Abstract Overfishing is one human-driven perturbation driving major evolutionary pressure on marine populations. Fishing is often highly selective for particular traits and elicits marked phenotypic changes, while the evolutionary basis of such trait change remains unresolved. Here, we used a unique time series of the overexploited Eastern Baltic cod (Gadus morhua) to investigate growth trends during 25 years of heavy fishing along with hypothesized genetic changes at the full genome level.