Change search
ReferencesLink to record
Permanent link

Direct link
Day and night drift-feeding by juvenile salmonids at low water temperatures
Karlstad University, Faculty of Social and Life Sciences, Department of Biology.ORCID iD: 0000-0002-4417-6636
Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
Karlstad University, Faculty of Social and Life Sciences, Department of Biology.ORCID iD: 0000-0003-2220-1615
Karlstad University, Faculty of Social and Life Sciences, Department of Biology.ORCID iD: 0000-0002-3191-7140
2014 (English)In: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 97, no 5, 505-513 p.Article in journal (Refereed) Published
Abstract [en]

Drift-feeding salmonids in boreal streams face temperatures below physical optima for extensive periods of the year. Because juvenile salmonids react to low water temperatures by becoming nocturnal, knowledge about their foraging ability at low light intensities in cold water is needed to accurately estimate energy intake during non-summer conditions. In a laboratory stream channel, we studied temperature effects on the drift-feeding behaviour of juvenile Atlantic salmon, brown trout, and European grayling in simulated daylight and moonlight at temperatures ranging from 2 °C to 11 °C. Prey capture probability was positively related to temperature, but the temperature dependence did not agree with predictions of the Metabolic Theory of Ecology. Furthermore, reaction distance was positively related to temperature for the three species, which may be one of the underlying mechanisms responsible for the temperature effects on prey capture probability. Overall, the three species had similar capture rates at the different temperature and light levels, although there were species differences. European grayling had a slightly higher prey capture probability than brown trout, and brown trout had a shorter reaction distance than Atlantic salmon and European grayling. These results have implications for both energetics-based drift-foraging theory and for studies of winter ecology.

Place, publisher, year, edition, pages
Springer Netherlands, 2014. Vol. 97, no 5, 505-513 p.
Keyword [en]
Foraging, grayling, reaction distance, salmon, trout, winter
National Category
Ecology
Research subject
Biology
Identifiers
URN: urn:nbn:se:kau:diva-29309DOI: 10.1007/s10641-013-0190-yISI: 000334126100006OAI: oai:DiVA.org:kau-29309DiVA: diva2:653887
Note

Publication was published as manuscript in licentiate thesis "Winter behaviour of stream salmonids: effects of temperature, light, and ice cover"

Available from: 2013-10-07 Created: 2013-10-07 Last updated: 2015-12-17Bibliographically approved
In thesis
1. Winter behaviour of stream salmonids: effects of temperature, light, and ice cover
Open this publication in new window or tab >>Winter behaviour of stream salmonids: effects of temperature, light, and ice cover
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In boreal streams, stream salmonids typically face low water temperatures and variable ice conditions during winter, and thus stream salmonids are expected to use different behavioural strategies to cope with these environmental conditions. The studies presented in this thesis explore how temperature, light intensity, and surface ice affect salmonid behaviour, with focus on drift-feeding and ventilation rates. The first paper reports results from a laboratory study designed to measure prey capture probabilities and reaction distances of drift-feeding Atlantic salmon, brown trout, and European grayling at light intensities simulating daylight and moonlight at seven temperatures ranging from 2 to 11°C. There was a positive relationship between water temperature and prey capture probability for all three species at both light levels, but the temperature-dependence did not scale according to the Metabolic Theory of Ecology. Reaction distance was also positively related to temperature for the three species, which may explain the temperature effects on prey capture probability. The results from this study should be of interest for those working with energetic-based drift-foraging models. In the second paper, the effects of ice cover on the diel behaviour and ventilation rate of brown trout were studied in a laboratory stream. Ice cover is believed to afford protection against endothermic predators, and thus the need for vigilance should be reduced under ice cover. This hypothesis was tested by observing ventilation rates at night, dawn, and during the day in the presence and absence of real, light-permeable surface ice. Further, trout were offered drifting prey during the day to test if ice cover increased daytime foraging activity. Ice cover reduced ventilation rates at dawn and during the day, but not at night. Moreover, trout made more daytime foraging attempts in the presence of ice cover than in its absence. These results suggest that ice cover affects the behaviour of brown trout and presumably has a positive effect on winter survival. Global warming, by reducing the extent or duration of surface ice, may therefore have negative consequences for many lotic fish populations in boreal streams.

Abstract [en]

BAKSIDESTEXT

In boreal streams, salmonids typically face low water temperatures and variable ice conditions from autumn to spring. The studies presented in this thesis explore how temperature, light intensity, and ice cover affect salmonid behaviour, with focus on drift-feeding and ventilation rates. In Paper I, drift-foraging was studied at light intensities simulating daylight and moonlight at seven temperatures ranging from 2 to 11°C. There was a positive relationship between temperature and foraging success at both light levels, but the temperature-dependence did not scale according to the Metabolic Theory of Ecology. Moreover, reaction distance was positively related to temperature. In Paper II, the effects of ice cover on behaviour and ventilation rate of brown trout were studied. Ice cover is believed to afford protection against predators, and thus the need for vigilance should be reduced under ice. This hypothesis was tested by observing ventilation rates at night, dawn, and during the day in the presence and absence of surface ice. Ice cover reduced ventilation rates and increased daytime foraging activity, suggesting that ice cover presumably has a positive effect on winter survival.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2013. 21 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2013:18
Keyword
stream salmonids, winter behaviour, efftect of temperatur, light, ice cover, environment, fish populations
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-26809 (URN)978-91-7063-495-6 (ISBN)
Presentation
2013-05-27, 11D227 - Erlander, Universitetsgatan 2, 651 88 Karlstad, 10:15 (English)
Opponent
Supervisors
Available from: 2013-05-06 Created: 2013-04-02 Last updated: 2014-09-10Bibliographically approved
2. 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: 2016-06-07Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full texthttp://link.springer.com/article/10.1007/s10641-013-0190-y

Search in DiVA

By author/editor
Watz, JohanPiccolo, JohnBergman, EvaGreenberg, Larry
By organisation
Department of Biology
In the same journal
Environmental Biology of Fishes
Ecology

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 142 hits
ReferencesLink to record
Permanent link

Direct link