Change search
Refine search result
1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Alexander, Karen A.
    et al.
    Heymans, Johanna J.
    Magill, Shona
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Holmes, Steven J.
    Wilding, Thomas A.
    Investigating the recent decline in gadoid stocks in the west of Scotland shelf ecosystem using a foodweb model2015In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 72, no 2, p. 436-449Article in journal (Refereed)
    Abstract [en]

    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.

  • 2.
    Axenrot, Thomas
    et al.
    e of Freshwater Research, Swedish Board of Fisheries.
    Ogonowski, Martin
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sandström, Alfred
    e of Freshwater Research, Swedish Board of Fisheries.
    Didrikas, Tomas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Multifrequency discrimination of fish and mysids2009In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 66, no 6, p. 1106-1110Article in journal (Refereed)
    Abstract [en]

    The opossumshrimp (Mysis relicta) is common in many lakes in the northernparts of Eurasia and North America. The shrimp is often an importantlink in the foodweb for fish, either throughout life or in earlylife stages. Generally, quantitative measurements of mysidsin large volumes of water are difficult to obtain with traditionalsampling methods. In this pilot study, measurements of volume-backscatteringstrength (Sv) at 38, 120, and 200 kHz were used to separatebackscattering from fish and mysids. Mysids were sampled withtrawls. Where mysids were caught, the correlations between mysidbiomass (dry weight) and mean Sv at 120 and 200 kHz were positive(r2 = 0.89 and 0.81, respectively). Where mysids were abundant,the Sv exhibited a characteristic frequency response. This wasnot found where mysids were scarce or absent. Therefore, areaswith great abundances of mysids can be identified, and theirbiomasses estimated from data collected during ecosystem monitoring.

  • 3.
    Bauer, Barbara
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Meier, H. E. Markus
    Casini, Michele
    Hoff, Ayoe
    Margoński, Piotr
    Orio, Alessandro
    Saraiva, Sofia
    Steenbeek, Jeroen
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Reducing eutrophication increases spatial extent of communities supporting commercial fisheries: a model case study2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 4, p. 1306-1317Article in journal (Refereed)
    Abstract [en]

    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.

  • 4. Bucas, M.
    et al.
    Bergström, U.
    Downie, A-L
    Sundblad, G.
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    von Numers, M.
    Siaulys, A.
    Lindegarth, M.
    Empirical modelling of benthic species distribution, abundance, and diversity in the Baltic Sea: evaluating the scope for predictive mapping using different modelling approaches2013In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 70, no 6, p. 1233-1243Article in journal (Refereed)
    Abstract [en]

    The predictive performance of distribution models of common benthic species in the Baltic Sea was compared using four non-linear methods: generalized additive models (GAMs), multivariate adaptive regression splines, random forest (RF), and maximum entropy modelling (MAXENT). The effects of data traits were also tested. In total, 292 occurrence models and 204 quantitative (abundance and diversity) models were assessed. The main conclusions are that (i) the spatial distribution, abundance, and diversity of benthic species in the Baltic Sea can be successfully predicted using several non-linear predictive modelling techniques; (ii) RF was the most accurate method for both models, closely followed by GAM and MAXENT; (iii) correlation coefficients of predictive performance among the modelling techniques were relatively low, suggesting that the performance of methods is related to specific responses; (iv) the differences in predictive performance among the modelling methods could only partly be explained by data traits; (v) the response prevalence was the most important explanatory variable for predictive accuracy of GAM and MAXENT on occurrence data; (vi) RF on the occurrence data was the only method sensitive to sampling density; (vii) a higher predictive accuracy of abundance models could be achieved by reducing variance in the response data and increasing the sample size.

  • 5. Cheung, William W. L.
    et al.
    Frolicher, Thomas L.
    Asch, Rebecca G.
    Jones, Miranda C.
    Pinsky, Malin L.
    Reygondeau, Gabriel
    Rodgers, Keith B.
    Rykaczewski, Ryan R.
    Sarmiento, Jorge L.
    Stock, Charles
    Watson, James R.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Princeton University, USA.
    Building confidence in projections of the responses of living marine resources to climate change2016In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 73, no 5, p. 1283-1296Article in journal (Refereed)
    Abstract [en]

