Variation in growth and quality of Saccharina latissima cultivated in the Faroe Islands

Macroalgal cultivation is a developing industry in the western part of the world, and in the Faroe Islands experimental cultivation including Alaria esculenta, Laminaria hyperborea and Saccharina latissima, has been carried out since 2005. The cultivation experiments with A. esculenta and S. latissima have shown promising results with regard to growth and yield, but the quality and composition of the cultivated biomass has not been investigated.

Protein level and amino acid composition are essential factors when estimating the quality of the produced biomass for food and/or feed, but how does e.g. seasonality, exposure and nutrient levels affect these factors. Current work investigated growth and yield in cultivated S. latissima in a sound in the Faroe Islands, and studied the variation in total Kjeldal nitrogen, nitrate and protein content and changes in amino acid composition with regard to season (spring and summer), and exposure (current exposed, wave exposed and sheltered).

To enable comparison we also investigated the variation in total Kjeldal nitrogen, nitrate and protein content and changes in amino acid compositon in wild S. latissima populations. In the cultivated biomass there was a significantly lower yield at the current exposed site (5.2 ± 0.4 kg m-1) compared to the sheltered (9.9 ± 1.3 kg m-1) and the wave exposed (8.0 ± 1.5 kg m-1).

The growth rate (SGR) did not differ with regard to exposure, however the weight of the individuals at the current exposed site was significantly higher compared to the individuals at the sheltered and wave exposed sites through out the cultivation period. In both the cultivated biomass and the natural populations a significant seasonal differences was observed in the total Kjeldal nitrogen, nitrate and protein levels and amino acid composition.

A significant difference related to exposure degree was observed in total Kjeldal nitrogen and nitrogen, but this was not observed for protein and amino acid composition.