Salmon aquaculture loses c.20% of annual production as a result of gill disease, which threatens the sustainability of the industry. Complex gill disease (CGD) is a condition caused by a suite of different stressors and jellyfish are increasingly considered as one of the important drivers. As there are no ‘treatments’ for these CGD agents, early warning can improve prevention and thus sustainability whilst allowing losses to be mitigated. In the current study, we present a seven-month longitudinal planktonic survey of salmon aquaculture on two different sites off the west coast of Scotland (UK), covering both spring and autumn blooms when the periods of highest mortalities in the farms typically occur. Our method combines environmental DNA (eDNA) metabarcoding and morphological data to assess plankton species diversity and abundance and relate these to fish health indicators, including mortality and CGD. Our results identify multiple planktonic species as potential drivers of the events including hydromedusae and other gelatinous zooplankton. We hope that our approach is a step change in mitigating losses caused by planktonic threats, improving both the sustainability and productivity of the salmonid aquaculture industry.

Primary Presenter: María Algueró-Muñiz, University of Glasgow (maria.alguero-muniz@glasgow.ac.uk)

Authors:

María Algueró-Muñiz, University of Glasgow  (maria.alguero-muniz@glasgow.ac.uk)

Bachar Cheaib, University of Glasgow  (bachar.cheaib@glasgow.ac.uk)

Michele De Noia, University of Glasgow  (michele.DeNoia@glasgow.ac.uk)

Antonella Bacigalupo, University of Glasgow  (antonella.bacigalupo@glasgow.ac.uk)

Brendan Robertson, University of Glasgow  (brendan.robertson@glasgow.ac.uk)

Sofie Spatharis, University of Glasgow  (sofie.spatharis@glasgow.ac.uk)

Martin Lewellyn, University of Glasgow  (martin.llewellyn@glasgow.ac.uk)