    The Fifth Assessment Report of the Intergovernmental Panel on Climate Change highlights that climate change and ocean acidification are challenging the sustainable management of living marine resources (LMRs). Formal and systematic treatment of uncertainty in existing LMR projections, however, is lacking. We synthesize knowledge of how to address different sources of uncertainty by drawing from climate model intercomparison efforts. We suggest an ensemble of available models and projections, informed by observations, as a starting point to quantify uncertainties. Such an ensemble must be paired with analysis of the dominant uncertainties over different spatial scales, time horizons, and metrics. We use two examples: (i) global and regional projections of Sea Surface Temperature and (ii) projection of changes in potential catch of sablefish (Anoplopoma fimbria) in the 21st century, to illustrate this ensemble model approach to explore different types of uncertainties. Further effort should prioritize understanding dominant, undersampled dimensions of uncertainty, as well as the strategic collection of observations to quantify, and ultimately reduce, uncertainties. Our proposed framework will improve our understanding of future changes in LMR and the resulting risk of impacts to ecosystems and the societies under changing ocean conditions.

  • 6. Daewel, Ute
    et al.
    Hjøllo, Solfrid Saetre
    Huret, Martin
    Ji, Rubao
    Maar, Marie
    Niiranen, Susa
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Travers-Trolet, Morgane
    Peck, Myron A.
    van de Wolfshaar, Karen E.
    Predation control of zooplankton dynamics: a review of observations and models2014In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 71, no 2, p. 254-271Article, review/survey (Refereed)
    Abstract [en]

    We performed a literature review to examine to what degree the zooplankton dynamics in different regional marine ecosystems across the Atlantic Ocean is driven by predation mortality and how the latter is addressed in available modelling approaches. In general, we found that predation on zooplankton plays an important role in all the six considered ecosystems, but the impacts are differently strong and occur at different spatial and temporal scales. In ecosystems with extreme environmental conditions (e.g. low temperature, ice cover, large seasonal amplitudes) and low species diversity, the overall impact of top-down processes on zooplankton dynamics is stronger than for ecosystems having moderate environmental conditions and high species diversity. In those ecosystems, predation mortality was found to structure the zooplankton mainly on local spatial and seasonal time scales. Modelling methods used to parameterize zooplankton mortality range from simplified approaches with fixed mortality rates to complex coupled multispecies models. The applicability of a specific method depends on both the observed state of the ecosystem and the spatial and temporal scales considered. Modelling constraints such as parameter uncertainties and computational costs need to be balanced with the ecosystem-specific demand for a consistent, spatial-temporal dynamic implementation of predation mortality on the zooplankton compartment.

  • 7.
    Didrikas, Tomas
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Effects of light intensity on activity and pelagic dispersion of fish: studies with a seabed-mounted echosounder2009In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 66, p. 388-395Article in journal (Refereed)
    Abstract [en]

    A seabed-mounted, upwards-pinging echosounder was used to study fish activity and pelagic dispersion in relation to fish size, light, and temperature. Four phases (day, dusk, night, dawn) in fish dispersion were distinguished over the diel cycle, and the swimming speed of fish varied among these phases. Notably, average swimming speed by day was twice as high as by night. For all phases combined, fish size, light intensity, and temperature explained 52% of the variability in swimming speed. When different phases were analysed separately, fish size was the most important variable by day, whereas light had the strongest effects on swimming speed in the evening. During the mornings, variability in swimming speed was best correlated with temperature, but by night all factors (fish size, light intensity, temperature) had similar effects on activity. These results have implications for fish bioenergetics models. Such models should account for seasonal, light-driven cycles in activity-induced respiration estimates, in particular when modelling populations at high latitudes.

  • 8. Dietz, Rune
    et al.
    Teilmann, Jonas
    Andersen, Signe M.
    Riget, Frank
    Olsen, Morten T.
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Movements and site fidelity of harbour seals (Phoca vitulina) in Kattegat, Denmark, with implications for the epidemiology of the phocine distemper virus2013In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 70, no 1, p. 186-195Article in journal (Refereed)
    Abstract [en]

    Twenty-seven harbour seals were caught and tagged at the island of Anholt in central Kattegat, Denmark, the epicentre of the phocine distemper virus (PDV) outbreaks in 1988 and 2002 that killed 50-60% of the populations. The satellite tagging shows that harbour seals from Anholt moved widely across Kattegat with a maximum distance of 249 km from the tagging haul-out site. Overall, females travelled over a wider area compared with males [90% kernel home range (KHR) females, 5189 km(2); males, 3293 km(2)). KHR calculated for yearlings (6414 km(2)) is larger than for subadults (2534 km(2)), which again is larger than for adult seals (1713 km(2)), showing a strong site fidelity, indicating limited gene flow between haul-out sites. Distances moved and home range sizes increased across autumn, peaked in February-March, and decreased through spring. During the breeding season in spring, all seals were very stationary around Anholt. The onset of the PDV epizootics in 1988 and 2002 took place when the Anholt harbour seals congregate on the Island during April. Anholt seal were also documented to have contact with infected seal locations at Hesselo, L so, and the Swedish west coast, although this contact takes place during winter prior to the documented summer outbreaks.

