (including size limits, no-take areas and spawning closures), habitat protection and restoration, and an ecosystem-based approach to management considering also the impact of natural predators

A pan-Baltic assessment of temporal trends in coastal pike populations

The northern pike (Esox lucius) is an iconic predatory fish species of significant recreational value and ecological role in the Baltic Sea. Some earlier studies indicate local declines of pike in the region, but a thorough spatial evaluation of regional population trends of pike in the Baltic Sea is lacking. In this study, we collate data from 59 unique time-series from fisheries landings and fishery-independent monitoring programs to address temporal trends in pike populations since the mid-2000′s in eight countries surrounding the Baltic Sea. In a common analysis considering all time-series in concert, we found indications of an overall regional temporal decline of pike in the Baltic Sea, but trends differed among countries. Individual negative trends in time-series were moreover found in several regions of the Baltic Sea, but predominantly so in the central and southern parts, while positive trends were only found in Estonia and northern Finland. The mix of data used in this study is inherently noisy and to some extent of uncertain quality, but as a result of the overall negative trends, together with the socioeconomic and ecological importance of pike in coastal areas of the Baltic Sea, we suggest that actions should be taken to protect and restore pike populations. Management measures should be performed in combination with improved fishery-independent monitoring programs to provide data of better quality and development of citizen-science approaches as a data source for population estimates. Possible measures that could strengthen pike populations include harvest regulations (including size limits, no-take areas and spawning closures), habitat protection and restoration, and an ecosystem-based approach to management considering also the impact of natural predators

A pan-Baltic assessment of temporal trends in coastal pike populations

The northern pike (Esox lucius) is an iconic predatory fish species of significant recreational value and ecological role in the Baltic Sea. Some earlier studies indicate local declines of pike in the region, but a thorough spatial evaluation of regional population trends of pike in the Baltic Sea is lacking. In this study, we collate data from 59 unique time-series from fisheries landings and fishery-independent monitoring programs to address temporal trends in pike populations since the mid-2000′s in eight countries surrounding the Baltic Sea. In a common analysis considering all time-series in concert, we found indications of an overall regional temporal decline of pike in the Baltic Sea, but trends differed among countries. Individual negative trends in time-series were moreover found in several regions of the Baltic Sea, but predominantly so in the central and southern parts, while positive trends were only found in Estonia and northern Finland. The mix of data used in this study is inherently noisy and to some extent of uncertain quality, but as a result of the overall negative trends, together with the socioeconomic and ecological importance of pike in coastal areas of the Baltic Sea, we suggest that actions should be taken to protect and restore pike populations. Management measures should be performed in combination with improved fishery-independent monitoring programs to provide data of better quality and development of citizen-science approaches as a data source for population estimates. Possible measures that could strengthen pike populations include harvest regulations (including size limits, no-take areas and spawning closures), habitat protection and restoration, and an ecosystem-based approach to management considering also the impact of natural predators

Report of the Joint EIFAAC/ICES/GFCM Working Group on Eels (WGEEL)

The Joint EIFAAC/ICES/GFCM Working group on eels (WGEEL) met in a split meeting from 4–8 September (online) and 25 September–02 October 2023 (hybrid meeting) in Helsinki, Finland, to provide the scientific basis for the ICES advice on fishing opportunities and conservation aspects for the European eel and address requests from EIFAAC and GFCM.WGEEL assessed the state of the European eel and its fisheries, collated and analysed biometric data, reviewed the implementation of the WKFEA (Workshop on the future of eel advice) roadmap, examined available recruitment data from coastal and marine habitats, reported on any updates to the scientific basis of the advice, new and emerging threats or opportunities, including developments in the Mediterranean region.After high levels in the late 1970s, the recruitment declined dramatically in the 1980s and remains low. Compared to 1960–1979, the recruitment in the “North Sea” was 0.4% in 2023 (provisional) and 0.7 % in 2022 (final). In the “Elsewhere Europe” index series was 8.8 % in 2023 (provisional) and 11.3% in 2022 (final). For the yellow eel data series, recruitment for 2022 was 9% (final). Time-series from 1980 to 2023 show that glass eel recruitment remains at a very low level, with an historical minimum value in the North Sea.Silver eel time series have been analysed to identify patterns in abundance trends. These analyses are exploratory and have enabled us to test certain statistical methods and their limitations for analysing temporal series on silver eels. Although they give us an initial idea of trends in silver eel abundance, their results should be treated with caution. In fact, several problems have been identified and these points need to be improved in order to be able to interpret the results. The trend of reported commercial landings shows a long-term continuing decline, from a level of around 10,000 t in the 1960s, reported commercial landings have now dropped to 2028 (glass eel + yellow eel + silver eel) in 2022. The commercial glass eel fishery in 2022 was 60.1 t and 53.6 t in 2023. Reported landings from yellow and silver eel commercial fisheries (Y, S, YS) add up to 2914 t in 2021 and 2437 t in 2022. Spain was the only country allowing a recreational catch of glass eel, with landings estimated at 0.72 t in 2022 and 1.32 t in 2023. Reported recreational landings for yellow and silver eel combined were 240 t for 2021 (11 countries reporting) and 249 t for 2022.Progress with regards to the ‘road map’ developed within WKFEA was evaluated. The returns from the three questionnaires distributed by WKSMEEL to WGEEL members were summarised. In relation to the progress of the WKFEA roadmap, item 1; the inclusion of biological data is advanced with biometry data included in the annual data call. Item 2 relates to the reconstruction of the landings data and a workshop will take place in December 2023. Items 3 and 4 are also in progress, the Spatial database and Model for Eel (WKSMEEL) workshop was held in June 2023 with a follow up workshop planned for October 2023. A questionnaire for 3 topics (electrofishing, hydrographic network, and river obstructions & hydropower) was circulated to WGEEL members in August 2023. Of the 21 countries who responded, a large majority carry out electrofishing, have available hydrographic networks and hold some information of obstructions to migration. However, it was recognised that considerable effort and resources will be required before the available data could be collated

