A sensory and nutritional validation of open ocean mussels (Mytilus galloprovincialis Lmk.) cultured in SE Bay of Biscay (Basque Country) compared to their commercial counterparts from Galician Rías (Spain)

Mussel shell biometry, nutritional quality as well as consumer sensory evaluation of experimental open ocean cultured mussel Mytilus galloprovincialis (Lamarck 1819) were analyzed and compared to that of commercial mussels from Galician Rías available in the local market. Both mussel products were of the same commercial size. In this study, open ocean mussels were significantly higher and wider than those of Galician Rías. In addition, with the exception of ash content, both mussel products showed similar biochemical composition. Regarding fatty acid profiles, however, statistical differences were detected. These differences were not fully reflected in the sensory assessment. In terms of consumer acceptability, both mussel products were considered equally satisfactory.

     

Analysis of culture production and growth rate patterns of mussel (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> Lmk.) cultured in the open ocean of the SE Bay of Biscay for the commercial product development

Mytilus galloprovincialis Lmk. mussels were cultured at two culture depths in a submerged longline system, located in the SE Bay of Biscay, from June 2013 to August 2014. The Von Bertalanffy Seasonal Growth Function (VBSGF) of the original seeded batch, without newly settled seed, at each culture depth was assessed. Mussels maintained their reached size during the slow growing months and size increased thereafter. In addition, to test both culture depth scenarios for resource management, the production of commercial pieces (“small” and “large” mussels) in quantity (mussel classification) was assessed. VBSGF output proved that commercial mussels may well be harvested throughout the year in the studied site. The culture period required to produce mussels of a commercial size was 1 to 1.5 years, depending on seeding date.     

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

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-to-year maximum reproductive output, however, wild mussels harvest should be avoided from spring to the end of summer in this region.