Aquaculture of Fucus species in the Baltic Sea by means of vegetative reproduction

• Main Author: Meichßner, Rafael
• Other Authors: Schulz, Rüdiger, Weinberger, Florian
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2021
• Subjects: thesis; ddc:570; Fucus; aquaculture; vegetative reproduction; Baltic Sea; Iceland
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2021-00688-1; https://macau.uni-kiel.de/receive/macau_mods_00002038; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00003117/Dissertation%20Rafael%20Meichßner_MACAU.pdf

Species of the brown algal genus Fucus are important ecosystem engineers of northern hemisphere coasts. Their biomass is harvested commercially for the production of cosmetic extracts and food supplements, e.g., at the coasts of France, Ireland and Iceland. However, environmental change (e.g., warming, eutrophication) poses increasing risk on wild Fucus stocks and has already caused some population declines, for instance in the Baltic Sea, where harvesting of wild stocks is prohibited as consequence. Commercial cultivation of Fucus would therefore be a useful alternative to the harvesting of wild stocks especially in the light of an increasing interest in algal products. But so far, no cultivation method for the commercial production of Fucus species has been developed. Therefore, a theoretical vegetative cultivation approach has been described which includes the following steps: thallus pieces with apical meristems (“seedlings”) are cut from wild plants and reared unattached in baskets/ net cages deployed in the sea; after a season of growth, the biomass is harvested and new seedlings are cut from the harvest which are used as initial biomass for the next growth season. This process is then repeated after each growth season. The aim of this doctoral thesis was to test various aspects of this cultivation approach in culture experiments. The experiments were performed in an experimental farm located in the Kiel fjord, western Baltic Sea. Two local Fucus species (F. vesiculosus, F. serratus) were used. First, it was tested if Fucus thalli survive long-term culture with the described cultivation method and which role the formation of sexual organs (receptacles) plays in the cultivation process. It could be shown that principally thalli survive and grow continually in culture with the described method. However, the formation of receptacles and their natural degradation after gamete shedding reduced the growth potential significantly. Therefore, the question was raised how culture biomass with low fertility (i.e., a ...