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Bergman, E. & Eriksson, M. (2024). Med en doktorsexamen från Karlstads universitet: Alumner om forskarstudier och arbete 2022. Karlstads universitet
Open this publication in new window or tab >>Med en doktorsexamen från Karlstads universitet: Alumner om forskarstudier och arbete 2022
2024 (Swedish)Report (Other (popular science, discussion, etc.))
Place, publisher, year, edition, pages
Karlstads universitet, 2024. p. 25
National Category
Other Humanities
Identifiers
urn:nbn:se:kau:diva-97988 (URN)
Available from: 2024-01-12 Created: 2024-01-12 Last updated: 2024-01-12Bibliographically approved
Carlsson, N., Nyquist, N. & Bergman, E. (2023). Diet hos adult insjölevande lax (Salmo salar) och öring (Salmo trutta) i Vänern.. Karlstads universitet
Open this publication in new window or tab >>Diet hos adult insjölevande lax (Salmo salar) och öring (Salmo trutta) i Vänern.
2023 (Swedish)Report (Other academic)
Abstract [sv]

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.

Place, publisher, year, edition, pages
Karlstads universitet, 2023
National Category
Biological Sciences Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-94598 (URN)
Available from: 2023-05-11 Created: 2023-05-11 Last updated: 2023-05-24Bibliographically approved
Filipsson, K., Erlandsson, A., Greenberg, L., Österling, M., Watz, J. & Bergman, E. (2023). Do predator odours and warmer winters affect growth of salmonid embryos?. Ecology of Freshwater Fish (1), Article ID e12747.
Open this publication in new window or tab >>Do predator odours and warmer winters affect growth of salmonid embryos?
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2023 (English)In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, no 1, article id e12747Article in journal (Refereed) Published
Abstract [en]

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. 

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
brown trout, climate change, development, egg incubation, predation, yolk
National Category
Ecology Zoology Fish and Aquacultural Science
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-96852 (URN)10.1111/eff.12747 (DOI)2-s2.0-85170696207 (Scopus ID)
Funder
Karlstad University
Available from: 2023-10-02 Created: 2023-10-02 Last updated: 2023-12-11Bibliographically approved
Näslund, J., Bowes, R., Sandin, L., Bergman, E. & Greenberg, L. (2023). Fish biodiversity in different types of tributary mouths located within impounded sections of Swedish boreal rivers. International Journal of Ecohydrology and Hydrobiology, 23(1), 48-65
Open this publication in new window or tab >>Fish biodiversity in different types of tributary mouths located within impounded sections of Swedish boreal rivers
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2023 (English)In: International Journal of Ecohydrology and Hydrobiology, ISSN 1642-3593, E-ISSN 2080-3397, Vol. 23, no 1, p. 48-65Article in journal (Refereed) Published
Abstract [en]

Large boreal rivers in Sweden are generally impounded by hydropower dams and a large proportion of main stem shallow flowing habitats have been lost. Tributaries often contain the last undisturbed habitats and could be important for the conservation of species diversity. In particular, tributary mouth areas could be biodiversity hot-spots, due to their vicinity to the main stem and favorable environmental conditions. In this study, we investigate whether tributary mouth areas in two impounded boreal rivers (Ume River and Lule River) could be regarded as biodiversity hot-spots for fish. Based on standardized electrofishing in 20 tributary mouths, we find that overall fish diversity is generally low. The highest species richness and diversity was found in mouth areas dominated by intermediate substrate sizes (gravel – cobble). Few, if any, species were found in areas where fine sediments (smaller than sand) dominated. The tributary mouth areas had similar species richness and diversity as areas in the tributaries located 1-km upstream of the mouth, but the fish community composition often differed between these two types of sites. Management action favoring fish diversity in the tributary mouth areas could include protection or rehabilitation of areas dominated by medium sized substrate and reduction of erosion and transport of fine sediments in the tributaries. Overall, we find no support for tributary mouths being hot-spots for fish biodiversity and while some patterns in diversity gives hints on suitable management action, it is important to further understand impacts in tributaries and their mouths and the temporal dynamics of the fish community.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Aggradation, Boreal rivers, Fish biodiversity, River morphology, River sediment size, Tributary confluence
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-92780 (URN)10.1016/j.ecohyd.2022.11.004 (DOI)000927440400001 ()2-s2.0-85143146243 (Scopus ID)
Funder
Energy ResearchSwedish Energy AgencyUmeå UniversitySwedish Agency for Marine and Water ManagementKarlstad University
Available from: 2022-12-29 Created: 2022-12-29 Last updated: 2023-03-31Bibliographically approved
Bowes, R. E., Bergman, E., Donadi, S., Greenberg, L., Sandin, L. & Lind, L. (2023). Landscape features control river's confluences water quality and tributary fish composition. Rivers Research and Applications: an international journal devoted to river research and management, 39(6), 1025-1036
Open this publication in new window or tab >>Landscape features control river's confluences water quality and tributary fish composition
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2023 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 39, no 6, p. 1025-1036Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
fish diversity, landscape, tributary, water quality
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-94634 (URN)10.1002/rra.4133 (DOI)000973690300001 ()2-s2.0-85153311351 (Scopus ID)
Funder
Energy ResearchKarlstad University
Available from: 2023-05-12 Created: 2023-05-12 Last updated: 2023-12-11Bibliographically approved
Hansen, H. H., Andersen, K. H. & Bergman, E. (2023). Projecting fish community responses to dam removal – Data-limited modeling. Ecological Indicators, 154, Article ID 110805.
Open this publication in new window or tab >>Projecting fish community responses to dam removal – Data-limited modeling
2023 (English)In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 154, article id 110805Article in journal (Refereed) Published
Abstract [en]

