| 1. |
- Mylrea-Foley, Bronacha, et al.
(författare)
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Perinatal and 2-year neurodevelopmental outcome in late preterm fetal compromise : the TRUFFLE 2 randomised trial protocol
- 2022
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Following the detection of fetal growth restriction, there is no consensus about the criteria that should trigger delivery in the late preterm period. The consequences of inappropriate early or late delivery are potentially important yet practice varies widely around the world, with abnormal findings from fetal heart rate monitoring invariably leading to delivery. Indices derived from fetal cerebral Doppler examination may guide such decisions although there are few studies in this area. We propose a randomised, controlled trial to establish the optimum method of timing delivery between 32 weeks and 36 weeks 6 days of gestation. We hypothesise that delivery on evidence of cerebral blood flow redistribution reduces a composite of perinatal poor outcome, death and short-term hypoxia-related morbidity, with no worsening of neurodevelopmental outcome at 2 years.Methods and analysis: Women with non-anomalous singleton pregnancies 32+0 to 36+6 weeks of gestation in whom the estimated fetal weight or abdominal circumference is <10th percentile or has decreased by 50 percentiles since 18-32 weeks will be included for observational data collection. Participants will be randomised if cerebral blood flow redistribution is identified, based on umbilical to middle cerebral artery pulsatility index ratio values. Computerised cardiotocography (cCTG) must show normal fetal heart rate short term variation (>= 4.5 msec) and absence of decelerations at randomisation. Randomisation will be 1:1 to immediate delivery or delayed delivery (based on cCTG abnormalities or other worsening fetal condition). The primary outcome is poor condition at birth and/or fetal or neonatal death and/or major neonatal morbidity, the secondary non-inferiority outcome is 2-year infant general health and neurodevelopmental outcome based on the Parent Report of Children's Abilities-Revised questionnaire.Ethics and dissemination: The Study Coordination Centre has obtained approval from London-Riverside Research Ethics Committee (REC) and Health Regulatory Authority (HRA). Publication will be in line with NIHR Open Access policy.
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| 2. |
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| 4. |
- Andersson, Anders, 1980-, et al.
(författare)
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Recreational trolling effort and catch of Atlantic salmon and brown trout in Vänern, the EU's largest lake
- 2020
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Ingår i: Fisheries Research. - : Elsevier. - 0165-7836 .- 1872-6763. ; 227
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Tidskriftsartikel (refereegranskat)abstract
- Recreational fishing has grown substantially worldwide; for some recreational fisheries both catch and economic value now exceeds that of commercial fisheries. Monitoring of recreational fisheries effort and catch is therefore important for sustainable fisheries management. We developed and implemented an angler survey to estimate effort and catch for the recreational trolling fishery for landlocked Atlantic salmon (Salmo salar) and brown trout (S. trutta) in Lake Vänern, Sweden. Major challenges were the large spatial scale and dispersed fishing effort, a lack of revenue from fishing licence sales, and a lack of catch reporting requirements. We developed a complemented roving/mail-in survey to estimate effort and catch during the main fishing periods, spring and fall, 2014. Instantaneous counts from major access sites were used for effort estimates, and mail-in surveys were used for catch rates. Our results show that Vänern supports a salmon and trout fishery of some 28.7 ± 3.3 tonnes per year. Fishing effort was higher in the spring than in the fall, and there were seasonal differences in catch rates for trout but not for salmon. Estimates show that the recreational trolling fishery now harvests more salmon and trout annually than do the commercial and subsistence fisheries combined. This highlights the importance of continuing an angler survey program for Vänern as a key element for sustainable fisheries management, and can serve as a model for other recreational fisheries at large spatial scales.
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| 5. |
- Bergman, Eva, 1959-, et al.
(författare)
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Atlantic salmon and brown trout in Lake Vänern : A proposal for a co-management system
- 2014
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Ingår i: Aquatic Ecosystem Health & Management. - : Taylor & Francis Group. - 1463-4988 .- 1539-4077. ; 17:4, s. 365-373
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Tidskriftsartikel (refereegranskat)abstract
- Co-management is of increasing interest for fisheries management. We explore possibilities for, and barriers to, developing a co-management system, using threatened populations of landlocked Atlantic Salmon and Brown Trout as examples. Good management of natural resources requires not only knowledge about the resource but also suitable tools to collect information and make decisions. In large ecosystems this can be difficult because many actors are involved, and various societal borders and traditions become barriers. Vänern is the largest lake in the EU and it holds several distinct populations of large-bodied landlocked Atlantic Salmon and Brown Trout. The lake is used for commercial, subsistence, and sport fishing as well as for other recreational activities, and in Klarälven, the largest river entering Vänern, sport fishing is popular. These salmonid populations were at critically low levels during the 1960s, but a stocking program since then has maintained the fishery, and at least one wild stock appears to be recovering since being protected in 1993. Ecosystem users all have different needs: in the lake, sport fishermen say that catches of hatchery fish have declined, and commercial fishermen have focused on other species. In the river, wild salmon may be recovering: sport fishing is popular and an ongoing project investigates the possibilities for salmon to be able to circumvent hydro-electrical plants and reach historical Norwegian spawning areas. Not only do we lack information about the salmonids’ different life stages, we also lack a suitable socio-political organization to find sustainable solutions to the different needs of diverse user groups. We argue that a co-management system that enfranchises user groups in the Vänern-Klarälven ecosystem will improve sustainable management of wild and hatchery fish.
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| 6. |
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| 7. |
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| 8. |
- Bergman, Eva, et al.
(författare)
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'Grasp life again'. A qualitative study of the motive power in myocardial infarction patients
- 2003
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Ingår i: European Journal of Cardiovascular Nursing. - 1474-5151 .- 1873-1953. ; 2:4, s. 303-310
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Tidskriftsartikel (refereegranskat)abstract
- Myocardial infarction is the most common cause of death in Sweden today and is responsible for approximately 30% of all deaths. The aim of this study was to obtain increased knowledge and understanding of what motive power is and how it affects the individual's rehabilitation and return to a functioning daily life. Thirteen patients, six females and seven males, who had experienced a myocardial infarction, aged between 39 and 72 years and with a minimum interval from myocardial infarction diagnosis of at least 12 months, were interviewed. Grounded theory was the method used for data collection and analysis, since the method is focusing on social processes and interaction. The analysis process identified motive power as a core category: zest for life. The participants expressed a desire and a longing to continue living. The participants' experiences of their disease as well as being discharged from hospital forced them to reorientation. Autonomy, the individual's own active decision-making, plays a significant role in this zest for life. Care for was identified as the support base for zest for life. As health-care professionals we must, at a very early stage on the ward, form an idea of what kind of patient we have in front of us. ⌐ 2003 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
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| 9. |
- Bergman, Eva, 1959-, et al.
(författare)
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Lax och öring i Klarälven - möjligheter för vild fisk och kvalité på odlad fisk : Slutrapport 2008-2012
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Data från 1800-talet visar att fångsterna av lax och öring i både älv och sjö varit mycket högre än idag. Storskaliga dämmen, kraftigt fiske i Dejeforsen, nio kraftverk i den svenska delen av Klarälvens huvudfåra, och användandet av älven för timmerflottning har bidragit till detta. Efter att utsättning av kompensationsodlad fisk startade ökade fångsten igen, även om den fortfarande är låg.Fältundersökningar av vild laxsmolt visade att 16 % av smolten klarade sig hela vägen förbi de åtta kraftverken mellan Edebäck och Forshaga. Under studien var vattenföringen, och därmed spillet, lågt, vilket troligen bidragit till de höga förlusterna. Normalt spills det inte under hela smoltvandringsperioden, vilket är olyckligt.Lax och öring uppfödda under normala odlingsförhållanden är oftast större och fetare än vild fisk. Vi födde upp lax med olika fodertyper och fodermängder. Mängden föda påverkade laxens tillväxt och smoltmognad, och lax som fått fettfattigt foder var mest ”naturlik”. Den klarade också vandringen bäst, 80 % tog sig till Vänern medan 55 % av laxen som fått normalt eller lite foder. Bara 20 % av tidigt könsmogna hanar tog sig till Vänern.Rapporten avslutas med implikationer och förslag till åtgärder och fortsatta studier.
