Filtration and fertilisation effects of the bivalves Mytilus edulis and Magallana gigas on the kelp Saccharina latissima in tank culture

• Published in: Journal of Applied Phycology
• Main Authors: Hargrave, Matthew S., Ekelund, Anothai, Nylund, Göran M., Pavia, Henrik
• Other Authors: University of Gothenburg
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: Plant Science; Aquatic Science; Pacific; Pacific oyster
• Online Access: http://dx.doi.org/10.1007/s10811-021-02553-6; https://link.springer.com/content/pdf/10.1007/s10811-021-02553-6.pdf; https://link.springer.com/article/10.1007/s10811-021-02553-6/fulltext.html

Abstract Biofouling by opportunistic epiphytes is a major concern in seaweed aquaculture. Colonisation of fouling organisms contributes to a reduction in algal performance as well as a lower quality crop. Further, epiphyte removal techniques often increase maintenance costs of cultivation systems. There have been a variety of methods to mitigate fouling in tank cultivations of seaweed, including the use of biological controls. Here, we present the use of filter feeding bivalves, the blue mussel ( Mytilus edulis ) and Pacific oyster ( Magallana gigas ), as a novel biofilter that also serves as a source of dissolved inorganic nitrogen in tank cultivations of the sugar kelp, Saccharina latissima. We observed significant reductions of fouling epiphytes on seaweed blades of around 50% by bivalve filtration, significant elevations of ammonium (NH 4 + ) and phosphate (PO 4 3− ) by bivalves and alterations to kelp tissue quality when co-cultivated with bivalves rather than supplied with ambient seawater. Stable isotope ratios and seawater chlorophyll a concentrations provided evidence for bivalve biofiltration and the incorporation of their by-products into kelp tissue.