Rasmus Ern

About

Marie Sklodowska-Curie Action fellow working on metabolism and behaviour in zebrafish.

Experimental Ecophysiology丨Fisheries Science丨Fishes丨Crustaceans丨Metabolism丨Behaviour丨Performance丨Climate change丨Temperature丨Hypoxia丨Ocean Acidification丨

Email: rasmus@ern.dk

Research

As a comparative animal ecophysiologist, I take a trait-based approach to understand how fishes and crustaceans are affected by environmental stressors, particularly water temperature, dissolved oxygen, salinity, and pH. I integrate cellular stress responses, metabolic rates, and cardiorespiratory function with whole-animal behaviour, performance and tolerance limits to identify functionally linked traits and the mechanisms through which environmental change affects aquatic ectotherms. This mechanistic focus underpins my long-term research programme to develop trait-based frameworks that quantify responses to multiple stressors and enable cross-species comparisons, supporting forecasts of performance and distribution under global change.

Jutfelt Fish Ecophysiology Lab

The Metabolic Niche Framework – Linking Metabolic Changes and Behavioural Responses of Fishes to Climate Change

This MSCA-IF project combines my expertise in fish metabolism with Dr Jutfelt’s expertise in zebrafish behaviour to investigate how fish responses to aquatic hypoxia and ocean warming are mediated by changes in metabolic processes.

Publications

2025

Raby, Graham D.; Rogers, Alice; Bonville, Jeremy De; Reynolds, Leroy; Storm, Zoe; Cowan, Zara-Louise. (2025) Oxygen supersaturation has negligible effects on warming tolerance across diverse aquatic ectotherms. PLoS Biology
Academic article
Raby, Graham D.; Morgan, Rachael; Andreassen, Anna H.; Stewart, Erin M. C.; Bonville, Jeremy De; Hoots, Elizabeth C.. (2025) Measuring critical thermal maximum in aquatic ectotherms: A practical guide. Methods in Ecology and Evolution
Academic article
Garay, Diana Lorena Silva; Andersen, Rasmus Ern; Andreassen, Anna Haukedal; Reiersen, Marie; Jutfelt, Fredrik Walter Jonas. (2025) No oxygen limitation of upper thermal tolerance in zebrafish regardless of acclimation temperature. Journal of Thermal Biology
Academic article
Andersen, Rasmus Ern; Faber, Andreas; Madsen, Niels. (2025) Short-term discard survival and catch-related trauma in European plaice (Pleuronectes platessa) caught in the Baltic Sea by Danish seine during summer. Fisheries Research
Academic article

2024

Andersen, Rasmus Ern; Jutfelt, Fredrik Walter Jonas. (2024) The OptoReg system: a simple and inexpensive solution for regulating water oxygen. Conservation Physiology
Academic article

2023

Andersen, Rasmus Ern; Madsen, Niels. (2023) Initial experiments to assess potential short-term discard survival of cod (Gadus morhua) in the Baltic Sea set-net fishery. Fisheries Research
Academic article
Andersen, Rasmus Ern; Andreassen, Anna Haukedal; Jutfelt, Fredrik Walter Jonas. (2023) Physiological mechanisms of acute upper thermal tolerance in fish. Physiology
Academic article

2022

Woods, H. Arthur; Moran, Amy L.; Atkinson, David; Audzijonyte, Asta; Berenbrink, Michael; Borges, Francisco O.. (2022) Integrative Approaches to Understanding Organismal Responses to Aquatic Deoxygenation. The Biological Bulletin
Academic article
Brohus, Malene; Rohde, Palle Duun; Echers, Simon Gregersen; Westphal, Klaus Ringsborg; Andersen, Rasmus Ern; Jensen, Helene Halkjær. (2022) Exploring Approaches for Blended Learning in Life Sciences. Journal of Problem Based Learning in Higher Education
Academic article
Roche, Dominique G.; Raby, Graham D.; Norin, Tommy; Andersen, Rasmus Ern; Scheuffele, Hanna; Skeeles, Michael. (2022) Paths towards greater consensus building in experimental biology. Journal of Experimental Biology
Academic article

