| 1. |
- Andreasen, Laura, et al.
(författare)
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Brugada syndrome-associated genetic loci are associated with J-point elevation and an increased risk of cardiac arrest
- 2018
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 9:JUL
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: A previous genome-wide association study found three genetic loci, rs9388451, rs10428132, and rs11708996, to increase the risk of Brugada Syndrome (BrS). Since the effect of these loci in the general population is unknown, we aimed to investigate the effect on electrocardiogram (ECG) parameters and outcomes in the general population. Materials and Methods: A cohort of 6,161 individuals (median age 45 [interquartile range (IQR) 40-50] years, 49% males), with available digital ECGs, was genotyped and subsequently followed for a median period of 13 [IQR 12.6-13.4] years. Data on outcomes were collected from Danish administrative healthcare registries. Furthermore, ~400,000 persons from UK Biobank were investigated for associations between the three loci and cardiac arrest/ventricular fibrillation (VF). Results: Homozygote carriers of the C allele in rs6800541 intronic to SCN10A had a significantly larger J-point elevation (JPE) compared with wildtype carriers (11 vs. 6 μV, P < 0.001). There was an additive effect of carrying multiple BrS-associated risk alleles with an increased JPE in lead V1. None of the BrS-associated genetic loci predisposed to syncope, atrial fibrillation, or total mortality in the general Danish population. The rs9388451 genetic locus adjacent to the HEY2 gene was associated with cardiac arrest/VF in an analysis using the UK Biobank study (odds ratio = 1.13 (95% confidence interval: 1.08-1.18), P = 0.006). Conclusions: BrS-associated risk alleles increase the JPE in lead V1 in an additive manner, but was not associated with increased mortality or syncope in the general population of Denmark. However, the HEY2 risk allele increased the risk of cardiac arrest/VF in the larger population study of UK Biobank indicating an important role of this common genetic locus.
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| 2. |
- Bernes, Claes, et al.
(författare)
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What is the influence of a reduction of planktivorous and benthivorous fish on water quality in temperate eutrophic lakes? : A systematic review
- 2015
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Ingår i: Environmental Evidence. - : BioMed Central. - 2047-2382. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIn recent decades, many attempts have been made to restore eutrophic lakes through biomanipulation. Reducing the populations of planktivorous and benthivorous fish (either directly or through stocking of piscivorous fish) may induce ecosystem changes that increase water transparency and decrease the risk of algal blooms and fish kills, at least in the short term. However, the generality of biomanipulation effects on water quality across lake types and geographical regions is not known. Therefore, we have undertaken a systematic review of such effects in eutrophic lakes in temperate regions throughout the world.MethodsSearches for literature were made using online publication databases, search engines, specialist websites and bibliographies of literature reviews. Search terms were developed in English, Danish, Dutch and Swedish. Identified articles were screened for relevance using inclusion criteria set out in an a priori protocol. To reduce the risk of bias, we then critically appraised the combined evidence found on each biomanipulation. Data were extracted on outcomes such as Secchi depth and chlorophyll a concentration before, during and/or after manipulation, and on effect modifiers such as lake properties and amounts of fish removed or stocked.ResultsOur searches identified more than 14,500 articles. After screening for relevance, 233 of them remained. After exclusions based on critical appraisal, our evidence base included useful data on 128 biomanipulations in 123 lakes. Of these interventions, 85% had been made in Europe and 15% in North America. Meta-analysis showed that removal of planktivores and benthivores (with or without piscivore stocking) leads to increased Secchi depth and decreased chlorophyll a concentration during intervention and the first three years afterwards. Piscivore stocking alone has no significant effect. The response of chlorophyll a levels to biomanipulation is stronger in lakes where fish removal is intense, and in lakes which are small and/or have high pre-manipulation concentrations of total phosphorus.ConclusionsOur review improves on previous reviews of biomanipulation in that we identified a large number of case studies from many parts of the world and used a consistent, repeatable process to screen them for relevance and susceptibility to bias. Our results indicate that removal of planktivorous and benthivorous fish is a useful means of improving water quality in eutrophic lakes. Biomanipulation tends to be particularly successful in relatively small lakes with short retention times and high phosphorus levels. More thorough fish removal increases the efficacy of biomanipulation. Nonetheless successes and failures have occurred across a wide range of conditions.
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| 3. |
- Bernes, Claes, et al.
(författare)
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What is the influence on water quality in temperate eutrophic lakes of a reduction of planktivorous and benthivorous fish? : A systematic review protocol
- 2013
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Ingår i: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 2:1
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Forskningsöversikt (refereegranskat)abstract
- Background: In lakes that have become eutrophic due to sewage discharges or nutrient runoff from land, problems such as algal blooms and oxygen deficiency often persist even when nutrient supplies have been reduced. One reason is that phosphorus stored in the sediments can exchange with the water. There are indications that the high abundance of phytoplankton, turbid water and lack of submerged vegetation seen in many eutrophic lakes may represent a semi-stable state. For that reason, a shift back to more natural clear-water conditions could be difficult to achieve. In some cases, though, temporary mitigation of eutrophication-related problems has been accomplished through biomanipulation: stocks of zooplanktivorous fish have been reduced by intensive fishing, leading to increased populations of phytoplankton-feeding zooplankton. Moreover, reduction of benthivorous fish may result in lower phosphorus fluxes from the sediments. An alternative to reducing the dominance of planktivores and benthivores by fishing is to stock lakes with piscivorous fish. These two approaches have often been used in combination. The implementation of the EU Water Framework Directive has recently led to more stringent demands for measures against eutrophication, and a systematic review could clarify whether biomanipulation is efficient as a measure of that kind. Methods: The review will examine primary field studies of how large-scale biomanipulation has affected water quality and community structure in eutrophic lakes or reservoirs in temperate regions. Such studies can be based on comparison between conditions before and after manipulation, on comparison between treated and nontreated water bodies, or both. Relevant outcomes include Secchi depth, concentrations of oxygen, nutrients, suspended solids and chlorophyll, abundance and composition of phytoplankton, zooplankton and fish, and coverage of submerged macrophytes.
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| 4. |
- Brodersen, Jakob, et al.
(författare)
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Condition-dependent individual decision-making determines cyprinid partial migration
- 2008
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 89:5, s. 1195-1200
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Tidskriftsartikel (refereegranskat)abstract
- Partial migration is a common phenomenon among many animals and occurs in many types of ecosystems. Understanding the mechanisms behind partial migration is of major importance for the understanding of population dynamics and, eventually, ecosystem processes. We studied the effects of food availability on the seasonal partial migration of cyprinid fish from a lake to connected streams during winter by the use of passive telemetry. Fish with increased access to food were found to migrate in higher proportion, earlier in the season, and to reside in the streams for a longer period compared to fish with decreased access to food. Furthermore, fewer unfed migrants returned to the lake, indicating higher overwinter mortality. Our results suggest that individual fish trade off safety from predation and access to food differently depending on their body condition, which results in a condition-dependent partial migration. Hence, our main conclusion is that individual decision-making is based on assessment of own condition which offers a mechanistic explanation to partial migration. Moreover, this may be of high importance for understanding population responses to environmental variation as well as ecosystem dynamics and stability. Read More: http://www.esajournals.org/doi/abs/10.1890/07-1318.1
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Brodersen, Jakob, et al.