Modeling fish community responses to dam removal is an emerging field of study as dam removals become more common, but uncertainties concerning recovery time and community stability remain. In Europe, an EU-wide biodiversity strategy plans to restore around 25,000 km of rivers to free-flowing status, which emphasizes the importance of being able to predict fish community responses after dam removal. We developed a multi-species size spectrum model for a fish community in the Mörrum River in Sweden to identify possible outcomes after a dam was removed in 2020. Electrofishing monitoring before the dam removal was used to calibrate the model. We projected multiple scenarios into the future to explore patterns of community stability, individual species responses, and recovery time while varying parameters related to dam removal mortality, base resource rate change, and maximum recruitment change. We created 30 hypothetical scenarios using an abrupt change perspective (parameters are step-based) and 30 scenarios using a gradual change perspective (parameters are smooth). In both perspectives, dam removal mortality and a decreasing resource rate reduced community biomass and delayed recovery time compared to pre-dam removal conditions. Our results demonstrate that recovery from a dam removal scenario is not necessarily a benefit for all species. In scenarios where dam removal practices or dam failures cause high mortality events and sustained impacts on base trophic level resources, recovery of pre-removal biomass may take decades, while community stability may be unstable for twice that time-period. Our study shows that size spectrum models can be applied to dam removal scenarios to explore potential recovery outcomes, particularly from a risk avoidance perspective. A benefit of using such an approach is the relatively low data requirements needed to perform projections (e.g., present species, fish growth rates, relative fish abundance). Implementing this model in other river systems, particularly at the reach scale, can help river restoration and management assess tradeoffs associated with different habitat restoration approaches prior to committing to a dam removal plan.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Data-limited approach, Free-flowing rivers, Predator–prey interactions, Risk-assessment, River restoration, Size spectrum models, Sweden, Biodiversity, Dams, Fish, Population statistics, Recovery, Restoration, Risk perception, Rivers, Uncertainty analysis, Dam removal, Free flowing, Free-flowing river, Predator-prey interaction, Risks assessments, Size spectrum, Size spectrum model, Spectra modeling, biomass, growth rate, habitat restoration, recruitment (employment), trophic level, Risk assessment
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-97133 (URN)10.1016/j.ecolind.2023.110805 (DOI)001059012500001 ()2-s2.0-85172172858 (Scopus ID)
Funder
EU, Horizon 2020, 860800
Available from: 2023-10-20 Created: 2023-10-20 Last updated: 2023-12-05Bibliographically approved
Marker, J., Bergman, E., Bowes, R. E. & Lafage, D. (2023). Small stream predators rely heavily on terrestrial matter energy input in the fall, regardless of riparian buffer size. Food Webs, 36, Article ID e00302.
Open this publication in new window or tab >>Small stream predators rely heavily on terrestrial matter energy input in the fall, regardless of riparian buffer size
2023 (English)In: Food Webs, E-ISSN 2352-2496, Vol. 36, article id e00302Article in journal (Refereed) Published
Abstract [en]