  • 9. Eero, Margit
    et al.
    Hjelm, Joakim
    Behrens, Jane
    Buchmann, Kurt
    Cardinale, Massimiliano
    Casini, Michele
    Gasyukov, Pavel
    Holmgren, Noel
    Horbowy, Jan
    Hussy, Karin
    Kirkegaard, Eskild
    Kornilovs, Georgs
    Krumme, Uwe
    Koster, Friedrich W.
    Oeberst, Rainer
    Plikshs, Maris
    Radtke, Krzysztof
    Raid, Tiit
    Schmidt, Joern
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Vinther, Morten
    Zimmermann, Christopher
    Storr-Paulsen, Marie
    Food for Thought Eastern Baltic cod in distress: biological changes and challenges for stock assessment2015In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 72, no 8, p. 2180-2186Article in journal (Refereed)
    Abstract [en]

    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.

  • 10.
    Gorokhova, Elena
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Fagerberg, Towe
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Predation by herring (Clupea harengus) and sprat (Sprattus sprattus) on Cercopagis pengoi in a wastern Baltic Sea bay2004In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 61, no 6, p. 959-965Article in journal (Refereed)
  • 11.
    Hansson, Sture
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergström, Ulf
    Bonsdorff, Erik
    Härkönen, Tero
    Jepsen, Niels
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lundström, Karl
    Lunneryd, Sven-Gunnar
    Ovegård, Maria
    Salmi, Juhani
    Sendek, Dmitry
    Vetemaa, Markus
    Competition for the fish - fish extraction from the Baltic Sea by humans, aquatic mammals, and birds2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 3, p. 999-1008Article in journal (Refereed)
    Abstract [en]

    Seals and fish-eating birds have increased in the Baltic Sea and there is concern that they compete with fisheries. Using data from around year 2010, we compare consumption of different fish species by seals and birds to the catch in the commercial and recreational fishery. When applicable this is done at the geographical resolution of ICES subdivisions. Predation by birds and mammals likely has limited impact on the populations of the commercially most important species (herring, sprat, and cod). In the central and southern Baltic, seals and birds consume about as much flatfish as is caught by the fishery and competition is possible. Birds and seals consume 2-3 times as much coastal fish as is caught in the fishery. Many of these species are important to the fishery (e. g. perch and whitefish) and competition between wildlife and the fishery is likely, at least locally. Estimated wildlife consumption of pike, sea trout and pikeperch varies among ICES subdivisions and the degree of competition for these species may differ among areas. Competition between wildlife and fisheries need to be addressed in basic ecosystem research, management and conservation. This requires improved quantitative data on wildlife diets, abundances and fish production.

  • 12.
    Hansson, Sture
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergström, Ulf
    Bonsdorff, Erik
    Jepsen, Niels
    Lundström, Karl
    Lunneryd, Sven-Gunnar
    Ovegård, Maria
    Salmi, Juhani
    Sendek, Dmitry
    Vetemaa, Markus
    Response to comments by Heikinheimo et al. (in press) on Hansson et al. (2018): competition for the fish—fish extraction from the Baltic Sea by humans, aquatic mammals, and birds2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 5, p. 1837-1839Article in journal (Refereed)
    Abstract [en]

    As discussions and debates are crucial to science, we appreciate the comments by Heikinheimo et al. (in press) on our article on competition for Baltic Sea fish resources between fishery and wildlife. We cannot see that the comments by Heikinheimo et al. changes the general conclusion derived in our original article—that there are cases of competition between wildlife and fisheries in the Baltic Sea, although not for all species and not to the same extent everywhere. Our responses are structured in the same order as the comments by Heikinheimo et al.

