The plastic and evolutionary response of cod metapopulations to human-induced rapid environmental change (CARE-COD)

In the face of human-induced rapid environmental change (HIREC), which threatens biodiversity on a global scale, our understanding of species' adaptability to adapt to these changes critically lags. The Atlantic cod (Gadus morhua), with its diverse ecotypes, stands at the forefront of this challenge. Genomic analysis now allows us to differentiate population ecotypes through chromosomal inversions, or 'supergenes,' revealing complex variations in adaptation that potentially make them resilient to rapid environmental shifts and human pressures. Despite these advances, the full extent of cod ecotype's role in creating resilience against HIREC, particularly against the backdrop of Norway's changing coastal ecosystems—which are currently undergoing massive changes due to the presence of net pen farming—remains uncharted. The CARE-COD project aims to bridge this gap by integrating cutting-edge genomic analysis with behavioural tracking within the UNESCO Nordhordland Biosphere Reserve. We will identify the behavior and life-history of different cod ecotypes and how they are differentially responding to the massive changes that are now occurring in Norwegian waters due to human activity and climate change. Furthermore, we will move beyond understanding contemporary state of affairs by combining the analysis of adaptive genetic markers that can trace ecotypes with ancient DNA (aDNA) extracted from sediment core samples that have been collected in the area. This approach will enable us to trace the evolutionary trajectories of different ecotypes along the temporal axis of HIREC introduced by fish farming, offering a window into the past that reveals how these populations have responded to environmental and anthropogenic pressures.