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| 10. |
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| 11. |
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| 12. |
- Bergman, Eva, 1959-, et al.
(författare)
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Relative growth estimated from self-administered symphysis fundal measurements
- 2011
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 90:2, s. 179-185
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To establish absolute-and relative-growth reference curves for the detection of intrauterine growth restriction from weekly self-administered symphysis-fundus (SF) measurements and to assess the influence of fetal sex, maternal obesity and parity. Design. Prospective longitudinal study. Setting. Pregnant women from six primary antenatal care centres. Population. Three hundred women with singleton ultrasound dated pregnancies. Methods. Weekly self-administered SF measurements from gestational week 25 until delivery were obtained. A linear mixed longitudinal model was used to estimate the absolute SF growth using the natural logarithm (lnSF). Relative lnSF growth was calculated as the lnSF measurement in one gestational week subtracted by the lnSF measurement in the previous gestational week. The influence of fetal sex, maternal obesity and parity was assessed in regression models and by a graphical display. Main Outcome Measures. Absolute lnSF and relative lnSF growth curves and influence of fetal sex, maternal obesity and parity on these. Results. SF measurements from 191 women were used to establish an SF-growth reference. The absolute lnSF growth was influenced by maternal obesity, and for fetal sex and parity, borderline significance was recorded; while there was no evidence that the relative lnSF growth could depend on these variables. Conclusions. Weekly self-administered SF measurements can be obtained and used to estimate SF growth. Relative growth of the lnSF height seems to be independent of fetal sex, maternal obesity and parity.
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| 13. |
- Bergman, Eva, 1959-, et al.
(författare)
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Self-administered symphysis-fundus measurements analyzed with a novel statistical method for detection of intrauterine growth restriction : a clinical evaluation
- 2011
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 90:8, s. 890-896
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To assess the ability of self-administered symphysis fundus measurements used with the Shiryaev-Roberts statistical method (SR method) to identify growth-restricted (IUGR) fetuses and compare it with the traditional SF method (symphysis fundus measurements used with a population-based reference curve). Design. Longitudinal study. Setting. Pregnant women attending primary antenatal care centres. Population. From a population of 1 888 women with singleton ultrasound-dated pregnancies, we analyzed data from 1 122 women. Methods. Weekly self-administered SF measurements from gestational week 25 until delivery were analyzed according to the SR method. Neonatal morbidity and small for gestational age (SGA) were used as proxies for IUGR. Small for gestational age was defined as a birthweight less than two standard deviations (SD) and <10th percentile. We assessed the sensitivity of the SR and the SF methods to detect neonatal morbidity and SGA. Main Outcome Measures. Birth-related mortality, respiratory distress, hypoglycemia, Apgar score <= 6 at five minutes, pH <= 7.00 in the umbilical artery, neonatal care, preterm delivery, operative delivery for fetal distress and SGA. Results. For the SR method, the sensitivity for neonatal morbidity was between 6.0 and 36.4%, for SGA <2SD 36.8%, and for SGA <10th percentile 20.9%. The SF method had a sensitivity between 6.0 and 13.8% for neonatal morbidity, 52.3% for SGA <2SD and 28.6% for SGA <10th percentile. Conclusions. The SR and the SF methods had low sensitivities for neonatal morbidity.
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| 14. |
- Bergman, Eva, 1959-
(författare)
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Symphysis Fundus Measurements for Detection of Intrauterine Growth Retardation
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A case-control study was performed to evaluate the Swedish population-based symphysis fundus (SF) reference curves. The study included 242 small for gestational age (SGA) neonates (169 term and 73 preterm infants) as cases and 296 non-SGA infants as controls. Two Swedish SF curves were evaluated. In term pregnancies they showed a sensitivity of 32 % and 51 % and a specificity of 90 % and 83 %, respectively, at a cut-off level of < - 2 SD from the mean according to the SF reference curve. The sensitivity for SGA was higher in preterm pregnancies (49 % and 58 %, respectively) and the first alarm below – 2 SD was noted before 32 weeks in 37 % and 43 % of the preterm pregnancies, respectively. (Study I) A study of self-administered SF measurements was designed to achieve more regular and frequent SF measurements. Thirty-three women with singleton, ultrasound dated pregnancies performed SF measurements on average 14 weeks from gestational week 20 to 25 until delivery. Self-administered SF measurements were higher and had higher variance than midwives’ measurements. Four consecutive SF measurements on each occasion can compensate for higher variance. Reliable self-administered SF measurements can be obtained. (Study II) Self-administered SF measurements from 191 women were used to construct absolute and relative SF growth references. The influence of fetal sex, maternal obesity and parity was assessed in regression models. The lnSF growth was statistically influenced by maternal obesity, and a borderline significance was recorded for fetal sex and parity. Statistical analysis and graphical displays show no evidence that the relative lnSF growth should be dependent on these variables. (Study III) To improve detection of infants with intrauterine growth restriction (IUGR) rather than SGA a new statistical model (the SR method) was used. The SR method was evaluated with SF measurements from 1122 pregnant women. The sensitivity for neonatal morbidity and SGA was low, between 6 and 36 % for SGA (< -2SD). Neonates classified as SGA (< -2SD and < 10th percentile) had increased morbidity compared with the total study group. Neonates suspected to be SGA before delivery by the population-based SF measurement method had lower morbidity than those not suspected. The SR method was found not to improve detection of fetuses with increased morbidity or SGA neonates in this study. Better screening methods to detect IUGR and SGA prior to delivery are needed. (Study IV)
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| 15. |
- Bergman, Eva, 1959-, et al.
(författare)
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Symphysis Fundus Measurements used with a novel Statistical Method for detection of Intrauterine Growth Retardation; a Clinical Evaluation.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: The statistical method of Shiryaev-Roberts (SR method), using altered growth speed, in combination with symphysis fundus (SF) measurements has theoretically a potential to improve antenatal detection of intrauterine growth restricted (IUGR) fetuses. The main objective of the present study was to compare the ability of the SR method and the SF method (SF measurements compared with a population based reference curve) to identify IUGR and small for gestational age (SGA) fetuses. Design: A longitudinal study design. Setting: Pregnant women from 27 primary antenatal care centres in 4 counties. Population: One thousand eight hundred and eighty eight women with singleton ultrasound dated pregnancies. Methods: Weekly self-administered SF measurements from gestational week 25 until delivery were analysed according to the SR method. Neonatal morbidity was used as a proxy for IUGR. SGA was defined as a birth weight < -2 standard deviations (SD) or < 10th percentile. Sensitivity for neonatal morbidity and SGA were assessed for alarms given for 5 to 30 % of the study population according to the SR-method and compared with the SF method. Main outcome measures: Respiratory distress, hypoglycaemia, Apgar < 7 at 5 min, pH < 7.01 in the umbilical artery, neonatal care, preterm delivery, operative delivery for fetal distress, SGA and any neonatal morbidity. Results: SF measurements from 1122 pregnant women were evaluated. For the SR method sensitivity for neonatal morbidity was between 6.0 and 36.4 %, for SGA (< -2 SD) 36.8 %, and for SGA (< 10th percentile) 20.9 %. The SF method had a sensitivity between 6.0 and 13.8% for neonatal morbidity, for SGA (< -2 SD) 52.3 % and for SGA (< 10th percentile) 28.6 %. Neonates classified as SGA (< -2SD and < 10th percentile) had increased morbidity. Neonates suspected to be SGA before delivery by the SF method had lower morbidity than those not suspected. Conclusions: The SR method was not found to improve detection of fetuses with increased morbidity or SGA neonates in this study. SGA neonates defined as < – 2 SD or < 10th percentile have increased neonatal morbidity.