Journal publications

Raby, Graham D.; Rogers, Alice; Bonville, Jeremy De; Reynolds, Leroy; Storm, Zoe; Cowan, Zara-Louise. (2025) Oxygen supersaturation has negligible effects on warming tolerance across diverse aquatic ectotherms. PLoS Biology
Academic article
Raby, Graham D.; Morgan, Rachael; Andreassen, Anna H.; Stewart, Erin M. C.; Bonville, Jeremy De; Hoots, Elizabeth C.. (2025) Measuring critical thermal maximum in aquatic ectotherms: A practical guide. Methods in Ecology and Evolution
Academic article
Garay, Diana Lorena Silva; Andersen, Rasmus Ern; Andreassen, Anna Haukedal; Reiersen, Marie; Jutfelt, Fredrik Walter Jonas. (2025) No oxygen limitation of upper thermal tolerance in zebrafish regardless of acclimation temperature. Journal of Thermal Biology
Academic article
Andersen, Rasmus Ern; Faber, Andreas; Madsen, Niels. (2025) Short-term discard survival and catch-related trauma in European plaice (Pleuronectes platessa) caught in the Baltic Sea by Danish seine during summer. Fisheries Research
Academic article
Andersen, Rasmus Ern; Jutfelt, Fredrik Walter Jonas. (2024) The OptoReg system: a simple and inexpensive solution for regulating water oxygen. Conservation Physiology
Academic article
Andersen, Rasmus Ern; Madsen, Niels. (2023) Initial experiments to assess potential short-term discard survival of cod (Gadus morhua) in the Baltic Sea set-net fishery. Fisheries Research
Academic article
Andersen, Rasmus Ern; Andreassen, Anna Haukedal; Jutfelt, Fredrik Walter Jonas. (2023) Physiological mechanisms of acute upper thermal tolerance in fish. Physiology
Academic article
Woods, H. Arthur; Moran, Amy L.; Atkinson, David; Audzijonyte, Asta; Berenbrink, Michael; Borges, Francisco O.. (2022) Integrative Approaches to Understanding Organismal Responses to Aquatic Deoxygenation. The Biological Bulletin
Academic article
Brohus, Malene; Rohde, Palle Duun; Echers, Simon Gregersen; Westphal, Klaus Ringsborg; Andersen, Rasmus Ern; Jensen, Helene Halkjær. (2022) Exploring Approaches for Blended Learning in Life Sciences. Journal of Problem Based Learning in Higher Education
Academic article
Roche, Dominique G.; Raby, Graham D.; Norin, Tommy; Andersen, Rasmus Ern; Scheuffele, Hanna; Skeeles, Michael. (2022) Paths towards greater consensus building in experimental biology. Journal of Experimental Biology
Academic article

Teaching

Courses

Most of my teaching experience comes from my current position at the Norwegian University of Science and Technology (NTNU) and a previous post at Aalborg University (AAU). At AAU, I completed the University Pedagogy for Assistant Professors (Appendix 1), during which I taught three courses, earned CEFR C1 certification in English-medium instruction (Appendix 2), and carried out a pedagogical project (Appendix 3). I also co-authored a project report with four colleagues that was subsequently published (Appendix 4). At NTNU, 33% of my appointment is dedicated to teaching, including preparing and delivering auditorium lectures, running laboratory exercises, leading seminars, organising fieldwork, drafting and grading written exams, and conducting oral examinations. I have taught four courses and served as course organiser for one. Over the past three years, I have led a one-week field course at the Sletvik Marine Field Station. I currently co-supervise two PhD students, and I have guided undergraduate and postgraduate students through the different stages of academic development – from formulating hypotheses and drafting project proposals to designing and conducting experiments, analysing data, writing manuscripts, and publishing in peer-reviewed journals.

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