(författare)
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Variable individual consistency in timing and destination of winter migrating fish
- 2012
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 8, s. 21-23
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Tidskriftsartikel (refereegranskat)abstract
- Migration is an important event in the life history of many animals, but there is considerable variation within populations in the timing and final destination. Such differential migration at the population level can be strongly determined by individuals showing different consistencies in migratory traits. By tagging individual cyprinid fish with uniquely coded electronic tags, and recording their winter migrations from lakes to streams for 6 consecutive years, we obtained highly detailed long-term information on the differential migration patterns of individuals. We found that individual migrants showed consistent site fidelities for over-wintering streams over multiple migratory seasons and that they were also consistent in their seasonal timing of migration. Our data also suggest that consistency itself can be considered as an individual trait, with migrants that exhibit consistent site fidelity also showing consistency in migratory timing. The finding of a mixture of both consistent and inconsistent individuals within a population furthers our understanding of intrapopulation variability in migration strategies, and we hypothesize that environmental variation can maintain such different strategies.
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| 9. |
- Brönmark, Christer, et al.
(författare)
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Ponds as experimental arenas for studying animal movement : current research and future prospects
- 2023
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Ingår i: Movement Ecology. - 2051-3933. ; 11
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Forskningsöversikt (refereegranskat)abstract
- Animal movement is a multifaceted process that occurs for multiple reasons with powerful consequences for food web and ecosystem dynamics. New paradigms and technical innovations have recently pervaded the field, providing increasingly powerful means to deliver fine-scale movement data, attracting renewed interest. Specifically in the aquatic environment, tracking with acoustic telemetry now provides integral spatiotemporal information to follow individual movements in the wild. Yet, this technology also holds great promise for experimental studies, enhancing our ability to truly establish cause-and-effect relationships. Here, we argue that ponds with well-defined borders (i.e. “islands in a sea of land”) are particularly well suited for this purpose. To support our argument, we also discuss recent experiences from studies conducted in an innovative experimental infrastructure, composed of replicated ponds equipped with modern aquatic telemetry systems that allow for unparalleled insights into the movement patterns of individual animals.
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| 10. |
- Brönmark, Christer, et al.
(författare)
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Regime shifts in shallow lakes: the importance of seasonal fish migration
- 2010
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 646:1, s. 91-100
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Konferensbidrag (refereegranskat)abstract
- Shallow eutrophic lakes commonly exist in two alternative stable states: a clear-water state and a turbid water state. A number of mechanisms, including both abiotic and biotic processes, buffer the respective states against changes, whereas other mechanisms likely drive transitions between states. Our earlier research shows that a large proportion of zooplanktivorous fish populations in shallow lakes undertake seasonal migrations where they leave the lake during winter and migrate back to the lake in spring. Based on our past research, we propose a number of scenarios of how feedback processes between the individual and ecosystem levels may affect stability of alternative stable states in shallow lakes when mediated by fish migration. Migration effects on shallow lakes result from processes at different scales, from the individual to the ecosystem. Our earlier research has shown that ecosystem properties, including piscivore abundance and zooplankton productivity, affect the individual state of zooplanktivorous fish, such as growth rate or condition. Individual state, in turn, affects the relative proportion and timing of migrating zooplanktivorous fish. This change, in turn, may stabilize states or cause runaway processes that eventually lead to state shifts. Consequently, such knowledge of processes coupled to seasonal migration of planktivorous fish should increase our understanding of shallow lake dynamics.
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| 11. |
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| 12. |
- Brönmark, Christer, et al.
(författare)
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Seasonal migration determined by a trade-off between predator avoidance and growth
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Migration is a common phenomenon in many organisms, terrestrial as well as aquatic, and considerable effort has been spent to understand the evolution of migratory behaviour and its consequences for population and community dynamics. In aquatic systems, studies on migration have mainly been focused on commercially important fish species, such as salmon and trout. However, seasonal mass-migrations may occur also among other freshwater fish, e.g. in cyprinids that leave lakes and migrate into streams and wetlands in the fall and return back to the lake in spring. In a conceptual model, we hypothesized that this is an adaptive behaviour in response to seasonal changes in predation (P) and growth (G) and that migrating fish change habitat so as to minimise the ratio between predation mortality and growth rate (P/G). Estimates from bioenergetic modelling showed that seasonal changes in the ratio between predator consumption rate and prey growth rate followed the predictions from the conceptual model and also gave more precise predictions for the timing of the habitat change. By quantifying the migration of more than 1800 individually marked fish, we showed that actual migration patterns followed predictions with a remarkable accuracy, suggesting that migration patterns have evolved in response to seasonally fluctuating trade-offs between predator avoidance and foraging gains. Thus, the conceptual model provides a mechanistic understanding to mass–migration in prey fish. Further, we also show that the dominant prey fish is actually absent from the lake during a major part of the year, which should have strong implications for the dynamics of the lake ecosystem through direct and indirect food-web interactions.
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| 13. |
- Chapman, Ben, et al.
(författare)
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A foraging cost of migration for a partially migratory cyprinid fish
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Migration has evolved as a strategy to maximise individual fitness in response to seasonally changing ecological and environmental conditions. However, migration can also incur costs, and quantifying these costs can provide important clues to the ultimate ecological forces that underpin migratory behaviour. A key emerging model to explain migration in many systems posits that migration is driven by seasonal changes to a predation/growth potential (p/g) trade-off that a wide range of animals face. In this study we assess a key assumption of this model for a common cyprinid partial migrant, the roach Rutilus rutilus, which migrates from shallow lakes to streams during winter. By sampling fish from stream and lake habitats in the autumn and spring and measuring their stomach fullness and diet composition, we tested if migrating roach pay a cost of reduced foraging when migrating. Resident fish had fuller stomachs containing more high quality prey items than migrant fish. Hence, we document a feeding cost to migration in roach, which adds additional support for the validity of the p/g model of migration in freshwater systems.
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| 14. |
- Chapman, Ben, et al.
(författare)
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To boldly go: individual differences in boldness influence migratory tendency.
