The increasing global demand for seafood has intensified pressure on marine resources and hence the need to adopt sustainable fishing practices and promote sustainable products. Raising consumer awareness about the variability in ecological sustainability of seafood is an important tool to facilitate prevention of marine resource overexploitation, minimise the impact of fishing on ecosystems, and ensure long-term renewal of aquatic resources. Here we propose a simple but comprehensive and generic assessment framework with three indicators that inform on the impact of fishing practices on seabed habitats, fish stock status, and bycatch risk of sensitive species for any given product, whether domestically caught or imported, based on publicly available information. A rating scale from 1 to 5 is used for clarity and effectiveness in communicating the respective risks. The indicators provide a user-friendly tool for consumers, policymakers, and industry professionals to make informed decisions about seafood sustainability. Our results show contrasted ecological risks among the main fishing methods, which is crucial for value chain actors for making informed choices that support sustainable fishing practices. Our method enables scientifically proven practices for mitigating by-catches of sensitive species to be accounted for. A clear, transparent, fair and adaptable scoring system can enhance societal awareness and steer the market towards more sustainable seafood products.

Maximum sustainable yields and maintaining the intraspecific biodiversity are the aim in fish stock management. Here populations-based management would be the preferred practice. Yet available stock discrimination methods result in establishing the conventional assessment/management units as a compromise. The Baltic herring (Clupea harengus membras L.) exhibits remarkable geographical variability, forming up to12 local populations. Due to reasons mentioned above, only two distinct local populations (Gulf of Riga, (GoR) herring and Gulf of Bothnia herring), are treated as separate assessment and management units. The paper describes the annual workflow of the management process, collection of the biological information from commercial catches and from the research surveys. Management history of GoR herring has revealed a number of challenges. Acoustic estimates are the only fisheries-independent data applied in GoR herring stock assessment. The study highlights the need for methodological changes what are expected to allow enhancing the quality of stock estimates, serving as the basis for the management decisions. We show that while before climate - driven regime shift (prior- 1990s) recruitment was determined by the winter temperature, affecting survival of Young of the year, a new major productivity bottleneck is in increasing spring-summer water temperatures during hatching and larval first-feeding stage.

Direct abundance estimates obtained during the acoustic surveys are essential in stock assessment and management process of pelagic fish stocks. The conventional methodology of surveys includes direct hydroacoustic measurements of fish abundance along the pre-defined transects, combined with biological data, obtained from trawl hauls. Considerable amount of survey time and resource are currently allocated to steaming along transects. High operational costs of the research vessel are the major issue in performing such surveys. However, the advances in modern technologies potentially allow to overcome this problem by deploying the autonomous surface vehicles (ASV) for the routine acoustic measurements. A hybrid solution of reduced survey vessel usage by allocating suitable tasks to ASV, would be the most cost-effective solution, but currently not fully compatible with the requirements of maintaining the long -term time series. We argue that autonomous vessels should be considered as an economical alternative and tested through pilot studies.

The Baltic herring (Clupea harengus membras L.) is traditionally one of the main targets of pelagic fisheries in the Baltic Sea, taken mostly in mixed fishery with sprat. The annual total landings amounted around 258 000 t on average for the most recent 20 years. The international management of the Baltic herring stocks rely on the Total Allowable Catch (TAC) agreements and on a few technical measures (gear restrictions in certain areas, closed areas and periods for fishery) as the operational management tools. There are three major agreed management units of herring in the Baltic: Central Baltic herring, Herring in the Gulf of Bothnia and Gulf of Riga herring. Despite of decades-long efforts in applying of regulatory measures, the fate of the stocks has been different: The Central Baltic herring has shown two major declines during its management history while the two other stocks have shown broadly opposite trends. The paper is discussing the possible reasons for the different outcome of management like compliance of fishery with the scientific advice and changes on pelagic communities of the Baltic, focusing on the dynamics in mean weight of herring as another factor potentially effecting on management success across the area.

The Gulf of Riga stock of Baltic herring (Clupea harengus membras L.) has been maintained through several management tools. One such tool is the restriction of vessels’ main engine power (<221 kW). This restriction was implemented in the early 1990s and is based on the vessel types available in the area and on the assumption that the gear size used in trawl fishery depends on the vessel size (power). In the current study, we compared vessels with different engine powers using the same gears currently allowed in the gulf, to identify whether vessel power had any relation to catch structure. The results showed that engine power did not explain the differences in catch structure, which were more dependent on season and depth of water. Easing the power restriction of the trawl vessels in the Gulf of Riga will most likely not have a major negative impact on the sustainable management of the herring population. However, vessels with higher engine power should not use larger trawl gear than is currently used in the gulf.

