Browsing by Author "Umapathy, Uthesh"
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- Reproductive cycle of the common limpet (patella vulgata) and rough limpet (patella ulyssiponensis) in southern PortugalPublication . Umapathy, Uthesh; Gaspar, Miguel B.; Moura, PaulaThe common limpet (Patella vulgata Linnaeus, 1758) and the rough limpet (Patella ulyssiponensis Gmelin, 1791) are common species in intertidal rocky shores along the Atlantic coasts of Europe. Both species are collected by professional harvesters and recreational harvesters in mainland Portugal. These patellid limpets are protandrous hermaphrodites that have been subject to diverse studies on reproductive features throughout their distributional ranges along the coasts of the northeastern Atlantic Ocean. In order to describe the reproductive cycle of P. vulgata and P. ulyssiponensis, individuals of both species were sampled monthly from intertidal rocky areas from Praia da Luz in Lagos (Algarve coast – southern Portugal) during two consecutive years (January 2017 – December 2018) and subjected to gonad histology and calculation of the mean gonadal index (GI). Overall, were analysed 882 individuals with broad size ranges, 444 P. vulgata (19.5 – 43.0 mm SL) and 438 P. ulyssiponensis (12.3 – 55.4 mm SL). Both species presented balanced sex ratios (P. vulgata = 1M: 0.98F; P. ulyssiponensis = 1M: 1.03F), similar size-frequency distribution between sexes and equivalent mean shell length and total weight between males and females. The estimated size at sex change was slightly smaller in P. vulgata (SL50 ≈ 29 mm) than in P. ulyssiponensis (SL50 ≈ 36 mm). In general, the reproductive cycles of P. vulgata and P. ulyssiponensis were characterised by a short resting period mainly during summer. In P. vulgata, ripe and spawning gonads were mostly recorded from early autumn until early spring, with a main spawning season in early spring – early summer. In P. ulyssiponensis, ripe and spawning gonads were scattered almost year-round, with a main spawning season also in early spring – early summer. Both species also displayed subsidiary spawning events scattered throughout the year (variable depending on the sampling year). The reproductive cycles of P. vulgata and P. ulyssiponensis were influenced by the seasonal variation in surface seawater temperature (SST), with resting periods coincident with warmer SST in summer, gametogenic development and gonadal maturation triggered by decreasing SST during autumn, and main spawning seasons roughly synchronised with increasing SST during early spring – early summer. Populations of P. vulgata and P. ulyssiponensis from southern Portugal have the later spawning period reported throughout their distributional ranges in the northeastern Atlantic Ocean. Overall, this study provides relevant information for conservation purposes and for the proposal of management measures for the harvesting of P. vulgata and P. ulyssiponensis in southern Portugal.
- 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)Publication . Vasconcelos, Paulo; Umapathy, Uthesh; Moura, Paula; Pereira, Fábio; Carvalho, André N.; Gaspar, MiguelThis 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 approximate to 29 mm) than in P. ulyssiponensis (SL50 approximate to 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.