- 2011
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X. ; 14, s. 871-876
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Tidskriftsartikel (refereegranskat)abstract
- Ecology Letters (2011) ABSTRACT: Partial migration, whereby only a fraction of the population migrates, is thought to be the most common type of migration in the animal kingdom, and can have important ecological and evolutionary consequences. Despite this, the factors that influence which individuals migrate and which remain resident are poorly understood. Recent work has shown that consistent individual differences in personality traits in animals can be ecologically important, but field studies integrating personality traits with migratory behaviour are extremely rare. In this study, we investigate the influence of individual boldness, an important personality trait, upon the migratory propensity of roach, a freshwater fish, over two consecutive migration seasons. We assay and individually tag 460 roach and show that boldness influences migratory propensity, with bold individuals being more likely to migrate than shy fish. Our data suggest that an extremely widespread personality trait in animals can have significant ecological consequences via influencing individual-level migratory behaviour.
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| 15. |
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| 16. |
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| 17. |
- Engstedt, Olof, 1980-, et al.
(författare)
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Annual spawning migration of anadromous pike (Esox lucius L.) in streams entering the Baltic Sea
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The movement of pike (n = 3415) was investigated in four streams entering the Baltic Sea in the Kalmar Sound region, Sweden. Migration patterns were monitored during spawning in three of the streams and during the whole year in the forth stream using passive integrated transponders and outer tags. The study was conducted yearly between 2006 and 2010. Mature pike returned (22 – 45%) to the same streams year after year and some fish returned to the same regions of the streams. No incidence of fish visiting another stream than the one where they were marked was recorded and no fish missed the spawning season to return the next year. These results indicated that the reason for fish not returning was due to mortality. The proportions of returning fish indicated homing and the spawning ground fidelity (stream) was high. Return rates were influenced by size of fish, sex and stream identity. We also investigated if sex, size or individual behaviour influenced timing of arrival, departure or duration of stay in freshwater. Diurnal activity was examined in one year in each stream suggesting activity peaks in the morning and evening. The results show that pike in the Baltic Sea are anadromous and that the migration behavior is likely to create barriers for gene flow. The separation in populations by spawning are similar to salmonid species and the management of pike in the Baltic Sea must consider this process in strategies and plans of fishing.
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| 18. |
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| 19. |
- Granholm, Anders, et al.
(författare)
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Empirical meropenem versus piperacillin/tazobactam for adult patients with sepsis (EMPRESS) trial : Protocol
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Ingår i: Acta Anaesthesiologica Scandinavica. - 0001-5172.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Piperacillin/tazobactam may be associated with less favourable outcomes than carbapenems in patients with severe bacterial infections, but the certainty of evidence is low. Methods: The Empirical Meropenem versus Piperacillin/Tazobactam for Adult Patients with Sepsis (EMPRESS) trial is an investigator-initiated, international, parallel-group, randomised, open-label, adaptive clinical trial with an integrated feasibility phase. We will randomise adult, critically ill patients with sepsis to empirical treatment with meropenem or piperacillin/tazobactam for up to 30 days. The primary outcome is 30-day all-cause mortality. The secondary outcomes are serious adverse reactions within 30 days; isolation precautions due to resistant bacteria within 30 days; days alive without life support and days alive and out of hospital within 30 and 90 days; 90- and 180-day all-cause mortality and 180-day health-related quality of life. EMPRESS will use Bayesian statistical models with weak to somewhat sceptical neutral priors. Adaptive analyses will be conducted after follow-up of the primary outcome for the first 400 participants concludes and after every 300 subsequent participants, with adaptive stopping for superiority/inferiority and practical equivalence (absolute risk difference <2.5%-points) and response-adaptive randomisation. The expected sample sizes in scenarios with no, small or large differences are 5189, 5859 and 2570 participants, with maximum 14,000 participants and ≥99% probability of conclusiveness across all scenarios. Conclusions: EMPRESS will compare the effects of empirical meropenem against piperacillin/tazobactam in adult, critically ill patients with sepsis. Due to the pragmatic, adaptive design with high probability of conclusiveness, the trial results are expected to directly inform clinical practice.
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| 20. |
- Hansen, Joan H., et al.
(författare)
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Ecological consequences of animal migration : Prey partial migration affects predator ecology and prey communities
- 2019
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Ingår i: Ecosystems (New York. Print). - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; , s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of animal migration and the ecological forces that shape them have been studied for centuries. Yet ecological impacts caused by the migration, such as altered predator–prey interactions and effects on community structure, remain poorly understood. This is to a large extent due to the scarcity of naturally replicated migration systems with negative controls, that is, ecosystems without migration. In this study, we tested whether partial migration of certain species within the overall prey community affects foraging ecology of top predators and thereby alters energy pathways in food webs. We carried out the study in independent replicated freshwater lake systems, four with and four without opportunity for prey migration. Specifically, we compared predator foraging mode in lakes where cyprinid prey fish perform seasonal partial migrations into connected streams with lakes lacking migratory opportunities for prey fish. We found clear seasonal bottom-up effects of prey migration on predators, including changes in size structure and total biomass of ingested prey, size-specific changes in littoral versus pelagic origin of diet, and a higher degree of feast-and-famine for predators in systems with migratory prey. Our analyses further showed that partially migratory prey species constitute a larger part of the prey community in systems that allow migration. Hence, prey migrations have important implications for predator foraging ecology and may cause seasonal shifts in the importance of their supporting energy pathways. We suggest that such bottom-up effects of partial migration may be a widespread phenomenon both in aquatic and in terrestrial ecosystems. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
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| 21. |
- Hansson, Lars-Anders, et al.
(författare)
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A lake as a microcosm : Reflections on developments in aquatic ecology
- 2013
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Ingår i: Aquatic Ecology. - : Springer Science and Business Media LLC. - 1386-2588 .- 1573-5125. ; 47, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we aim at relating Forbes' remarkable paper on "The lake as a microcosm", published 125 years ago, to the present status of knowledge in our own research group. Hence, we relate the observations Forbes made to our own microcosm, Lake Krankesjon in southern Sweden, that has been intensively studied by several research groups for more than three decades. Specifically, we focus on the question: Have we made any significant progress or did Forbes and colleagues blaze the trail through the unknown wilderness and we are mainly paving that intellectual road? We conclude that lakes are more isolated than many other biomes, but have, indeed, many extensions, for example, input from the catchment, fishing and fish migration. We also conclude that irrespective of whether lakes should be viewed as microcosms or not, the paper by Forbes has been exceptionally influential and still is, especially since it touches upon almost all aspects of the lake ecosystem, from individual behaviour to food web interactions and environmental issues. Therefore, there is no doubt that even if 125 years have passed, Forbes' paper still is a source of inspiration and deserves to be read. Hence, although aquatic ecology has made considerable progress over the latest century, Forbes might be viewed as one of the major pioneers and visionary scientists of limnology.
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| 22. |
- Hansson, Lars-Anders, et al.
