UV-protective agents threaten bivalve reproduction: impacts of octocrylene and benzophenone on gamete quality and fertilization in the Pacific oyster (Magallana gigas)

), on the oxidative balance, DNA integrity, and fertilization success of Pacific oyster (Magallana gigas) gametes. OC and BP induced spermiotoxicity via DNA damage without affecting acrosome integrity or redox status, while oocyte redox status and energy profile were unchanged. Nevertheless, fertilization decreased across all treatments when oocytes or sperm were exposed individually, and at the highest concentrations when both gametes were exposed. A 10-30% drop in fertilization proved sensitive for detecting impairment. Overall, low OC and BP levels reduce oyster fertilization through effects not captured by standard biochemical biomarkers, supporting fertilization success as an integrative, sensitive endpoint of gamete function.