The status of Eastern Baltic cod (EBC) Gadus morhua has remained poor despite low fishing mortality for over a decade, including a fishing ban since 2019. Although the decline in productivity can be explained by lower individual growth and survival rates, other aspects of life-history changes such as maturation patterns for EBC has so far not been sufficiently explored. According to current stock assessments, the median size at maturity (L50) has halved from 40 to around 20 cm in total length since the 1990s, while the overall size distribution has become increasingly truncated. It has previously been suggested that changes in L50 can be attributed to both fishing-induced evolution and phenotypic plasticity induced by growth rates. However, since L50 is currently occurring around 20 cm, the maturation process must have been initiated at much smaller sizes, that is, long before the fish could be caught in the dominant trawl fishery at around 35 cm. In this study, we aimed to further investigate what drivers may have led to reduced productivity in EBC by determining variations in size at sexual maturity in longer time series than has been done before (1930s to 1980s) and include prey productivity and quality. We found that L50 declined already in the 1930s and thereafter remained stable at around 40 cm up to the 1990s. On a centurial perspective, L50 has been positively correlated to growth potential (L95), length diversity, total stock biomass, total catch and yield per recruit, while Fulton’s condition factor was not related to L50. Our results suggest that the links between life-history parameters and external drivers are complex, but the present unprecedented early onset of maturity and hence decline in L50 since the 1990s signals a decline in growth potential, which also has hampered the productivity of EBC. 

Ecological risk assessments are important as scientific support for the implementation of ecosystem-based fisheries management. Marine invertebrates are important to ecosystem structure and function and may be sensitive to fishing pressure. Some are also of increasing commercial value – but have hitherto not been paid much attention to in ecological risk assessments. Here, catches of invertebrates in Swedish west-coast fisheries with demersal trawls and creels are examined from an ecological risk assessment perspective. It is found that few non-commercial invertebrate species have been regularly recorded in onboard observer programs. Furthermore, for being a comparatively well-studied area, it is striking to find that out of the 93 species included, 56% could be classified as data deficient in terms of known attributes needed to perform basic ecological risk assessments. This implies that there is little or no available information on the basic life history traits important for estimating productivity. Additionally, onboard observer data for invertebrates are inadequate beyond targeted commercial species for robust statistical analysis on volumes generated over time and between fisheries. However, over 18% of the studied species are categorized as red-listed on the Swedish IUCN Red List. Combined with the few records available in observer data programs, the study illustrates the need to pay more attention to marine invertebrates in fisheries monitoring programs and research, especially bycaught and non-commercial invertebrate species.

Seafood has an important role to play to achieve a sustainable food system that provides healthy food to a growing world population. Future seafood production will be increasingly reliant on aquaculture where feed innovation is essential to reduce environmental impacts and minimize feed and food competition. This study aimed to investigate whether a novel single cell protein feed ingredient based on Paecilomyces variotii grown on a side stream from the forest industry could improve environmental sustainability of farmed rainbow trout (Oncorhynchus mykiss) by replacing the soy protein concentrate used today. A Life Cycle Assessment including commonly addressed impacts but also the rarely assessed biodiversity impacts was performed. Furthermore, feeding trials were included for potential effects on fish growth, i.e., an assessment of the environmental impacts for the functional unit ‘kg feed required to produce 1 kg live-weight rainbow trout’. Results showed that the best experimental diet containing P. variotii performed 16–73 % better than the control diet containing soy protein concentrate in all impact categories except for energy demand (21 % higher impact). The largest environmental benefits from replacing soy protein with P. variotii in rainbow trout diets was a 73 % reduction of impact on biodiversity and halved greenhouse gas emissions. The findings have high relevance for the aquaculture industry as the production scale and feed composition was comparable to commercial operations and because the effect on fish growth from inclusion of the novel ingredient in a complete diet was evaluated. The results on biodiversity loss from land use change and exploitation through fishing suggest that fishery can dominate impacts and exclusion thereof can greatly underestimate biodiversity impact. Finally, a novel feed ingredient grown on side streams from the forest industry has potential to add to food security through decreasing the dependence on increasingly scarce agricultural land resources. 

