Saccharina latissima (Laminariales, Ochrophyta) farming in an industrial IMTA system in Galicia (Spain)

The development of integrated multitrophic aquaculture (IMTA) systems in Spain has been rather limited so far. However, trials carried out in recent years at experimental and at small industrial scale have been very promising. One of the most encouraging experiences involves the development of seaweed farming for human consumption in combination with mussel rafts in Galicia (NW Spain). Here, we describe a new and more productive marine farming system of Saccharina latissima (sugar kelp) combined with mussel rafts. We show its level of integration in terms of harvest and protein content as well as an assessment of the sources of assimilated nitrogen through the analysis of delta N-15 isotope ratios. Oceanographic conditions in Northwest Spain make S. latissima behave like a winter-spring species in culture with a growing period of just 5-6 months. Nonetheless, production values in our experiment equalled or exceeded those recorded in northern parts of the Atlantic where the culturing period is almost twice as long. Compared to natural populations, S. latissima from mussel-integrated culture systems had almost twice as much protein content, giving greater added value to the species both as food and feed.