Maturation-associated changes in the internal distribution of tetrodotoxin in the female goby Yongeichthys criniger

► Maturation-associated changes in the TTX distribution of a goby were investigated. ► TTX in the ovary considerably increased during the spawning period. ► Most TTX localized in the skin during the perinucleolus stage to yolk globule stage I. ► The ratio of ovarian TTX greatly increased as the maturation stage further advanced.