Blar i Bergen Open Research Archive på forfatter "Jørgensen, Christian"
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Adaptive host responses to infection can resemble parasitic manipulation
Jensen, Camilla Håkonsrud; Weidner, Jacqueline; Giske, Jarl; Jørgensen, Christian; Eliassen, Sigrunn; Mennerat, Adele (Journal article; Peer reviewed, 2023)Using a dynamic optimisation model for juvenile fish in stochastic food environments, we investigate optimal hormonal regulation, energy allocation and foraging behaviour of a growing host infected by a parasite that only ... -
Bergmann patterns in planktivorous fishes: A light-size or zooplankton community-size rule is just as valid explanation as the temperature-size rule
Ljungström, Anna Jeja Gabriella; Langbehn, Tom; Jørgensen, Christian (Journal article; Peer reviewed, 2024)Aim Bergman patterns, the tendency of organisms to be larger at higher latitudes and lower temperatures, are a well-studied biogeographic pattern. Yet, there is no consensus on the driver or underlying mechanisms. We ... -
Bioeconomic consequences of fishing-induced evolution: a model predicts limited impact on net present value
Zimmermann, Fabian; Jørgensen, Christian (Peer reviewed; Journal article, 2015-04)Fishing reduces stock size and shifts demographics, and selective mortality may also lead to evolutionary changes. Previous studies suggest that traits may change evolutionarily because of fishing on decadal time scales. ... -
Bioenergetics modelling of growth processes in parasitized Eastern Baltic cod (Gadus morhua L.)
Ryberg, Marie Plambech; Christensen, Asbjørn; Jørgensen, Christian; Neuenfeldt, Stefan; Skov, Peter V.; Behrens, Jane W. (Journal article; Peer reviewed, 2023)Changes in physiological processes can reveal how individuals respond to environmental stressors. It can be difficult to link physiological responses to changes in vital rates such as growth, reproduction and survival. ... -
Blue mussels in western Norway have vanished where in reach of crawling predators
Meister, Nadja; Langbehn, Tom; Varpe, Øystein; Jørgensen, Christian (Journal article; Peer reviewed, 2023)Blue mussels (Mytilus spp.) are declining around the world. In western Norway, they have widely disappeared from rocky shores but still thrive on floating structures. Other refugia are cracks in rocks, exposed sites, and ... -
Body size adaptions under climate change: Zooplankton community more important than temperature or food abundance in model of a zooplanktivorous fish
Ljungström, Anna Jeja Gabriella; Claireaux, Marion; Fiksen, Øyvind; Jørgensen, Christian (Journal article; Peer reviewed, 2020)One of the most well-studied biogeographic patterns is increasing body size with latitude, and recent body size declines in marine and terrestrial organisms have received growing attention. Spatial and temporal variation ... -
Climate change in fish: effects of respiratory constraints on optimal life history and behaviour
Holt, Rebecca; Jørgensen, Christian (Peer reviewed; Journal article, 2015)The difference between maximum metabolic rate and standard metabolic rate is referred to as aerobic scope, and because it constrains performance it is suggested to constitute a key limiting process prescribing how fish may ... -
Climate warming causes life-history evolution in a model for Atlantic cod (Gadus morhua)
Holt, Rebecca E.; Jørgensen, Christian (Peer reviewed; Journal article, 2014)Climate change influences the marine environment, with ocean warming being the foremost driving factor governing changes in the physiology and ecology of fish. At the individual level, increasing temperature influences ... -
Decision-making from the animal perspective: Bridging ecology and subjective cognition
Budaev, Sergei; Jørgensen, Christian; Mangel, Marc; Eliassen, Sigrunn; Giske, Jarl (Journal article; Peer reviewed, 2019-05-14)Organisms have evolved to trade priorities across various needs, such as growth, survival, and reproduction. In naturally complex environments this incurs high computational costs. Models exist for several types of decisions, ... -
Dying from the lesser of three evils: facilitation and non-consumptive effects emerge in a model with multiple predators