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| 16. |
- Borg, Carola, 1973-, et al.
(författare)
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Subject- and experience-bound differences in teachers' conceptual understanding of sustainable development
- 2014
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Ingår i: Environmental Education Research. - : Routledge. - 1350-4622 .- 1469-5871. ; 20:4, s. 526-551
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Tidskriftsartikel (refereegranskat)abstract
- This article describe the results of a nationwide questionnaire study of 3229 Swedish upper secondary school teachers’ understanding of sustainable development in relation to their subject discipline and teaching experience. Previous research has shown that teachers have difficulties understanding the complex concept of sustainable development. According to the Swedish curriculum all teachers in all subjects should integrate a holistic perspective of sustainable development including economic, ecological and social dimensions. This study shows that teachers differ in their understanding of the concept mostly according to their subject traditions. Social science teachers emphasize social dimensions, and science teachers’ ecological dimensions, respectively. Teachers are aware of the relevance of the three dimensions to various degrees, but do not generally have a holistic understanding. The greatest uncertainty in teachers’ understanding is related to the economic dimension. Science and social science teachers are critical of incorporating economic growth into the concept of sustainable development while language, vocational and esthetical-practical teachers are not. No experience-bound differences of the teachers’ understanding could be found, but recently qualified teachers consider their understanding of sustainable development to be poorer in comparison to more experienced teachers’ self-evaluation. The study highlights the need for further training in sustainable development since more than 70 % of the questioned teachers stated that they need such training.
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| 17. |
- Borg, Carola, 1973-, et al.
(författare)
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The barriers encountered by teachers implementing education for sustainable development
- 2012
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Ingår i: Research in Science & Technological Education. - : Informa UK Limited. - 0263-5143 .- 1470-1138. ; 30:2, s. 185-207
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Tidskriftsartikel (refereegranskat)abstract
- Background : According to the Swedish curriculum teachers in all subjects have a responsibility to integrate a holistic perspective of sustainable development (SD) and teach according to an education for sustainable development (ESD) approach. However previous research has shown that teachers from different subjects perceive SD differently. Purpose : The study aimed at investigating if and how teachers’ subject area influences their ability to implement a holistic perspective of ESD; we investigated both the impact of teaching traditions and the barriers that teachers experienced. Sample : A stratified sample of 224 Swedish upper secondary schools participated. An online questionnaire was sent and answered by a total of 3229 teachers at these schools. In total, there were 669 science teachers, 373 social science teachers, 483 language teachers, 713 vocational and esthetical–practical teachers, and 739 teachers from other disciplines who participated in the survey. Design and methods : The questionnaire consisted of questions requiring Likert-scale responses and multiple-choice questions. The data from the questionnaire were analyzed using Pearson’s Chi-square test and one-way ANOVA. The significance level accepted was p < 0.05. Results : Teachers were influenced by their own subject traditions. Science teachers in our study were grounded in the fact-based tradition and lectures were the most common teaching method used. The teaching tradition of the social science teachers seemed to be most in line to an ESD approach. Many language teachers (41%) stated they did not include SD issues in their teaching at all. Among the barriers identified, the most common obstacles were that the teachers lacked inspiring examples of how to include SD in their teaching and that they lacked the necessary expertise about SD. Conclusion : This study highlights the need for the management within schools to create opportunities for teachers to work collaboratively when teaching ESD. It is also important to provide further training that is adjusted to the needs of different disciplines.
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| 18. |
- Bowes, Rachel E., et al.
(författare)
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Cobble substrate in a surface bypass reduces bypass acceptance by common roach Rutilus rutilus
- 2021
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 172
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Tidskriftsartikel (refereegranskat)abstract
- Historically, ecological engineered solutions for fish passage across anthropogenic barriers in rivers has mainly focused on facilitating upstream passage for long-migrating diadromous fish, such as salmonids. More recently, passage solutions have shifted their focus to a more holistic ecological perspective, allowing passage for species with different swimming capacity, both upstream and downstream. This experiment investigated whether the addition of cobble in the passageway of a surface bypass could facilitate downstream movement of a cyprinid fish, the common roach Rutilus rutilus. Surface bypasses were constructed in large experimental flumes and roach were released into the flumes and monitored for bypass passage using PIT-telemetry through 11-h night-trials. Behavior was scored using four continuously-recording video cameras at the bypass construction. There was a negative effect of substrate-treatment on the passage rate through the bypass. The majority of the fish in the No substrate treatment had successfully passed within 4 h, while a lesser proportion of the fish in the Substrate treatment had done so (additional fish in the latter treatment passed later in the trials). Fish exposed to cobble substrate in the bypass passageway showed more avoidance-like behaviors at the ramp section of the bypass and tended to return back upstream more often than the fish in the no-substrate control trials. When reaching the passageway, the substrate-exposed fish expressed no behaviors that could be indicative of reduced passage success, as compared to controls. We conclude that passage was not hindered by the presence of cobble substrate, but passage was delayed due to avoidance behavior at the bypass ramp when cobble substrate was present. Based on these results, the addition of cobble substrate in a surface bypass cannot be recommended as a measure to facilitate the downstream passage performance of the common roach through surface bypasses.
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| 19. |
- Bowes, Rachel E., et al.
(författare)
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Landscape features control river's confluences water quality and tributary fish composition
- 2023
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Ingår i: Rivers Research and Applications. - : John Wiley & Sons. - 1535-1459 .- 1535-1467. ; 39:6, s. 1025-1036
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Tidskriftsartikel (refereegranskat)abstract
- Rivers networks represent hierarchical dendritic habitats within terrestrial landscapes and differences in connectivity and land use influence dispersal, and consequently biodiversity patterns. We, therefore, measured variation in water chemistry and fish abundance and related these to a number of landscape characteristics (e.g., wetland, urban, wooded, and agricultural) in the River Klaralven and its 30 permanently flowing tributaries. We hypothesized that these environmental attributes would differ between tributary and main stem habitat and that these differences would be driven by landscape attributes including land use. We found considerable intertributary variation in temperature and nutrient levels, and between the tributaries and the main stem. Generally, water temperature was lower in the tributaries, whereas nutrient levels were higher in the tributaries. The lower water temperature has implications for coldwater fishes, and we found two fishes, burbot and lamprey, associated with coldwater tributaries. We also found an inverse relationship between water quality and anthropogenic land use. Protecting tributaries with low anthropogenic impact will likely become increasingly important with ongoing global warming as they can function as thermal refugia for coldwater fishes. Hence, this study underscores the need to evaluate water courses at regional scales to identify spatial refuges and ensure connectivity.
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| 20. |
- Carlsson, Niclas, et al.
(författare)
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Diet hos adult insjölevande lax (Salmo salar) och öring (Salmo trutta) i Vänern.
