The effects of cultivation deployment- and harvest-timing, location and depth on growth and composition of Saccharina latissima at the Swedish west coast

Abstract

A study has been conducted to shed light on the effect of cultivation parameters on growth and chemical composition of Saccharina latissima. Longline cultivation took place at two separate locations in the Koster archipelago on the Swedish west coast, centred around three experiments that explored duration of pre-deployment hatchery processes (Exp 1), deployment and harvest time-frames (Exp 2), and cultivation at 2 m vs. 4 m depth (Exp 3). For all experiments the effects of these parameters were evaluated in terms of size/weight of specimens, and for experiments Exp 2 and Exp 3, concentrations of moisture, ash, carbohydrates, proteins, fatty acids, phlorotannins and common heavy metals were determined.The specific parameters used in this study are likely to vary from site to site, nevertheless trends were observed that resonate in the literature, and these lead to some general recommendations. The weight of harvested kelp blades was higher for the later harvest, earlier deployment and when grown at a shallower depth. Carbohydrates concentration increased with later harvests and at shallower depth. Later harvests also increased the concentration of phlorotannin, while ash and total fatty acids decreased. Protein and fucoidan content was higher for the deeper lines. Growth and chemical composition of the seaweeds showed only minor differences between the two study sites, mostly relating to heavy metal content.