Fouzai, Nadia; Opdal, Anders Frugård; Jørgensen, Christian; Fiksen, Øyvind (Peer reviewed; Journal article, 2019)Prey modify their behaviour to avoid predation, but dilemmas arise when predators vary in hunting style. Behaviours that successfully evade one predator sometimes facilitate exposure to another predator, forcing the prey ... -
Effects of copepod size on fish growth: A model based on data for North Sea sandeel
Van Deurs, Mikael; Jørgensen, Christian; Fiksen, Øyvind (Peer reviewed; Journal article, 2015-02-03)In productive marine off-shore ecosystems, the flow of energy from zooplankton to large predators is channeled through a few species of short-lived, highly abundant schooling planktivorous fish. There are indications that ... -
Effects of temperature and food availability on larval cod survival: A model for behaviour in vertical gradients
Fouzai, Nadia; Opdal, Anders Frugård; Jørgensen, Christian; Fiksen, Øyvind (Peer reviewed; Journal article, 2015-06-08)Recruitment success in living marine resources is variable due to high survival variability of early life stages. Improving our understanding of how environmental and ecological factors mechanistically interact and influence ... -
Emergence of games from ecological trade-offs: longevity changes strategies for extra-pair mating in birds
Ruminska, Agnieszka; Eliassen, Sigrunn; Jørgensen, Christian (Journal article; Peer reviewed, 2023)Each member of a breeding pair benefits if the other does more of the parental investment, so there is scope for behaviours that can be interpreted as both cooperative and competitive games between males and females. ... -
The emotion system promotes diversity and evolvability
Giske, Jarl; Eliassen, Sigrunn; Fiksen, Øyvind; Jakobsen, Per Johan; Aksnes, Dag Lorents; Mangel, Marc; Jørgensen, Christian (Peer reviewed; Journal article, 2014-08-06)Studies on the relationship between the optimal phenotype and its environment have had limited focus on genotype-to-phenotype pathways and their evolutionary consequences. Here, we study how multi-layered trait architecture ... -
Evolutionary effects of fishing gear on foraging behavior and life-history traits
Claireaux, Marion; Jørgensen, Christian; Enberg, Katja (Peer reviewed; Journal article, 2018-11)Fishing gears are designed to exploit the natural behaviors of fish, and the concern that fishing may cause evolution of behavioral traits has been receiving increasing attention. The first intuitive expectation is that ... -
Extra-pair mating and evolution of cooperative neighbourhoods
Eliassen, Sigrunn; Jørgensen, Christian (Peer reviewed; Journal article, 2014-07-02)A striking but unexplained pattern in biology is the promiscuous mating behaviour in socially monogamous species. Although females commonly solicit extra-pair copulations, the adaptive reason has remained elusive. We use ... -
Fish resist temptation from junk food: state-dependent diet choice in reproductive Atlantic cod Gadus morhua facing seasonal fluxes of lipid-rich prey
van Deurs, Mikael; Persson, Anders; Nilsson, P. Anders; Jørgensen, Christian (Journal article; Peer reviewed, 2022)In ecological sciences, animal diets are often simplified to ‘resources' or ‘caloric quantities'. However, in the present study, we investigated the optimal foraging strategy of Atlantic cod Gadus morhua when both macro- ... -
Fishing for answers
Jørgensen, Christian; Enberg, Katja (Journal article, 2019) -
From self-interest to cooperation: extra-pair mating as a driver of relaxed territorial aggression in social neighbourhoods
Ruminska, Agnieszka; Jørgensen, Christian; Eliassen, Sigrunn (Journal article; Peer reviewed, 2023)In socially monogamous bird species, males and females tailor their reproductive strategies to that of the other. Interactions are complex, and have elements of both conflict and cooperation. Breeding process is further ... -
From sensing to emergent adaptations: Modelling the proximate architecture for decision-making
Eliassen, Sigrunn; Andersen, Bjørn Snorre; Jørgensen, Christian; Giske, Jarl (Peer reviewed; Journal article, 2016-04)During the past 50 years, evolutionary theory for animal behaviour has branched into different methodological frameworks focussing on age-, state-, density-, and frequency-dependent processes. These approaches have led to ...