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Naturförvaltning kräver god kunskap om ekosystemet, och för en god fiskförvaltning är det en grundförutsättning att man har kunskap om fisksamhällets arter och hur näringsväven det ingår i är sammansatt. Idag finns flera olika metoder för att undersöka fiskars födoval (stabila isotoper, DNA mm) men traditionella maganalyser är fortfarande en bra metod för att undersöka fiskars diet, och den ger dessutom information om fiskens trofiska placering i födoväven. Vänern har stammar av endemisk sjövandrande av lax (Salmo salar) och öring (Salmo trutta) som har ett särskilt bevarandevärde och är skyddade av EU’s habitatdirektiv. I syfte att förstå mer av födoväven dessa stammar ingår i undersökte vi dieten hos odlad vuxen lax och öring fångad i Vänern. Detta genomfördes under åren 2021-2022 och prov samlades in både vår och höst med hjälp av sportfiskare i samband med årliga sportfisketävlingar. Fisk samlades in från hela Vänern, men fördelningen uppdelat på de tio fångstzonerna var ojämn. Sammanlagt 95 laxar och 265 öringar undersöktes varav 87% av laxarna fångades på våren och 64% av öringarna. Medianlängden var 71 cm och medianvikten 4,0 kg för de analyserade laxarna och 69 cm respektive 3,9 kg för öringarna. Resultaten visar att lax och öring i det undersökta storleksspannet har likartad diet och att nors dominerar i båda arternas diet. För både lax och öring var merparten av norsen i dieten i storleksspannet 50 – 130 mm, vilket i stort speglar storleksfördelningen av nors i Vänern, men laxen åt mindre byten i genomsnitt än vad öringen gjorde. Vi fann även siklöja och storspigg och ett fåtal abborrar i dieten. Ungefär en tredjedel av maginnehållet var så långt nedbrutet att artidentifiering inte var möjlig. Under 2022 noterade vi att det fanns parasiter (bandmasken Eubotrium sp.) i 100% av laxarna och 98% av öringarna. Insamlingsmetodiken innebär att bara odlad lax och öring med ett minimått på minst 60 cm ingår i studien.
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| 21. |
- Edling, Agnes, et al.
(författare)
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Second trimester induced abortions due to fetal anomalies—a population‐based study of diagnoses, examinations and clinical management
- 2021
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : John Wiley & Sons. - 0001-6349 .- 1600-0412. ; 100:12, s. 2202-2208
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Two-thirds of induced abortions after gestational week (gw) 18 are performed due to fetal anomalies. The potential of the fetus to survive outside the uterus after birth is the upper limit for induced abortions in Sweden. Due to advances in neonatal medicine, fetal viability and the upper limit of late induced abortions have been converging over the last few decades. The aim of the study was to examine clinical management of fetal anomalies, including time frames, leading to second trimester abortions.Material and methods All induced abortions due to fetal anomalies after gw 11+6 in Uppsala county, Sweden, from 2010 to 2017, were reviewed from electronic medical records in a retrospective descriptive study. In total, 180 women underwent 185 abortions divided into 107 (57.8%) in an early group (gw 12+0 to 18+0), and 78 (42.2%) in a late group (≥ gw 18+1). Examinations performed were genetic testing, fetal echocardiography, magnetic resonance imaging (MRI) and pediatric counseling. Time frames from suspicion of fetal anomaly to abortion were reviewed.Results Anomalies were subdivided into groups of diagnosis: chromosomal (n = 104), central nervous system (n = 22), heart (n = 12), urinary tract (n = 10) and others (n = 37). Chromosomal anomaly was present in 82 (76.6%) in the early group and 22 (28.2%) in the late group. In the early group, examinations performed preceding a conclusive diagnosis were mainly QF-PCR for trisomies (n = 97), microarray (n = 13), and genetic counseling (n = 14). In the late group, trisomy test was performed in 68, microarray in 31, MRI in 24, fetal echocardiography in 28, and pediatric or genetic counseling in 43 and six cases, respectively.Mean time interval from suspicion of fetal anomaly to the woman’s decision was 5 days before gw 18+1, 7 days in gw 18, and 13 days in gw 21. More than two examinations before reaching the decision to terminate the pregnancy were needed in two abortions (25.0%) in gw 18, increasing to 16 (80.0%) in gw 21.Conclusions Increasing complexity and diversity in fetal diagnoses require time-consuming examinations in late-induced abortions compared with earlier gestational weeks. A structured expedient process is necessary to allow for decision time and minimize terminations approaching the legal limit.
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| 22. |
- Emilson, Christina, et al.
(författare)
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A 10-year follow-up of tailored behavioural treatment and exercise-based physiotherapy for persistent musculoskeletal pain
- 2017
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Ingår i: Clinical Rehabilitation. - London : Sage Publications. - 0269-2155 .- 1477-0873. ; 31:2, s. 186-196
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the long-term outcomes of two interventions targeting patients with sub-acute and persistent pain in a primary care physiotherapy setting.DESIGN: A 10-year follow-up of a two-armed randomised controlled trial, initially including 97 participants.INTERVENTIONS: Tailored behavioural medicine treatment, applied in a physiotherapy context (experimental condition), and exercise-based physiotherapy (control condition).MAIN MEASURES: Pain-related disability was the primary outcome. The maximum pain intensity, pain control, fear of movement, sickness-related absence (register data) and perceived benefit and confidence in coping with future pain problems were the secondary outcomes.RESULTS: Forty-three (44%) participants responded to the follow-up survey, 20 in the tailored behavioural medicine treatment group and 23 in the exercise-based physiotherapy group. The groups did not differ in terms of the change in the scores for the primary outcome (p=0.17) of pain-related disability between the experimental group (median: 2.5, Q1-Q3: -2.5-14.25), and the control group (median: 0, Q1-Q3: -5-6). Further, there were also no significant differences found for the secondary outcomes except for sickness-related absence, where the exercise-based physiotherapy group had more days of sickness-related absence three months before treatment (p= 0.02), and at the 10-year follow-up (p=0.03).DISCUSSION: The beneficial effects favouring tailored behavioural medicine treatment that observed post-treatment and at the two-year follow-up were not maintained 10 years after treatment. © The Author(s) 2016
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| 23. |
- Enefalk, Åsa, 1972-, et al.
(författare)
-
Effects of fine wood addition on invertebrate drift in boreal forest streams
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Fine woody debris (FWD) is a key habitat component for stream-living organisms, but there have been few tests of its importance for macroinvertebrate drift in boreal forest streams. We experimentally investigated the effect of FWD addition on the drift fauna at seven sites in four boreal forest streams, from early June to mid-August 2011. This was done by anchoring bundles of FWD at each site and measuring drift upstream (within site control) and downstream of each bundle. We hypothesized that addition of FWD would increase drift density and biomass of stream invertebrates as well as drift taxon richness. Variation between sites was high, with site-specific minimum values of drift biomass of 0.2 - 4.1 mg wet mass/100 m3 and maximum values of 3.9 - 41.7 mg/100 m3. Despite this variation, there was a significant increase in total aquatic drift density and biomass 8 to 10 weeks after wood addition. Aquatic taxon richness in the drift also increased significantly after FWD addition. This study shows for the first time that FWD can increase drifting invertebrate density, biomass and taxon diversity in small boreal forest streams.
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| 24. |
- Enefalk, Åsa, 1972-, et al.