Baltic Sea herring fisheries have in recent years attracted considerable media interest in Sweden. The main concerns are deteriorating stock status and lack of herring catches suitable for human consumption. One recurring theme is that the demand of feed raw materials by the Norwegian salmon aquaculture industry is driving the development of increasing volumes destined for fishmeal and oil production. However, it is unclear to which extent Baltic Sea herring is used by the Norwegian salmon industry. This report has the specific objectives to map where Baltic Sea herring ends up, including identification of potential obstacles for full traceability – with the overall aim to identify how different actors may contribute to safeguarding long-term sustainable use of marine resources. Based on data provided by the Danish fishmeal and oil processing industry, it is found that Baltic Sea herring is primarily used for the aquaculture sector, especially the fish oil. However, although some feed and salmonid producers were helpful in providing the requested information, responses varied and only piecemeal information could be obtained on the next step in the value chain, i.e. to which specific species and countries. Although annual sustainability reports are published, efficient, fit-for-purpose extracts on the destination of raw material from a certain stock may be effort-demanding to extract and official data detailing this is at large lacking. The same situation also applies for certified aquaculture. Further, the definitions of ‘sustainable fisheries’ applied in current certification systems are inadequate to fully safeguard use of sustainable marine raw material for certified, farmed seafood. Several actors are however working with improvements, such as a new feed standard for Aquaculture Stewardship Council and updates on internal reporting systems by feed producers. In conclusion, to improve transparency and build consumer trust – and ultimately foster sustainable use – it calls for i) more efficient data management strategies and detailed reporting by feed producers to be able to meet questions raised; and ii) sharper rules for feed ingredients allowed by current aquaculture certification standards and a more distinct difference to non-certified seafood related to sustainability and transparency of marine resource use.

Purpose: The decline in biodiversity caused by human activities is a major global challenge. An important driver of biodiversity loss, especially in the oceans, is seafood production. However, methods for quantifying biodiversity impacts in life cycle assessment (LCA) are currently heavily focused on terrestrial systems. This study aims to identify and evaluate methods addressing aquatic biodiversity loss relevant for LCAs of seafood and to provide recommendations to research and LCA practitioners. Methods: The methodology comprised four key phases. First, environmental impacts from seafood production were identified and linked to biodiversity impacts. Second, it was assessed which impacts were addressed in existing seafood LCAs. Next, available biodiversity impact assessment methods were identified through a literature review. Finally, the identified assessment methods were evaluated and matched against the identified environmental impacts from seafood production to evaluate the efficacy of current LCA practices. Results and discussion: A total of 39 environmental impacts linked to seafood production were identified. Of these impacts, 90% were categorized as causing biodiversity loss and included effects on genetic, species, and ecosystem level. Only 20% out of the impacts associated to aquatic biodiversity loss had been included in previous seafood LCAs, indicating a narrow scope in practice, as methods were available for half of the impacts. The available methods were, however, mainly focused on impact on species level and on the drivers pollution and climate change rather than the main drivers of marine biodiversity loss: exploitation and sea-use change. Conclusions: Although many of the impacts from seafood production were related to biodiversity pressures, LCAs which are widely used to describe the environmental performance of seafood, disregard most biodiversity impacts from seafood production. The most severe limitations were the lack of methods for the pressures of exploitation and sea-use change and for effects on ecosystem and genetic biodiversity. This study provides recommendations to practitioners on how to best account for biodiversity impacts from seafood depending on the studied system, geographic area, and dataset. Future research should progress methods for impact pathways within the drivers exploitation and sea-use change, and effects on ecosystem biodiversity and genetic biodiversity. 