(författare)
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Consequences of fish predation, migration, and juvenile ontogeny on zooplankton spring dynamics
- 2007
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Ingår i: Limnology and Oceanography. - 1939-5590. ; 52:2, s. 696-706
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Tidskriftsartikel (refereegranskat)abstract
- In order to disentangle if and when resource supply and adult and young-of-the-year (0+) fish predation affect zooplankton dynamics during spring, we monitored zooplankton during three consecutive years in a lake in southern Sweden. We also experimentally assessed 0+ fish predation rates and estimated changes in predation rates of adult fish on zooplankton. Decline in abundances of large-sized zooplankters in early spring was not caused by 0+ fish predation. Instead, this decline was most likely a combined result of size-selective predation from adult fish (stationary in the lake and from those returning from surrounding streams) and competition for diminishing algal food resources. On the other hand, the decline in medium-sized zooplankton in the lake during spring was strongly affected by 0+ fish. Hence, during spring, zooplankton are facing predation both from adult fish selecting large prey and from 0+ fish, which start feeding on small-sized prey and eventually switch to larger. Neither predation by different ontogenetic stages of fish (adult and 0+) nor resource supply shape the zooplankton spring dynamics, but rather they affect the timing and strength of these events. 0+ cyprinids tend to have stronger effect on zooplankton dynamics than other taxa of 0+ fish. A combination of predation from adult and 0+ fish during spring is the main mechanism behind the crash of the zooplankton community, which in many lakes leads to the termination of the clear-water phase.
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| 23. |
- Holder, Peter E., et al.
(författare)
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Preparing for a changing future in recreational fisheries : 100 research questions for global consideration emerging from a horizon scan
- 2020
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Ingår i: Reviews in Fish Biology and Fisheries. - : Springer Science and Business Media LLC. - 0960-3166 .- 1573-5184. ; 30:1, s. 137-151
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Forskningsöversikt (refereegranskat)abstract
- Recreational fisheries hold immense ecological, social, and economic value. The management of these fisheries is increasingly important as we move forward in the Anthropocene. Recreational fisheries managers face several challenges as fisheries often involve diverse social and ecological systems comprised of complex feedback and stakeholder motivations and needs. Here, we used a horizon scanning exercise to yield 100 research questions related to recreational fisheries science and management in the Anthropocene. Initial research questions (n = 205) were collected from recreational fisheries experts (i.e., stakeholders, managers, researchers) from various sectors (i.e., industry, government, NGOs) and geographic locations (14 countries: Australia, Brazil, Canada, Czech Republic, Germany, Italy, New Zealand, Norway, South Africa, Spain, Sweden, Switzerland, United Kingdom, USA). These questions were subsequently categorized, thematized, and refined by our authorship team, eventually yielding what we considered to be the top 100 research questions of relevance to management of recreational fisheries. The key themes include: human dimensions; bioeconomics; resource monitoring and data acquisition; governance; management-regulatory actions; management-stock and habitat enhancement; catch-and-release; impacts of recreational fisheries on populations, communities and ecosystems; threats and sustainability; and angler outreach, education and engagement. It is our intention that this comprehensive and forward-looking list will create a framework to guide future research within this field, and contribute to evidence-based recreational fisheries management and policy.
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| 24. |
- Hulthén, Kaj, et al.
(författare)
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A predation cost to bold fish in the wild
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Studies of predator-mediated selection on behaviour are critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations. Consistent individual differences in prey behaviour, especially in the propensity to take risks (“boldness”), are widespread in the animal kingdom. Theory predicts that individual behavioural types differ in a cost-benefit trade-off where bolder individuals benefit from greater access to resources while paying higher predation-risk costs. However, explicitly linking predation events to individual behaviour under natural conditions is challenging and there is currently little data from the wild. We assayed individual behaviour and electronically tagged hundreds of fish (roach, Rutilus rutilus) before releasing them into their lake of origin, thereby exposing them to predation risk from avian apex predators (cormorants, Phalacrocorax carbo). Scanning for regurgitated tags at the cormorant roosting site provided data on individual predation events. We found that fish with higher boldness have a greater susceptibility to cormorant predation compared to relatively shy, risk-averse individuals. Our findings hereby provide unique and direct evidence of behavioural type-dependent predation vulnerability in the wild, i.e. that there is a predation cost to boldness, which is critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations.
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| 25. |
- Hulthén, Kaj, et al.
(författare)
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Timing and synchrony of migration in a freshwater fish : Consequences for survival
- 2022
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 91:10, s. 2103-2112
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Tidskriftsartikel (refereegranskat)abstract
- Animal migration is one of the most spectacular and visible behavioural phenomena in nature with profound implications for a range of ecological and evolutionary processes. Successful migration hinges on the ability to exploit temporary resources (e.g. food) and evade threats (e.g. predators) as they arise, and thus the timing of migration is often regarded as a dominant predictor of individual migratory success. However, with the exception of intensively studied taxa (mainly birds), relatively few studies have investigated inter-individual annual and seasonal variation in migratory timing and performance, or tested predictions on how migration across high and low predation-risk habitats may exert selection on migratory timing. In particular, studies that assess the survival consequences of variation in migratory timing remain rare, which is most likely due to the logistical challenges associated with monitoring survival success and population-level characteristics simultaneously. Here, we address the above-mentioned questions using roach Rutilus rutilus, a fish that migrates from lakes characterised by high predation risk into low-risk streams during winter. Specifically, we used individual-based tracking of roach in two European lake systems over multiple migration periods (9 and 7 years respectively), to obtain highly detailed (year-round scheduling, repeat journeys and the fate of individuals) data on the variability/synchrony of migratory timing in spring and autumn respectively. We report seasonal differences in the variability of migratory timing, with lower variance and higher migration synchrony in spring lake arrival timing as compared to autumn lake departure timing. Furthermore, the timing of autumn migration is more variable across years than the timing of spring migration. Second, we find that later arrival to the lake habitat is positively associated with apparent survival from 1 year to the next, whereas we found no effect of lake departure timing on survival probability. These findings represent rare evidence showing how intraspecific variation in timing in migratory fish differs across years and seasons, and how variation in timing can translate into survival consequences for prey in systems characterised by high predation risk.
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| 26. |
- Højskov, Ida Elisabeth, et al.
(författare)
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Early physical and psycho-educational rehabilitation in patients with coronary artery bypass grafting: A randomized controlled trial.