Hydroacoustic studies using acoustic measurements combined with biological data obtained from trawl hauls remain a challenging task. The main purpose of the present study is to identify sources of uncertainty and compare the calculation methods for a mixed pelagic fish community of Baltic Sea. Most of the calculation methodologies use conventional statistical borders to split the study area, ignoring the possible natural population distribution areas. We compared the proposed "nearest haul" and the "subdivision average" with the conventional "rectangle average" on the Estonian regular acoustic surveys in the northeast Baltic Sea. The abundance estimates of the target species – European sprat Sprattus sprattus (Linnaeus 1758) and Baltic herring Clupea harengus membras (Linnaeus 1758) – with the "nearest haul" were significantly different from the currently used method, which indicates a strong effect of the allocation method. Our results indicate a need for a large scale comparative study to consider alternative calculation methodologies.

The Scientific, Technical and Economic Committee for Fisheries (STECF) held its 65th plenary as virtual meeting from 9-13 November 2020.-- 152 pages

The Scientific, Technical and Economic Committee for Fisheries (STECF) not hold its 63rd Plenary Meeting as originally foreseen on 16-20 March 2020 but was requested to draft its advice by written procedure instead.-- 94 pages

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. The Scientific, Technical and Economic Committee for Fisheries held its 64th plenary as a virtual meeting from 6 to 10 July 2020.

Perch (Perca fluviatilis) and pike-perch (Sander lucioperca) are the valuable fishes in Estonia inhabiting both brackish coastal sea and inland waterbodies. Due to low fat content and highly assimilable proteins, the flesh of these species are highly valued on domestic and export markets. The aim of this study was to get an overview of the occurrence of dioxins (PCDD, PCDF) and dioxin-like PCB-s (dl-PCB), in perch and pike-perch to assess if their quality meets the human consumption standards. The fish samples were collected from the Gulf of Riga, western Gulf of Finland and from the Peipsi Lake in 2003 and in 2013. The results revealed the higher content of dioxins and dl-PCB-s in older specimens and in fish inhabiting more enclosed sea areas. The content of dioxins and dioxin like PCB-s was always higher in perch. However, in all samples analysed, the content remained below the EU food safety limits.

Baltic herring (Clupea harengus membras) is a total spawner with a group-synchronous ovarian organization. Age polymodality in total spawners is considered an important factor in assuring that a strong population is sustainable under an intensive harvesting regime and different climatic conditions. In the present study, we investigated the seasonal and inter-annual variation in spawner age structure and the effect of preceding winter thermal conditions on the start of the herring spawning and larvae retention period. Herring spawning season in the Gulf of Riga starts up to six weeks later after colder winters compared to milder winters. Significantly older individuals dominated at the beginning of the spawning season, and thus herring mean age gradually decreased towards the end of the spawning season from 1999-2015. On an annual scale, this pattern was obvious after cold winters, while after mild winters the pattern did not continue, indicating a more homogenous maturation cycle and spawning period, despite the age and size of the herring population in mild winters. Further, herring condition factor was studied in relation to age and spawning season following different winter thermal conditions. Young, 2- and 3- year old first-spawning herring experienced significantly lower conditions after cold winters compared to older ages, indicating an age-dependent effect of preceding winter on herring maturation cycle, condition and spawning time.

Commercial fishing pressure has selective effect on the exploited fish stocks, usually targeting individuals with larger individual growth rate/size and older age. Therefore, variability in the spatial and temporal fishing pressure is believed to result in fluctuations of fish species individual traits, like age/size structure of fish stocks. The intensity of fishing pressure can strongly affect the stock structure, and even destabilize the stock. We used two different sources (fishery independent survey results and commercial fishery) to evaluate the indicators of spatial variability in fishing pressure in parallel to fisheries-independent survey information to evaluate the possible effects of spatial concentration of fishing on sprat (Sprattus sprattus) and Baltic herring (Clupea harengus membras) populations in the Northeastern Baltic Sea. The study revealed no evidence in linking spatial concentration of fishing pressure and change in age structure or average body weight of fishes. Variable fishing pressure was linked to variabilities in stock size, which indicates that fluctuating harvest may cause undesired fluctuations in stock decline scenario. The results also indicate high mobility and plasticity of Baltic pelagic fish species in intensively exploited areas.