  • 13.
    Hentati-Sundberg, Jonas
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Hjelm, J.
    Österblom, Henrik
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Does fisheries management incentivize non-compliance? Estimated misreporting in the Swedish Baltic Sea pelagic fishery based on commercial fishing effort2014In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 71, no 7, p. 1846-1853Article in journal (Refereed)
    Abstract [en]

    Fisheries management agencies and fishing industry representatives depend on reliable estimates of fish biomass and mortality for the determin- ation of sustainable catch levels. Lack of data or misreporting may be reasons for unreliable stock assessment, which, in turn, may result in advice that does not reflect the availability of fisheries resources. It has been suggested that the mixed pelagic trawl fisheries in the Baltic represent a case of biased estimates of fish biomass and mortality resulting from misreporting. Here, we estimate the degree of misreporting in the Swedish pelagic fishery (1996 – 2009) and propose an approach for reconstructing historical catches based on commercial effort data. The analysis suggests that total catches have been underestimated during part of our study period and that systematic misreporting of species composition has taken place over the whole study period. The analysis also suggests that there is overcapacity in the fishery and that such economic incentive could explain the general patterns of misreporting. Applying our method for fisheries with suspected misreporting could significantly improve assessment accuracy, reduce uncertainty and thereby allow for a better link between catches and resource levels. 

  • 14. Lassalle, Geraldine
    et al.
    Lobry, Jeremy
    Le Loc'h, Francois
    Mackinson, Steven
    Sanchez, Francisco
    Tomczak, Maciej Tomasz
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Niquil, Nathalie
    Ecosystem status and functioning: searching for rules of thumb using an intersite comparison of food-web models of Northeast Atlantic continental shelves2013In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 70, no 1, p. 135-149Article in journal (Refereed)
    Abstract [en]

    This work aimed to provide a better understanding of how the structure and function of marine ecosystems and trophic control mechanisms influence their response to perturbations. Comparative analysis of Ecopath models of four Northeast Atlantic ecosystems was used to search for rules of thumb defining the similarities and differences between them. Ecosystem indicators, related to the ecology of species interactions, were derived from these models and compared. Two main questions were addressed. (i) What are the main energy pathways and mechanisms of control? (ii) Do these ecosystems exhibit the widespread and potentially stabilizing food-web structure such that top predators couple distinct energy pathways? A strong bentho-pelagic coupling operated over the Bay of Biscay Shelf, while energy reached higher trophic levels mostly through pelagic compartments, in northern areas. Zooplankton was demonstrated to be trophically important in all ecosystems, acting as a regulator of the abundance of small pelagic fish. A latitudinal pattern in flow control was highlighted by this analysis, with a significant contribution of top-down effect at higher latitudes. This top-down control of the Baltic Sea, combined with the fact that this ecosystem did not exhibit the potentially stabilizing two-channel structure, suggested a non-stable environment.

  • 15. Lundström, Karl
    et al.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lunneryd, Sven-Gunnar
    Karlsson, Olle
    Understanding the diet composition of marine mammals: grey seals (Halichoerus grypus) in the Baltic Sea2010In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 67, no 6, p. 1230-1239Article in journal (Refereed)
    Abstract [en]

    Dietary studies are important in understanding the ecological role of marine mammals and in formulating appropriate management plans in terms of their interactions with fisheries. The validity of such studies has, however, often been compromised by unrepresentative sampling procedures, resulting in false weight being given to external factors seeming to influence diet composition. The bias caused by non-random sampling was examined, using canonical correspondence analysis to assess how the prey species composition in digestive tract samples of Baltic grey seals (Halichoerus grypus) was related to spatial, temporal, and demographic factors and to whether the samples were collected in association with fishing gear or not (“sampling condition”). Geographic region explained the largest fraction of the observed variation, followed by sampling condition, age group, and year. Season and gender were not statistically significant. Segregation of the two age categories “pups” and “juveniles–adults”, and the two geographic categories “Baltic proper” and “Gulf of Bothnia” are proposed to estimate the diet and fish consumption of the Baltic grey seal population as a whole. Atlantic herring was the most commonly recovered prey item in all areas and age groups, followed by European sprat in the south, and common whitefish in the north. Pups had eaten relatively more small non-commercial species than older seals.

