| 1. |
- Karp, Melissa A., et al.
(författare)
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Increasing the uptake of multispecies models in fisheries management
- 2023
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 80:2, s. 243-257
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Tidskriftsartikel (refereegranskat)abstract
- Multispecies models have existed in a fisheries context since at least the 1970s, but despite much exploration, advancement, and consideration of multispecies models, there remain limited examples of their operational use in fishery management. Given that species and fleet interactions are inherently multispecies problems and the push towards ecosystem-based fisheries management, the lack of more regular operational use is both surprising and compelling. We identify impediments hampering the regular operational use of multispecies models and provide recommendations to address those impediments. These recommendations are: (1) engage stakeholders and managers early and often; (2) improve messaging and communication about the various uses of multispecies models; (3) move forward with multispecies management under current authorities while exploring more inclusive governance structures and flexible decision-making frameworks for handling tradeoffs; (4) evaluate when a multispecies modelling approach may be more appropriate; (5) tailor the multispecies model to a clearly defined purpose; (6) develop interdisciplinary solutions to promoting multispecies model applications; (7) make guidelines available for multispecies model review and application; and (8) ensure code and models are well documented and reproducible. These recommendations draw from a global assemblage of subject matter experts who participated in a workshop entitled “Multispecies Modeling Applications in Fisheries Management”.
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| 2. |
- Voss, Rudi, et al.
(författare)
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Ecological-Economic Fisheries Management Advice—Quantification of Potential Benefits for the Case of the Eastern Baltic COD Fishery
- 2017
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Fishing is a social and economic activity, and consequently socio-economic considerations are important for resource management. While this is acknowledged in the theory of Ecosystem-Based Management (EBM) and its sector-specific development Ecosystem-Based Fisheries Management (EBFM), currently applied fishery management objectives often ignore economic considerations. Year-to-year management, however, implicitly responds to short-term economic interests, and consequently, regularly resorts to tactical short-term rather than strategic long-term decisions. The aim of this article is to introduce a new way of estimating management advice referred to as an “ecologically-constrained Maximum Economic Yield” (eMEY) strategy, which takes into account ecological criteria as well as short- to medium-term economic costs. We further illustrate what net cost reductions per year are possible applying the eMEY strategy compared with the existing way of setting total allowable catches (TACs). The eMEY approach aims at maximizing the economic benefits for the fishery as well as society (consumers), while safeguarding precautionary stock sizes. Using an age-structured optimization model parameterized for the Eastern Baltic cod case study, we find that application of eMEY advice results in more stability in catch advice. Quantification and visualization of the costs of deviating from eMEY advice offers a transparent basis for evaluating decision-making outcomes. The costs of overfishing are mainly borne by the commercial fishery, while fishing less than optimal is particularly costly for the processing industry and consumers. To foster the uptake of our eMEY approach in current advice given by the International Council for the Exploration of the Sea (ICES) and the EU fishery management system, we suggest an easy-to-implement scheme of providing integrated advice, also accounting for economic considerations.
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| 3. |
- Alexander, Karen A., et al.
(författare)
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Investigating the recent decline in gadoid stocks in the west of Scotland shelf ecosystem using a foodweb model
- 2015
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 72:2, s. 436-449
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Tidskriftsartikel (refereegranskat)abstract
- Abundance and biomass of cod, haddock, and whiting in the waters off of the west coast of Scotland (wcoS) have undergone large changes in recent years, most notably a recent decline. These three species contribute a considerable part of Scottish demersal landings from this area and as such it is important to understand why these stocks are behaving the way they are. A number of explanations for the decline have been proposed, including: seal predation, pressure from Nephrops trawls, and fishing pressure more generally. We used an ecosystem model of the wcoS continental shelf (<200 m depth) to investigate whether these proposed explanations for declining gadoid stocks are feasible. Results suggest that the rise in the grey seal population over recent years has not led to the decline in gadoid stocks; there is insufficient bycatch by the Nephrops fleet to have a large impact on gadoid stocks; however, fishing, as a key driver of the west of Scotland shelf ecosystem, has impacted stocks and by decreasing fishing levels to maximum sustainable yield cod biomass may increase slightly though not returning to previous levels. Although this means we are little further forward in understanding the cause of recent gadoid declines in the area, the development of this model has enabled us to further our knowledge and understanding of aspects of trophic structure and the impacts of fishing on the wcoS.