2020 Report of the EIFAAC/ICES/GFCM Working Group on Eels (WGEEL)

The Joint EIFAAC/ICES/GFCM Working group on eels (WGEEL) met by correspondence and video conference from September 21–28 in 2020 to assess the state of the European eel, investigate the effects of habitat loss on the eel stock and its management, review and update the Stock Annex, prepare the 2021 Data Call and report on any updates to the scientific basis of the advice, new and emerging threats or opportunities. Furthermore, data on fisheries landings, aquaculture and restocking are presented. Analyses were carried out on two glass eel recruitment indices (comprising 28 time-series in the Elsewhere Europe area and 24 time-series in the North Sea) and one yellow recruitment index (comprising 16 time-series). Note, that some data from the current year are always provisional to allow for a small proportion of late reporting series, but this is not considered to materially affect the trends. The potential impacts of COVID-19 on the data collection and quality were noted by the WG and described in detail in the report. The recruitment of European eel strongly declined from 1980 to 2011. The glass eel recruitment compared to that in 1960–1979 in the “North Sea” index area was 0.5% in 2020 (provisional) and 1.4% in 2019 (final). In the “Elsewhere Europe” index series it was 6.5% in 2020 (provisional) and 5.6% in 2019 (final), based on available dataseries. For the yellow eel dataseries, recruitment for 2019 was 17% (final) of the 1960–1979 level; the 2020 data collection for yellow eel is ongoing. Statistical analyses of the time-series from 1980 to 2020 show that recruitment has stopped decreasing in 2011 but the trend thereafter is rather unclear. A Bayesian assessment model (GEREM), structured to allow the existence of potential different trends among regions, and provide absolute recruitment per zone has been run. While still preliminary, this model confirms the trend in recruitment, points out the need of new time-series of recruitment, and could in the future allow a part of the analytical assessment of the stock. The collection of yellow and silver eel series and their biometric data, started last year, has continued and a first analysis has been run. There is a large spatial variability in trends of abundance among locations but the analysis of the long-term time-series shows that current silver eel abundance is low when compared to the pre-1980 levels. The analysis of biometric data allows a first analysis of the biological characteristics of the series and points out missing fields in data collection. Emerging threats and opportunities that have been reported over the past decade were reviewed, and diseases, parasites, contaminants and hydropower were identified as routinely reported and thus established. Climate change was repeatedly reported in the past; yet knowledge remains limited. Moreover, the threat of the EU exit of the UK raised concerns regarding the accessability of glass eels for stocking and the potentially increased availability of glass eel from the UK being traded illegally to Asia The issue of COVID-19 was addressed and impacts were found to fall largely in three categories: i) scientific monitorings, ii) restocking programmes and iii) closures/delays in commercial fishing and loss of markets. The WG has a new standing annual activity to examine quantification of the impacts of nonfishery factors and in 2020 i) reviewed the literature on the effects of habitat loss with a focus on the biological processes operating, ii) the national Eel Management Plans and (latest) triannual assessments identifying whether and to what extent the effects of habitat loss have been taken into account, iii) develop a workplan aiming at the quantification of habitat loss and its effect on eel production in the coming years, and iv) present a number of actual case studies. Due to the lack of appropriate data, a meaningful quantitative assessment is not possible at the moment. Overall, the working group has made progress towards the assessment of the standing stock and spawning–stock biomass (i.e. yellow and silver eel time-series) and the implementation of an additional model for the recruitment data provides towards further analyses (e.g. with respect to regional differences). The WG identified relevant issues for future research, highlighting the limited knowledge on the complex effects of climate change as well as the need for additional and specific data collection to quantify the effects of habitat loss