Euskal kostaldeko fitoplanktona eta bere garrantzia bibalbioen akuikulturan

Lately, aquaculture has undergone a great development worldwide and, in the Basque Country, there is an increasing interest for developing it. Nowadays, there is an offshore aquaculture site in Mendexa, which started producing mussels recently. Alternative locations have been discussed to continue developing the sector, such as the port of Mutriku. In this context, studying the phytoplankton community is essential, since it is the main source of energy for bivalves and the main potential toxicity risk. In the last years, several studies on the suitability of the phytoplankton communities from Mendexa and Mutriku as a food resource for bivalves have been carried out. For that, phytoplankton community composition and biomass were analyzed, paying special attention to toxic taxa and concentrations of toxins in mussel flesh. Diatoms and haptophytes, together with dinoflagellates, were the most important groups at both stations in terms of abundance and/or biomass, which could favor mussel growth due to high fatty acid content. Moreover, the predominant cell size of the comunities (2-20 μm) would enable an efficient ingestion and retention for mussels. However, chlorophyll a waslow at both sites comparing with other aquaculture areas in Europe, with an average concentration of 0.5 μg/L approximately. Regarding shellfish toxicity, alert limits were exceeded several times, being Dinophysis the most compromising genus for Basque aquaculture, especially in Mendexa, where higher cell abundances and toxin concentrations (okadaic acid) of this genus were recorded. Consequently, the phytoplankton monitoring should be carefully conducted in order to detect possible toxicity risks.