A new method for cultivation of the carragenophyte and edible red seaweed Chondracanthus chamissoi based on secondary attachment disc: Development in outdoor tanks

•A new technique for propagation of C. chamissoi based on a secondary attachment disc.•Cultivation of C. chamissoi by secondary attachment disc.•Vegetative propagation of C. chamissoi by secondary attachment disc.

Chondracanthus chamissoi is a carragenophyte and edible red seaweed which is harvested from its natural habitat, and which, in recent years, has been diminishing along the Chilean coast. It is in this location that a new technique for the vegetative propagation of C. chamissoi by secondary attachment disc (SAD) was evaluated for the first time. In order to achieve this, SAD development was seasonally analyzed on natural and artificial substrata submitted to different water exchange and nutrient enrichment conditions. Cystocarpic and vegetative thalli were able to reattach and develop SADs during winter and summer under all tested conditions. However, higher values were observed in vegetative thalli cultivated in the winter. The size of shoots formed from SADs was higher in summer than in winter, varying in length between 0.2 and 5.4 mm after 40 days of cultivation. A continuous seawater exchange was the appropriate condition for SAD development whereas nutrient enrichment was not necessary. High adaptability of these structures to outdoor conditions was observed, as expressed in high survival rates of SADs. This study shows the technical feasibility of culturing C. chamissoi by means of SADs, which could be an alternative to spore and macrofragmentation strategies.