Evidence of sequential hermaphroditism in alfonsinos (Beryx spp.) from the deep northeast Atlantic

Among 572 specimens of Beryx splendens and B. decadactylus collected in the Azores (northeast Atlantic), we identified 66 hermaphroditic females, primarily of medium size and at early stages of gonadal development. Hermaphroditism was observed more frequently in winter for B. splendens and in spring-summer for B. decadactylus. These findings challenge the prevailing assumption that both species are strictly gonochoristic and reveal previously unrecognized reproductive plasticity. This has important implications for stock assessment and management, given recent evaluations indicating a low abundance of large, fecund individuals in the population.