(författare)
-
Fine stream wood decreases growth of juvenile brown trout (Salmo trutta)
- 2019
-
Ingår i: Environmental Biology of Fishes. - : Springer. - 0378-1909 .- 1573-5133. ; 102:5, s. 759-770
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, the growth rate, gut fullness, diet composition and spatial distribution of brown trout was compared between artificial channels with and without fine wood (FW). Access to FW resulted in significantly lower brown trout growth rates over the study period from late summer to early winter as water temperatures declined from 17 °C to 1 °C. Access to FW resulted in minor differences in occurrence of the most common taxa found in brown trout diets, except for chironomid larvae which were found in c. 60% of the brown trout guts from control treatments but in only 30% of the guts from FW treatments in early winter. Diet consisted primarily of case-bearing and free-living Trichoptera larvae, Asellus, chironomid and Ephemeroptera larvae. Brown trout gut fullness was not significantly affected by access to FW bundles. Brown trout aggregated among FW but were more evenly distributed in channels lacking it. Our results suggest that juvenile brown trout use FW as a shelter at a wide range of water temperatures, and that this behaviour may result in reduced growth rates during their first fall and the onset of their first winter. We also show that prey availability and the composition of brown trout diet changes from late summer to early winter and that FW has a small but significant effect on brown trout diet composition.
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| 25. |
- Enefalk, Åsa, 1972-, et al.
(författare)
-
Juvenile brown trout response to fine woody debris in experimental stream channels
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Changes in riparian vegetation due to forest harvesting may affect the input of fine woody debris, an important structural element, to streams. Woody debris has been shown to benefit trout populations. In-stream fine woody debris (FWD) has not been studied as extensively as large woody debris, but is probably important to smaller-sized trout. In a laboratory stream experiment we tested young-of-the-year wild brown trout, Salmo trutta, responses to three densities of fine woody debris (FWD). The trout were tested as singletons and four together. Swimming activity increased with increasing fish density and decreasing FWD density. Foraging decreased and time spent in FWD increased with increasing FWD density. Aggressiveness was lowest in intermediate FWD density. Our study shows that FWD impact on trout is related to fish rank, fish density and FWD density, and that juvenile trout response to fine WD is different from the response to large WD reported by others.
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| 26. |
- Enefalk, Åsa, 1972-, et al.
(författare)
-
Winter sheltering by juvenile brown trout (Salmo trutta) : Effects of stream wood and an instream ecothermic predator
- 2017
-
Ingår i: Freshwater Biology. - : John Wiley & Sons. - 0046-5070 .- 1365-2427. ; 62:1, s. 111-118
-
Tidskriftsartikel (refereegranskat)abstract
- In boreal streams, juvenile salmonids spend substantial amounts of time sheltering in the streambed and in stream wood, presumably as a means of protection against the physical environment and from terrestrial endothermic predators. Relatively little is known about sheltering by salmonids in response to instream ectothermic predators.We tested the effects of burbot (Lota lota) on the winter sheltering behaviour of PIT-tagged 0+ brown trout (Salmo trutta) in daylight and darkness. Sheltering in the streambed by trout was studied in the presence and absence of fine wood bundles.We found that the use of streambed and fine wood was lower in darkness than in daylight. Availability of fine wood significantly decreased sheltering in the streambed, and this effect was more pronounced in daylight than in darkness. The presence of a burbot significantly decreased sheltering in the streambed, had no effect on use of fine wood and resulted in a higher number of exposed trout.Our results indicate that juvenile brown trout decrease streambed sheltering in response to a burrowing, ectothermic predator.
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| 27. |
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| 28. |
- Eros, Tibor, et al.
(författare)
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Forest-Stream linkages : Effects of Terrestrial Invertebrate Input and Light on Diet and Growth of Brown Trout (Salmo trutta) in a Boreal Forest Stream
- 2012
-
Ingår i: PLOS ONE. - San Francisco, CA, USA : Public library science. - 1932-6203. ; 7:5, s. 1-11
-
Tidskriftsartikel (refereegranskat)abstract
- Subsidies of energy and material from the riparian zone have large impacts on recipient stream habitats. Human-induced changes, such as deforestation, may profoundly affect these pathways. However, the strength of individual factors on stream ecosystems is poorly understood since the factors involved often interact in complex ways. We isolated two of these factors, manipulating the flux of terrestrial input and the intensity of light in a 2 x 2 factorial design, where we followed the growth and diet of two size-classes of brown trout (Salmo trutta) and the development of periphyton, grazer macroinvertebrates, terrestrial invertebrate inputs, and drift in twelve 20 m long enclosed stream reaches in a five-monthlong experiment in a boreal coniferous forest stream. We found that light intensity, which was artificially increased 2.5 times above ambient levels, had an effect on grazer density, but no detectable effect on chlorophyll a biomass. We also found a seasonal effect on the amount of drift and that the reduction of terrestrial prey input, accomplished by covering enclosures with transparent plastic, had a negative impact on the amount of terrestrial invertebrates in the drift. Further, trout growth was strongly seasonal and followed the same pattern as drift biomass, and the reduction of terrestrial prey input had a negative effect on trout growth. Diet analysis was consistent with growth differences, showing that trout in open enclosures consumed relatively more terrestrial prey in summer than trout living in covered enclosures. We also predicted ontogenetic differences in the diet and growth of old and young trout, where we expected old fish to be more affected by the terrestrial prey reduction, but we found little evidence of ontogenetic differences. Overall, our results showed that reduced terrestrial prey inputs, as would be expected from forest harvesting, shaped differences in the growth and diet of the top predator, brown trout.
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| 29. |
- Filipsson, Karl, et al.
(författare)
-
Do predator odours and warmer winters affect growth of salmonid embryos?
- 2023
-
Ingår i: Ecology of Freshwater Fish. - : John Wiley & Sons. - 0906-6691 .- 1600-0633. ; :1
-
Tidskriftsartikel (refereegranskat)abstract
- Conditions early in ontogeny can have considerable effects later on in life. Many salmonids spawn during the autumn, and temperature during subsequent embryogenesis may have far-reaching effects on life-history traits, especially when considering ongoing climate change. Even biotic conditions during embryogenesis, such as predation threat, may affect later life stages. Here, we examined how predator odours and increased temperatures affect embryonic growth and development of a fish (brown trout Salmo trutta). We found that embryos had lower body mass and greater yolk volume close to hatching when subjected to predator odours. Trout embryos incubated at temperatures representing natural winter conditions were larger than embryos incubated at higher temperatures, although the latter hatched earlier. Fry sizes at emergence did not differ between treatments, perhaps because of compensatory growth during spring. This study shows that predator presence can have similar effects on embryonic growth of salmonids as warming winters, with possible impact later in ontogeny.
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| 30. |
- Filipsson, Karl
(författare)
-
Early life stages of brown trout - Anti-predator responses under warming winters
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During winter, juvenile salmonids in boreal streams are vulnerable to predation, mainly from mammals and birds. Encounters with terrestrial predators can be reduced or avoided if fish limit activity to the darker periods of the day or to periods with surface ice. As piscivorous fish also are active in winter, they may be a threat under low light conditions when juvenile salmonids do not avoid terrestrial predators. Abiotic conditions, especially temperature, have major effects on fish in winter. High temperatures alter ice conditions in winter and lead to increased metabolism and physiological performance of fish. Water temperature also influences embryogenesis, with repercussions for fish throughout their life. Considering the rapid warming of winters in boreal regions, insights into how salmonids are adapted to winter conditions can aid in efforts to predict and mitigate anthropogenic effects that alter the winter environment.In this doctoral thesis, I explore anti-predator responses of brown trout (Salmo trutta) during its early life stages. I have examined the effects of predators, temperature, light and ice on the behaviour and physiology of juvenile trout during winter. In addition, I have studied how temperature and predators affect embryogenesis and the behaviour of fry after hatching. Anti-predator responses were evident in both the behaviour and physiology of juveniles and during embryogenesis. Trout exhibited diel behavioural changes when piscivorous fish were present, and were more vigilant towards piscivorous fish in darkness. Furthermore, temperature affected trout behaviour and physiology, with higher activity levels and lower mRNA expression of stress-related genes at higher temperatures. Trout also behaved differently depending on the temperature they experienced as eggs, as increased egg-incubation temperatures resulted in trout being more active and prone to risk taking.
