Confirmation of functional hermaphroditism in six grouper species (Epinephelidae: Epinephelinae) from the Gulf of Mexico
Diagnosing hermaphroditism in teleost fish requires careful assessment and is particularly challeng- ing in groupers. Established, reliable criteria to detect functional protogynous hermaphroditism were used to col- lect data on sexual pattern in six minimally studied grouper populations on the continental shelf of the Yucatan Peninsula. Individuals in the process of changing sex (transitional individuals), considered strongly indicative of protogyny, were observed. Functional protogynous hermaphroditism was confirmed for Epinephelus morio (Valenciennes, 1828) and Mycteroperca venenosa (Linnaeus, 1758), and for populations of Epinephelus guttatus (Linnaeus, 1758), Mycteroperca bonaci (Poey, 1860) and Mycteroperca tigris (Valenciennes, 1833) from the southern Gulf of Mexico. Although Mycteroperca microlepis (Goode & Bean, 1880) has been confirmed as protogynic in previous studies, distinctive transitional individuals were not identified in the analysed sample. Transitional individual rates were low in the studied sample: 1.0% for E. morio; 0.5% for E. guttatus and M. bonaci; 0.6% for M. tigris; and 0.2% for M. venenosa. Timing of sex change in these grouper species did not exhibit any seasonal pattern. For E. morio, M. bonaci and M. microlepis, the lack of primary males or bisexual individuals among juveniles collected from inshore waters, and the presence of morphological features characteristic of secondary males in testes from adults collected from offshore waters, suggest monandry in the southern Gulf of Mexico populations of these three species.