Histological distinction between immature and regenerating females and its effect on maturity ogive estimation in three tropical hermaphroditic groupers

Accuracy of the muscle bundle criterion is analysed to distinguish regenerating ovaries from immature ones in three commercially important hermaphroditic grouper species from the southern Gulf of Mexico: red grouper Epinephelus morio (Valenciennes, 1828); black grouper Mycteroperca bonaci (Poey, 1860); and gag Mycteroperca microlepis (Goode & Bean, 1880). The presence of muscle bundles in ovaries is a generally accurate criterion for distinguishing between regenerating and immature females in these species. However, reproductively inactive specimens could not be exactly identified as regenerating or immature females in 22% of E. morio, 4% of M. bonaci and 9% of M. microlepis, and are classified as being of uncertain maturity. Median size and size-frequency distributions analysis among females in different reproductive phases indicate that uncertain maturity E. morio females are probably immature, while uncertain maturity M. bonaci females are probably regenerating. The reproductive status of uncertain maturity M. microlepis females could not be clarified. Maturity ogive and size at maturity estimates for females of the studied species exhibit variable bias in response to the percentage of uncertain maturity females.