Modelling temperature effects on population-specific growth patterns of Atlantic cod (Gadus morhua)

Abstract

Human-induced climate change has been affecting oceans' temperatures for several decades (IPCC, 2014). Temperature is one of the most important environmental factors influencing metabolic rates and therefore development, growth and reproduction of terrestrial and marine organisms (Clarke, 2017). Growth rates of ectotherms (e.g. fish species) are expected to be altered by climate-induced temporal and spatial changes in ocean temperatures (Pörtner, 2010; Pörtner et al., 2014). Studies suggest that warming will have differential effects on fish body size with the major trend of reduction in mean species size across latitudes (Forster et al., 2012; Cheung et al., 2013; Audzijonyte et al., 2020). The thesis aims to bridge advanced knowledge and methodology of various kinds of research, such as climate physics and climate modelling, theoretical, experimental and observational biology, and biophysical modelling in order to investigate temperature effects on fish growth from both historical and future climate perspectives. In particular, the study is dedicated to the main subject - the role of different thermal environments in shaping the growth patterns of Atlantic cod (Gadus morhua) with the focus on the Northeast Atlantic populations. Additionally, the author addresses methodological aspects, advantages and limitations of a modelling study in a context of eco-physiological research and introduces an open source modelling tool that can help link findings from experimental (physiology) and observational (ecology) studies.