Reproductive cycle of Mytilus galloprovincialis (Lamarck, 1819) and Perna perna (Linné, 1758) for sustainable exploitation of natural mussel beds in Massa-Tifnit (On the Moroccan Atlantic Coast)

Abstract

The reproductive cycles of the mussel species Mytilus galloprovincialis and Perna perna, were studied at three sites on the Atlantic coast of southern Morocco (Sidi R′bat, Douira and Tifnit). Monitoring of temporal variations in the condition index, gonadal index and histological analyses of the gonadal maturity stages and sex ratio was conducted monthly, from January to December 2018.

The results indicate that the sex ratio favored males in both species, with a maximum ratio of 1.9: 0.53 for M. galloprovincialis at Tifnit; in contrast, the P. perna population at Tifnit presented a female-dominated ratio of 0.84:1.19. The spawning event for M. galloprovincialis occurred over three periods: two primary spawning periods in spring and autumn, and a secondary period in winter. P. perna spawns all year, with a primary spawning period from spring to autumn and several secondary spawning events. A small number of individuals (undifferentiated) were found in the sexual resting stage, recorded mainly in July and August. The variation in the condition index and gonadal index confirmed the periods of reproduction and the nutritive status of the bivalves.

The aim of this work is to contribute to a better understanding of mytiliculture potential by studying the reproductive cycle and recruitment of M. galloprovincialis and P. perna in their natural populations. Additionally, it supports the development of conservation and protection measures to sustain healthy populations and ensure sustainable fishing yields. Our results indicate that the mussel beds in this region possess several characteristics that make them suitable for aquaculture development.