Browsing NTNU Open by Author "Einum, Sigurd"
Now showing items 1-20 of 63
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Among-river pattern in relative abundance of two salmonid fishes reflects temperature-dependent competition
Skoglund, Helge; Forseth, Torbjørn; Einum, Sigurd (Journal article; Peer reviewed, 2024)Temperature is a key driver in determining species distribution and abundance across climatic and geographical gradients. This occurs through direct physiological effects of temperature on performance, but may also result ... -
Assessing risks of invasion through gamete performance: Farm Atlantic salmon sperm and eggs show equivalence in function, fertility, compatibility and competitiveness to wild Atlantic salmon
Yeates, Sarah E.; Einum, Sigurd; Fleming, Ian A.; Holt, William V.; Gage, Matthew J.G. (Journal article; Peer reviewed, 2014)Adaptations at the gamete level (a) evolve quickly, (b) appear sensitive to inbreeding and outbreeding and (c) have important influences on potential to reproduce. We apply this understanding to problems posed by escaped ... -
Automated measurement of upper thermal limits in small aquatic animals
Burton, Tim; Zeis, Bettina; Einum, Sigurd (Journal article; Peer reviewed, 2018)We present a method for automating the measurement of upper thermal limits in small aquatic organisms. Upper thermal limits are frequently defined by the cessation of movement at high temperature, with measurement being ... -
Can variation in standard metabolic rate explain context- dependent performance of farmed Atlantic salmon offspring?
Robertsen, Grethe; Reid, Donald; Einum, Sigurd; Aronsen, Tonje; Fleming, Ian A.; Sundt-Hansen, Line Elisabeth Breivik; Karlsson, Sten; Kvingedal, Eli; Ugedal, Ola; Hindar, Kjetil (Journal article; Peer reviewed, 2018)Escaped farmed Atlantic salmon interbreed with wild Atlantic salmon, leaving off- spring that often have lower success in nature than pure wild salmon. On top of this, presence of farmed salmon descendants can impair ... -
Causes and consequences of variation in age at maturity in Atlantic salmon (Salmo salar)
Raunsgard, Astrid (Doctoral theses at NTNU;2024:163, Doctoral thesis, 2024)Understanding the causes and consequences of variation in life-history traits is fundamental for managing natural populations in a changing environment. Atlantic salmon (Salmo salar) spend 1–5 years feeding at sea before ... -
Change in Thermal Metabolic Rate Reaction Norms of Daphnia in Response to Rearing Temperature
Gajic, Tijana (Master thesis, 2013)Temperature is an important environmental factor that affects the distribution of organisms. It affects the biochemical and physiological processes which are the basis of life. The metabolic cold adaptation (MCA) hypothesis ... -
Changes in freshwater zooplankton communities in response to invasive planktivorous fish
Konst, Lindis H. (Master thesis, 2020)Cladocera samfunnets respons til invasjon av planktivore fisk ble vurdert ved hjelp av et BACI (befor-after-control-impact) studiedesign. Hypotesen som ble testet var om sik og abbor forårsaket en endring i cladocera ... -
Combined effects of environmental variation and pollution on zooplankton life history and population dynamics
Issa, Semona (Doctoral theses at NTNU;2021:49, Doctoral thesis, 2021)Toxicity studies on aquatic organisms are commonly conducted under highly standardized conditions that exclude interactions with environmental factors. However, aquatic organisms such as Daphnia regularly experience ... -
Cryptic choice of conspecific sperm controlled by the impact of ovarian fluid on sperm swimming behavior
Yeates, SE; Diamond, SE; Einum, Sigurd; Emerson, Brent C.; Holt, WV; Gage, MJG (Journal article; Peer reviewed, 2013)Despite evidence that variation in male–female reproductive compatibility exists in many fertilization systems, identifying mechanisms of cryptic female choice at the gamete level has been a challenge. Here, under risks ... -
Density effect on growth rate of juvenile Atlantic salmon (Salmo salar) in manipulated large rivers