Baltic herring (Clupea harengus membras) is one of the most abundant and economically valuable fish species in Estonian waters dominating both in offshore and coastal sea fishery. Herring has been historically one of the most important species both on the domestic market and for export. The aim of the present study is to get an overview of the occurrence of some organic pollutants in the Baltic herring caught in Estonian Exclusive Economic Zone (EEZ). The samples of Baltic herring were collected from the Gulf of Riga and from the Gulf of Finland in 2013-4 with the aim to assess its suitability for human consumption standards in the Estonian EEZ. The observed content of dioxins (PCDD, PCDF, dioxins), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), organic tin (OT), perfluorocompounds (PFAS) are examined and discussed in the study. The results revealed that higher content of all studied organic pollutants were observed in older Baltic herring and in fish from semi-enclosed gulfs and these contents may cause concern with respect to human health.

Predator-prey interactions are a primary structuring force in marine foodwebs and they play an important role in the dynamics of both marine fish populations and their prey. We investigated the individual and spatial patterns in the feeding of two dominant zooplanktivorous clupeids-herring Clupea harengus membras and sprat Sprattus sprattus-in the Baltic Sea in summer, by means of a taxonomic analysis of stomach content. Both species consumed predominantly the small-sized copepods (Temora longicornis, Eurytemora affinis, and Acartia spp.). E. affinis and T. longicornis were generally positively selected by both species. Centropages hamatus was selected only by sprat. With the exception of Pleopis/ Podon spp. in the case of small sprat, the remaining prey, i. e. the zooplankton taxa that were found in fish stomachs, were consumed at similar proportions as they occurred in zooplankton. Stomach fullness of fish increased with the increasing proportions of prey in the zooplankton community. The share of empty stomachs was lower for sprat, and among smaller fish in both species. Pairwise dietary overlap between fish decreased when zooplankton diversity increased. Dietary overlap was also lowest among the individuals of sprat, probably due to the wider diet spectrum and diversity of stomach content compared to herring. Our results point to high interspecific competition, where sprat seems to be more successful than herring in finding and consuming prey, and therefore may have an advantage over herring when the zooplankton community is dominated by small-sized taxa.

Age of fish at maturation depends on the species and environmental factors but, in general, investment in growth is prioritized until the first sexual maturity, after which a considerable and increasing proportion of resources are used for reproduction. The present study summarizes for the first the key elements of the maturation of European smelt ( Osmerus eperlanus ) young of the year (YoY) in the North-eastern Gulf of Riga (the Baltic Sea). Prior to the changes in climatic conditions and collapse of smelt fishery in the 1990s in the Gulf of Riga, smelt attained sexual maturity at the age of 3–4 years. We found a substantial share (22%) of YoY smelt with maturing gonads after the collapse of the smelt fisheries. Maturing individuals had a significantly higher weight, length and condition factor than immature YOY, indicating the importance of individual growth rates in the maturation process. The proportion of maturing YoY individuals increased with fish size. We discuss the factors behind prioritizing reproduction overgrowth in early life and its implications for the smelt population dynamics.

Fish samples of Baltic herring, sprat, flounder, perch, salmon, and river lamprey were collected from the Gulf of Finland in 2013 and 2014 with the aim to get an overview of the occurrence of pollutants in fish caught in Estonian waters. The content of non-dioxin-like polychlorinated biphenyls (ndl PCBs), polybrominated diphenyl ethers (PBDEs), organic tin (OT) and perfluorocompounds (PFAS) are examined and discussed in the study. The results revealed that potentially higher content of organo-tin compounds, perfluorocompounds and polybrominated diphenyl ethers in Baltic herring, salmon and river lamprey may cause concern regarding human exposure.It is important to link pollutant content to lipid content of fish taking into account their seasonal variation in different age classes.

The ICES Baltic Fisheries Assessment Working Group (WGBFAS) met 19-26 April 2017(Chair: Tomas Grohsler, Germany and Co-chair: Michele Casini, Sweden), with 41 participants and 9 countries represent ...