Variability of the reproductive cycle in estuarine and coastal populations of the mussel Mytilus galloprovincialis Lmk. from the SE Bay of Biscay (Basque Country)

Abstract

Mussel commercial production depends on wild populations to obtain the seed. Therefore, any new farming initiative needs deep knowledge on reproductive cycle of native mussel populations. The reproductive cycle of Mytilus galloprovincialis Lmk. from five sites, three estuarine and two coastal, along the coast of the Basque Country were assessed using gonad index and stereology over 2 consecutive years (2010 and 2011). Sex ratios, developmental stages of gonads, as well as reserve tissue cycle were analyzed. The onset of gametogenesis was observed from winter to spring, with spawning occurring from spring till summer. A resting phase followed with an increase in reserve tissues (adipogranular cells) was observed in fall. Mussels stayed ripe during winter until favorable environmental conditions were met in spring. Differences in reproductive cycles were found among populations, and also, year-to-year variability was observed within each population. In two of the studied sites asynchrony in the timing of spawning was observed between genders. These timing differences, however, did not prevent mussels at those sites from reproducing successfully. The Bidasoa estuary points to the potential of such studied sites for becoming the main source of wild mussel spats for future expected commercial mussel farming in the Basque Country. To ensure year-toyear maximum reproductive output, however, wild mussels harvest should be avoided from spring to the end of summer in this region.

Influence of season-depending ecological variables on biomarker baseline levels in mussels (Mytilus trossulus) from two Baltic Sea subregions

“…Thus, variability in some biomarker responses is a natural feature of the annual physiological cycle of the species (Sheehan and Power, 1999). More precisely, the remarkable seasonal variability in temperature and food abundance observed in the Baltic Sea (Kautsky, 1982) gives rise to a more marked annual pattern in their reproductive cycle of mussels than encountered in many other seas (Ortiz-Zarragoitia et al, 2011;Azpeitia et al, 2017). Therefore, the main goal of this pilot study was to depict the effects of season-related environmental factors on a selected battery of biomarkers in two environmentally different subregions of the Baltic Sea in order to establish reference data for biomonitoring purposes.…”

Molecular and biochemical responses of vitellogenin in the mussel Mytilus galloprovincialis exposed to the glyphosate-based herbicide Roundup® Power 2.0

“…In the present study, we assessed for the first time the effects of a commercial formulation of GBH, the Roundup® Power 2.0, on vitellogenin in male and female mussels using b o t h b i o c h e m i c a l a n d m o l e c u l a r a n a l y s e s . I n M. galloprovincialis from the Mediterranean area, the onset of gametogenesis occurs from winter to spring (Azpeitia et al 2017). During this phase, mussels can be more responsive to estrogen exposure (Ciocan et al 2010).…”

“…Animals were collected at the beginning of March 2018 (water temperature of 11°C) in a licensed area for bivalve culture near Chioggia in the Venice Lagoon, during the early gametogenesis stage of mussels (Da Ros et al 1985;Azpeitia et al 2017). Specimens (240) were divided in homogeneous groups according to their size (average length 6.5 cm) and maintained for 1 week in six glass tanks (two tanks per experimental conditions, 40 mussels per tank) with aerated seawater (about 30 L) and without sandy bottom, in order to allow the acclimatization of the mussels.…”

Effects of environmental factors on changing sex structure of cultivated mussels (Mytilus galloprovincialis, Lamarck, 1819) in the coastal zone of the Black Sea

“…It was noted that the number of mussel males increases in adverse environmental conditions (Сhelyadina, 2014; Machkevsky et al, 2011). For other habitats of M. galloprovincialis (e.g., the Atlantic), there is only limited information on the sex ratio bias toward males (Azpeitia et al, 2017; Jeon et al, 2013). The female‐to‐male sex ratio in the mussel population is known to depend on genetic mechanisms of sex determination and on the environmental conditions (Lee, 2015; Yusa et al, 2013).…”