Overview

• Eastern Baltic cod once exceeded one meter in length and 40 kilograms but now reach sexual maturity at under 20 centimeters.
• A fishing moratorium imposed in 2019 has failed to reverse declines in both size distribution and overall population.
• Researchers analyzed otoliths from 152 cod caught between 1996 and 2019 in the Bornholm Basin to map age, growth and genetic shifts.
• Selective removal of large individuals has nearly eradicated fast-growing genotypes, demonstrating fisheries-induced evolutionary change.
• Smaller cod programmed for early reproduction yield fewer offspring, exacerbating ecological strain on the Baltic Sea.