As seaweed farming gains prominence in future blue economies, scientifically robust environmental evaluations are vital. Harmonizing life cycle assessment (LCA) studies provides nuanced insights, allowing generalizations and potentially more accurate results than individual studies. This study recalculates life cycle inventory (LCI) data to offer a comprehensive perspective on sugar kelp Saccharina latissima. The findings affirm and validate previous studies, emphasizing critical hotspots such as fuel use for boats at sea, impacts from the use of plastic ropes, buoys and metal components at sea, and electrical energy use in the hatchery. The overall environmental impacts of seaweed farming remain relatively low compared to other seafood and biomass sources. The study also highlights the importance of how fuel use is modelled for the outcome. While harmonization enhances certainty and facilitates robust comparisons, challenges arise from the lack of standardized methods for data collection and reporting, along with data gaps between studies. Addressing these limitations calls for standardized protocols and improved data sharing practices in the field. 

The ocean is increasingly used for industry, energy and recreation or protected for conservation, resulting in increasing spatial restrictions for fisheries. Simultaneously, producing seafood with a low climate footprint is becoming increasingly important. Despite this, the effects of spatial restrictions on the emissions of fishing fleets are poorly known. In the Northeast Atlantic, the withdrawal of the United Kingdom from the EU (Brexit) meant that the UK regained autonomy in its Exclusive Economic Zone (EEZ). This suddenly imposed a spatial restriction for several foreign fishing fleets targeting Northeast Atlantic mackerel (Scomber scombrus). Here, we use this natural experiment and open fisheries data to investigate how Brexit affected the performance and emissions of the Norwegian mackerel fishery. As the fleet was excluded from fishing grounds in the UK, the catch per fishing trip almost halved, while the number of trips per vessel doubled. As a result, fuel use intensity (FUI) more than doubled from ∼0.08 to ∼0.18 L fuel per kg mackerel. We estimate that this shift required an additional 23 million liters of fuel per year, causing additional fuel costs of ∼€18 million annually and emitting an additional ∼72,000 tonnes CO2 per year. The policy change undid ∼15 years of improved fuel efficiency in Norwegian pelagic fisheries. These findings provide rare empirical evidence on how spatial restrictions can undermine progress towards decreasing greenhouse gas emissions in fisheries, highlighting the need to monitor and account for emissions in fisheries management and consider these trade-offs in marine spatial management. 

Does Swedish consumption of farmed salmon drive increase in industrial fisheries in the Baltic Sea?

Swedish fishing in the Baltic Sea with large vessels to produce fish meal and oil, and the deteriorating conditions for small-scale fishing and herring stocks, has in recent years been heavily debated in media. A link between current large-scale fishing and Swedish consumption of Norwegian salmon is often made, i.e., that Norwegian salmon farming is a driver behind the recent development. The Swedish Fishing Industry Association has therefore commissioned this report with the aim to improve current knowledge. The overarching questions are whether i) there is a dependency, and ii) if Norwegian salmon farming can be considered a driver for Swedish large-scale fishing of herring in the Baltic Sea. It is found that the development from the 1950s needs to be taken into account to fully understand today's situation. The current Swedish fishing fleet in the Baltic Sea is in line with national fisheries’ objectives to make pelagic fishing more efficient, and the development of stocks is in turn governed by the EU Common Fisheries Policy – both independent to both Swedish consumption and Norwegian salmon farming. Several factors affect destination of landings, where an important aspect is quality of the catch. Current fishing pattern, with fewer and larger boats, have resulted in considerably larger landing volumes per vessel – compromising opportunities for processing for direct consumption. The exact link between Swedish fisheries and Norwegian salmon farming is however complicated. The different traceability systems for fish caught for feed versus direct consumption are not integrated, although detailed information "one step forward, one step back" is available from individual actors. This challenge an effective tracing of a certain fish volume caught for fish meal and oil production to the final use. Overall, available data find that the total share of herring (from all waters) in one kilo Norwegian salmon feed is small (3.77%), and a very small fraction is based on fisheries directly destined for fish meal and oil production (0.8%) – the largest share is based on trimmings from processing for direct consumption. However, most of the Swedish landings of herring from the Baltic Sea is directly destined for fishmeal and oil production in Denmark. The largest share of the total production in Denmark goes to aquaculture, mainly to Norway. Conclusions are that i) Norwegian salmon farming does not appear to use herring from the Baltic Sea to a large extent, although a large share of the fish meal and oil production from the Baltic Sea are destined to aquaculture, and ii) it is the fisheries management (EU and Swedish) that has shaped the fishing that exists today by creating the basic conditions. The report concludes with recommendations for follow-up measures to reduce conflict between fishing for feed and direct consumption, and to better ensure full traceability even for fish intended for feed production.