Vae, Eivind (Master thesis, 2015)Growth rate of young-of-the-year (YOY) Atlantic salmon (Salmo salar) in low-density rivers was substantial better relative to YOY captured in normal density rivers. Mean growth index ± SD for YOY in low-density rivers was ... -
Density independent use of shallow riverine areas in juvenile Atlantic salmon
Puffer, Michael; Berg, Ole Kristian; Hamnes, Frøydis Bolme; Bentsen, Vidar; Koch, Wouter; Ugedal, Ola; Forseth, Torbjørn; Arnekleiv, Jo Vegar; Einum, Sigurd (Journal article; Peer reviewed, 2018)Habitat use of aquatic organisms is essential to evaluate effects of many environmental challenges like effects of hydro-power regulation, where stranding may occur under hydropeaking (rapid dewatering of shallow river ... -
Desnity dependent habitat use of Atlantic salmon, Salmo salar L.- stranding in hydropower rivers
Bentsen, Vidar Johan (Master thesis, 2011)An experiment was performed in four artificial stream channels during summer and autumn to investigate the effects of biotic and abiotic factors on habitat choice of juvenile Atlantic salmon (Salmo salar). To investigate ... -
Divergence in rates of phenotypic plasticity among ectotherms
Einum, Sigurd; Burton, Tim (Peer reviewed; Journal article, 2022)An individual's fitness cost associated with environmental change likely depends on the rate of adaptive phenotypic plasticity, and yet our understanding of plasticity rates in an ecological and evolutionary context remains ... -
Divergence in Thermal Reaction Norms of Life-History Traits Among Populations of Daphnia magna
Bartuseviciute, Vitalija (Master thesis, 2018)Patterns of phenotypic and genetic variance in thermal reaction norms allow predicting evolutionary response for a population. The ability of phenotypic traits to respond to selection depends on their genetic variance, and ... -
Do genetic differences in growth thermal reaction norms maintain genetic variation in timing of diapause induction?
Fossen, Erlend Ignacio Fleck; Raeymaekers, Joost A. M.; Einum, Sigurd (Peer reviewed; Journal article, 2021)An optimal timing for diapause induction through the sexual production of dormant propagules is expected in organisms with temporary populations. Yet, empirical studies often find high within-population genetic variation ... -
Ecological modeling of metabolic rates predicts diverging optima across food abundances
Einum, Sigurd (Journal article; Peer reviewed, 2014)Genetically based variation in metabolic rates of resting animals (RMR) suggests a potential role for evolutionary adaptations, but mechanistic models yielding evolutionary predictions are lacking. Here I utilize the ... -
Effects of intra- and interspecific competition and hydropeaking on growth of juvenile Atlantic salmon (Salmo salar)
Puffer, Michael; Berg, Ole Kristian; Huusko, Ari; Vehanen, Teppo; Einum, Sigurd (Journal article, 2017)The effects of hydropeaking and intra- and interspecific competition on the growth performance (growth in length, mass and lipid content) of juvenile Atlantic salmon Salmo salar and brown trout Salmo trutta were studied ... -
Effects of introduced planktivorous fish on the seasonal dynamics of freshwater zooplankton
Larsen, Silje Margrethe Nessjø (Master thesis, 2022)Introdusert planktivore fisk i ferskvann kan ha en betydelig effekt på næringsnettet ved å fungere som en kontroll ovenfra og ned på zooplankton, med mulige kaskadeeffekter på lavere trofiske nivåer. Imidlertid er det ... -
An empirical test for a zone of canalization in thermal reaction norms
Fossen, Erlend Ignacio Fleck; Pelabon, Christophe; Einum, Sigurd (Journal article; Peer reviewed, 2018)Theoretical models on the evolution of phenotypic plasticity predict a zone of canalization where reaction norms cross, and genetic variation is minimized in the environment a population most frequently encounter. Empirical ... -
Energetic Consequences of Stranding of Juvenile Atlantic Salmon (Salmo salar L.)
Puffer, Michael; Berg, Ole Kristian; Einum, Sigurd; Saltveit, Svein Jakob; Forseth, Torbjørn (Journal article, 2017)An effect of hydropower and hydropeaking regulation in rivers is stranding of fish. Those fishes that survive stranding may experience stranding as a stressful situation. In four experimental stranding experiments (each ...