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| 31. |
- Filipsson, Karl, et al.
(författare)
-
Effects of temperature and a piscivorous fish on diel winter behaviour of juvenile brown trout (Salmo trutta)
- 2019
-
Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 64:1+, s. 1797-1805
-
Tidskriftsartikel (refereegranskat)abstract
- Low winter temperatures constrain predator-detection and escape capabilities, making poikilotherms vulnerable to predation. Investigations of temperature effects on predator-prey interactions can therefore be of special importance in light of ongoing climate change, where winter temperatures are predicted to increase substantially at northern latitudes. Behavioral responses of stream fishes to terrestrial predators in winter are well recognised, whereas responses to predatory fish have received little attention. Using stream flumes, we examined the anti-predator behaviour of one-summer-old brown trout (Salmo trutta) at 3 and 8 degrees C in the presence and absence of burbot (Lota lota) under night, dawn, and daylight conditions. Burbot was placed upstream of the trout, separated by net screens. Lower temperature and the presence of burbot reduced trout activity. Light increased trout shelter use, and trout sheltered more in the presence of burbot. An interaction between the presence of burbot and light conditions affected trout position in the flumes: at night and dawn, trout positioned themselves further downstream when burbot were present than when absent, whereas during the day, trout maintained the same position in the presence or absence of the predator. Our results suggest that piscivorous fish, in addition to terrestrial predators, shape the behaviour of prey fishes in streams during winter. We show how predator avoidance results in altered diel patterns of juvenile brown trout under winter conditions, and that temperature has additional effects on trout behaviour.
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| 32. |
- Filipsson, Karl, 1991-
(författare)
-
From behaviour to genes: anti-predator responses of brown trout (Salmo trutta) under winter conditions
- 2020
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Temperature has major effects on the performance of poikilotherms. In encounters with predators, low winter temperatures constrain predator detection and escape capabilities in prey fishes. Most studies of the anti-predator responses of fish under winter conditions focus on endothermic terrestrial predators, whereas effects of piscivorous fish are generally overlooked. The studies presented in this thesis explore behavioural and physiological responses of juvenile brown trout (Salmo trutta) at winter temperatures of 3 and 8 °C in the presence and absence of a winter-active piscivorous fish (burbot, Lota lota). In Paper I, I report behavioural responses of trout in relation to the time of day. At the lower temperature and in the presence of burbot, trout reduced their activity. Trout used overhead shelter the most during the day and in the presence of burbot. Trout also spatially avoided burbot at night and at dawn but not during the day. In Paper II, I examined plasma cortisol and mRNA expression of stress-related genes. A redundancy analysis showed that both temperature and the presence of burbot explained a significant amount of the observed variation. Trout had higher cortisol levels when exposed to the burbot. Analyses of individual gene expressions revealed that trout had higher mRNA expression at 3 than at 8 °C for 11 of the 16 examined genes. Only one gene, RBP1, was expressed to a higher degree in the presence of burbot, but there were also interaction effects between temperature and burbot presence for two genes coding for serotonin and glucocorticoid receptors. My studies show that piscivorous fish shape anti-predator responses of juvenile brown trout, both behaviourally and at the gene level, under winter conditions. The observed thermal effects on mRNA levels underscore the importance of temperature in fish stress responses, with implications for stream salmonids in a warmer climate.
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| 33. |
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| 34. |
- Filipsson, Karl, et al.
(författare)
-
Temperature and predator-mediated regulation of plasma cortisol and brain gene expression in juvenile brown trout (Salmo trutta)
- 2020
-
Ingår i: Frontiers in Zoology. - : BioMed Central. - 1742-9994. ; 17:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background Temperature affects many aspects of performance in poikilotherms, including how prey respond when encountering predators. Studies of anti-predator responses in fish mainly have focused on behaviour, whereas physiological responses regulated through the hypothalamic-pituitary-interrenal axis have received little attention. We examined plasma cortisol and mRNA levels of stress-related genes in juvenile brown trout (Salmo trutta) at 3 and 8 degrees C in the presence and absence of a piscivorous fish (burbot,Lota lota). Results A redundancy analysis revealed that both water temperature and the presence of the predator explained a significant amount of the observed variation in cortisol and mRNA levels (11.4 and 2.8%, respectively). Trout had higher cortisol levels in the presence than in the absence of the predator. Analyses of individual gene expressions revealed that trout had significantly higher mRNA levels for 11 of the 16 examined genes at 3 than at 8 degrees C, and for one gene (retinol-binding protein 1), mRNA levels were higher in the presence than in the absence of the predator. Moreover, we found interaction effects between temperature and predator presence for two genes that code for serotonin and glucocorticoid receptors. Conclusions Our results suggest that piscivorous fish elicit primary stress responses in juvenile salmonids and that some of these responses may be temperature dependent. In addition, this study emphasizes the strong temperature dependence of primary stress responses in poikilotherms, with possible implications for a warming climate.
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| 35. |
- Filipsson, Karl, et al.
(författare)
-
Temperature during embryonic development in brown trout influences juvenile behaviour in encounters with predators
- 2024
-
Ingår i: Journal of Zoology. - : John Wiley & Sons. - 0952-8369 .- 1469-7998. ; 322:3, s. 241-250
-
Tidskriftsartikel (refereegranskat)abstract
- Variation in thermal conditions during embryogenesis can have far-reaching impact throughout ontogeny and may give rise to behavioural variation. Many animals, such as salmonids, exhibit behavioural trade-offs related to foraging and predator avoidance. How embryonic temperature affects these behaviours has remained unexplored. Not only abiotic conditions during embryogenesis but also biotic factors such as predator conditioning may affect fish behaviour, especially anti-predator responses. We examined how elevated temperatures and predator odours throughout embryogenesis affect the behaviour of 28-37 mm young-of-the-year brown trout (Salmo trutta) in encounters with predators, namely Atlantic salmon (Salmo salar; 20 cm) and burbot (Lota lota; 40 cm). Juvenile brown trout were more active and aggressive if they were incubated in warmer water as eggs than if they were incubated in colder water, and trout remained inactive longer when encountering predators if they were cold incubated. Brown trout were less active and aggressive when an Atlantic salmon was present than when a burbot or no predator was present. Behavioural responses did not differ between trout that had been subjected to water with versus without predator odours during embryogenesis, possibly because brown trout were not subjected to conspecific alarm cues during egg incubation. This study shows that thermal conditions during embryogenesis can influence fish behaviour early in life and thus contribute to behavioural variation, with potential effects on life history. Considering the rapid warming of northern regions, elevated embryonic temperatures may contribute substantially to variation in salmonid behaviour in the near future. Variation in environmental conditions during embryogenesis of salmonids can have far-reaching impact throughout ontogeny and may give rise to variation in anti-predator behaviour. In a laboratory experiment, we showed that elevated temperatures throughout embryogenesis increased the activity and aggression of 28-37 mm brown trout fry and reduced the time to first movement in encounters with predators (burbot and Atlantic salmon). Predator odour during embryogenesis did not affect brown trout fry behaviour.image
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| 36. |
- Filipsson, Karl, et al.