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| 4. |
- Ammar, Yosr, et al.
(författare)
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Exploring future ecosystem novelty and resilience using the adaptive cycle
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Marine ecosystems worldwide are under unprecedented pressure from the impacts of climate change and human activities. Such pressure increased novelty in species assemblages, i.e., assemblages increasingly outside their historical range of variation. It may further rise in the future, and whether it will unfold and influence resilience remains unclear. Using the adaptive cycle, we explore the relationship between resilience and novelty under the compound effect of climate, nutrient load, and fishing management scenarios in the Finnish Archipelago Sea (FAS) future food web model. Novelty was measured as the minimum dissimilarity over time relative to a specific baseline. Ecological Network Analysis indices associated to the model: ascendancy, capacity, and overhead flow, were used as indicators of connectedness, potential, and resilience axes of the adaptive cycle. A model-based clustering method distinguished four regimes determined by the impact of the nutrient load and climate on the bottom-up dynamic of the FAS food web. Resilience decreased in regimes where higher and faster novelty emerged in response to warmer climate pathways. The number of reorganization phases of the adaptive cycle, characterized by the generation of novelty, was greater in regimes under low nutrient load management scenarios. We highlight the importance of understanding ecosystem reorganization and resilience in a growing Anthropogenic novelty to inform future management.
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| 5. |
- Bauer, Barbara, et al.
(författare)
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Food web and fisheries in the future Baltic Sea
- 2019
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 48:11, s. 1337-1349
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Tidskriftsartikel (refereegranskat)abstract
- We developed numerical simulations of potential future ecological states of the Baltic Sea ecosystem at the end of century under five scenarios. We used a spatial food web (Ecospace) model, forced by a physical-biogeochemical model. The scenarios are built on consistent storylines that describe plausible developments of climatic and socioeconomic factors in the Baltic Sea region. Modelled species diversity and fish catches are driven by climate- and nutrient load-related changes in habitat quality and by fisheries management strategies. Our results suggest that a scenario including low greenhouse gas concentrations and nutrient pollution and ecologically focused fisheries management results in high biodiversity and catch value. On the other hand, scenarios envisioning increasing societal inequality or economic growth based on fossil fuels, high greenhouse gas emissions and high nutrient loads result in decreased habitat quality and diminished biodiversity. Under the latter scenarios catches are high but they predominantly consist of lower-valued fish.
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| 6. |
- Bauer, Barbara, et al.
(författare)
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Model uncertainty and simulated multispecies fisheries management advice in the Baltic Sea
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Different ecosystem models often provide contrasting predictions (model uncertainty), which is perceived to be a major challenge impeding their use to support ecosystem-based fisheries management (EBFM). The focus of this manuscript is to examine the extent of model disagreements which could impact management advice for EBFM in the central Baltic Sea. We compare how much three models (EwE, Gadget and a multispecies stock production model) differ in 1) their estimates of fishing mortality rates (Fs) satisfying alternative hypothetical management scenario objectives and 2) the outcomes of those scenarios in terms of performance indicators (spawning stock biomasses, catches, profits). Uncertainty in future environmental conditions affecting fish was taken into account by considering two seal population growth scenarios and two nutrient load scenarios. Differences in the development of the stocks, yields and profits exist among the models but the general patterns are also sufficiently similar to appear promising in the context of strategic fishery advice. Thus, we suggest that disagreements among the ecosystem models will not impede their use for providing strategic advice on how to reach management objectives that go beyond the traditional maximum yield targets and for informing on the potential consequences of pursuing such objectives. This is especially true for scenarios aiming at exploiting forage fish sprat and herring, for which the agreement was the largest among our models. However, the quantitative response to altering fishing pressure differed among models. This was due to the diverse environmental covariates and the different number of trophic relationships and their functional forms considered in the models. This suggests that ecosystem models can be used to provide quantitative advice only after more targeted research is conducted to gain a deeper understanding into the relationship between trophic links and fish population dynamics in the Baltic Sea.
