Cultivation of the red alga Chondracanthus chamissoi: sexual reproduction and seedling production in culture under controlled conditions

The red alga Chondracanthus chamissoi (Gigartinales) is endemic to the southern-central region of South America. In the Pacific Ocean, it is distributed from north-central Peru to Chiloe Island. This species is of economic importance because it is edible and used for carrageenan production. The tetrasporophyte phase was grown in the laboratory, obtaining male and female gametophytes that were incubated under different photoperiod, pH, salinity and temperature conditions. These gametophytes developed and generated reproductive structures that led to in vitro maturation. Subsequently, fertilisation occurred and formation of cystocarps was observed. Finally, carpospores were released and the formation of sporophytes completed the life history of this species under laboratory conditions. Reproductive phase growth rates were recorded for each of the different culture conditions used. Sporophytes reached the highest daily growth rate (22%), while gametophyte’s daily growth rate was slower (9%). This research confirms, in vitro, the assumption that C. chamissoi has a sexual triphasic life history Polysiphonia type with isomorphic gametophytes and tetrasporophytes. The development of the complete life history took 20 months in the laboratory.