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.     

Growth of the commercial carrageenophyte Sarcothalia crispata (Rhodophyta, Gigartinales) on suspended culture in central Chile

Laboratory and field studies on growth of Sarcothalia crispata, whichis one of the most important carrageenophytes of Chile, were made in toassess its viability and growth in a system of suspended culture. Invitro experiments on the survival of the germlings and on the effect oftemperature and irradiance on its growth allowed to determine the besttemperature and irradiance for seeding polypropylene culture ropes inindoors conditions. The growth of plants developed on ropes at threedepths in Coliumo Bay (central Chile) supports the idea that it is feasiblebiologically to manage the resource via aquaculture. Fouling and epiphyteswere the main problem at the experimental site. The results suggest thatmaintaining the cultures in deeper water during summer could minimize thisproblem.