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| 7. |
- Bauer, Barbara, et al.
(författare)
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Reducing eutrophication increases spatial extent of communities supporting commercial fisheries : a model case study
- 2018
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 75:4, s. 1306-1317
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Tidskriftsartikel (refereegranskat)abstract
- In this study we investigate if eutrophication management has the potential to substantially affect which areas are going to be most suitable for commercial fishing in the future. We use a spatial ecosystem model, forced by a coupled physical-biogeochemical model, to simulate the spatial distribution of functional groups within a marine ecosystem, which depends on their respective tolerances to abiotic factors, trophic interactions, and fishing. We simulate the future long-term spatial developments of the community composition and their potential implications for fisheries under three different nutrient management scenarios and changing climate. The three nutrient management scenarios result in contrasting developments of bottom oxygen concentrations and phytoplankton abundance, with substantial effects on fish production. Nutrient load reduction increases the spatial extent of the areas suitable for the commercially most valuable demersal fish predator and all types of fisheries. This suggests that strategic planning of fishery management strategies could benefit from considering future changes in species distributions due to changes in eutrophication. We show that combining approaches from climate research, physical oceanography, biogeochemistry, biogeography, and trophic ecology with economical information provides a strong foundation to produce scientific knowledge that can support a multisectoral management of ecosystems.
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| 8. |
- Bergström, Lena, et al.
(författare)
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Report of the ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB)
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea(WGIAB) was established in 2007 as a forum for developing and combining ecosystembasedmanagement efforts for the Baltic Sea. The group intends to serve as a scientificcounterpart and support for the ICES Baltic Fisheries Assessment Working Group(WGBFAS) as well as for efforts and projects related to Integrated Ecosystem Assessments(IEA) within ICES and HELCOM. The group works in cooperation with similargroups within the ACOM/SCICOM Steering Group on Integrated Ecosystem Assessments(SSGIEA).The 2015 WGIAB meeting was held in Cádiz, Spain, from 9–13 March, back-to-backwith the meeting of its counterpart in the Working Group on Ecosystem Assessmentof Western European Shelf Seas (WGEAWESS). The meetings had joint sessions as wellas WG specific work, and some participants effectively participated in both meetings.The WGIAB meeting was attended by 27 participants from nine countries. The meetingwas chaired by Christian Möllmann, Germany, Laura Uusitalo, Finland and Lena Bergström,Sweden.This was the last year of the ongoing three-year Terms of Reference (ToR) for WGIAB.The main working activities in 2015 were to i) conduct studies on Baltic Sea ecosystemfunctioning with the goal to publish case studies from different parts of the Baltic Seain peer-reviewed journals, ii) work on the demonstration exercise to develop ecosystem-based assessment and advice for Baltic fish stocks focusing on cod (DEMO) withmultiple approaches, iii) plan further how to integrate the social and economic aspectsmore tightly in the WGIAB work, and iv) discuss the future focus and format of theWGIAB work.The Baltic ecosystem functioning activity focused on identifying and exploring keytrends and linkages in the Baltic Sea foodweb. This was pursued by presentation andfurther discussion of ongoing intersessional work on foodweb modelling and integratedanalyses, and by exercises to develop conceptual models Baltic Sea foodwebsand the links to ecosystem function. Long-term monitoring datasets on the abiotic andbiotic parts of the Baltic Sea Proper ecosystem were updated for use in the continuedwork to develop environmental indicators for fisheries and marine management.The focus of the DEMO 3 (DEMOnstration exercise for Integrated Ecosystem Assessmentand Advice of Baltic Sea cod) was on finding a way to use the results from theDEMO1 and DEMO2 workshops in short and midterm projections/scenarios of Balticcod dynamics based on different types of modelling, as