Algae have gained increasing attention as promising food from both an environmental and nutritional perspective. However, current understanding is still limited. This report summarizes the status of knowledge for this emerging sector, focusing on micro- and macroalgae species most relevant for Europe (particularly Sweden). Environmental impacts, with focus on climate, are evaluated through literature reviews and analysis of existing life cycle assessments (LCAs), and nutritional potential in the form of data compilation and calculation of nutrient density scores. Overall, findings reveal that current data is incomplete and of poor representativeness. Most LCAs are not performed on commercial production, but at pilot or experimental scale, why often only indicative drivers for greenhouse gas emissions may be identified. For microalgae, there is a wide diversity of production systems in different conditions across the globe. Based on the data at hand, energy use is a key hotspot across most studies for this production, driven by the requirements of different types of systems and species, and to location. For macroalgae production, despite poor representativeness of especially green and red macroalgae, key aspects for minimizing greenhouse gas emissions are associated with energy consumption and use of materials for farming such as ropes. No LCA exists on wild harvested macroalgae, representing the largest production volume in Europe (>95%); large-scale wild harvest may also be associated with risks to ecosystems unless suitable management is enforced. Significant data gaps also exist in food composition databases regarding nutrient and heavy metal content in algae (e.g., vitamins and omega-3 fatty acids). When available, nutrient content was found to be highly variable within and across species, but overall, the evaluation of nutritional quality indicated that algae may be a considerable source of minerals and vitamin B12. The contribution of fiber and protein is generally minimal in a 5 g dry weight portion of macroalgae; microalgae may have higher protein content, and also fat. However, excessive amounts of iodine and several heavy metals may be represented even in very small amounts of unprocessed macroalgae. In summary, the suggested potential of farmed algae as a sustainable food resource is overall strengthened by its generally low carbon footprint during production compared to other food raw materials. However, more input data are needed to fill data gaps regarding both environmental impacts and nutrient quality, and effects from different processing, as well as improved understanding of nutrient and contaminant bioavailability. Pending further research, careful considerations of risks and benefits associated with algae production and consumption should be applied.

Seafood offers opportunities for more sustainable diets through having a generally high nutritional value at lower environmental pressures relative to other animal protein. Opportunities for, and challenges of, seafood production and consumption are however context dependent. Here, a case study of Swedish fisheries for Atlantic herring Clupea harengus in the Baltic Sea is added to the scientific discourse. Motivated from a heated public debate in Sweden, the purpose is to provide a first sustainability assessment of current value chains: direct consumption versus fish meal and oil production. The case study highlights the importance of taking a value chain perspective for seafood from capture fisheries – i.e., the prerequisites, constraints and opportunities for different actors – and pay attention to misaligned economic incentives that may conflict sustainable use. Although lower greenhouse gas emissions, higher nutritional value, more affordable seafood for consumers and higher economic value for fishermen may be achieved by direct consumption of herring, several challenges exist. These include above all an urgent need to safeguard sustainable and equitable fisheries exploitation; current management is increasingly eroding opportunities for value chains producing herring for food. It is also vital with realistic expectations; redirecting more herring to direct consumption also requires strategies for how potential health risks can be reduced and consumer interest could increase. Overall, the study illustrates net-effects on marine resource utilization from interplay between actors along the value chain in various ways – with implications and insights of importance for a long-term sustainable Blue Economy.