The effect of predator exposure and reproduction on oxidative stress parameters in the Catarina scallop Argopecten ventricosus

Predation is known to impact growth and reproduction, and the physiological state of the prey, including its susceptibility to oxidative stress. In this study, we investigated how prolonged exposure to predators modulates tissue specific antioxidant defense and oxidative damage in the short-lived epibenthic scallop Argopecten ventricosus (2 years maximum lifespan). Scallops that were experimentally exposed to predators had not only lower antioxidant capacities (superoxide dismutase and catalase), but also lower oxidative damage (protein carbonyls and TBARS = thiobarbituric acid reactive substances including lipid peroxides) in gills and mantle compared to individuals not exposed to predators. In contrast, oxidative damage in the swimming muscle was higher in predator-exposed scallops. When predator-exposed scallops were on the verge of spawning, levels of oxidative damage increased in gills and mantle in spite of a parallel increase in antioxidant defense in both tissues. Levels of oxidative damage increased also in the swimming muscle whereas muscle antioxidant capacities decreased. Interestingly, post-spawned scallops restored antioxidant capacities and oxidative damage to immature levels, suggesting they can recover from spawning-related oxidative stress. Our results show that predator exposure and gametogenesis modulate oxidative damage in a tissue specific manner and that high antioxidant capacities do not necessarily coincide with low oxidative damage.