- 2019
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Ingår i: Journal of Rehabilitation Medicine. - : Medical Journals Sweden AB. - 1650-1977. ; 51:2, s. 136-143
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Tidskriftsartikel (refereegranskat)abstract
- Rehabilitation of patients following coronary artery bypass grafting (CABG) has been widely studied; however, research into early rehabilitation after CABG is sparse. The aim of this trial was to assess the impact of early rehabilitation, compared with usual care in patients following CABG.Randomized controlled trial.A total of 326 patients treated with CABG.Patients treated with CABG were randomized 1:1 to 4 weeks of comprehensive early rehabilitation or usual care. The primary outcome was the Six Minute Walk Test (6MWT). Secondary outcomes were mental health and physical activity (Medical Outcome Study Short Form; SF-12); anxiety and depression (Hospital Anxiety and Depression Scale; HADS); physical and emotional scores; sleep (Pittsburgh Sleep Quality Index; PSQI); pain (Örebro Musculoskeletal Screening Questionnaire; ÖMSQ) and muscle endurance (Sit-To-Stand test).Sixteen patients dropped out. No significant differences between groups in the primary outcome (6MWT) were found after 4 weeks (p=0.27). For secondary outcomes the odds ratio of HADS-D ≥8 decreased in favour of the experimental intervention (p=0.04). There was non-adherence to parts of the intervention. Per-protocol analysis showed differences between groups for the 6MWT (p=0.02) and the Sit-To-Stand test (p=0.046).In general, the intervention had no effect on the 6MWT, or secondary outcomes, except for depressive symptoms. However, in adherent participants, the intervention had a positive effect for the primary and several secondary outcomes.
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| 27. |
- Højskov, Ida Elisabeth, et al.
(författare)
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SheppHeartCABG trial-comprehensive early rehabilitation after coronary artery bypass grafting: a protocol for a randomised clinical trial.
- 2017
-
Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Patients undergoing coronary artery bypass graft surgery often experience a range of symptoms. Studies indicate that non-pharmacological interventions such as exercise training and psychoeducation have a positive physiological and psychological effect in early outpatient rehabilitation. The SheppHeartCABG trial will investigate the effect of early comprehensive rehabilitation in early phase rehabilitation versus usual care. The aim of this paper is to present the protocol for the SheppHeartCABG trial.SheppHeartCABG is an investigator-initiated randomised clinical superiority trial with blinded outcome assessment, employing 1:1 central randomisation to rehabilitation plus usual care versus usual care alone. On the basis of a sample size calculation, 326 patients undergoing coronary artery bypass grafting will be included from two clinical sites. All patients receive usual care and patients allocated to the experimental intervention follow 4weeks rehabilitation consisting of an exercise programme, psycho-educative consultations and a compact mindfulness programme. The primary outcome is physical function measured by the 6-min walk test. The secondary outcomes are mental health and physical activity measured by the Medical Outcome Study Short Form (SF-12), anxiety and depression measured by the Hospital Anxiety and Depression Scale questionnaire, physical, emotional and global scores by the HeartQoL questionnaire, sleep measured by the Pittsburgh Sleep Quality Index, pain measured by the Örebro Musculoskeletal Screening Questionnaire and muscle endurance measured by the sit-to-stand test. A number of explorative analyses will also be conducted.SheppHeartCABG is approved by the regional ethics committee (no. H-4-2014-109) and the Danish Data Protection Agency (no. 30-1309) and is performed in accordance with good clinical practice and the Declaration of Helsinki in its latest form. Positive, neutral and negative results of the trial will be submitted to international peer-reviewed journals. Furthermore, results will be presented at national and international conferences relevant to the subject fields.NCT02290262; pre-results.
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| 28. |
- Jönsson, Mikael, et al.
(författare)
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Temporal clumping of prey and coexistence of unequal interferers: experiments on social forager groups of brown trout feeding on invertebrate drift
- 2008
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Ingår i: Oikos. - : Wiley. - 1600-0706 .- 0030-1299. ; 117:12, s. 1782-1787
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Tidskriftsartikel (refereegranskat)abstract
- Environmental fluctuations have been proposed to enhance the coexistence of competing phenotypes. Evaluations are here presented on the effects of prey density and short-term temporal clumping of prey availability on the relative foraging success of unequal interferers in social forager groups of juvenile brown trout Salmo trutta feeding on drifting invertebrate prey (frozen chironomids). Groups of three trout with established linear dominance hierarchies (dominant, intermediate and subordinate) were subjected to three different total numbers of prey, combined with three different levels of temporal clumping of prey arrival, resulting in nine treatment combinations. Higher total number of prey increased the consumption for all dominance ranks, while higher temporal clumping decreased the consumption for the dominant individuals and increased the consumption for the subordinate individuals. The proportion of prey eaten was smaller at high prey numbers. Similarly, there was a trend that increased temporal clumping also decreased the proportion of prey eaten. We conclude that density and temporal clumping of prey contribute to the coexistence of unequal interferers, and that there is a potential positive feedback between prey behaviour and phenotypic coexistence through decreased per capita predation risk for prey that drift synchronously in high densities.
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| 29. |
- Lane, Jennifer C E, et al.
(författare)
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Risk of depression, suicide and psychosis with hydroxychloroquine treatment for rheumatoid arthritis: a multinational network cohort study.
- 2021
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Ingår i: Rheumatology (Oxford, England). - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 60:7, s. 3222-3234
-
Tidskriftsartikel (refereegranskat)abstract
- Concern has been raised in the rheumatology community regarding recent regulatory warnings that HCQ used in the coronavirus disease 2019 pandemic could cause acute psychiatric events. We aimed to study whether there is risk of incident depression, suicidal ideation or psychosis associated with HCQ as used for RA.We performed a new-user cohort study using claims and electronic medical records from 10 sources and 3 countries (Germany, UK and USA). RA patients ≥18years of age and initiating HCQ were compared with those initiating SSZ (active comparator) and followed up in the short (30days) and long term (on treatment). Study outcomes included depression, suicide/suicidal ideation and hospitalization for psychosis. Propensity score stratification and calibration using negative control outcomes were used to address confounding. Cox models were fitted to estimate database-specific calibrated hazard ratios (HRs), with estimates pooled where I2<40%.A total of 918144 and 290383 users of HCQ and SSZ, respectively, were included. No consistent risk of psychiatric events was observed with short-term HCQ (compared with SSZ) use, with meta-analytic HRs of 0.96 (95% CI 0.79, 1.16) for depression, 0.94 (95% CI 0.49, 1.77) for suicide/suicidal ideation and 1.03 (95% CI 0.66, 1.60) for psychosis. No consistent long-term risk was seen, with meta-analytic HRs of 0.94 (95% CI 0.71, 1.26) for depression, 0.77 (95% CI 0.56, 1.07) for suicide/suicidal ideation and 0.99 (95% CI 0.72, 1.35) for psychosis.HCQ as used to treat RA does not appear to increase the risk of depression, suicide/suicidal ideation or psychosis compared with SSZ. No effects were seen in the short or long term. Use at a higher dose or for different indications needs further investigation.Registered with EU PAS (reference no. EUPAS34497; http://www.encepp.eu/encepp/viewResource.htm? id=34498). The full study protocol and analysis source code can be found at https://github.com/ohdsi-studies/Covid19EstimationHydroxychloroquine2.
