Change search
ReferencesLink to record
Permanent link

Direct link
Prey capture rates of two species of salmonids (Salmo trutta and Thymallus thymallus) in an artificial stream: effects of temperature on their functional response
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. (River Ecology and Management)ORCID iD: 0000-0002-4417-6636
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. (NRRV - Naturresurs Rinnande Vatten)ORCID iD: 0000-0003-2220-1615
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. (River Ecology and Management)
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.ORCID iD: 0000-0002-3191-7140
2014 (English)In: Marine and Freshwater Behaviour & Physiology, ISSN 1023-6244, Vol. 47, no 2, 93-99 p.Article in journal (Refereed) Published
Abstract [en]

The foraging success of predators depends on how their consumption of prey is affected by prey density under different environmental settings. Here, we measured prey capture rates of drift-feeding juvenile brown trout and European grayling at different prey densities in an artificial stream channel at 5 and 11 °C. Capture rates were lower at 5 than at 11 °C, and the difference was most pronounced at high prey densities. At high prey densities, we also observed that European grayling had higher capture rates than brown trout. Type III functional response curves, i.e. sigmoidal relationships between capture rates and prey densities, fitted the data better than type I (linear) and II (hyperbolic) curves for all four combinations of temperatures and species. These results may explain the dominance of grayling in stream habitats with low water velocities and results such as these may be of use when developing foraging-based food web models of lotic ecosystems that include drift-feeding salmonids.

Place, publisher, year, edition, pages
London, UK: Taylor & Francis, 2014. Vol. 47, no 2, 93-99 p.
Keyword [en]
drift, feeding, foraging, food web, grayling, lotic, prey density, trout
National Category
Ecology
Research subject
Biology
Identifiers
URN: urn:nbn:se:kau:diva-32035DOI: 10.1080/10236244.2014.900210ISI: 000335822300003OAI: oai:DiVA.org:kau-32035DiVA: diva2:715684
Available from: 2014-05-06 Created: 2014-05-06 Last updated: 2015-12-17Bibliographically approved
In thesis
1. Salmonid behaviour under winter conditions
Open this publication in new window or tab >>Salmonid behaviour under winter conditions
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Winter conditions are believed to play an important role in the population dynamics of northern temperate stream fish, challenging the ability of fish to physiologically and behaviourally adapt. Climate change is predicted to increase both mean temperature and temperature fluctuations, especially during winter, leading to dynamic environmental conditions in terms of river ice production and flow. Therefore, knowledge about the winter ecology of stream fish is important for predicting and mitigating anthropogenic impacts on fish production in boreal streams. Stream salmonids are relatively active throughout winter, and behavioural responses to different winter conditions may be critical for survival. Yet, relatively little is known about overwintering behaviour of salmonids, particularly in streams with ice. In this doctoral thesis, I report the results from experimental field and laboratory studies on the behavioural ecology of juvenile salmonids under winter conditions. My results from the field show that salmonids grow more and use a broader range of habitats in the presence of surface ice than in its absence. Results from the laboratory experiments show that the presence of surface ice increases food intake rates, reduces stress and affects social interactions. These laboratory results may explain the positive effects of ice cover on growth that was found in the field experiment. Moreover, I show that drift-feeding ability is reduced at low temperatures, and that nocturnal drift foraging under winter conditions has a low efficiency.

Abstract [sv]

Vinterförhållanden kan spela en avgörande roll för förekomsten av fisk i våra vattendrag. Laxfiskar, som till exempel lax, öring och harr, är vinteraktiva och måste därför anpassa sin fysiologi och sitt beteende till en miljö som karakteriseras av låga och föränderliga vattenflöden, liten tillgång på föda, kallt vatten, is och mörker. Trots att dessa anpassningar är avgörande för chansen att överleva vintern, vet man relativt lite om laxfiskars vinterbeteende, speciellt i vattendrag som täcks av is. I denna avhandling presenterar jag resultat från fält- och laboratoriestudier av laxfiskars beteende under vinterförhållanden och resultaten visar att närvaron av yttäckande is ökar tillväxt och födointag, minskar stress samt påverkar var fiskar uppehåller sig och hur fiskarna interagerar med varandra. Jag har också undersökt hur laxfiskars beteende i rinnande vatten påverkas av ljusintensitet och vattentemperatur i samband med födointag. Resultaten visar att den minskade dagaktiviteten som laxfiskar uppvisar på vintern medför en kostnad i form av försämrad förmåga att fånga byten.

Abstract [en]

Winter conditions are believed to play an important role in the population dynamics of northern temperate stream fish, challenging the ability of fish to physiologically and behaviourally adapt. Climate change is predicted to increase both mean temperature and temperature fluctuations, especially during winter, leading to dynamic environmental conditions in terms of river ice production and flow. Therefore, knowledge about the winter ecology of stream fish is important for predicting and mitigating anthropogenic impacts on fish production in boreal streams.

Stream salmonids are active throughout winter, and behavioural responses to different winter conditions may be critical for survival. Yet, relatively little is known about overwintering behaviour of salmonids, particularly in streams with ice. This doctoral thesis focuses on the behavioural ecology of salmonids under winter conditions, and results from field and laboratory experiments show that the presence of surface ice increases food intake rates, reduces stress and affects social interactions, with effects on growth and habitat use. Moreover, drift-feeding ability is reduced at low temperatures, and nocturnal drift foraging under winter conditions has a low efficiency.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2015. 40 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2015:55
Keyword
climate change, drift, energy budget, foraging, grayling, ice cover, lotic, metabolic rate, predation, salmon, stream, stress, temperature, trout
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-38354 (URN)978-91-7063-674-5 (ISBN)
Public defence
2016-01-22, 9C203, Nyquistsalen, Universitetsgatan 2, Karlstad, 10:15 (English)
Opponent
Supervisors
Note

Artikel 1 i avhandlingen som manuskript. Nu publicerad.

Available from: 2015-12-17 Created: 2015-11-11 Last updated: 2016-12-07Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Watz, JohanBergman, EvaPiccolo, JohnGreenberg, Larry
By organisation
Department of Environmental and Life Sciences
In the same journal
Marine and Freshwater Behaviour & Physiology
Ecology

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 92 hits
ReferencesLink to record
Permanent link

Direct link