Cod is a key species in the Barents Sea; it is arguably one of the most ecologically and economically important species in the North Atlantic. Despite the Northeast Arctic cod stock being in good condition as well as harvested sustainably, it is under threat from the effects of global climate change.
Climate change is often thought of and studied as the single effect of increased temperature. However, the effects of climate change are more wide-reaching than that and can affect the cod in unknown ways.
An understudied combined effect of climate change is changing food availability for the cod. The cod’s normal food, like capelin and herring may change in abundance and distribution affecting the cod’s diet. Furthermore, the Barents Sea may become home to an increased number of invasive species, like the snow crab and red king crab, potentially disrupting the environment and relationships between cod and their normal food.
A crucial question therefore is, how do changes in temperature and food availability affect cod at both the individual and population level?
In this young research talent project, we have the unique opportunity to use rare and extensive long-term datasets, combined with innovative modelling tools to investigate the impacts of increased temperature and changing food availability on Northeast Arctic cod.
A second meeting took place in Oslo with UiO and IMR (Oslo based) colleagues in June 2025 at the University of Oslo. Several stimulating discussions took place for planning and conducting the research going forward. A further meeting will take place in late November / early December for further research developments.
Two articles have been published as part of this project since the last progress update. The first identifies interactions between three key species in the sea ice reduced Arctic Barents Sea system (https://doi.org/10.1098/rspb.2024.1408). The second publication focusses on the consequences of climate warming for spawning cod, and investigates how changes in spawning location may affect individual size of cod offspring (https://doi.org/10.1139/cjfas-2024-0380).
Two further manuscripts have reached the resubmission stage (accepted with major/minor reviewer revisions) as part of the project. The first of which focusses on the importance of capelin in the diet of Barents Sea predators and the second focusses on drivers of fluctuations in recruitment of Norwegian spring-spawning herring.
Additionally, a master’s student has also been added to the project, based at the University of Bergen supervised by Christian Jørgensen, Anders Opdal and Jon Egil Skjæraasen (IMR) and will focus on the interplay between temperature, bioenergetics and life-history traits.
Many studies focus on a single driver within global climate change, primarily temperature, but fail to consider the wider implications of environmental change at the individual and population level. In this project, we will develop and apply a multifaceted innovative modelling approach, combined with extensive high-resolution long-term data to evaluate the potential impacts of changing food environment (through prey availability, prey composition, diet: prey type, energy content and digestibility) and temperature on the economically and ecologically important Northeast Arctic cod (Gadus morhua) in the Barents Sea
We will use extensive unique spatio-temporal datasets, including the NEA cod stomach content database, spatiotemporal prey abundance datasets that reflect NEA cod diet, and environmental datasets for temperature in the Barents Sea. These data sources together with existing empirical knowledge will be used to quantitatively analyse past and present changes in predator-prey dynamics, prey availability and NEA cod diet (WP 1 & 2).
This vital information will be used to parametrise, and develop, novel trait-based models to examine the effects of changing temperature and spatio-temporal food environment on important population characteristics, such as survival, growth, reproduction, mortality, and productivity of NEA cod (WP3).
We will use a mechanistic approach, focusing on the well-known respiratory physiology mechanism allowing us to provide predictions of temperature- and food-environment-induced adaptations for life-histories and behaviour at the population level, allowing for an innovative study on the synergistic effects of external stressors on arguably one of the most ecologically and economically important species in the North Atlantic, Northeast Arctic cod.