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| 30. |
- Nilsson, Anders, et al.
(författare)
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Environmental Conditions and Intraspecific Interference: Unexpected Effects of Turbidity on Pike (Esox lucius) Foraging
- 2009
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Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 115:1, s. 33-38
-
Tidskriftsartikel (refereegranskat)abstract
- Interference among predators decreases per capita foraging rates and has implications for both community dynamics and top-down trophic processes. Interference originates from behavioural interactions among foragers, and these behaviours could be affected by environmental conditions. In experiments on pike foraging alone or among conspecifics in different levels of water turbidity, we expected high turbidity to decrease the perceived risk of intraspecific interactions among pike, and thereby decrease the strength of interference, as turbidity would decrease the visual contact between individuals and act as a refuge from behavioural interactions. The results show that this is not the case, but suggest that interference is induced instead of reduced in high turbidity. Per capita foraging rates do not differ between pike foraging alone or in groups in our clear and moderately turbid treatments, indicating no effect of interference. As high turbidity enhances prey consumption for pike individuals foraging alone, but does not have this effect for pike in groups, high turbidity induces the relative interference effect. We suggest that future evaluations of the stabilizing effects of interference on community dynamics and its reduction of predation impact on top-down trophic cascades should consider potential unexpected effects of environmental conditions.
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| 31. |
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| 32. |
- Nilsson, P. Anders, et al.
(författare)
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Finding food and staying alive
- 2018
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Ingår i: Biology and ecology of pike. - Boca Raton : CRC Press. - 9781482262902 ; , s. 9-31
-
Bokkapitel (refereegranskat)
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| 33. |
- Nilsson, Per Anders, 1968-, et al.
(författare)
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Species integrity enhanced by a predation cost to hybrids in the wild
- 2017
-
Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 13:7, s. 1-4
-
Tidskriftsartikel (refereegranskat)abstract
- Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of par- ental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post- zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of- concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3–4 years later ident- ified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.
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| 34. |
- Nourbakhsh, Nima, et al.
(författare)
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Effects of Corticosteroid Treatment on Mycophenolic Acid Exposure in Renal Transplant Patients—Results From the SAILOR Study
- 2021
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Ingår i: Frontiers in Pharmacology. - : Frontiers Media SA. - 1663-9812. ; 12:September 2021
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Mycophenolic acid (MPA) is a potent immunosuppressive agent used in solid organ transplantation. MPA exhibits large interindividual variation in dose-normalized plasma concentrations but is nevertheless usually prescribed as a fixed dose without use of therapeutic drug monitoring (TDM). Data on the effect of corticosteroid (CS) treatment on MPA concentrations during concomitant tacrolimus treatment remains sparse. Methods: Data is based on TDM of MPA area under the concentration curve (AUC) in 210 renal transplant recipients participating in the prospective, randomized, controlled, multi-center trial (SAILOR) where a steroid-free immunosuppressive regimen with mycophenolate mofetil (MMF) and low-dose tacrolimus was compared with a conventional prednisolone-based treatment regimen. Multilevel mixed-effects linear regression post-hoc analyses of MPA AUC was performed. Results: Median MPA AUC at baseline (within the first 2 weeks post-transplant) in patients taking 2 g MMF daily was 53 mg*h/L (interquartile range: 43–69 mg*h/L, min: 24—max: 117 mg*h/L). Between-patient variation in MPA AUC was up to 5-fold on the same MMF dose. Patients in the steroid-free group had 12.5% lower (95% CI; 3.2–20.9%, p = 0.01) MPA AUC levels at baseline compared to the steroid treated group. During follow-up (14 days–2 years post-transplant) there were no significant differences in MPA AUC between the groups with MPA AUC being 4.2% lower (95% CI: −4.8%−12,5%, p = 0.35) in the steroid-free vs standard treatment group in restricted analysis after multivariate adjustment for tacrolimus trough level, body weight, time after transplantation and MMF dose. MMF dose was positively correlated with MPA AUC (p < 0.001) whereas body weight was negatively correlated with MPA AUC (p < 0.001). MPA AUC was 0.4% (95% CI: 0.2–0.6%, p < 0.001) lower per 1 kg increase in weight. Tacrolimus trough levels had no significant effect on MPA AUC. Conclusion: Immunosuppression with CS during concomitant tacrolimus treatment was shortly after transplantation associated with a significantly higher MPA exposure but the effect was small and not maintained during follow-up. Low body weight was associated with higher MPA exposure, which suggests a potential for weight adjusted MMF dosing.
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| 35. |
- Persson, Anders, et al.
(författare)
-
Trophic interactions
- 2018
-
Ingår i: Biology and ecology of pike. - Boca Raton : CRC Press. - 9781482262902
-
Bokkapitel (refereegranskat)
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| 36. |
- Pärssinen, Varpu, et al.
(författare)
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Maladaptive migration behaviour in hybrids links to predator-mediated ecological selection
- 2020
-
Ingår i: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656. ; 89:11, s. 2596-2604
-
Tidskriftsartikel (refereegranskat)abstract
- Different migratory species have evolved distinct migratory characteristics that improve fitness in their particular ecological niches. However, when such species hybridize, migratory traits from parental species can combine maladaptively and cause hybrids to fall between parental fitness peaks, with potential consequences for hybrid viability and species integrity. Here, we take advantage of a natural cross-breeding incident to study migratory behaviour in naturally occurring hybrids as well as in their parental species and explore links between migratory traits and predation risk. To achieve this, we used electronic tags and passive telemetry to record detailed individual migration patterns (timing and number of migratory trips) in two common freshwater fish species, roachRutilus rutilus, common breamAbramis bramaas well as their hybrids. Next, we scanned for tags regurgitated by a key avian predator (great cormorantPhalacrocorax carbo) at nearby roosting sites, allowing us to directly link migratory behaviour to predation risk in the wild. We found that hybrid individuals showed a higher number of short, multi-trip movements between lake and stream habitats as compared to both parental species. The mean date of first lake departure differed between bream and roach by more than 10 days, while hybrids departed in two distinct peaks that overlapped with the parental species' averages. Moreover, the probability of cormorant predation increased with multi-trip movement frequency across species and was higher for hybrids. Our data provide novel insights into hybrid viability, with links to predator-mediated ecological selection. Increased exposure to predators via maladaptive migratory behaviour reduces hybrid survival and can thereby reinforce species integrity.
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| 37. |
- Skov, Christian, et al.
(författare)
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A field evaluation of long-term effects of PIT tagging
- 2020
-
Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 96:4, s. 1055-1059
-
Tidskriftsartikel (refereegranskat)abstract
- Passive integrated transponder (PIT)-tagging is commonly used in behavioural studies of fish, although long-term evaluations of effects from tagging under natural conditions are scarce. We PIT-tagged common bream Abramis brama, European perch Perca fluviatilis, pike Esox lucius and roach Rutilus rutilus, released them in their lakes of origin and recaptured them after 103–3269 days. Overall, tagged fish did not differ in condition from non-tagged fish, except for small R. rutilus that had a lower length-specific body mass in one lake in 1 year. We conclude that PIT-tagging in general has negligible long-term effects on fish condition.
