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dc.contributor.advisorKnudsen, Rune
dc.contributor.advisorAmundsen, Per-Arne
dc.contributor.advisorSmalås, Aslak
dc.contributor.authorDalbak, Katrine
dc.date.accessioned2021-02-18T12:15:29Z
dc.date.available2021-02-18T12:15:29Z
dc.date.issued2020-12-21
dc.description.abstractOver the last 20 years there has been a large change in the fish community structure in Lille Rostavatn, northern Norway. The relative contribution of the cold-water adapted fish species, Arctic charr (<i>Salvelinus alpinus</i>) and burbot (<i>Lota lota</i>), has distinctly decreased whereas the more temperate-adapted fish species, grayling (<i>Thymallus thymallus</i>) and brown trout (<i>Salmo trutta</i>), have increased, presumably because of a rise in water temperature which is shown to be a significant increase in the Målselv watercourse from 1991 to 2018. In this study the spatial and temporal variation in relative contribution, habitat use, and diet of these four fish species were studied from four years of gill net sampling in August and October between 1997 and 2018, exploring general patterns in resource partitioning and possible climaterelated changes in habitat and dietary utilization. Arctic charr dominated the total catches, followed by grayling. A distinct resource segregation was observed between the cold-water and the temperate-adapted fish species according to habitat use and the selection of specific prey types, especially in the littoral habitat. The habitat partitioning was particularly clear in August, when the cold-water adapted fish species decreased in densities in the littoral habitat over time. In October, at lower water temperatures, Arctic charr and burbot, showed a minor increase in the littoral catches. The dietary overlap between the species were in general low and the intraspecific dietary similarity showed high overlap between the four years, indicating small changes in resource utilization over time. Analysis of stomach content revealed a narrow trophic niche of Arctic charr as they fed mainly on zooplankton in all habitats of the lake. Previous field studies from Lille Rostavatn have demonstrated that Arctic charr are adapted to a planktivore diet due to strong interspecific resource competition for the benthic resources by burbot and in the more recent years this may have been amplified due to increasing grayling and brown trout population. The diet of burbot was dominated mainly by benthic invertebrates in all habitats whereas grayling and brown trout consumed surface insects and benthic invertebrates. These findings suggest that interspecific competition leading to changes in resource partitioning under a changing climate is not the key factor influencing the shift in fish community structure in Lille Rostavatn. The observed resource segregation might be a result of biotic interactions mediated by abiotic conditions.en_US
dc.identifier.urihttps://hdl.handle.net/10037/20582
dc.language.isoengen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2020 The Author(s)
dc.rights.urihttps://creativecommons.org/licenses/by-nc-sa/4.0en_US
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)en_US
dc.subject.courseIDBIO-3950
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Limnologi: 498en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Limnology: 498en_US
dc.subjectArctic charren_US
dc.subjectSalvelinus alpinusen_US
dc.subjectBrown trouten_US
dc.subjectSalmo truttaen_US
dc.subjectGraylingen_US
dc.subjectThymallus thymallusen_US
dc.subjectBurboten_US
dc.subjectLota lotaen_US
dc.subjectFish community structureen_US
dc.subjectClimate changeen_US
dc.subjectresource partitioningen_US
dc.subjectcold-water adapteden_US
dc.subjecttemperate-adapteden_US
dc.titleThe effect of climate change on the fish community in Lille Rostavatn, northern Norwayen_US
dc.typeMaster thesisen_US
dc.typeMastergradsoppgaveen_US


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Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)