(författare)
-
Winter Behavior of Juvenile Brown Trout in a Changing Climate : How Do Light and Ice Cover Affect Encounters with Instream Predators?
- 2023
-
Ingår i: Fishes. - 2410-3888. ; 8:10
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- During winter, stream fishes are vulnerable to semi-aquatic predators like mammals and birds and reduce encounters by being active in darkness or under surface ice. Less is known about the behavior of fishes towards instream piscivorous fishes. Here, we examined how surface ice and light affected the anti-predator behavior of juvenile brown trout (Salmo trutta Linnaeus, 1758) in relation to piscivorous burbot (Lota lota Linnaeus, 1758) and northern pike (Esox lucius Linnaeus, 1758) at 4 degrees C in experimental flumes. Trout had lower foraging and swimming activity and spent more time sheltering when predators were present than when absent. In daylight, trout's swimming activity was not affected by predators, whereas in darkness trout were less active when predators were present. Trout consumed more drifting prey during the day when ice was present, and they positioned themselves further upstream when under ice cover, regardless of light conditions. Trout stayed closer to conspecifics under ice, but only in the presence of pike. Piscivorous fishes thus constitute an essential part of the predatory landscape of juvenile trout in winter, and thus loss of ice cover caused by climate warming will likely affect trout's interactions with predators.
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| 37. |
- Gordon, T. A. C., et al.
(författare)
-
Fishes in a changing world : learning from the past to promote sustainability of fish populations
- 2018
-
Ingår i: Journal of Fish Biology. - : John Wiley & Sons. - 0022-1112 .- 1095-8649. ; 92:3, s. 804-827
-
Tidskriftsartikel (refereegranskat)abstract
- Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.
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| 38. |
- Greenberg, Larry A., 1955-, et al.
(författare)
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The effects of egg incubation temperature and parental cross on the swimming activity of juvenile brown trout Salmo trutta
- 2023
-
Ingår i: Behavioral Ecology and Sociobiology. - : Springer. - 0340-5443 .- 1432-0762. ; 77:10
-
Tidskriftsartikel (refereegranskat)abstract
- Personality varies among individuals and is influenced by the environment. Here, we tested the hypothesis that egg incubation temperature had carry-over effects on swimming activity of juvenile brown trout, Salmo trutta. Eggs from different crosses involving anadromous and lacustrine-adfluvial parents were incubated under two temperature regimes, unheated (cold) or heated c. 2.5 degree celsius above ambient temperature (warm), until first exogenous feeding. In the laboratory, we used open-field tests to quantify swimming activity in a new environment, and mirror-image tests to measure time spent swimming and resting motionless near a mirror, measures often used as proxies for aggression. These tests were conducted for two cohorts, with one tested in June 2018 and the other in June and August 2019, enabling us to test for repeatability and if differences persisted over the summer. In June, when adjusting for differences in body size between cold- and warm-incubated trout, we found that juvenile trout incubated as embryos at cold temperatures showed more swimming activity and took less time to initiate swimming for their size than those incubated in warm water. There were also body size and year effects but no effects of parental cross. For August, none of the incubation temperature effects observed in June persisted, but cold-incubated trout spent a larger proportion of their time motionless near the mirror than warm-incubated trout and there was a general body size effect on time to initiate swimming. The lack of any persistent effects of incubation temperature between June and August suggests that the effect is ephemeral. Notwithstanding, these results support the hypothesis that incubation temperature has short-term effects on activity of juvenile of brown trout during their first summer.
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| 39. |
- Greenberg, Larry, 1955-, et al.
(författare)
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Body shape and fin size in juvenile Atlantic salmon (Salmo salar) : effects of temperature during embryogenesis
- 2021
-
Ingår i: Canadian Journal of Zoology. - : CANADIAN SCIENCE PUBLISHING. - 0008-4301 .- 1480-3283. ; 99:5, s. 381-389
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Tidskriftsartikel (refereegranskat)abstract
- Temperature during egg incubation and early development influences later life stages of fishes, potentially influencing survival. Throughout its distribution, Atlantic salmon (Salmo salar Linnaeus, 1758) have experienced population declines, and in view of ongoing global warming, we tested if temperature during the earliest developmental stages modified body shape and fin size when temperatures averaged 2.6 vs. 5.6 degrees C. This temperature difference simulates increases predicted in climate change scenarios. Based on previous studies, we hypothesized that salmon originating from eggs subjected to cold incubation temperatures would have slimmer bodies and larger pectoral and dorsal fins than salmon from eggs that experienced warmer temperatures. After hatching, the juveniles were raised for 1 year under identical temperatures, after which we measured their body shape and fin areas. We found no support for our hypothesis regarding body shape. Indeed, we found the opposite, with cold-incubated salmon having deeper bodies than warm-incubated salmon. For fin size, the pectoral fins of cold-incubated salmon were larger than for warm-incubated salmon as predicted, but there was no difference in dorsal fin size. These results suggest that global warming may lead to altered body shape and fin size, possibly affecting swimming performance, and thus raise questions about the ecological consequences of the changes.
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| 40. |
- Greenberg, Larry, 1955-, et al.
(författare)
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Effects of Predation and Intraspecific Interactions on Habitat Use and Foraging by Brown Trout in Artificial Streams
- 1997
-
Ingår i: Ecology of Freshwater Fish. - : Wiley. - 0906-6691 .- 1600-0633. ; 6:1, s. 16-26
-
Tidskriftsartikel (refereegranskat)abstract
- We studied habitat use, foraging rates and behavior of 10 cm and 12 cm long brown trout, Salmo trutta, at two densities, 1.5 and 3.0 fish. m−2, in artificial streams that contained either the amphipod, Gammarus pulex, alone or G. pulex together with the piscivore, northern pike, Esox lucius. Gammarus were stocked in and largely restricted to the pools at a density of 128 Gammurus. m−2. pool−1 Large trout (12 cm) used pools more and riffles less when small trout (10 cm) were present than when small trout were absent. Small trout consumed fewer Gammarus when together with large trout than when alone, but showed no difference in habitat use in the presence and abscnce of large trout. Habitat use and number of Gammarus consumed per trout were not affected by trout density for either size-class when alone. For both size-classes of trout, use of pools and foraging rates were higher in the absence than in the presence of pike, and pike primarily resided in the pools. The number of aggressive interactions by both size-classes of trout decreased when pike was present. Our results indicate that for habitats that differ in food resources and predation risk, size structure may affect habitat use and foraging by brown trout.
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| 41. |
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| 42. |
- Greenberg, Larry, 1955-, et al.
(författare)
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Landlocked atlantic salmon in a large river-lake ecosystem : Managing an endemic, large-bodied population of high conservation value
- 2021
-
Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 78:6, s. 787-796
-
Tidskriftsartikel (refereegranskat)abstract
- Managing and conserving threatenedmigratory salmonid populations in large river-lake ecosystems is challenging not only because of the ecosystems’ large size, but also because there is often more than one anthropomorphic stressor. The River Klarälven - Lake Vänern ecosystem, situated in Norway and Sweden, is a large, highly modified ecosystem, home to a threatened, endemic, large-bodied population of landlocked Atlantic salmon (Salmo salar). With 11 dams, the salmon population has been maintained through extensive stocking and a truck and transport system for spawners. Here we review what we have learned about the salmon after 15 years of research, highlighting the major findings for each life stage. Our studies indicate that the salmon population is below carrying capacity, and we suggest measures to increase the number of spawners and downstream passage success. Habitat restoration to compensate for losses from former log-driving activities is expected to further increase carrying capacity. Re-establishing salmon in Klarälven’s upper reaches in Norway, while possible, is fraught with both ecological and legislative hurdles. Substantial long-termfunding is needed to foster co-management and ensure a sustainable fishery.