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| 38. |
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| 39. |
- Skov, Christian, et al.
(författare)
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Biomanipulating streams : A supplementary tool in lake restoration
- 2019
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Ingår i: Hydrobiologia. - : Springer. - 0018-8158 .- 1573-5117. ; 829:1, s. 205-216
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Tidskriftsartikel (refereegranskat)abstract
- Removal of cyprinid fish is a widely used biomanipulation tool to transform turbid shallow eutrophic lakes in north temperate regions into a clear water state. We here evaluate the removal of cyprinids from streams as a supplement to lake fishing. Since cyprinids often aggregate in high densities in lake inlet/outlet streams during winter migration, removal of fish in this space-confined habitat may be cost-efficient as compared to fish removal in the lake habitat. In two consecutive years, we annually removed up to 35% of the dominant cyprinids from an inlet stream to a lake and argue that this could easily be increased with a more targeted fishing effort. Concurrently, we monitored species- and length-specific variation in migration propensity, to explore how this relates to efficient fish removal. Smaller planktivores generally had a much higher migratory propensity than larger benthivores. Hence, stream fishing specifically targets species and size groups that are less efficiently controlled with traditional lake fishing methods. As a rule of thumb, stream fishing is most efficient when water temperature is 2–6°C. Prior to implementing fish removals from streams, the potential evolutionary consequences of the targeted removal of migratory phenotypes should be considered.
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| 40. |
- Skov, Christian, et al.
(författare)
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Evaluating stocking of YOY pike Esox lucius as a tool in the restoration of shallow lakes
- 2007
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Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 52:9, s. 1834-1845
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Tidskriftsartikel (refereegranskat)abstract
- 1. Stocking of piscivores in shallow, eutrophicated lakes to reduce cyprinid densities is a common approach in lake restorations. Young-of-the-year (YOY) pike Esox lucius are frequently used to reduce cyprinid densities, but their effectiveness is equivocal. This study uses a simple model to assess the efficacy of pike stocking as a lake restoration tool. 2. The model evaluates YOY pike consumption in relation to different survival and growth patterns, timing of stocking, degree of piscivory of pike as well as YOY cyprinid growth patterns and productivity. The parameters used in the model are obtained from field surveys in eight study lakes stocked with YOY pike as well as from the literature. 3. Our model showed that all parameters studied were important for predicting the effects of pike stocking on cyprinids. In particular, body size at stocking, cyprinid production and pike survival were good predictors of biomanipulation success. 4. However, our model showed that only under very specific circumstances will stocking of YOY pike result in a reduction of YOY cyprinid densities large enough to affect water quality. 5. The findings of this study question the efficacy of pike stocking as an appropriate and reliable tool for restoration programmes in shallow lakes, and indicate that when used efforts should be made to optimize the timing of stocking in relation to YOY cyprinid production and to increase the stocking body size of the pike.
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| 41. |
- Skov, Christian, et al.
(författare)
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Evaluation of PIT-tagging in cyprinids.
- 2005
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 67:5, s. 1195-1201
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Tidskriftsartikel (refereegranskat)abstract
- Laboratory and field experiments were used to investigate how different marking procedures, with 23 mm PIT (passive integrated transponders) – tags, affected mortality, body condition and tag expulsion in small roach Rutilus rutilus and rudd Scardinus erythrophthalmus (117 to 163 mm total length). In a laboratory experiment mortality was low (≤ 6%) and only occurred among fishes that had their incision closed with sutures. The latter also had a specific growth rate that tended to be lower than the fish tagged without sutures. The different marking procedures did not adversely affect the body condition of fishes either in the laboratory experiment (after 37 days) or in the field experiment (up to 369 days). No tag expulsions were observed among laboratory fishes PITtagged without sutures. Marking without the use of sutures to close the incision, appears to be the most appropriate PIT tagging procedure for small cyprinids.
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| 42. |
- Skov, Christian, et al.
(författare)
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Habitat-choice interactions between pike predators and perch prey depend on water transparency
- 2007
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 70:1, s. 298-302
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Tidskriftsartikel (refereegranskat)abstract
- A mesocosm experiment indicated that water transparency influenced antipredator behaviour in young-of-the-year perch Perca fluviatilis, which partly contradicts another study by showing that high transparency decreases rather than increases perch antipredatory use of vegetated habitats when predators are also free to choose habitat. The present study emphasizes the importance of simultaneously considering both prey and predator habitat-choice behaviours when evaluating predator-prey interactions in relation to water visibility.
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| 43. |
- Skov, Christian, et al.
(författare)
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Influences of environmental cues, migration history, and habitat familiarity on partial migration
- 2010
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 21:6, s. 1140-1146
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Tidskriftsartikel (refereegranskat)abstract
- The factors that drive partial migration in organisms are not fully understood. Roach (Rutilus rutilus), a freshwater fish, engage in partial migration where parts of populations switch between summer habitats in lakes and winter habitats in connected streams. To test if the partial migration trait is phenotypically plastic or has genetic components, we translocated roach from 2 populations with different opportunities for migration to a lake with migration opportunity, containing a local roach population. This enabled monitoring of partial migration of fish in 3 different situations: 1) previous opportunity for migration, migrating in a familiar environment (the local population); 2) previous opportunity for migration, migrating in an unfamiliar environment; and 3) no previous opportunity for seasonal migration, migrating in an unfamiliar environment. In addition, we evaluated the migration patterns of roach in the lake with migration opportunity where from group 2 fish were translocated. Directional migration in and out of the lakes was monitored using Passive Integrated Transponder technology. Translocated fish with previous migration opportunity showed migration patterns more similar to local fish than to their home lake population, and individuals translocated from the lake without migration opportunity migrated when given the opportunity, suggesting that partial migration is phenotypically plastic and triggered by lake-specific environmental cues. We found temperature to be a proximate cue for migration decisions. Individuals without previous migration opportunity migrated at a lower proportion and with different small-scale migration patterns, suggesting that also genetic components are involved in the expression of the partial migration trait.
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| 44. |
- Skov, Christian, et al.
