Growth, biochemical profile, and fatty acid composition of mussel (Mytilus galloprovincialis Lmk.) cultured in the open ocean of the Bay of Biscay (northern Spain)

• This is the first validation study on open ocean mussel (M. galloprovincialis) aquaculture from the Bay of Biscay.
• The results herein provide useful descriptive information for further studies on mussel biology within the region.
• The last-term influence of high hydrodynamic scenarios herein offers relevant information for further operational decisions.

Growth performance, allometry, condition index, and biochemistry of mussel (Mytilus galloprovincialis Lmk.) cultured in a submerged longline system were investigated from June 2013 to August 2014. Mussels grew faster from spring to autumn. Chlorophyll-a concentration along with sea current speed will represent major factors controlling mussel seasonal growth and survival success in the case-study region. The lowest condition indices and highest ash contents were respectively found within winter; so the most favorable conditions for mussel harvesting and commercialization operations would tentatively occur within autumn, spring and summer. The positive mussel growth and low chlorophyll-a concentrations found during summer may also indicate utilization of non-phytoplankton food sources. No clear evidence of local depth associated physiological effects on the mussel individuals was detected. This contribution represents the first available information on open ocean mussel aquaculture from the southeastern Bay of Biscay.Statement of relevance(1.)The present contribution fills a noticeable gap in the literature on mussel biology and aquaculture science in the Bay of Biscay.(2.)The present contribution reports the first technical and scientific success of open ocean mussel aquaculture practices in the Bay of Biscay.(3.)The present contribution offers scientific information for further data comparisons within the context of other case studies or hypothesis.(4.)The present contribution offers valuable information for decision-making processes on commercial open ocean aquaculture.