well as designing methodologyand modelling data for practical implementation of Integrated Advice for Baltic cod.The WGIAB was positively inclined towards including social and economic aspectsinto the integrated assessment. Openings to this path were provided by presentationon ongoing project work, and discussing their linkages to ecological aspects. It wasseen as crucial that experts on social and economic analysis should be included andtake an active part in the future work of the group.The group concluded that its upcoming work should focus more closely on functionaldiversity, which was identified as a recurring issue in the Baltic Sea. This approach wasalso identified as a useful connection point between scientific and management aspectsin order for the group to continue serving as a forum for developing ecosystem-basedmanagement efforts in the Baltic Sea. A focus on functional diversity was also seen as2 | ICES WGIAB REPORT 2015a potentially feasible way of bringing together management aspects for different sectors,by linking to ecosystem services concepts.The group proposed Saskia Otto, Germany and Martin Lindegren, Denmark as newincoming Chairs, together with Lena Bergström, Sweden and Laura Uusitalo, Finland.Having four Chairs is justified due to the wide scope of the group's work, as well asthe increased work load due to the planned new foci.
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| 9. |
- Costalago, David, et al.
(författare)
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The necessity of a holistic approach when managing marine mammal–fisheries interactions : Environment and fisheries impact are stronger than seal predation
- 2019
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 48:6, s. 552-564
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Tidskriftsartikel (refereegranskat)abstract
- Seal populations are recovering in many regions around the world and, consequently, they are increasingly interacting with fisheries. We used an Ecopath with Ecosim model for the offshore Central Baltic Sea to investigate the interactions between the changes in fish stocks and grey seal (Halichoerus grypus) population under different fishing and environmental scenarios for the twenty-first century. The assumed climate, eutrophication and cod (Gadus morhua) fisheries scenarios modified seal predation impacts on fish. Fish biomass and catches are more affected by fishing mortality and the environment than by seal predation. Our results highlight that the impacts of the increasing seal population on lower trophic levels are complex; thus, we emphasize the need to consider a range of possible ecosystem contexts when evaluating potential impacts of top predators. Finally, we suggest that an increasing seal population is not likely to hinder the preservation of the main Baltic fish stocks.
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| 10. |
- Eero, Margit, et al.
(författare)
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Food for Thought Eastern Baltic cod in distress : biological changes and challenges for stock assessment
- 2015
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 72:8, s. 2180-2186
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Tidskriftsartikel (refereegranskat)abstract
- The eastern Baltic (EB) cod (Gadus morhua) stock was depleted and overexploited for decades until the mid-2000s, when fishing mortality rapidly declined and biomass started to increase, as shown by stock assessments. These positive developments were partly assigned to effective management measures, and the EB cod was considered one of the most successful stock recoveries in recent times. In contrast to this optimistic view, the analytical stock assessment failed in 2014, leaving the present stock status unclear. Deteriorated quality of some basic input data for stock assessment in combination with changes in environmental and ecological conditions has led to an unusual situation for cod in the Baltic Sea, which poses new challenges for stock assessment and management advice. A number of adverse developments such as low nutritional condition and disappearance of larger individuals indicate that the stock is in distress. In this study, we (i) summarize the knowledge of recent changes in cod biology and ecosystem conditions, (ii) describe the subsequent challenges for stock assessment, and (iii) highlight the key questions where answers are urgently needed to understand the present stock status and provide scientifically solid support for cod management in the Baltic Sea.
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