  • 16. Moellmann, Christian
    et al.
    Lindegren, Martin
    Blenckner, Thorsten
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Bergström, Lena
    Casini, Michele
    Diekmann, Rabea
    Flinkman, Juha
    Muller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Neuenfeldt, Stefan
    Schmidt, Joern O.
    Tomczak, Maciej
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Voss, Ruediger
    Gårdmark, Anna
    Implementing ecosystem-based fisheries management: from single-species to integrated ecosystem assessment and advice for Baltic Sea fish stocks2014In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 71, no 5, p. 1187-1197Article in journal (Refereed)
    Abstract [en]

    Theory behind ecosystem-based management (EBM) and ecosystem-based fisheries management (EBFM) is now well developed. However, the implementation of EBFM exemplified by fisheries management in Europe is still largely based on single-species assessments and ignores the wider ecosystem context and impact. The reason for the lack or slow implementation of EBM and specifically EBFM is a lack of a coherent strategy. Such a strategy is offered by recently developed integrated ecosystem assessments (IEAs), a formal synthesis tool to quantitatively analyse information on relevant natural and socio-economic factors, in relation to specified management objectives. Here, we focus on implementing the IEA approach for Baltic Sea fish stocks. We combine both tactical and strategic management aspects into a single strategy that supports the present Baltic Sea fish stock advice, conducted by the International Council for the Exploration of the Sea (ICES). We first review the state of the art in the development of IEA within the current management framework. We then outline and discuss an approach that integrates fish stock advice and IEAs for the Baltic Sea. We intentionally focus on the central Baltic Sea and its three major fish stocks cod (Gadus morhua), herring (Clupea harengus), and sprat (Sprattus sprattus), but emphasize that our approach may be applied to other parts and stocks of the Baltic, as well as other ocean areas.

  • 17. Olsson, Jens
    et al.
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ojaveer, Henn
    Gårdmark, Anna
    Pöllumäe, Arno
    Muller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ustups, Didzis
    Dinesen, Grete E.
    Peltonen, Heikki
    Putnis, Ivars
    Szymanek, Lena
    Simm, Mart
    Heikinheimo, Outi
    Gasyukov, Pavel
    Axe, Philip
    Bergström, Lena
    Temporal development of coastal ecosystems in the Baltic Sea over the past two decades2015In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 72, no 9, p. 2539-2548Article in journal (Refereed)
    Abstract [en]

    Coastal areas are among the most biologically productive aquatic systems worldwide, but face strong and variable anthropogenic pressures. Few studies have, however, addressed the temporal development of coastal ecosystems in an integrated context. This study represents an assessment of the development over time in 13 coastal ecosystems in the Baltic Sea region during the past two decades. The study covers between two to six trophic levels per system and time-series dating back to the early 1990s. We applied multivariate analyses to assess the temporal development of biological ecosystem components and relate these to potential driving variables associated with changes in climate, hydrology, nutrient status, and fishing pressure. Our results show that structural change often occurred with similar timing in the assessed coastal systems. Moreover, in 10 of the 13 systems, a directional development of the ecosystem components was observed. The variables representing key ecosystem components generally differed across systems, due to natural differences and limitation to available data. As a result of this, the correlation between the temporal development of the biological components in each area and the driving variables assessed was to some extent area-specific. However, change in nutrient status was a common denominator of the variables most often associated with changes in the assessed systems. Our results, additionally, indicate existing strengths as well as future challenges in the capacity of currently available monitoring data to support integrated assessments and the implementation of an integrated ecosystem-based approach to the management of the Baltic Sea coastal ecosystems.

  • 18. Pekcan-Hekim, Zeynep
    et al.
    Gardmark, Anna
    Karlson, Agnes M. L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish University of Agricultural Sciences, Sweden .
    Kauppila, Pirkko
    Bergenius, Mikaela
    Bergstrom, Lena
    The role of climate and fisheries on the temporal changes in the Bothnian Bay foodweb2016In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 73, no 7, p. 1739-1749Article in journal (Refereed)
    Abstract [en]

    Climate change, eutrophication, and fishing are main pressures associated with changes in the abiotic and biotic environment in several sub-basins of the Baltic Sea. Identifying the nature of such changes is of relative importance for fisheries and environmental management. The Bothnian Bay is the northernmost sub-basin in the Baltic Sea and the responses of the foodweb to long-term changes in combined pressures have not been investigated. In this study, we explore long-term changes in the Bothnian Bay foodweb, represented by key species across all trophic levels over the past 34 years, and identify potential environmental and anthropogenic drivers. The results indicate that salinity is the most important driver to explain changes in the composition of the offshore biota in the Bothnian Bay. These changes are probably driven by indirect effects of salinity rather than bottom-up effects. A decline in the herring spawning-stock biomass was most plausibly attributed to an increased competition for food due to a parallel increase in vendace, which uses the same food resources (zooplankton and zoobenthos) and may benefit from declining salinity due to its limnic origin. A strong increase in the abundance of grey seal and ringed seal populations was seen in the late 2000s but was not related to any of the pressure variables analysed. Temperature and nutrients were not identified as important drivers of changes in the overall biota. Our study explores correlative relationships between variables and identifies potential interactions in the foodweb to generate hypotheses for further studies.

