Size at sex change and reproductive cycle of the limpets Patella vulgata and Patella ulyssiponensis (Mollusca: Patellogastropoda) from intertidal rocky shores of the Algarve coast (southern Portugal)

ABSTRACT

This study describes the reproductive cycle of the common limpet (Patella vulgata) and rough limpet (Patella ulyssiponensis) from the Algarve coast (southern Portugal). Individuals of both species were sampled monthly during two consecutive years, and subjected to gonad histology and calculation of the mean gonadal index (GI). Both species had balanced sex ratios (P. vulgata = 1M: 0.98F; P. ulyssiponensis = 1M: 1.03F), similar size-frequency distribution between sexes, and equivalent mean shell lengths (SL) and total weights (TW) between males and females. In these protandrous hermaphrodites, the estimated size at sex change was slightly smaller in P. vulgata (SL₅₀ ≈ 29 mm) than in P. ulyssiponensis (SL₅₀ ≈ 36 mm). The reproductive cycles of both species were characterised by a main spawning season in early spring to early summer, sometimes including subsidiary spawning events. A comparison of the main spawning season throughout the species distributional ranges revealed that populations of P. vulgata and P. ulyssiponensis from southern Portugal have later spawning periods than other populations from the northeastern Atlantic Ocean. The present information is relevant for conservation purposes and for the proposal of management measures for the harvesting activity targeting P. vulgata and P. ulyssiponensis in southern Portugal.

KEYWORDS:

• Gastropoda
• protandrous hermaphrodite
• sex ratio
• size at sex change
• gonad histology
• harvesting management measures

Acknowledgments

The authors would like to acknowledge the Portuguese Hydrographic Institute (IH) for kindly providing data on seawater temperature in the study area. Sincere thanks are also due to the Managing Editor of IR&D (Professor Alan Hodgson) and two anonymous reviewers for valuable suggestions that greatly improved the revised version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The sampling and histological procedures were performed within the framework of the research project ‘Contributo para a Gestão Sustentada da Pequena Pesca e da Apanha (PESCAPANHA)’, funded by the Fisheries Operational Programme (MAR 2020) and co-financed by the European Maritime and Fisheries Fund (EMFF 2014–2020). The participation of the co-first author (Uthesh Umapathy) in the International Master of Science in Marine Biological Resources (IMBRSea) was funded by the Corporation Bank of India.