Reproductive Dynamics and Hermaphroditism in the Black-Footed Limpet (Patella depressa Pennant, 1777) on an Intertidal Rocky Shore on the Algarve Coast (Southern Portugal)

The present study aimed to describe the reproductive cycle of the black-footed limpet (Patella depressa Pennant, 1777) from an intertidal rocky shore on the Algarve coast (southern Portugal). Samples were collected monthly between January 2017 and December 2018, with the species’ gametogenic cycle being described based on gonad histology and the mean gonadal index. The presence of both transitional and mosaic hermaphrodites indicates that some individuals are able to change sex (sequential hermaphroditism). Despite the occurrence of hermaphroditism, sex proportions were approximately equal, suggesting the absence of protandric sex change in this species. The population exhibited an extensive occurrence of ripe and spawning gonads throughout almost the whole study period, probably related to consecutive processes of gonadal re-ripening and partial spawning events. The reproductive dynamics of P. depressa displayed clear inter-annual differences, with a short resting period recorded in 2017 (June–August) and the absence of resting gonads in 2018. The continued monitoring of this population and collection of environmental data are required to further improve knowledge of the reproductive dynamics of this species. Such information is crucial for proposing additional management measures for the sustainable harvesting of limpets in southern Portugal.