The sea lamprey Petromyzon marinus (Petromyzontidae) during its trophic migration towards the sea suffers dramatic alterations in metabolism which can generate reactive oxygen species (ROS), such as H2O2 that cause damages in proteins, nucleic acids, and lipids. These deleterious effects can be avoid by antioxidant enzymes such as catalase (CAT) and glutathione peroxidase (GPx) that convert H2O2 in water, prese...