  • 19.
    Svedäng, Henrik
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Swedish Institute for the Marine Environment (SIME), Sweden; Swedish University of Agricultural Sciences (SLU), Sweden.
    Barth, Julia M. I.
    Svensson, Anders
    Jonsson, Patrik
    Jentoft, Sissel
    Knutsen, Halvor
    André, Carl
    Local cod (Gadus morhua) revealed by egg surveys and population genetic analysis after longstanding depletion on the Swedish Skagerrak coast2019In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 76, no 2, p. 418-429Article in journal (Refereed)
    Abstract [en]

    Dramatic and persistent reductions in Atlantic cod (Gadus morhua) are common in many coastal areas. While offshore cod stocks still were abundant and productive, the Swedish west coast showed signs of diminishing adult cod abundance at the beginning of the 1980s, where the local cod component was considered to be extirpated. To survey the present cod spawning activity and stock composition, we initiated egg trawling over two consecutive years (203 hauls in total) in combination with population genetic analyses (425 individually genotyped eggs). Here, we provide evidence of cod spawning at the Swedish Skagerrak coast, suggesting recolonization or that local cod has recovered from a nearly depleted state. Early stage eggs were found inside fjords too far to have been transported by oceanic drift from offshore spawning areas. The cod eggs were genetically similar in early to late life-stages and cluster mainly with the local adult cod, indicating that eggs and adults belong to the same genetic unit. The cod eggs were genetically differentiated from adult North Sea cod, and, to a lesser degree, also from the Kattegat and Öresund cod, i.e. indicating a possible recovery of local coastal stock.

    The patterns of the genetic structure in the inshore areas are, however, difficult to fully disentangle, as Atlantic cod in the North Sea-Skagerrak area seem to be a mixture of co-existing forms: local cod completing their entire life cycle in fjords and sheltered areas, and oceanic populations showing homing behaviours. The egg abundances are considerably lower compared with what is found in similar studies along the Norwegian Skagerrak coast. Nevertheless, the discovery of locally spawning cod along the Swedish west coast—although at low biomasses—is an encouraging finding that highlights the needs for endurance in protective measures and of detailed surveys to secure intraspecific biodiversity and ecosystem services.

  • 20. Tam, Jamie C.
    et al.
    Link, Jason S.
    Rossberg, Axel G.
    Rogers, Stuart I.
    Levin, Philip S.
    Rochet, Marie-Joelle
    Bundy, Alida
    Belgrano, Andrea
    Libralato, Simone
    Tomczak, Maciej
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    van de Wolfshaar, Karen
    Pranovi, Fabio
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Large, Scott I.
    Niquil, Nathalie
    Greenstreet, Simon P. R.
    Druon, Jean-Noel
    Lesutiene, Jurate
    Johansen, Marie
    Preciado, Izaskun
    Patricio, Joana
    Palialexis, Andreas
    Tett, Paul
    Johansen, Geir O.
    Houle, Jennifer
    Rindorf, Anna
    Towards ecosystem-based management: identifying operational food-web indicators for marine ecosystems2017In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 74, no 7, p. 2040-2052Article in journal (Refereed)
    Abstract [en]

    Modern approaches to Ecosystem-Based Management and sustainable use of marine resources must account for the myriad of pressures (interspecies, human and environmental) affecting marine ecosystems. The network of feeding interactions between co-existing species and populations (food webs) are an important aspect of all marine ecosystems and biodiversity. Here we describe and discuss a process to evaluate the selection of operational food-web indicators for use in evaluating marine ecosystem status. This process brought together experts in food-web ecology, marine ecology, and resource management, to identify available indicators that can be used to inform marine management. Standard evaluation criteria (availability and quality of data, conceptual basis, communicability, relevancy to management) were implemented to identify practical food-web indicators ready for operational use and indicators that hold promise for future use in policy and management. The major attributes of the final suite of operational food-web indicators were structure and functioning. Indicators that represent resilience of the marine ecosystem were less developed. Over 60 potential food-web indicators were evaluated and the final selection of operational food-web indicators includes: the primary production required to sustain a fishery, the productivity of seabirds (or charismatic megafauna), zooplankton indicators, primary productivity, integrated trophic indicators, and the biomass of trophic guilds. More efforts should be made to develop thresholds-based reference points for achieving Good Environmental Status. There is also a need for international collaborations to develop indicators that will facilitate management in marine ecosystems used by multiple countries.