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| 43. |
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| 44. |
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| 45. |
- Gustafsson, Pär, 1973-, et al.
(författare)
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Effects of woody debris and the supply of terrestrial invertebrates on the diet and growth of brown trout (Salmo trutta) in a boreal stream
- 2014
-
Ingår i: Freshwater Biology. - : John Wiley & Sons. - 0046-5070 .- 1365-2427. ; 59:12, s. 2488-2501
-
Tidskriftsartikel (refereegranskat)abstract
- Changes to the riparian vegetation of forest streams during timber harvesting may have considerable impacts on stream biota, but few studies have attempted to separate the effects of individual factors that are altered during clear-felling operations.We studied the effects of large wood and terrestrial invertebrate supply, two factors affected by forest harvesting, on the growth and diet of two size classes of brown trout (Salmo trutta) during a two-month (June–August) field enclosure experiment. Twelve 20-m-long enclosed stream reaches were used in a 2 × 2 factorial design, with large wood either absent or added to mimic pre-modern forestry conditions, and terrestrial invertebrate inputs either reduced or maintained at ambient levels.The addition of large wood had a positive effect on the growth of large trout but no effect on small trout, whereas terrestrial invertebrate input had no effect on the growth of either size class. Growth rates were highest in the treatment with ambient terrestrial invertebrate inputs and added wood, were lowest in the treatment with reduced terrestrial invertebrate inputs and no added wood and were intermediate in the other two treatments.Dietary analyses showed no difference in treatments with and without added wood, perhaps because instream wood influences growth by producing profitable stream positions for trout, rather than by acting as a source of prey. Terrestrial invertebrate inputs affected the diet, as trout in enclosures with reduced inputs had a lower proportion of terrestrial invertebrate biomass in the diet than trout in enclosures with ambient terrestrial inputs.Our results suggest that leaving woody debris in streams when harvesting forests may enhance trout growth and that this is probably due to the physical changes in depth and current velocity caused by the wood rather than to changes in dietary prey composition.
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| 46. |
- Gustafsson, Pär, 1973-, et al.
(författare)
-
Functional response and size-dependent foraging on aquatic and terrestrial prey by brown trout (Salmo trutta L.)
- 2010
-
Ingår i: Ecology of Freshwater Fish. - : Wiley. - 0906-6691 .- 1600-0633. ; 19:2, s. 170-177
-
Tidskriftsartikel (refereegranskat)abstract
- Terrestrial invertebrate subsidies are believed to be important energy sources for drift-feeding salmonids. Despite this, size-specific use of and efficiency in procuring this resource have not been studied to any great extent. Therefore, we measured the functional responses of three size classes of wild brown trout Salmo trutta (0+, 1+ and ≥2+) when fed either benthic- (Gammarus sp.) or surface-drifting prey (Musca domestica) in laboratory experiments. To test for size-specific prey preferences, both benthic and surface prey were presented simultaneously by presenting the fish with a constant density of benthic prey and a variable density of surface prey. The results showed that the functional response of 0+ trout differed significantly from the larger size classes, with 0+ fish having the lowest capture rates. Capture rates did not differ significantly between prey types. In experiments when both prey items were presented simultaneously, capture rate differed significantly between size classes, with larger trout having higher capture rates than smaller trout. However, capture rates within each size class did not change with prey density or prey composition. The two-prey experiments also showed that 1+ trout ate significantly more surface-drifting prey than 0+ trout. In contrast, there was no difference between 0+ and ≥2+ trout. Analyses of the vertical position of the fish in the water column corroborated size-specific foraging results: larger trout remained in the upper part of the water column between attacks on surface prey more often than smaller trout, which tended to seek refuge at the bottom between attacks. These size-specific differences in foraging and vertical position suggest that larger trout may be able to use surface-drifting prey to a greater extent than smaller conspecifics.
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| 47. |
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| 48. |
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| 49. |
- Gustafsson, Pär, 1973-, et al.
(författare)
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The influence of large wood on brown trout (Salmo trutta) behaviour and surface foraging
- 2012
-
Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 57:5, s. 1050-1059
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Tidskriftsartikel (refereegranskat)abstract
- 1. Changes in riparian vegetation owing to forest harvesting may affect the input of large wood, a major structural element, to streams. Studies of large wood impacts on stream fish have focused on population-level responses, whereas little attention has been given to how wood affects fish behaviour.2. In a laboratory stream experiment, we tested how two size classes of brown trout, Salmo trutta, (mean size of 85 and 125 mm), alone and together, responded to a gradient of large wood in terms of activity, foraging on terrestrial drift and interactions between conspecifics.3. The results showed that the presence of large wood significantly reduced the overall activity of the fish, the number of agonistic interactions between individuals and the proportion of captured prey. However, activity decreased relatively more than the proportion of captured prey, resulting in a significant positive net effect of wood on the number of prey captures per time spent active (PTA). This indicates that trout living in habitats with high wood density may have a higher net energy gain than trout living in habitats with less wood.4. There were no observable size-class differences in the benefits of large wood or in the utilisation of surface-drifting terrestrial prey.5. These results suggest that the presence of large wood may be an important factor shaping stream communities and that a lack of structural complexity may decrease energy gain, increase agonistic interactions and, consequently, lower the production of brown trout
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- Gustafsson, Pär, 1973-, et al.
(författare)
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Woody debris and terrestrial invertebrates : effects on prey resourses for brown trout (Salmo trutta) in a boreal stream
- 2014
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Ingår i: Environmental Biology of Fishes. - : Springer Science and Business Media LLC. - 0378-1909 .- 1573-5133. ; 97:5, s. 529-542
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Tidskriftsartikel (refereegranskat)abstract
- Intensive forestry and other activities that alter riparian vegetation may disrupt the connectivity and the flux of energy between terrestrial and aquatic habitats and have large effects on biota, especially in small streams. We manipulated the amount of in-stream wood and the flux of terrestrial invertebrate subsidies to determine how these factors affected potential food resources for drift-feeding brown trout (Salmo trutta ) in a boreal Swedish forest stream. Specifically, we followed the effects on the abundance of aquatic and terrestrial invertebrate fauna from June to August 2007. The treatments were 1) addition of wood, unmanipulated terrestrial invertebrate inputs, 2) reduction of terrestrial invertebrate inputs (using canopy covers), no addition of wood, 3) unmanipulated ambient conditions, 4) simultaneous addition of wood and reduction of terrestrial invertebrate inputs. Added wood resulted in greater biomass of aquatic invertebrate biomass, and both input and drift of terrestrial invertebrates were reduced by canopy covers. In terms of total potential prey biomass, the addition of wood with ambient levels of terrestrial invertebrate inputs had the highest standing crop of benthic, wood-living and terrestrial invertebrates combined, whereas the treatment with reduced terrestrial input and no wood added had the lowest standing crop. Our study indicates that forest practices that both reduce the recruitment of wood and the input of terrestrial invertebrates to small streams have negative effects on prey availability for drift-feeding brown trout. The positive effects of wood addition on biomass of aquatic macroinvertebrates may partly compensate for the negative effects of reduced terrestrial invertebrate subsidies.
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