(författare)
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Inter- and size-specific patterns of fish seasonal migration between a shallow lake and its streams
- 2008
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Ingår i: Ecology of Freshwater Fish. - : Wiley. - 0906-6691 .- 1600-0633. ; 17:3, s. 406-415
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in Undetermined This study used passive telemetry (passive integrated transponders) to evaluate winter migration in three species of cyprinids (roach (Rutilus rutilus (L.)), white bream (Blicca bjoerkna (L.)) and rudd (Scardinius erythrophthalmus (L.))) and their potential predators (pike (Esox lucius (L.)) and perch (Perca fluviatilis (L.))) between a shallow lake and its streams. Migration patterns were investigated from October to June, and a substantial part of the roach (40%) and white bream (55%) populations tagged in the lake during autumn migrated during winter into the streams, whereas only very few piscivores (< 2%) migrated. In contrast to roach and white bream, only few rudd (< 6%) migrated, which is likely a consequence of different overwintering strategies, e.g., rudd overwintering in shallow highly structured habitats. Small rudd migrated more than larger rudd, whereas there were no size-differentiated migration patterns for roach or white bream. Migration of the cyprinid fishes was generally initiated in late October and ended in May, and specific synchronised bursts of migration were observed in December, January and April, suggesting that migration is triggered by one or more proximate environmental cues. The cyprinid fishes generally entered the streams in late afternoon or in the morning, depending on season, but overall migration patterns varied between the three streams. We suggest and discuss that our results have great implications for lake management as well as for the interpretation of seasonal trophic dynamics in shallow lakes.
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| 45. |
- Skov, Christian, et al.
(författare)
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Migration confers survival benefits against avian predators for partially migratory freshwater fish
- 2013
-
Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 9:2, s. 20121178-
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Tidskriftsartikel (refereegranskat)abstract
- The importance of predation risk in shaping patterns of animal migration is not well studied, mostly owing to difficulties in accurately quantifying predation risk for migratory versus resident individuals. Here, we present data from an extensive field study, which shows that migration in a freshwater fish (roach, Rutilus rutilus) that commonly migrates from lakes to streams during winter confers a significant survival benefit with respect to bird (cormorant, Phalacrocorax carbo spp.) predation. We tagged over 2000 individual fish in two Scandinavian lakes over 4 years and monitored migratory behaviour using passive telemetry. Next, we calculated the predation vulnerability of fish with differing migration strategies, by recovering data from passive integrated transponder tags of fish eaten by cormorants at communal roosts close to the lakes. We show that fish can reduce their predation risk from cormorants by migrating into streams, and that probability of being preyed upon by cormorants is positively related to the time individuals spend in the lake during winter. Our data add to the growing body of evidence that highlights the importance of predation for migratory dynamics, and, to our knowledge, is one of the first studies to directly quantify a predator avoidance benefit to migrants in the field.
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| 46. |
- Skov, Christian, et al.
(författare)
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Sizing up your enemy : individual predation vulnerability predicts migratory probability
- 2011
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 278, s. 1414-1418
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Tidskriftsartikel (refereegranskat)abstract
- Partial migration, in which a fraction of a population migrate and the rest remain resident, occurs in anextensive range of species and can have powerful ecological consequences. The question of what drivesdifferences in individual migratory tendency is a contentious one. It has been shown that the timing ofpartial migration is based upon a trade-off between seasonal fluctuations in predation risk and growthpotential. Phenotypic variation in either individual predation risk or growth potential should thus mediatethe strength of the trade-off and ultimately predict patterns of partial migration at the individual level (i.e.which individuals migrate and which remain resident). We provide cross-population empirical support forthe importance of one component of this model—individual predation risk—in predicting partialmigration in wild populations of bream Abramis brama, a freshwater fish. Smaller, high-risk individualsmigrate with a higher probability than larger, low-risk individuals, and we suggest that predation riskmaintains size-dependent partial migration in this system.
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| 47. |
- Skov, Morten W., et al.
(författare)
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Risk prediction of atrial fibrillation based on electrocardiographic interatrial block
- 2018
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Ingår i: Journal of the American Heart Association. - 2047-9980. ; 7:11
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Tidskriftsartikel (refereegranskat)abstract
- Background--The electrocardiographic interatrial block (IAB) has been associated with atrial fibrillation (AF). We aimed to test whether IAB can improve risk prediction of AF for the individual person. Methods and Results--Digital ECGs of 152 759 primary care patients aged 50 to 90 years were collected from 2001 to 2011. We identified individuals with P-wave ≥120 ms and the presence of none, 1, 2, or 3 biphasic P-waves in inferior leads. Data on comorbidity, medication, and outcomes were obtained from nationwide registries. We observed a dose-response relationship between the number of biphasic P-waves in inferior leads and the hazard of AF during follow-up. Discrimination of the 10-year outcome of AF, measured by time-dependent area under the curve, was increased by 1.09% (95% confidence interval 0.43-1.74%) for individuals with cardiovascular disease at baseline (CVD) and 1.01% (95% confidence interval 0.40-1.62%) for individuals without CVD, when IAB was added to a conventional risk model for AF. The highest effect of IAB on the absolute risk of AF was observed in individuals aged 60 to 70 years with CVD. In this subgroup, the 10-year risk of AF was 50% in those with advanced IAB compared with 10% in those with a normal P-wave. In general, individuals with advanced IAB and no CVD had a higher risk of AF than patients with CVD and no IAB. Conclusions--IAB improves risk prediction of AF when added to a conventional risk model. Clinicians may consider monitoring patients with IAB more closely for the occurrence of AF, especially for high-risk subgroups.
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| 48. |
- Sunde, Johanna, et al.
(författare)
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Drivers of neutral and adaptive differentiation in pike (Esox lucius) populations from contrasting environments
- 2022
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Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 31:4, s. 1093-1110
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Tidskriftsartikel (refereegranskat)abstract
- Understanding how eco-evolutionary processes and environmental factors drive population differentiation and adaptation are key challenges in evolutionary biology of relevance for biodiversity protection. Differentiation requires at least partial reproductive separation, which may result from different modes of isolation such as geographic isolation (allopatry) or isolation by distance (IBD), resistance (IBR), and environment (IBE). Despite that multiple modes might jointly influence differentiation, studies that compare the relative contributions are scarce. Using RADseq, we analyse neutral and adaptive genetic diversity and structure in 11 pike (Esox lucius) populations from contrasting environments along a latitudinal gradient (54.9-63.6 degrees N), to investigate the relative effects of IBD, IBE and IBR, and to assess whether the effects differ between neutral and adaptive variation, or across structural levels. Patterns of neutral and adaptive variation differed, probably reflecting that they have been differently affected by stochastic and deterministic processes. The importance of the different modes of isolation differed between neutral and adaptive diversity, yet were consistent across structural levels. Neutral variation was influenced by interactions among all three modes of isolation, with IBR (seascape features) playing a central role, wheares adaptive variation was mainly influenced by IBE (environmental conditions). Taken together, this and previous studies suggest that it is common that multiple modes of isolation interactively shape patterns of genetic variation, and that their relative contributions differ among systems. To enable identification of general patterns and understand how various factors influence the relative contributions, it is important that several modes are simultaneously investigated in additional populations, species and environmental settings.
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