Open-sea cultivation by transplanting young fronds of the kelp Saccharina latissima

Saccharina latissima is an economically and ecologically important native kelp. As its limited supply from wild stock cannot meet increasing current and future demands, methods for its cultivation in the ocean need to be developed. This kelp is now beginning to be farmed off the Atlantic coast of Spain using a regular method similar to the “forced cultivation” technique used with Asian kelps (kombu). Its cultivation is also a growing enterprise in other European countries. In this study, the open-sea farming of S. latissima using the transplanting method is tested on a commercial scale. This cultivation method has not been studied with kelp species outside Asian waters. The tested method includes the following steps: indoor production of seedlings, pre-culture in greenhouse tanks, and open-sea cultivation by transplanting young fronds. Results demonstrate that open-sea cultivation using transplanted young fronds is a technically and biologically viable method. The mean yield obtained (7.8 kg fresh wt per meter rope equivalent to 45.6 t fresh wt per hectare farm) is satisfactory, considering the low densities of transplanted fronds (25–30 fronds per meter rope). Moreover, these values are comparable to those reported in previous cultivations with this species, as well as in the farming of similar kelps. The transplanting method used in conjunction with the regular cultivation method has valuable practical applications for the commercial farming of S. latissima.