Stream ecosystems are reliant on the reciprocal exchange of terrestrial and aquatic energy subsides to maintain a productive and stable food web. Land use around streams can have strong effects on the size and availability of resource subsidies for stream and riparian predators such as fish and spiders. A common forestry technique around streams is the establishment of forested buffers to protect aquatic and riparian ecosystems from upland disturbances. Buffer size may determine prey abundance, richness, and spatial extent of prey reach into both the aquatic and terrestrial systems. To test the effects of forested buffers subsidy direction, we explored the carbon and nitrogen stable isotope signatures of brown trout (Salmo trutta), Tetragnathidae and Lycosidae spiders, and their aquatic and terrestrial prey sources around twelve streams in southern Sweden. For both predator groups, buffer presence showed no effect on resource subsidy source. We found that both brown trout and spiders are significantly reliant on terrestrial sources of prey for their diets in the fall. To support the terrestrial subsidy into small streams it is vital to maintain ecologically functional riparian zones by conserving complex surrounding habitats that optimize habitat and both terrestrial and aquatic prey diversity.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Allochthonous resources, Aquatic subsidies, Forested buffers, Riparian, Stable isotopes, Terrestrial subsidies
National Category
Ecology Environmental Sciences related to Agriculture and Land-use
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-96326 (URN)10.1016/j.fooweb.2023.e00302 (DOI)001050735300001 ()2-s2.0-85165632660 (Scopus ID)
Funder
Swedish Research Council Formas, 2018-00412
Available from: 2023-08-10 Created: 2023-08-10 Last updated: 2023-11-08Bibliographically approved
Filipsson, K., Bergman, E., Erlandsson, A., Greenberg, L., Österling, M. & Watz, J. (2023). Temperature during embryonic development in brown trout influences juvenile behaviour in encounters with predators. Journal of Zoology
Open this publication in new window or tab >>Temperature during embryonic development in brown trout influences juvenile behaviour in encounters with predators
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2023 (English)In: Journal of Zoology, ISSN 0952-8369, E-ISSN 1469-7998Article in journal (Refereed) Epub ahead of print
Abstract [en]

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

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
anti-predator behaviour, climate change, development, embryogenesis, incubation temperature, salmonid
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-97834 (URN)10.1111/jzo.13135 (DOI)001118606000001 ()2-s2.0-85179367718 (Scopus ID)
Funder
Karlstad University
Available from: 2023-12-22 Created: 2023-12-22 Last updated: 2024-01-03Bibliographically approved
Greenberg, L. A., Filipsson, K., Bergman, E. & Jonsson, B. (2023). The effects of egg incubation temperature and parental cross on the swimming activity of juvenile brown trout Salmo trutta. Behavioral Ecology and Sociobiology, 77(10), Article ID 114.
Open this publication in new window or tab >>The effects of egg incubation temperature and parental cross on the swimming activity of juvenile brown trout Salmo trutta
2023 (English)In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 77, no 10, article id 114Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Behavior, Brown trout phenotypes, Counter-gradient variation, Early life history effects, Locomotor activity, Personality
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-97287 (URN)10.1007/s00265-023-03384-w (DOI)001082484100001 ()2-s2.0-85173974045 (Scopus ID)
Funder
The Research Council of Norway, 268005
Available from: 2023-11-02 Created: 2023-11-02 Last updated: 2023-11-22Bibliographically approved
Filipsson, K., Åsman, V., Greenberg, L., Österling, M., Watz, J. & Bergman, E. (2023). Winter Behavior of Juvenile Brown Trout in a Changing Climate: How Do Light and Ice Cover Affect Encounters with Instream Predators?. Fishes, 8(10), Article ID 521.
Open this publication in new window or tab >>Winter Behavior of Juvenile Brown Trout in a Changing Climate: How Do Light and Ice Cover Affect Encounters with Instream Predators?
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2023 (English)In: Fishes, E-ISSN 2410-3888, Vol. 8, no 10, article id 521Article in journal (Other academic) Published
Abstract [en]

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.

Keywords
anti-predator, global changer, diel behavior, foraging, piscivores, predators
National Category
Ecology Zoology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-88204 (URN)10.3390/fishes8100521 (DOI)001089943500001 ()2-s2.0-85175046960 (Scopus ID)
Funder
Karlstad University
Note

This paper was included as a manuscript in doctoral thesis entitled "Early life stages of brown trout - Anti-predator responses under warming winters" 2022:2

Available from: 2022-01-26 Created: 2022-01-26 Last updated: 2023-11-28Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2220-1615

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