  • 21. Vehmaa, Anu
    et al.
    Kremp, Anke
    Tamminen, Timo
    Hogfors, Hedvig
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Spilling, Kristian
    Engstrom-Ost, Jonna
    Copepod reproductive success in spring-bloom communities with modified diatom and dinoflagellate dominance2012In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 69, no 3, p. 351-357Article in journal (Refereed)
    Abstract [en]

    Dinoflagellates have increased and diatoms decreased in the Baltic Sea in recent decades, possibly because of changes in the climate and altered patterns of stratification. The hypothesis that grazing copepods would benefit from the change in species composition was tested experimentally by studying the reproductive output of the crustacean copepod Eurytemora affinis in five Baltic Sea phytoplankton spring communities dominated by different dinoflagellates (Biecheleria baltica, Gymnodinium corollarium) and diatoms (Chaetoceros cf. wighamii, Skeletonema marinoi, and Thalassiosira baltica). After a 5-d acclimation and a 4-d incubation, egg production, egg hatching success, and the RNA: DNA ratio of E. affinis were measured. Egg production was highest on a G. corollarium-dominated diet and lowest on a S. marinoi-dominated diet and on a B. baltica-dominated natural spring bloom, but there were no differences in hatching success. The results demonstrate strong species-specific effects unconstrained by the dominating group. Hence, the hypothesis of specific effects derived from a diatom or dinoflagellate diet is too simplistic, and there is a need to explore phytoplankton taxa at a species level to reveal the reasons for copepod reproductive success.

  • 22.
    Wilhelmsson, Dan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Malm, Torleif
    Öhman, Marcus
    Stockholm University, Faculty of Science, Department of Zoology.
    The influence of offshore wind power on demersal fish2006In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 63, no 5, p. 775-784Article in journal (Refereed)
    Abstract [en]

    A significant expansion of offshore windpower is expected in northwestern Europe in the near future. Little is known about the impacts it may have on the marine environment. Here, we investigate the potential for wind turbines to function as artificial reefs and fish aggregation devices (FADs), i.e. whether they would locally increase fish densities or alter fish assemblages. Fish communities and habitat composition were investigated using visual transects at two windpower farms off the southeastern coast of Sweden, central Baltic Sea. Fish abundance was greater in the vicinity of the turbines than in surrounding areas, while species richness and Shannon–Wiener diversity (H') were similar. On the monopiles of the turbines, fish community structure was different, and total fish abundance was greater, while species richness and diversity (H') were lower than on the surrounding seabed. Blue mussels and barnacles covered most of the submerged parts of the turbines. On the seabed, more blue mussels and a lesser cover of red algae were recorded around the power plants than elsewhere. Results from this study suggest that offshore windfarms may function as combined artificial reefs and fish aggregation devices for small demersal fish.

  • 23.
    Österblom, Henrik
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Hentati-Sundberg, Jonas
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Swedish University of Agricultural Sciences, Sweden.
    Nevonen, Nea
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Veem, Katarina
    Tinkering with a tanker-slow evolution of a Swedish ecosystem approach2017In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 74, no 1, p. 443-452Article in journal (Refereed)
    Abstract [en]

    The ecosystem approach is a salient policy paradigm originating from a scientific understanding of the reality of complex ecosystem dynamics. In this article, we investigate how Swedish national marine policies and practice between 2002 and 2015 have changed towards an ecosystem approach. Government documents, the scientific literature, institutional changes, changes in legislation, pilot projects, and changes in science and public opinion were reviewed and combined with information from expert interviews. We found that changes in policy and practice have slowly stimulated the development of an ecosystem approach, but that limited political leadership, challenges of coordination, different agency cultures, and limited learning appears to be key barriers for further and more substantial change. We compare and contrast the Swedish national process of change with other documented experiences of implementing an ecosystem approach and find that several countries struggle with similar challenges. Substantial work still remains in Sweden and we provide suggestions for how to stimulate further and more substantial change at the national level.

1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf